423 results on '"Parker PJ"'
Search Results
2. Non-battle injury among repatriated UK armed forces since cessation of combat operations: a prospective observational study
- Author
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Toman, Emma, Beaven, A, Naumann, DN, Myatt, RW, Parker, PJ, Kay, AR, Toman, Emma, Beaven, A, Naumann, DN, Myatt, RW, Parker, PJ, and Kay, AR
- Abstract
AIM: To describe the mechanisms, burden of injury, inpatient management and rehabilitation requirements of wounded military personnel at the UK Role 4 (R4) facility within the first 12 months following cessation of combat operations in Afghanistan. METHODS: All aeromedical evacuations were recorded prospectively between October 2014 and October 2015. Demographic, logistical and clinical data were derived manually from referring medical unit and patient movement requests in addition to host nation and R4 medical records. RESULTS: Ninety-five patients were repatriated to R4 following traumatic injury: 98.9% (n=94) were male, and median age was 27 years (IQR 25-36 years). The most common mechanisms of injury (MOIs) were sports 26.3% (n=25), falls <2 m 11.6% (n=11) and road traffic collisions 9.8% (n=9). The most common anatomical regions of injury were isolated lower limb 24.1% (n=22), isolated hand 20.0% (n=19) and polytrauma 14.7% (n=14). Median Injury Severity Score was 4 (IQR 4-9), mean 8 (range 1-41). Eleven patients (11.6%) were discharged to rehabilitation units, of whom 7 (63.6%) required neurorehabilitation. CONCLUSION: Although service personnel sustain civilian-type injuries, the specific rehabilitation goals and shift in the acute rehabilitation requirements for military personnel must be considered in the absence of enduring combat operations. It is notable that permanent medical downgrading secondary to trauma still occurs outside of warfare. The colocation of civilian major trauma services and R4 has ensured a mutually beneficial partnership that contributes to institutional memory and improves the coordination of patient pathways. The importance of relevant resource allocation, training, support and logistical considerations remain, even during the current scale of military activity overseas
- Published
- 2018
3. PKC\u03b5 Regulation of an \uf0615 Integrin\u2013ZO-1 Complex Controls Lamellae Formation in Migrating Cancer Cells
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Tuomi, S, Mai, A, Nevo, J, Laine, JO, Vilkki, V, xd6hman, TJ, Gahmberg, CG, Parker, PJ. and Ivaska, J., Tuomi, S., Mai, A., Nevo, J., Laine, JO, Vilkki, V., xd6hman, TJ., Gahmberg, CG., Parker, PJ., and Ivaska, J.
- Published
- 2009
4. Amputation and the assessment of limb viability: perceptions of two hundred and thirty two orthopaedic trainees
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Eardley, WGP, primary, Taylor, DM, additional, and Parker, PJ, additional
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- 2010
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5. AUTHORS' RESPONSE
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Eardley, WGP, primary, Taylor, DM, additional, and Parker, PJ, additional
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- 2010
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6. Training in the practical application of damage control and early total care operative philosophy – perceptions of UK orthopaedic specialist trainees
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Eardley, WGP, primary, Taylor, DM, additional, and Parker, PJ, additional
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- 2010
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7. Gluteal Compartment Syndrome following Joint Arthroplasty under Epidural Anaesthesia: A Report of 4 Cases
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Kumar, V, primary, Saeed, K, additional, Panagopoulos, A, additional, and Parker, PJ, additional
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- 2007
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8. Crystal structure of the C2 domain from protein kinase C-δ
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Pappa, H, primary, Murray-Rust, J, additional, Dekker, LV, additional, Parker, PJ, additional, and McDonald, NQ, additional
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- 1998
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9. An evaluation of two tourniquet systems for the control of prehospital lower limb hemorrhage.
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Taylor DM, Vater GM, and Parker PJ
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- 2011
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10. Domain interactions in protein kinase C
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Pears, CJ, primary and Parker, PJ, additional
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- 1991
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11. (ii) Initial medical and surgical management.
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Parker PJ
- Abstract
This paper sets out the basic principles of the initial medical and surgical management of those affected by blast, mine and ballistic injury. The principles are unchanged since the American Civil War--and many come from pre-history; put simply: Resuscitate, Penicillin, Anti-Tetanus, Debride, Wash, Fasciotomise, Pack, stabilise, Leave--open and alone! [ABSTRACT FROM AUTHOR]
- Published
- 2006
12. Conjugation of monoclonal antibodies to a synthetic peptide substrate for protein kinase: a method for labelling antibodies with 32P.
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Foxwell, BMJ, Band, HA, Long, J, Jeffery, WA, Snook, D, Thorpe, PE, Watson, G, Parker, PJ, Epenetos, AA, Creighton, AM, Foxwell, B M, Band, H A, Jeffery, W A, Thorpe, P E, Parker, P J, Epenetos, A A, and Creighton, A M
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- 1988
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13. Smoking behavior among enlisted military personnel during deployment.
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Parker PJ, Brown DW, and Brown, David W
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- 2007
14. Re: An evaluation of two tourniquet systems for the control of prehospital lower limb hemorrhage.
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Taylor DM and Parker PJ
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- 2012
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15. Tech update. E-scribing: more realistic than ever.
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Parker PJ
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- 2002
16. A class I PI3K signalling network regulates primary cilia disassembly in normal physiology and disease.
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Conduit SE, Pearce W, Bhamra A, Bilanges B, Bozal-Basterra L, Foukas LC, Cobbaut M, Castillo SD, Danesh MA, Adil M, Carracedo A, Graupera M, McDonald NQ, Parker PJ, Cutillas PR, Surinova S, and Vanhaesebroeck B
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- Animals, Mice, Humans, Ciliopathies metabolism, Ciliopathies genetics, Ciliopathies pathology, Kinesins metabolism, Kinesins genetics, Cilia metabolism, Signal Transduction, Class I Phosphatidylinositol 3-Kinases metabolism, Class I Phosphatidylinositol 3-Kinases genetics
- Abstract
Primary cilia are antenna-like organelles which sense extracellular cues and act as signalling hubs. Cilia dysfunction causes a heterogeneous group of disorders known as ciliopathy syndromes affecting most organs. Cilia disassembly, the process by which cells lose their cilium, is poorly understood but frequently observed in disease and upon cell transformation. Here, we uncover a role for the PI3Kα signalling enzyme in cilia disassembly. Genetic PI3Kα-hyperactivation, as observed in PIK3CA-related overgrowth spectrum (PROS) and cancer, induced a ciliopathy-like phenotype during mouse development. Mechanistically, PI3Kα and PI3Kβ produce the PIP
3 lipid at the cilia transition zone upon disassembly stimulation. PI3Kα activation initiates cilia disassembly through a kinase signalling axis via the PDK1/PKCι kinases, the CEP170 centrosomal protein and the KIF2A microtubule-depolymerising kinesin. Our data suggest diseases caused by PI3Kα-activation may be considered 'Disorders with Ciliary Contributions', a recently-defined subset of ciliopathies in which some, but not all, of the clinical manifestations result from cilia dysfunction., (© 2024. The Author(s).)- Published
- 2024
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17. Drug-resistant EGFR mutations promote lung cancer by stabilizing interfaces in ligand-free kinase-active EGFR oligomers.
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Iyer RS, Needham SR, Galdadas I, Davis BM, Roberts SK, Man RCH, Zanetti-Domingues LC, Clarke DT, Fruhwirth GO, Parker PJ, Rolfe DJ, Gervasio FL, and Martin-Fernandez ML
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- Humans, Ligands, ErbB Receptors metabolism, Mutation, Protein Kinase Inhibitors pharmacology, Protein Kinase Inhibitors therapeutic use, Drug Resistance, Neoplasm genetics, Lung Neoplasms drug therapy, Lung Neoplasms genetics, Carcinoma, Non-Small-Cell Lung drug therapy, Carcinoma, Non-Small-Cell Lung genetics
- Abstract
The Epidermal Growth Factor Receptor (EGFR) is frequently found to be mutated in non-small cell lung cancer. Oncogenic EGFR has been successfully targeted by tyrosine kinase inhibitors, but acquired drug resistance eventually overcomes the efficacy of these treatments. Attempts to surmount this therapeutic challenge are hindered by a poor understanding of how and why cancer mutations specifically amplify ligand-independent EGFR auto-phosphorylation signals to enhance cell survival and how this amplification is related to ligand-dependent cell proliferation. Here we show that drug-resistant EGFR mutations manipulate the assembly of ligand-free, kinase-active oligomers to promote and stabilize the assembly of oligomer-obligate active dimer sub-units and circumvent the need for ligand binding. We reveal the structure and assembly mechanisms of these ligand-free, kinase-active oligomers, uncovering oncogenic functions for hitherto orphan transmembrane and kinase interfaces, and for the ectodomain tethered conformation of EGFR. Importantly, we find that the active dimer sub-units within ligand-free oligomers are the high affinity binding sites competent to bind physiological ligand concentrations and thus drive tumor growth, revealing a link with tumor proliferation. Our findings provide a framework for future drug discovery directed at tackling oncogenic EGFR mutations by disabling oligomer-assembling interactions., (© 2024. The Author(s).)
