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256 results on '"Schonbrunn A"'

1. Group 3 medulloblastoma transcriptional networks collapse under domain specific EP300/CBP inhibition

Author

Shendy, Noha A. M., Bikowitz, Melissa, Sigua, Logan H., Zhang, Yang, Mercier, Audrey, Khashana, Yousef, Nance, Stephanie, Liu, Qi, Delahunty, Ian M., Robinson, Sarah, Goel, Vanshita, Rees, Matthew G., Ronan, Melissa A., Wang, Tingjian, Kocak, Mustafa, Roth, Jennifer A., Wang, Yingzhe, Freeman, Burgess B., Orr, Brent A., Abraham, Brian J., Roussel, Martine F., Schonbrunn, Ernst, Qi, Jun, and Durbin, Adam D.

Published
2024
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2. SARS-CoV-2 Period Seroprevalence and Related Factors, Hillsborough County, Florida, USA, October 2020-March 2021

Author

Giuliano, Anna R., Pilon-Thomas, Shari, Schell, Michael J., Abrahamsen, Martha, Islam, Jessica Y., Isaacs-Soriano, Kimberly, Kennedy, Kayoko, Dukes, Christopher W., Whiting, Junmin, Rathwell, Julie, Hensel, Jonathan A., Mangual, Leslie N., Schonbrunn, Ernst, Bikowitz, Melissa, Grassie, Dylan, and Yang, Yan

Subjects
Hillsborough County, Florida -- Health aspects, Infection control -- Analysis, Company distribution practices, Health
Abstract

In late 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in China, ultimately leading to a global pandemic (1). Since January 2020, the United States has observed a dramatic [...]

Published
2022
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10. Discovery of Marinopyrrole A (Maritoclax) as a Selective Mcl-1 Antagonist that Overcomes ABT-737 Resistance by Binding to and Targeting Mcl-1 for Proteasomal Degradation

Author

Doi, Kenichiro, Li, Rongshi, Sung, Shen-Shu, Wu, Hongwei, Liu, Yan, Manieri, Wanda, Krishnegowda, Gowdahalli, Awwad, Andy, Dewey, Alden, Liu, Xin, Amin, Shantu, Cheng, Chunwei, Qin, Yong, Schonbrunn, Ernst, Daughdrill, Gary, Loughran, Thomas P., Jr., Sebti, Said, and Wang, Hong-Gang

Published
2012
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19. Real-Time Signaling Assays Demonstrate Somatostatin Agonist Bias for Ion Channel Regulation in Somatotroph Tumor Cells

Author

Agnes Schonbrunn, Melissa Rodriguez, and Jeffrey A. Frost

Subjects
0301 basic medicine, Agonist, calcium, medicine.drug_class, Chemistry, Somatostatin receptor, Endocrinology, Diabetes and Metabolism, Membrane hyperpolarization, somatostatin, medicine.disease, Signaling Pathways, Growth hormone secretion, Cell biology, internalization, 03 medical and health sciences, SOM230, 030104 developmental biology, Somatostatin, Sstr2A, cAMP, Acromegaly, medicine, Secretion, Signal transduction, Research Articles
Abstract

Acromegaly is a neuroendocrine disorder caused by excess secretion of GH by somatotroph tumor cells. It is often treated with somatostatin receptor (SSTR) 2 agonists, which suppress GH secretion. SOM230 is a somatostatin analogue that targets multiple SSTRs and was recently approved for patients with treatment-resistant acromegaly. Previous reports indicate that SOM230 may function as a biased agonist, suggesting that its ability to selectively activate SSTR-dependent signaling events may contribute to its therapeutic efficacy. To better understand how SOM230 modulates Sstr2A function, which is the most commonly expressed SSTR in somatotrophs, we used real-time assays to study SOM230-dependent signaling in rat pituitary tumor cells. We observed that SOM230 suppressed cAMP production in a Gαi-dependent manner, similar to conventional Sstr2A agonists. However, it did not cause receptor internalization as would be expected for an Sstr2A agonist. Surprisingly, SOM230 did not cause membrane hyperpolarization, which is an important mechanism by which Sstr2a activation suppresses intracellular calcium (Ca2+) accumulation and GH secretion. In fact, SOM230 inhibited the ability of conventional somatostatin analogues to control membrane potential. However, SOM230 still inhibited intracellular Ca2+ accumulation in a novel, Gβγ-dependent manner. These studies show that SOM230 exhibits strong agonist bias in regulating signaling pathways downstream of Sstr2A that control GH secretion., Using real-time measurements, we find that the SSTR agonist SOM230 exhibits bias toward signaling pathways linked to suppression of GH secretion in pituitary tumor cells.