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- 2024
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18. Into the fold: advances in understanding aPKC membrane dynamics.
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Cobbaut M, Parker PJ, and McDonald NQ
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- Cell Membrane metabolism, Protein Kinase C metabolism
- Abstract
Atypical protein kinase Cs (aPKCs) are part of the PKC family of protein kinases and are atypical because they don't respond to the canonical PKC activators diacylglycerol (DAG) and Ca2+. They are central to the organization of polarized cells and are deregulated in several cancers. aPKC recruitment to the plasma membrane compartment is crucial to their encounter with substrates associated with polarizing functions. However, in contrast with other PKCs, the mechanism by which atypical PKCs are recruited there has remained elusive until recently. Here, we bring aPKC into the fold, summarizing recent reports on the direct recruitment of aPKC to membranes, providing insight into seemingly discrepant findings and integrating them with existing literature., (© 2023 The Author(s).)
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- 2023
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19. Cell cycle responses to Topoisomerase II inhibition: Molecular mechanisms and clinical implications.
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Soliman TN, Keifenheim D, Parker PJ, and Clarke DJ
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- Cell Cycle Proteins metabolism, G2 Phase Cell Cycle Checkpoints, Mitosis, DNA Topoisomerases, Type II genetics, DNA Topoisomerases, Type II metabolism, Topoisomerase II Inhibitors pharmacology
- Abstract
DNA Topoisomerase IIA (Topo IIA) is an enzyme that alters the topological state of DNA and is essential for the separation of replicated sister chromatids and the integrity of cell division. Topo IIA dysfunction activates cell cycle checkpoints, resulting in arrest in either the G2-phase or metaphase of mitosis, ultimately triggering the abscission checkpoint if non-disjunction persists. These events, which directly or indirectly monitor the activity of Topo IIA, have become of major interest as many cancers have deficiencies in Topoisomerase checkpoints, leading to genome instability. Recent studies into how cells sense Topo IIA dysfunction and respond by regulating cell cycle progression demonstrate that the Topo IIA G2 checkpoint is distinct from the G2-DNA damage checkpoint. Likewise, in mitosis, the metaphase Topo IIA checkpoint is separate from the spindle assembly checkpoint. Here, we integrate mechanistic knowledge of Topo IIA checkpoints with the current understanding of how cells regulate progression through the cell cycle to accomplish faithful genome transmission and discuss the opportunities this offers for therapy., (© 2023 Soliman et al.)
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- 2023
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20. Abdominal Aortic Junctional Tourniquet - Stabilized (AAJTS) can be applied both successfully and rapidly by Combat Medical Technicians (CMTs).
- Author
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Smith TN, Beaven A, Handford C, Sellon E, and Parker PJ
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- Animals, Humans, Combat Medics, Hemorrhage therapy, Hemorrhage etiology, Aorta, Abdominal, Tourniquets
- Abstract
Background: 'Non-compressible' haemorrhage is the leading cause of preventable battlefield death, often requiring surgical or radiological intervention, which is precluded in the pre-hospital environment. One-fifth of such bleeds are junctional and therefore potentially survivable. We examine the use of the Abdominal Aortic Junctional Tourniquet - Stabilized (AAJTS) among UK Combat Medical Technicians (CMTs) as a device to control junctional haemorrhage with external compression of the abdominal aorta-compression of junctional haemorrhage previously considered 'non-compressible.' This follows animal studies showing that the AAJTS achieves control of haemorrhage and improves physiological parameters., Methods: CMTs were selected and applied the AAJTS to each other following a 1-hour training package. A consultant radiologist-operated hand-held ultrasound monitored flow changes in the subjects' common femoral artery. CMTs were then surveyed for their opinions as to utility and function., Results: 21 CMTs were screened and 17 CMTs participated with 34 total applications (16 day and 18 low-light). 27/34 (79%) achieved a successful application. The median application time was 75 s in daylight and 57 s in low-light conditions. There was no significant difference in Body Mass Index (p=0.23), median systolic blood pressure (p=0.19), nor class of CMT (p=0.10) between successful and unsuccessful applications. Higher systolic blood pressure was associated with longer application times (p=0.03). Users deemed the device easy to use (median score 4.4 on a 5-point Likert scale)., Conclusion: CMTs can use AAJTS successfully after a 1-hour training session in the majority of applications. Application was successful in both daylight and low-light conditions. Self-reported usability ratings were high., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2023
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21. Control of atypical PKCι membrane dissociation by tyrosine phosphorylation within a PB1-C1 interdomain interface.
- Author
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Cobbaut M, McDonald NQ, and Parker PJ
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- Phosphorylation, Tyrosine metabolism, Humans, HEK293 Cells, Protein Binding, Mutation, Cell Polarity physiology, Cell Membrane metabolism, Protein Kinase C metabolism, Protein Processing, Post-Translational
- Abstract
Atypical PKCs are cell polarity kinases that operate at the plasma membrane where they function within multiple molecular complexes to contribute to the establishment and maintenance of polarity. In contrast to the classical and novel PKCs, atypical PKCs do not respond to diacylglycerol cues to bind the membrane compartment. Until recently, it was not clear how aPKCs are recruited; whether aPKCs can directly interact with membranes or whether they are dependent on other protein interactors to do so. Two recent studies identified the pseudosubstrate region and the C1 domain as direct membrane interaction modules; however, their relative importance and coupling are unknown. We combined molecular modeling and functional assays to show that the regulatory module of aPKCι, comprising the PB1 pseudosubstrate and C1 domains, forms a cooperative and spatially continuous invariant membrane interaction platform. Furthermore, we show the coordinated orientation of membrane-binding elements within the regulatory module requires a key PB1-C1 interfacial β-strand (beta-strand linker). We show this element contains a highly conserved Tyr residue that can be phosphorylated and that negatively regulates the integrity of the regulatory module, leading to membrane release. We thus expose a hitherto unknown regulatory mechanism of aPKCι membrane binding and release during cell polarization., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2023. Published by Elsevier Inc.)
- Published
- 2023
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22. Functional Engagement of the PD-1/PD-L1 Complex But Not PD-L1 Expression Is Highly Predictive of Patient Response to Immunotherapy in Non-Small-Cell Lung Cancer.
- Author
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Sánchez-Magraner L, Gumuzio J, Miles J, Quimi N, Martínez Del Prado P, Abad-Villar MT, Pikabea F, Ortega L, Etxezarraga C, Martín-Algarra S, Lozano MD, Saiz-Camin M, Egurrola-Izquierdo M, Barredo-Santamaría I, Saiz-López A, Gomez-Mediavilla J, Segues-Merino N, Juaristi-Abaunz MA, Urruticoechea A, Geraedts EJ, van Elst K, Claessens NJM, Italiano A, Applebee CJ, Del Castillo S, Evans C, Aguirre F, Parker PJ, and Calleja V
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- Humans, Immunotherapy methods, B7-H1 Antigen, Carcinoma, Non-Small-Cell Lung drug therapy, Lung Neoplasms drug therapy
- Abstract
Purpose: In many cancers, the expression of immunomodulatory ligands leads to immunoevasion, as exemplified by the interaction of PD-L1 with PD-1 on tumor-infiltrating lymphocytes. Profound advances in cancer treatments have come with the advent of immunotherapies directed at blocking these immuno-suppressive ligand-receptor interactions. However, although there has been success in the use of these immune checkpoint interventions, correct patient stratification for these therapies has been challenging., Materials and Methods: To address this issue of patient stratification, we have quantified the intercellular PD-1/PD-L1 interaction in formalin-fixed paraffin-embedded tumor samples from patients with non-small cell lung carcinoma, using a high-throughput automated quantitative imaging platform (quantitative functional proteomics [QF-Pro])., Results: The multisite blinded analysis across a cohort of 188 immune checkpoint inhibitor-treated patients demonstrated the intra- and intertumoral heterogeneity of PD-1/PD-L1 immune checkpoint engagement and notably showed no correlation between the extent of PD-1/PD-L1 interaction and PD-L1 expression. Importantly, PD-L1 expression scores used clinically to stratify patients correlated poorly with overall survival; by contrast, patients showing a high PD-1/PD-L1 interaction had significantly better responses to anti-PD-1/PD-L1 treatments, as evidenced by increased overall survival. This relationship was particularly strong in the setting of first-line treatments., Conclusion: The functional readout of PD-1/PD-L1 interaction as a predictive biomarker for the stratification of patients with non-small-cell lung carcinoma, combined with PD-L1 expression, should significantly improve the response rates to immunotherapy. This would both capture patients excluded from checkpoint immunotherapy (high PD-1/PD-L1 interaction but low PD-L1 expression, 24% of patients) and additionally avoid treating patients who despite their high PD-L1 expression do not respond and suffer from side effects.
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- 2023
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23. Chemical Genetic Identification of PKC Epsilon Substrates in Mouse Brain.
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Dugan MP, Ferguson LB, Hertz NT, Chalkley RJ, Burlingame AL, Shokat KM, Parker PJ, and Messing RO
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- Mice, Animals, Ethanol, Alcohol Drinking genetics, Brain metabolism, Protein Kinase C-epsilon genetics, Protein Kinase C-epsilon metabolism, Signal Transduction
- Abstract
PKC epsilon (PKCε) plays important roles in behavioral responses to alcohol and in anxiety-like behavior in rodents, making it a potential drug target for reducing alcohol consumption and anxiety. Identifying signals downstream of PKCε could reveal additional targets and strategies for interfering with PKCε signaling. We used a chemical genetic screen combined with mass spectrometry to identify direct substrates of PKCε in mouse brain and validated findings for 39 of them using peptide arrays and in vitro kinase assays. Prioritizing substrates with several public databases such as LINCS-L1000, STRING, GeneFriends, and GeneMAINA predicted interactions between these putative substrates and PKCε and identified substrates associated with alcohol-related behaviors, actions of benzodiazepines, and chronic stress. The 39 substrates could be broadly classified in three functional categories: cytoskeletal regulation, morphogenesis, and synaptic function. These results provide a list of brain PKCε substrates, many of which are novel, for future investigation to determine the role of PKCε signaling in alcohol responses, anxiety, responses to stress, and other related behaviors., Competing Interests: Conflicts of Interest The authors with the exception of K. M. S. and N. T. H declare that there are no competing interests associated with the manuscript. K. M. S. is an inventor on patents covering the analog sensitive and analog specific kinase engineering owned by Princeton University. K. M. S. has consulting agreements for the following companies, which involve monetary and/or stock compensation: Revolution Medicines, Black Diamond Therapeutics, BridGene Biosciences, Denali Therapeutics, Dice Molecules, eFFECTOR Therapeutics, Erasca, Genentech/Roche, Janssen Pharmaceuticals, Kumquat Biosciences, Kura Oncology, Mitokinin Inc, Nested, Type6 Therapeutics, Venthera, Wellspring Biosciences (Araxes Pharma), Turning Point, Ikena, Initial Therapeutics, Vevo, and BioTheryX. N. T. H owns shares and is an employee of Mitokinin Inc., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2023
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24. PKN2 deficiency leads both to prenatal 'congenital' cardiomyopathy and defective angiotensin II stress responses.
- Author
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Marshall JJT, Cull JJ, Alharbi HO, Zaw Thin M, Cooper STE, Barrington C, Vanyai H, Snoeks T, Siow B, Suáarez-Bonnet A, Herbert E, Stuckey DJ, Cameron AJM, Prin F, Cook AC, Priestnall SL, Chotani S, Rackham OJL, Meijles DN, Mohun T, Clerk A, and Parker PJ
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- Angiotensin II metabolism, Angiotensin II pharmacology, Animals, Cardiomegaly metabolism, Female, Mice, Mice, Knockout, Myocardium metabolism, Myocytes, Cardiac metabolism, Pregnancy, Cardiomyopathies metabolism, Cardiomyopathies pathology, Hypertension metabolism, Hypertension pathology, Protein Kinase C metabolism
- Abstract
The protein kinase PKN2 is required for embryonic development and PKN2 knockout mice die as a result of failure in the expansion of mesoderm, cardiac development and neural tube closure. In the adult, cardiomyocyte PKN2 and PKN1 (in combination) are required for cardiac adaptation to pressure-overload. The specific role of PKN2 in contractile cardiomyocytes during development and its role in the adult heart remain to be fully established. We used mice with cardiomyocyte-directed knockout of PKN2 or global PKN2 haploinsufficiency to assess cardiac development and function using high resolution episcopic microscopy, MRI, micro-CT and echocardiography. Biochemical and histological changes were also assessed. Cardiomyocyte-directed PKN2 knockout embryos displayed striking abnormalities in the compact myocardium, with frequent myocardial clefts and diverticula, ventricular septal defects and abnormal heart shape. The sub-Mendelian homozygous knockout survivors developed cardiac failure. RNASeq data showed up-regulation of PKN2 in patients with dilated cardiomyopathy, suggesting an involvement in adult heart disease. Given the rarity of homozygous survivors with cardiomyocyte-specific deletion of PKN2, the requirement for PKN2 in adult mice was explored using the constitutive heterozygous PKN2 knockout. Cardiac hypertrophy resulting from hypertension induced by angiotensin II was reduced in these haploinsufficient PKN2 mice relative to wild-type littermates, with suppression of cardiomyocyte hypertrophy and cardiac fibrosis. It is concluded that cardiomyocyte PKN2 is essential for heart development and the formation of compact myocardium and is also required for cardiac hypertrophy in hypertension. Thus, PKN signalling may offer therapeutic options for managing congenital and adult heart diseases., (© 2022 The Author(s).)
- Published
- 2022
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25. Genome-Protective Topoisomerase 2a-Dependent G2 Arrest Requires p53 in hTERT-Positive Cancer Cells.
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Lockwood N, Martini S, Lopez-Pardo A, Deiss K, Segeren HA, Semple RK, Collins I, Repana D, Cobbaut M, Soliman T, Ciccarelli F, and Parker PJ
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- Animals, Cell Line, Tumor, DNA Damage, Humans, Mice, S Phase, Signal Transduction genetics, DNA Topoisomerases, Type II metabolism, Neoplasms genetics, Poly-ADP-Ribose Binding Proteins metabolism, Tumor Suppressor Protein p53 metabolism
- Abstract
Topoisomerase 2a (Topo2a)-dependent G2 arrest engenders faithful segregation of sister chromatids, yet in certain tumor cell lines where this arrest is dysfunctional, a PKCε-dependent failsafe pathway can be triggered. Here we elaborate on recent advances in understanding the underlying mechanisms associated with this G2 arrest by determining that p53-p21 signaling is essential for efficient arrest in cell lines, in patient-derived cells, and in colorectal cancer organoids. Regulation of this p53 axis required the SMC5/6 complex, which is distinct from the p53 pathways observed in the DNA damage response. Topo2a inhibition specifically during S phase did not trigger G2 arrest despite affecting completion of DNA replication. Moreover, in cancer cells reliant upon the alternative lengthening of telomeres (ALT) mechanism, a distinct form of Topo2a-dependent, p53-independent G2 arrest was found to be mediated by BLM and Chk1. Importantly, the previously described PKCε-dependent mitotic failsafe was engaged in hTERT-positive cells when Topo2a-dependent G2 arrest was dysfunctional and where p53 was absent, but not in cells dependent on the ALT mechanism. In PKCε knockout mice, p53 deletion elicited tumors were less aggressive than in PKCε-replete animals and exhibited a distinct pattern of chromosomal rearrangements. This evidence suggests the potential of exploiting synthetic lethality in arrest-defective hTERT-positive tumors through PKCε-directed therapeutic intervention., Significance: The identification of a requirement for p53 in stringent Topo2a-dependent G2 arrest and engagement of PKCε failsafe pathways in arrest-defective hTERT-positive cells provides a therapeutic opportunity to induce selective synthetic lethality., (©2022 The Authors; Published by the American Association for Cancer Research.)
- Published
- 2022
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26. The Candida albicans toxin candidalysin mediates distinct epithelial inflammatory responses through p38 and EGFR-ERK pathways.
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Nikou SA, Zhou C, Griffiths JS, Kotowicz NK, Coleman BM, Green MJ, Moyes DL, Gaffen SL, Naglik JR, and Parker PJ
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- Animals, ErbB Receptors metabolism, Mice, Phosphorylation, p38 Mitogen-Activated Protein Kinases genetics, p38 Mitogen-Activated Protein Kinases metabolism, Candida albicans metabolism, Fungal Proteins metabolism, MAP Kinase Signaling System
- Abstract
The fungal pathogen Candida albicans secretes the peptide toxin candidalysin, which damages epithelial cells and drives an innate inflammatory response mediated by the epidermal growth factor receptor (EGFR) and mitogen-activated protein kinase (MAPK) pathways and the transcription factor c-Fos. In cultured oral epithelial cells, candidalysin activated the MAPK p38, which resulted in heat shock protein 27 (Hsp27) activation, IL-6 release, and EGFR phosphorylation without affecting the induction of c-Fos. p38 activation was not triggered by EGFR but by two nonredundant pathways involving MAPK kinases (MKKs) and the kinase Src, which differentially controlled p38 signaling outputs. Whereas MKKs mainly promoted p38-dependent release of IL-6, Src promoted p38-mediated phosphorylation of EGFR in a ligand-independent fashion. In parallel, candidalysin also activated the EGFR-ERK pathway in a ligand-dependent manner, resulting in c-Fos activation and release of the neutrophil-activating chemokines G-CSF and GM-CSF. In mice, early clearance events of oral C. albicans infection required p38 but not c-Fos. These findings delineate how candidalysin activates the pathways downstream of the MAPKs p38 and ERK that differentially contribute to immune activation during C. albicans infection.
- Published
- 2022
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27. Editorial: Signaling by Small GTPases in Metastatic Disease.
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Parker PJ and Kishore U
- Abstract
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
- Published
- 2022
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28. A genetically-encoded crosslinker screen identifies SERBP1 as a PKCε substrate influencing translation and cell division.
- Author
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Martini S, Davis K, Faraway R, Elze L, Lockwood N, Jones A, Xie X, McDonald NQ, Mann DJ, Armstrong A, Ule J, and Parker PJ
- Subjects
- Aurora Kinase B metabolism, HEK293 Cells, HeLa Cells, Humans, Chromosome Segregation, Mitosis, Protein Biosynthesis, Protein Kinase C-epsilon metabolism, RNA-Binding Proteins metabolism
- Abstract
The PKCε-regulated genome protective pathway provides transformed cells a failsafe to successfully complete mitosis. Despite the necessary role for Aurora B in this programme, it is unclear whether its requirement is sufficient or if other PKCε cell cycle targets are involved. To address this, we developed a trapping strategy using UV-photocrosslinkable amino acids encoded in the PKCε kinase domain. The validation of the mRNA binding protein SERBP1 as a PKCε substrate revealed a series of mitotic events controlled by the catalytic form of PKCε. PKCε represses protein translation, altering SERBP1 binding to the 40 S ribosomal subunit and promoting the assembly of ribonucleoprotein granules containing SERBP1, termed M-bodies. Independent of Aurora B, SERBP1 is shown to be necessary for chromosome segregation and successful cell division, correlating with M-body formation. This requirement for SERBP1 demonstrates that Aurora B acts in concert with translational regulation in the PKCε-controlled pathway exerting genome protection., (© 2021. The Author(s).)
- Published
- 2021
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29. Immunogenomics of Colorectal Cancer Response to Checkpoint Blockade: Analysis of the KEYNOTE 177 Trial and Validation Cohorts.
- Author
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Bortolomeazzi M, Keddar MR, Montorsi L, Acha-Sagredo A, Benedetti L, Temelkovski D, Choi S, Petrov N, Todd K, Wai P, Kohl J, Denner T, Nye E, Goldstone R, Ward S, Wilson GA, Al Bakir M, Swanton C, John S, Miles J, Larijani B, Kunene V, Fontana E, Arkenau HT, Parker PJ, Rodriguez-Justo M, Shiu KK, Spencer J, and Ciccarelli FD
- Subjects
- Antibodies, Monoclonal, Humanized adverse effects, Biomarkers, Tumor genetics, CD8-Positive T-Lymphocytes drug effects, CD8-Positive T-Lymphocytes immunology, Clinical Trials as Topic, Colorectal Neoplasms genetics, Colorectal Neoplasms immunology, Cytotoxicity, Immunologic drug effects, Gene Expression Profiling, Humans, Immune Checkpoint Inhibitors adverse effects, Lymphocytes, Tumor-Infiltrating drug effects, Lymphocytes, Tumor-Infiltrating immunology, Mutation, Nivolumab adverse effects, Predictive Value of Tests, Programmed Cell Death 1 Receptor antagonists & inhibitors, RNA-Seq, Reproducibility of Results, Time Factors, Transcriptome, Treatment Outcome, Tumor-Associated Macrophages drug effects, Tumor-Associated Macrophages immunology, Exome Sequencing, Antibodies, Monoclonal, Humanized therapeutic use, Colorectal Neoplasms drug therapy, Immune Checkpoint Inhibitors therapeutic use, Immunogenetic Phenomena, Immunogenetics, Nivolumab therapeutic use, Tumor Microenvironment
- Abstract
Background & Aims: Colorectal cancer (CRC) shows variable response to immune checkpoint blockade, which can only partially be explained by high tumor mutational burden (TMB). We conducted an integrated study of the cancer tissue and associated tumor microenvironment (TME) from patients treated with pembrolizumab (KEYNOTE 177 clinical trial) or nivolumab to dissect the cellular and molecular determinants of response to anti- programmed cell death 1 (PD1) immunotherapy., Methods: We selected multiple regions per tumor showing variable T-cell infiltration for a total of 738 regions from 29 patients, divided into discovery and validation cohorts. We performed multiregional whole-exome and RNA sequencing of the tumor cells and integrated these with T-cell receptor sequencing, high-dimensional imaging mass cytometry, detection of programmed death-ligand 1 (PDL1) interaction in situ, multiplexed immunofluorescence, and computational spatial analysis of the TME., Results: In hypermutated CRCs, response to anti-PD1 immunotherapy was not associated with TMB but with high clonality of immunogenic mutations, clonally expanded T cells, low activation of Wnt signaling, deregulation of the interferon gamma pathway, and active immune escape mechanisms. Responsive hypermutated CRCs were also rich in cytotoxic and proliferating PD1
+ CD8 T cells interacting with PDL1+ antigen-presenting macrophages., Conclusions: Our study clarified the limits of TMB as a predictor of response of CRC to anti-PD1 immunotherapy. It identified a population of antigen-presenting macrophages interacting with CD8 T cells that consistently segregate with response. We therefore concluded that anti-PD1 agents release the PD1-PDL1 interaction between CD8 T cells and macrophages to promote cytotoxic antitumor activity., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)- Published
- 2021
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30. Co-ordinated control of the Aurora B abscission checkpoint by PKCε complex assembly, midbody recruitment and retention.
- Author
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Watson L, Soliman TN, Davis K, Kelly J, Lockwood N, Yang X, Lynham S, Scott JD, Crossland V, McDonald NQ, Mann DJ, Armstrong A, Eggert U, and Parker PJ
- Subjects
- 14-3-3 Proteins genetics, Aurora Kinase B genetics, HEK293 Cells, Humans, Phosphorylation, Protein Kinase C-epsilon genetics, Signal Transduction, Spindle Apparatus, 14-3-3 Proteins metabolism, Aurora Kinase B metabolism, Cytokinesis, Protein Kinase C-epsilon metabolism
- Abstract
A requirement for PKCε in exiting from the Aurora B dependent abscission checkpoint is associated with events at the midbody, however, the recruitment, retention and action of PKCε in this compartment are poorly understood. Here, the prerequisite for 14-3-3 complex assembly in this pathway is directly linked to the phosphorylation of Aurora B S227 at the midbody. However, while essential for PKCε control of Aurora B, 14-3-3 association is shown to be unnecessary for the activity-dependent enrichment of PKCε at the midbody. This localisation is demonstrated to be an autonomous property of the inactive PKCε D532N mutant, consistent with activity-dependent dissociation. The C1A and C1B domains are necessary for this localisation, while the C2 domain and inter-C1 domain (IC1D) are necessary for retention at the midbody. Furthermore, it is shown that while the IC1D mutant retains 14-3-3 complex proficiency, it does not support Aurora B phosphorylation, nor rescues division failure observed with knockdown of endogenous PKCε. It is concluded that the concerted action of multiple independent events facilitates PKCε phosphorylation of Aurora B at the midbody to control exit from the abscission checkpoint., (© 2021 The Author(s).)
- Published
- 2021
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31. Quantification of biomarker functionality predicts patient outcomes.
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Larijani B, Miles J, Ward SG, and Parker PJ
- Subjects
- Antineoplastic Combined Chemotherapy Protocols therapeutic use, B7-H1 Antigen antagonists & inhibitors, B7-H1 Antigen physiology, Biomarkers, Tumor isolation & purification, Carcinoma, Non-Small-Cell Lung diagnosis, Carcinoma, Non-Small-Cell Lung drug therapy, Carcinoma, Non-Small-Cell Lung genetics, Carcinoma, Non-Small-Cell Lung mortality, Humans, Immune Checkpoint Inhibitors therapeutic use, Immunohistochemistry methods, Lung Neoplasms diagnosis, Lung Neoplasms drug therapy, Lung Neoplasms genetics, Lung Neoplasms mortality, Neoplasms drug therapy, Neoplasms genetics, Neoplasms mortality, Prognosis, Programmed Cell Death 1 Receptor antagonists & inhibitors, Programmed Cell Death 1 Receptor physiology, Survival Analysis, Treatment Outcome, Biomarkers, Tumor analysis, Molecular Imaging methods, Neoplasms diagnosis
- Abstract
Implementation of a quantitative molecular imaging method (iFRET), which determines receptor-ligand interactions, has led to the finding that patients with a low extent of PD-1/PD-L1 interaction in metastatic NSCLC, and malignant melanoma, display significantly worsened overall survival compared to those with a high level of interaction.
- Published
- 2021
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32. Equivocal, explicit and emergent actions of PKC isoforms in cancer.
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Parker PJ, Brown SJ, Calleja V, Chakravarty P, Cobbaut M, Linch M, Marshall JJT, Martini S, McDonald NQ, Soliman T, and Watson L
- Subjects
- Animals, Humans, Isoenzymes physiology, Mutation, Phosphorylation, Promoter Regions, Genetic, Protein Kinase C antagonists & inhibitors, Protein Kinase C genetics, Tumor Microenvironment, Neoplasms enzymology, Protein Kinase C physiology
- Abstract
The maturing mutational landscape of cancer genomes, the development and application of clinical interventions and evolving insights into tumour-associated functions reveal unexpected features of the protein kinase C (PKC) family of serine/threonine protein kinases. These advances include recent work showing gain or loss-of-function mutations relating to driver or bystander roles, how conformational constraints and plasticity impact this class of proteins and how emergent cancer-associated properties may offer opportunities for intervention. The profound impact of the tumour microenvironment, reflected in the efficacy of immune checkpoint interventions, further prompts to incorporate PKC family actions and interventions in this ecosystem, informed by insights into the control of stromal and immune cell functions. Drugging PKC isoforms has offered much promise, but when and how is not obvious.
- Published
- 2021
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33. A cancer-associated, genome protective programme engaging PKCε.
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Parker PJ, Lockwood N, Davis K, Kelly JR, Soliman TN, Pardo AL, Marshall JJT, Redmond JM, Vitale M, and Silvia Martini
- Subjects
- Cell Proliferation, Humans, Neoplasms enzymology, Neoplasms pathology, Genomics, Neoplasms genetics, Protein Kinase C-epsilon metabolism
- Abstract
Associated with their roles as targets for tumour promoters, there has been a long-standing interest in how members of the protein kinase C (PKC) family act to modulate cell growth and division. This has generated a great deal of observational data, but has for the most part not afforded clear mechanistic insights into the control mechanisms at play. Here, we review the roles of PKCε in protecting transformed cells from non-disjunction. In this particular cell cycle context, there is a growing understanding of the pathways involved, affording biomarker and interventional insights and opportunities., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2020
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34. High PD-1/PD-L1 Checkpoint Interaction Infers Tumor Selection and Therapeutic Sensitivity to Anti-PD-1/PD-L1 Treatment.
- Author
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Sánchez-Magraner L, Miles J, Baker CL, Applebee CJ, Lee DJ, Elsheikh S, Lashin S, Withers K, Watts AG, Parry R, Edmead C, Lopez JI, Mehta R, Italiano A, Ward SG, Parker PJ, and Larijani B
- Subjects
- Adult, Aged, B7-H1 Antigen antagonists & inhibitors, B7-H1 Antigen immunology, Carcinoma, Non-Small-Cell Lung metabolism, Carcinoma, Non-Small-Cell Lung mortality, Carcinoma, Non-Small-Cell Lung pathology, Carcinoma, Renal Cell drug therapy, Carcinoma, Renal Cell metabolism, Carcinoma, Renal Cell pathology, Female, Fluorescence Resonance Energy Transfer methods, Humans, Kidney Neoplasms drug therapy, Kidney Neoplasms metabolism, Kidney Neoplasms pathology, Lung Neoplasms metabolism, Lung Neoplasms mortality, Lung Neoplasms pathology, Male, Melanoma drug therapy, Melanoma metabolism, Melanoma mortality, Middle Aged, Molecular Targeted Therapy, Programmed Cell Death 1 Receptor antagonists & inhibitors, Programmed Cell Death 1 Receptor immunology, Reproducibility of Results, Treatment Outcome, B7-H1 Antigen metabolism, Carcinoma, Non-Small-Cell Lung immunology, Carcinoma, Renal Cell immunology, Kidney Neoplasms immunology, Lung Neoplasms immunology, Melanoma immunology, Programmed Cell Death 1 Receptor metabolism
- Abstract
Many cancers are termed immunoevasive due to expression of immunomodulatory ligands. Programmed death ligand-1 (PD-L1) and cluster of differentiation 80/86 (CD80/86) interact with their receptors, programmed death receptor-1 (PD-1) and cytotoxic T-lymphocyte antigen-4 (CTLA-4), respectively, on tumor-infiltrating leukocytes eliciting immunosuppression. Immunotherapies aimed at blocking these interactions are revolutionizing cancer treatments, albeit in an inadequately described patient subset. To address the issue of patient stratification for immune checkpoint intervention, we quantitatively imaged PD-1/PD-L1 interactions in tumor samples from patients, employing an assay that readily detects these intercellular protein-protein interactions in the less than or equal to 10 nm range. These analyses across multiple patient cohorts demonstrated the intercancer, interpatient, and intratumoral heterogeneity of interacting immune checkpoints. The PD-1/PD-L1 interaction was not correlated with clinical PD-L1 expression scores in malignant melanoma. Crucially, among anti-PD-1-treated patients with metastatic non-small cell lung cancer, those with lower PD-1/PD-L1 interaction had significantly worsened survival. It is surmised that within tumors selecting for an elevated level of PD-1/PD-L1 interaction, there is a greater dependence on this pathway for immune evasion and hence, they exhibit more impressive patient response to intervention. SIGNIFICANCE: Quantitation of immune checkpoint interaction by direct imaging demonstrates that immunotherapy-treated patients with metastatic NSCLC with a low extent of PD-1/PD-L1 interaction show significantly worse outcome., (©2020 American Association for Cancer Research.)
- Published
- 2020
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35. A small molecule inhibitor of HER3: a proof-of-concept study.
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Colomba A, Fitzek M, George R, Weitsman G, Roberts S, Zanetti-Domingues L, Hirsch M, Rolfe DJ, Mehmood S, Madin A, Claus J, Kjaer S, Snijders AP, Ng T, Martin-Fernandez M, Smith DM, and Parker PJ
- Subjects
- Allosteric Regulation, Animals, CHO Cells, Cricetulus, Drug Screening Assays, Antitumor, Humans, Proof of Concept Study, Protein Binding, Receptor, ErbB-2 chemistry, Receptor, ErbB-2 genetics, Receptor, ErbB-2 metabolism, Protein Kinase Inhibitors chemistry, Protein Kinase Inhibitors pharmacology, Receptor, ErbB-3 antagonists & inhibitors, Receptor, ErbB-3 chemistry, Receptor, ErbB-3 genetics, Receptor, ErbB-3 metabolism
- Abstract
Despite being catalytically defective, pseudokinases are typically essential players of cellular signalling, acting as allosteric regulators of their active counterparts. Deregulation of a growing number of pseudokinases has been linked to human diseases, making pseudokinases therapeutic targets of interest. Pseudokinases can be dynamic, adopting specific conformations critical for their allosteric function. Interfering with their allosteric role, with small molecules that would lock pseudokinases in a conformation preventing their productive partner interactions, is an attractive therapeutic strategy to explore. As a well-known allosteric activator of epidermal growth factor receptor family members, and playing a major part in cancer progression, the pseudokinase HER3 is a relevant context in which to address the potential of pseudokinases as drug targets for the development of allosteric inhibitors. In this proof-of-concept study, we developed a multiplex, medium-throughput thermal shift assay screening strategy to assess over 100 000 compounds and identify selective small molecule inhibitors that would trap HER3 in a conformation which is unfavourable for the formation of an active HER2-HER3 heterodimer. As a proof-of-concept compound, AC3573 bound with some specificity to HER3 and abrogated HER2-HER3 complex formation and downstream signalling in cells. Our study highlights the opportunity to identify new molecular mechanisms of action interfering with the biological function of pseudokinases., (© 2020 The Author(s).)
- Published
- 2020
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36. Novel Essential Amino Acid Supplements Following Resistance Exercise Induce Aminoacidemia and Enhance Anabolic Signaling Irrespective of Age: A Proof-of-Concept Trial.
- Author
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Lees MJ, Wilson OJ, Webb EK, Traylor DA, Prior T, Elia A, Harlow PS, Black AD, Parker PJ, Harris N, Cooke M, Balchin C, Butterworth M, Phillips SM, and Ispoglou T
- Subjects
- Adult, Aged, Amino Acids, Essential metabolism, Female, Humans, Leucine administration & dosage, Leucine blood, Leucine metabolism, Male, Mechanistic Target of Rapamycin Complex 1 metabolism, Sarcopenia metabolism, Young Adult, Aging metabolism, Amino Acids, Essential administration & dosage, Amino Acids, Essential blood, Dietary Supplements, Exercise physiology, Muscle Proteins metabolism, Muscle, Skeletal metabolism, Resistance Training
- Abstract
We investigated the effects of ingesting a leucine-enriched essential amino acid (EAA) gel alone or combined with resistance exercise (RE) versus RE alone (control) on plasma aminoacidemia and intramyocellular anabolic signaling in healthy younger (28 ± 4 years) and older (71 ± 3 years) adults. Blood samples were obtained throughout the three trials, while muscle biopsies were collected in the postabsorptive state and 2 h following RE, following the consumption of two 50 mL EAA gels (40% leucine, 15 g total EAA), and following RE with EAA (combination (COM)). Protein content and the phosphorylation status of key anabolic signaling proteins were determined via immunoblotting. Irrespective of age, during EAA and COM peak leucinemia (younger: 454 ± 32 µM and 537 ± 111 µM; older: 417 ± 99 µM and 553 ± 136 µM) occurred ~60-120 min post-ingestion (younger: 66 ± 6 min and 120 ± 60 min; older: 90 ± 13 min and 78 ± 12 min). In the pooled sample, the area under the curve for plasma leucine and the sum of branched-chain amino acids was significantly greater in EAA and COM compared with RE. For intramyocellular signaling, significant main effects were found for condition (mTOR (Ser2481), rpS6 (Ser235/236)) and age (S6K1 (Thr421/Ser424), 4E-BP1 (Thr37/46)) in age group analyses. The phosphorylation of rpS6 was of similar magnitude (~8-fold) in pooled and age group data 2 h following COM. Our findings suggest that a gel-based, leucine-enriched EAA supplement is associated with aminoacidemia and a muscle anabolic signaling response, thus representing an effective means of stimulating muscle protein anabolism in younger and older adults following EAA and COM.
- Published
- 2020
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37. Author Correction: The Aurora B specificity switch is required to protect from non-disjunction at the metaphase/anaphase transition.
- Author
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Kelly JR, Martini S, Brownlow N, Joshi D, Federico S, Jamshidi S, Kjaer S, Lockwood N, Rahman KM, Fraternali F, Parker PJ, and Soliman TN
- Abstract
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
- Published
- 2020
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38. The Aurora B specificity switch is required to protect from non-disjunction at the metaphase/anaphase transition.
- Author
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Kelly JR, Martini S, Brownlow N, Joshi D, Federico S, Jamshidi S, Kjaer S, Lockwood N, Rahman KM, Fraternali F, Parker PJ, and Soliman TN
- Subjects
- Anaphase genetics, Aurora Kinase B chemistry, Aurora Kinase B genetics, Caspase 7 metabolism, Cell Cycle Proteins metabolism, Chromatids metabolism, Chromatin, Chromosomes metabolism, HEK293 Cells, Humans, Metaphase genetics, Mitosis genetics, Molecular Dynamics Simulation, Phosphorylation, Protein Kinase C-epsilon metabolism, Recombinant Proteins, Signal Transduction physiology, Anaphase physiology, Aurora Kinase B metabolism, Metaphase physiology, Mitosis physiology
- Abstract
The Aurora B abscission checkpoint delays cytokinesis until resolution of DNA trapped in the cleavage furrow. This process involves PKCε phosphorylation of Aurora B S227. Assessing if this PKCε-Aurora B module provides a more widely exploited genome-protective control for the cell cycle, we show Aurora B phosphorylation at S227 by PKCε also occurs during mitosis. Expression of Aurora B S227A phenocopies inhibition of PKCε in by-passing the delay and resolution at anaphase entry that is associated with non-disjunction and catenation of sister chromatids. Implementation of this anaphase delay is reflected in PKCε activation following cell cycle dependent cleavage by caspase 7; knock-down of caspase 7 phenocopies PKCε loss, in a manner rescued by ectopically expressing/generating a free PKCε catalytic domain. Molecular dynamics indicates that Aurora B S227 phosphorylation induces conformational changes and this manifests in a profound switch in specificity towards S29 TopoIIα phosphorylation, a response necessary for catenation resolution during mitosis.
- Published
- 2020
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39. Developing TCCC Guidelines for Unmanned Aerial Vehicle Casualty Evacuation.
- Author
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Parker PJ
- Subjects
- Humans, Military Medicine, War-Related Injuries therapy, Aircraft, Guidelines as Topic, Remote Sensing Technology, Transportation of Patients methods
- Published
- 2020
- Full Text
- View/download PDF
40. Skeletal muscle, haematological and splenic volume characteristics of elite breath-hold divers.
- Author
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Elia A, Wilson OJ, Lees M, Parker PJ, Barlow MJ, Cocks M, and O'Hara JP
- Subjects
- Breath Holding, Capillaries metabolism, Capillaries physiology, Humans, Male, Muscle, Skeletal metabolism, Oxygen metabolism, Diving physiology, Muscle, Skeletal physiology
- Abstract
Purpose: The aim of the study was to provide an evaluation of the oxygen transport, exchange and storage capacity of elite breath-hold divers (EBHD) compared with non-divers (ND)., Methods: Twenty-one healthy males' (11 EBHD; 10 ND) resting splenic volumes were assessed by ultrasound and venous blood drawn for full blood count analysis. Percutaneous skeletal muscle biopsies were obtained from the m. vastus lateralis to measure capillarisation, and fibre type-specific localisation and distribution of myoglobin and mitochondrial content using quantitative immunofluorescence microscopy., Results: Splenic volume was not different between groups. Reticulocytes, red blood cells and haemoglobin concentrations were higher (+ 24%, p < 0.05; + 9%, p < 0.05; + 3%, p < 0.05; respectively) and mean cell volume was lower (- 6.5%, p < 0.05) in the EBHD compared with ND. Haematocrit was not different between groups. Capillary density was greater (+ 19%; p < 0.05) in the EBHD. The diffusion distance (R
95 ) was lower in type I versus type II fibres for both groups (EBHD, p < 0.01; ND, p < 0.001), with a lower R95 for type I fibres in the EBHD versus ND (- 13%, p < 0.05). Myoglobin content was higher in type I than type II fibres in EBHD (+ 27%; p < 0.01) and higher in the type I fibres of EBHD than ND (+ 27%; p < 0.05). No fibre type differences in myoglobin content were observed in ND. Mitochondrial content was higher in type I than type II fibres in EBHD (+ 35%; p < 0.05), with no fibre type differences in ND or between groups., Conclusions: In conclusion, EBDH demonstrate enhanced oxygen storage in both blood and skeletal muscle and a more efficient oxygen exchange capacity between blood and skeletal muscle versus ND.- Published
- 2019
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41. The Potential Use of the Abdominal Aortic Junctional Tourniquet® in a Military Population: A Review of Requirement, Effectiveness, and Usability.
- Author
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Handford C and Parker PJ
- Subjects
- Humans, Treatment Outcome, Hemorrhage therapy, Military Personnel, Tourniquets
- Abstract
Uncontrolled hemorrhage is the leading cause of preventable prehospital death on the battlefield; 20% is junctional. This is a challenge to manage in the forward and prehospital military environment. With the widespread use of body armor, peripheral tourniquets and continued asymmetric warfare this consistent figure is unlikely to reduce. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an often-quoted potential solution; however, this invasive strategy requires a high skill level alongside a significant failure and complication rate. The Abdominal Aortic Junctional Tourniquet® (AAJT) is a noninvasive potential adjunct for the management of hemorrhage below the level of the aortic bifurcation with published case reports of successful use in prehospital blast and gunshot wounds. When placed at the level of the aortic bifurcation, alongside a pelvic binder, it can be used to control pelvic hemorrhage, buying time until definitive management. Importantly it has a low training burden and is easy to use. The AAJT has potential use as a prehospital device in the exsanguinating patient, those in traumatic cardiac arrest, as a bridging device, and as fluid conserving device in resource-limited environments. The evidence surrounding the AAJT is reviewed, and potential uses in the military setting are suggested., (2019.)
- Published
- 2019
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42. A global sampler of single particle tracking solutions for single molecule microscopy.
- Author
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Hirsch M, Wareham R, Yoon JW, Rolfe DJ, Zanetti-Domingues LC, Hobson MP, Parker PJ, Martin-Fernandez ML, and Singh SS
- Subjects
- Algorithms, Models, Theoretical, Motion, Single Molecule Imaging
- Abstract
The dependence on model-fitting to evaluate particle trajectories makes it difficult for single particle tracking (SPT) to resolve the heterogeneous molecular motions typical of cells. We present here a global spatiotemporal sampler for SPT solutions using a Metropolis-Hastings algorithm. The sampler does not find just the most likely solution but also assesses its likelihood and presents alternative solutions. This enables the estimation of the tracking error. Furthermore the algorithm samples the parameters that govern the tracking process and therefore does not require any tweaking by the user. We demonstrate the algorithm on synthetic and single molecule data sets. Metrics for the comparison of SPT are generalised to be applied to a SPT sampler. We illustrate using the example of the diffusion coefficient how the distribution of the tracking solutions can be propagated into a distribution of derived quantities. We also discuss the major challenges that are posed by the realisation of a SPT sampler., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
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43. The NATO Special Operations Surgical Team Development Course A Program Overview.
- Author
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Parker PJ
- Subjects
- Curriculum, Humans, Military Medicine education, Surgical Procedures, Operative education
- Abstract
The Special Operations Surgical Team Development Course (SOSTDC) is a 5-day course held two or three times a year at the North Atlantic Treaty Organization (NATO) training facility within the Special Operations Medical Branch (SOMB) of the Allied Centre for Medical Education (ACME). Its aim is to teach, train, develop, and encourage NATO partner nations to provide robust, hardened, and clinically able surgical resuscitation teams that are capable of providing close support to Special Operations Forces (SOF)., (2019.)
- Published
- 2019
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44. The Rho family GEF FARP2 is activated by aPKCι to control tight junction formation and polarity.
- Author
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Elbediwy A, Zhang Y, Cobbaut M, Riou P, Tan RS, Roberts SK, Tynan C, George R, Kjaer S, Martin-Fernandez ML, Thompson BJ, McDonald NQ, and Parker PJ
- Subjects
- Caco-2 Cells, Cell Polarity, Guanine Nucleotide Exchange Factors genetics, HCT116 Cells, Humans, Phosphorylation, Epithelial Cells cytology, Guanine Nucleotide Exchange Factors metabolism, Protein Kinase C metabolism, Tight Junctions metabolism, cdc42 GTP-Binding Protein metabolism
- Abstract
The elaboration of polarity is central to organismal development and to the maintenance of functional epithelia. Among the controls determining polarity are the PAR proteins, PAR6, aPKCι and PAR3, regulating both known and unknown effectors. Here, we identify FARP2 as a 'RIPR' motif-dependent partner and substrate of aPKCι that is required for efficient polarisation and junction formation. Binding is conferred by a FERM/FA domain-kinase domain interaction and detachment promoted by aPKCι-dependent phosphorylation. FARP2 is shown to promote GTP loading of Cdc42, which is consistent with it being involved in upstream regulation of the polarising PAR6-aPKCι complex. However, we show that aPKCι acts to promote the localised activity of FARP2 through phosphorylation. We conclude that this aPKCι-FARP2 complex formation acts as a positive feedback control to drive polarisation through aPKCι and other Cdc42 effectors.This article has an associated First Person interview with the first author of the paper., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2019. Published by The Company of Biologists Ltd.)
- Published
- 2019
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45. A genome-wide RNAi screen identifies the SMC5/6 complex as a non-redundant regulator of a Topo2a-dependent G2 arrest.
- Author
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Deiss K, Lockwood N, Howell M, Segeren HA, Saunders RE, Chakravarty P, Soliman TN, Martini S, Rocha N, Semple R, Zalmas LP, and Parker PJ
- Subjects
- Cell Cycle Proteins genetics, Cell Line, Chromosomal Proteins, Non-Histone genetics, DNA Damage drug effects, Diketopiperazines, Fibroblasts drug effects, Genome, Human genetics, Germ-Line Mutation genetics, Humans, Multiprotein Complexes genetics, Piperazines pharmacology, Poly-ADP-Ribose Binding Proteins antagonists & inhibitors, RNA Interference, Ubiquitin-Protein Ligases genetics, DNA Topoisomerases, Type II genetics, G2 Phase Cell Cycle Checkpoints genetics, Ligases genetics, Poly-ADP-Ribose Binding Proteins genetics, Sumoylation genetics
- Abstract
The Topo2a-dependent arrest is associated with faithful segregation of sister chromatids and has been identified as dysfunctional in numerous tumour cell lines. This genome-protecting pathway is poorly understood and its characterization is of significant interest, potentially offering interventional opportunities in relation to synthetic lethal behaviours in arrest-defective tumours. Using the catalytic Topo2a inhibitor ICRF193, we have performed a genome-wide siRNA screen in arrest-competent, non-transformed cells, to identify genes essential for this arrest mechanism. In addition, we have counter-screened several DNA-damaging agents and demonstrate that the Topo2a-dependent arrest is genetically distinct from DNA damage checkpoints. We identify the components of the SMC5/6 complex, including the activity of the E3 SUMO ligase NSE2, as non-redundant players that control the timing of the Topo2a-dependent arrest in G2. We have independently verified the NSE2 requirement in fibroblasts from patients with germline mutations that cause severely reduced levels of NSE2. Through imaging Topo2a-dependent G2 arrested cells, an increased interaction between Topo2a and NSE2 is observed at PML bodies, which are known SUMOylation hotspots. We demonstrate that Topo2a is SUMOylated in an ICRF193-dependent manner by NSE2 at a novel non-canonical site (K1520) and that K1520 sumoylation is required for chromosome segregation but not the G2 arrest., (© The Author(s) 2018. Published by Oxford University Press on behalf of Nucleic Acids Research.)
- Published
- 2019
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46. Cluster Analysis of Endogenous HER2 and HER3 Receptors in SKBR3 Cells.
- Author
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Roberts SK, Hirsch M, McStea A, Zanetti-Domingues LC, Clarke DT, Claus J, Parker PJ, Wang L, and Martin-Fernandez AML
- Abstract
The Human Epidermal Growth Factor Receptor (HER) family of receptor tyrosine kinases consists of four, single pass, transmembrane receptor homologs (HER1-4) that act to regulate many critical processes in normal and tumor cells. HER2 is overexpressed in many tumors, and the deregulated proliferation of cancerous cells is driven by cooperation with its preferred receptor partner, HER3. The assessment of the in-situ organization of tagged HER2 and HER3 using super-resolution microscopy reveals quantitative Single Molecule Localization Microscopy (SMLM) as an ideal bioanalytical tool to characterize receptor clusters. Clustering of receptors is an important regulatory mechanism to prime cells to respond to stimuli so, to understand these processes, it is necessary to measure parameters such as numbers of clusters, cluster radii and the number of localizations per cluster for different perturbations. Previously, Fluorescence Localization Imaging with Photobleaching (FLImP), another nanoscale, single-molecule technique, characterized the oligomerization state of HER1 [or Epidermal Growth Factor Receptors (EGFR)] in cell membranes. To achieve an unprecedented resolution (< 5 nm) for inter-molecular separations in EGFR oligomers using FLImP, very few receptors are tagged, and so this method is unsuitable for measurements of whole receptor populations in cancer cells where receptors are frequently upregulated. Here, in order to detect all receptors involved in cluster formation, we saturate endogenous HER2 and HER3 membrane receptors with ligands at a 1:1 dye to protein ratio, in the presence or absence of therapeutic drugs (lapatinib or bosutinib). This is performed in the commonly used breast cancer cell line model SKBR3 cells, where there are ~1.6 million HER2 receptors/cell and 10,000-40,000 HER3 receptors/cell. The basal state of these receptors is studied using HER2- or HER3-specific Affibodies, and likewise, the active state is probed using the natural HER3 ligand, Neuregulin-beta1 (NRGβ1). Stochastic Optical Reconstruction Microscopy (STORM), one form of SMLM, was used here to image cells, which were chemically fixed to minimize image blurring and provide data (x and y coordinates and standard deviation of the measured localizations) for cluster analysis. Further analysis can also determine proportions of receptor colocalizations. Our findings show that lapatinib-bound HER2, complexed with HER3 via a non-canonical kinase dimer structure, induces higher order oligomers. We hypothesized that nucleation of receptors creates signaling platforms that explain the counterintuitive, increase in cell proliferation upon ligand binding, in the presence of the HER2-inhibitor lapatinib., Competing Interests: Competing interestsAuthors declare no conflicts of interest or competing interests., (Copyright © The Authors; exclusive licensee Bio-protocol LLC.)
- Published
- 2018
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47. The architecture of EGFR's basal complexes reveals autoinhibition mechanisms in dimers and oligomers.
- Author
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Zanetti-Domingues LC, Korovesis D, Needham SR, Tynan CJ, Sagawa S, Roberts SK, Kuzmanic A, Ortiz-Zapater E, Jain P, Roovers RC, Lajevardipour A, van Bergen En Henegouwen PMP, Santis G, Clayton AHA, Clarke DT, Gervasio FL, Shan Y, Shaw DE, Rolfe DJ, Parker PJ, and Martin-Fernandez ML
- Subjects
- Animals, CHO Cells, Cell Membrane metabolism, Cricetinae, Cricetulus, Extracellular Matrix metabolism, Fluorescent Dyes chemistry, Fluorescent Dyes metabolism, Ligands, Models, Biological, Models, Molecular, Photobleaching, Polymers chemistry, Protein Domains, Protein Kinases chemistry, Protein Kinases metabolism, ErbB Receptors antagonists & inhibitors, ErbB Receptors chemistry, Protein Multimerization
- Abstract
Our current understanding of epidermal growth factor receptor (EGFR) autoinhibition is based on X-ray structural data of monomer and dimer receptor fragments and does not explain how mutations achieve ligand-independent phosphorylation. Using a repertoire of imaging technologies and simulations we reveal an extracellular head-to-head interaction through which ligand-free receptor polymer chains of various lengths assemble. The architecture of the head-to-head interaction prevents kinase-mediated dimerisation. The latter, afforded by mutation or intracellular treatments, splits the autoinhibited head-to-head polymers to form stalk-to-stalk flexible non-extended dimers structurally coupled across the plasma membrane to active asymmetric tyrosine kinase dimers, and extended dimers coupled to inactive symmetric kinase dimers. Contrary to the previously proposed main autoinhibitory function of the inactive symmetric kinase dimer, our data suggest that only dysregulated species bear populations of symmetric and asymmetric kinase dimers that coexist in equilibrium at the plasma membrane under the modulation of the C-terminal domain.
- Published
- 2018
- Full Text
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48. The Combat Application Tourniquet Versus the Tactical Mechanical Tourniquet.
- Author
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Beaven A, Ballard M, Sellon E, Briard R, and Parker PJ
- Subjects
- Adult, Female, Humans, Male, Middle Aged, Pain etiology, Pain Measurement, Popliteal Artery diagnostic imaging, Regional Blood Flow, Thigh, Time and Motion Studies, Ultrasonography, United Kingdom, Military Personnel, Self Care instrumentation, Tourniquets adverse effects
- Abstract
Background: Exsanguination from limb injury is an important battlefield consideration that is mitigated with the use of emergency tourniquets. The Combat Application Tourniquet (C-A-T®) is the current British military standard tourniquet., Methods: We tested the self-application of a newer tourniquet system, the Tactical Mechanical Tourniquet (TMT), against self-application of the C-A-T. A total of 24 healthy British military volunteers self-applied the C-A-T and the TMT to their mid thigh in a randomized, sequential manner. Popliteal artery flow was monitored with a portable ultrasound machine, and time until arterial occlusion was measured. Pain scores were also recorded. Results The volunteers allowed testing on their lower limbs (n = 48 legs). The C-A-T was applied successfully to 22 volunteers (92%), and the TMT was successfully applied to 17 (71%). Median time to reach complete arterial occlusion was 37.5 (interquartile range [IQR], 27-52) seconds with the C-A-T, and 35 (IQR, 29-42) seconds with the TMT. The 2.5-second difference in median times was not significant (ρ = .589). The 1-in-10 difference in median pain score was also not significant (ρ = .656). The success or failure of self-application between the two tourniquet models as assessed by contingency table was not significant (p= .137)., Conclusion: The TMT is effective when self-applied at the mid thigh. It does not offer an efficacy advantage over the C-A-T., (2018.)
- Published
- 2018
- Full Text
- View/download PDF
49. Protein kinase D displays intrinsic Tyr autophosphorylation activity: insights into mechanism and regulation.
- Author
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Cobbaut M, Derua R, Parker PJ, Waelkens E, Janssens V, and Van Lint J
- Subjects
- Amino Acid Sequence, Animals, COS Cells, Cells, Cultured, Chlorocebus aethiops, Drosophila, Enzyme Activation genetics, HEK293 Cells, Homeostasis genetics, Humans, Mutagenesis, Site-Directed, Phosphorylation genetics, Protein Kinase C genetics, Tyrosine genetics, Protein Kinase C chemistry, Protein Kinase C metabolism, Tyrosine metabolism
- Abstract
The protein kinase D (PKD) family is regulated through multi-site phosphorylation, including autophosphorylation. For example, PKD displays in vivo autophosphorylation on Ser-742 (and Ser-738 in vitro) in the activation loop and Ser-910 in the C-tail (hPKD1 numbering). In this paper, we describe the surprising observation that PKD also displays in vitro autocatalytic activity towards a Tyr residue in the P + 1 loop of the activation segment. We define the molecular determinants for this unusual activity and identify a Cys residue (C705 in PKD1) in the catalytic loop as of utmost importance. In cells, PKD Tyr autophosphorylation is suppressed through the association of an inhibitory factor. Our findings provide important novel insights into PKD (auto)regulation., (© 2018 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)
- Published
- 2018
- Full Text
- View/download PDF
50. Protein Kinase C-β Dictates B Cell Fate by Regulating Mitochondrial Remodeling, Metabolic Reprogramming, and Heme Biosynthesis.
- Author
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Tsui C, Martinez-Martin N, Gaya M, Maldonado P, Llorian M, Legrave NM, Rossi M, MacRae JI, Cameron AJ, Parker PJ, Leitges M, Bruckbauer A, and Batista FD
- Subjects
- Animals, Heme biosynthesis, Mice, Mice, Knockout, Mitochondria immunology, Mitochondria metabolism, Plasma Cells cytology, B-Lymphocytes immunology, Cell Differentiation immunology, Lymphocyte Activation immunology, Plasma Cells immunology, Protein Kinase C beta immunology
- Abstract
PKCβ-null (Prkcb
-/- ) mice are severely immunodeficient. Here we show that mice whose B cells lack PKCβ failed to form germinal centers and plasma cells, which undermined affinity maturation and antibody production in response to immunization. Moreover, these mice failed to develop plasma cells in response to viral infection. At the cellular level, we have shown that Prkcb-/- B cells exhibited defective antigen polarization and mTORC1 signaling. While altered antigen polarization impaired antigen presentation and likely restricted the potential of GC development, defective mTORC1 signaling impaired metabolic reprogramming, mitochondrial remodeling, and heme biosynthesis in these cells, which altogether overwhelmingly opposed plasma cell differentiation. Taken together, our study reveals mechanistic insights into the function of PKCβ as a key regulator of B cell polarity and metabolic reprogramming that instructs B cell fate., (Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.)- Published
- 2018
- Full Text
- View/download PDF
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