Published
2018

20. Molecular basis for the herbicide resistance of Roundup Ready crops

Author

Funke, Todd, Han, Huijong, Healy-Fried, Martha L., Fischer, Markus, and Schonbrunn, Ernst

Subjects
Genetic engineering -- Research, Herbicide resistance -- Research, Science and technology
Abstract

The engineering of transgenic crops resistant to the broad-spectrum herbicide glyphosate has greatly improved agricultural efficiency worldwide. Glyphosate-based herbicides, such as Roundup, target the shikimate pathway enzyme 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase, the functionality of which is absolutely required for the survival of plants. Roundup Ready plants carry the gene coding for a glyphosate-insensitive form of this enzyme, obtained from Agrobacterium sp. strain CP4. Once incorporated into the plant genome, the gene product, CP4 EPSP synthase, confers crop resistance to glyphosate. Although widely used, the molecular basis for this glyphosate-resistance has remained obscure. We generated a synthetic gene coding for CP4 EPSP synthase and characterized the enzyme using kinetics and crystallography. The CP4 enzyme has unexpected kinetic and structural properties that render it unique among the known EPSP synthases. Glyphosate binds to the CP4 EPSP synthase in a condensed, noninhibitory conformation. Glyphosate sensitivity can be restored through a single-site mutation in the active site (Ala-100-Gly), allowing glyphosate to bind in its extended, inhibitory conformation. conformational change | crystal structure | genetic modification | mutation

Published
2006

25. Somatostatin receptors (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

Author

Jean Claude Reubi, Yogesh C. Patel, Giovanni Tulipano, Herbert A. Schmid, Leo J. Hofland, Terry Reisine, Rebecca Hills, Zsolt Csaba, Micheal Culler, Stefan Schulz, Annamaria Vezzani, Marcus Schindler, Agnes Schonbrunn, Justo P. Castaño, John E. Taylor, Jacques Epelbaum, Wasyl Feniuk, Hans-Jürgen Wester, Patrick P.A. Humphrey, Pascal Dournaud, Corinne Bosquet, Hans-Jürgen Kreienkamp, Shlomo Melmed, Anthony J. Harmar, Wolfgang Meyerhof, Anne-Marie O'Carroll, Amelie Lupp, and Daniel Hoyer

Subjects
endocrine system, Somatostatin, Chemistry, Somatostatin receptor, Neuropeptide, Secretion, Endogeny, Pharmacology, Receptor, hormones, hormone substitutes, and hormone antagonists, Hormone
Abstract

Somatostatin (somatotropin release inhibiting factor) is an abundant neuropeptide, which acts on five subtypes of somatostatin receptor (SST1-SST5; nomenclature as agreed by the NC-IUPHAR Subcommittee on Somatostatin Receptors [89]). Activation of these receptors produces a wide range of physiological effects throughout the body including the inhibition of secretion of many hormones. Endogenous ligands for these receptors are somatostatin-14 (SRIF-14) and somatostatin-28 (SRIF-28). cortistatin-14 has also been suggested to be an endogenous ligand for somatostatin receptors [56].

Published
2019
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43. The fungal product terreic acid is a covalent inhibitor of the bacterial cell wall biosynthetic enzyme UDP-N-acetylglucosamine 1-carboxyvinyltransferase (MurA)

Author

Huijong Han, Yan Yang, Olesen, Sanne H., Becker, Andreas, Betzi, Stephane, and Schonbrunn, Ernst

Subjects
Enterobacter -- Physiological aspects, Enterobacter -- Genetic aspects, Enterobacteriaceae -- Physiological aspects, Enterobacteriaceae -- Genetic aspects, Enzyme inhibitors -- Chemical properties, Enzyme inhibitors -- Structure, Escherichia coli -- Physiological aspects, Escherichia coli -- Genetic aspects, Transferases -- Chemical properties, Transferases -- Structure, Biological sciences, Chemistry
Abstract

The crystal structure and kinetic characterization of enzyme MurA from Enterobacter cloacae and Escherichia coli is described. The differential kinetic and structural characteristics of MurA inactivation by terreic acid and fosfomycin reflected the importance of noncovalent binding potential, even for covalent inhibitors for ensuring inactivation efficiency and specificity.

Published
2010

44. X-ray crystallographic and solution state nuclear magnetic resonance spectroscopic investigations of [NADP.sup.+] binding to ferredoxin NADP reductase from Pseudomonas aeruginosa

Author

An Wang, Rodriguez, Juan Carlos, Huijong Han, Schonbrunn, Ernst, and Rivera, Mario

Subjects
X-ray crystallography -- Analysis, Nuclear magnetic resonance spectroscopy -- Analysis, Adenylic acid -- Spectra, Adenylic acid -- Chemical properties, Biological sciences, Chemistry
Abstract

Combination X-ray crystallography and solution NMR spectroscopy were used to characterize the ferredoxin nicotinamide adenine dinucleotide phosphate reductase from Pseudomonas aeruginosa (pa-FPR) in complex with [NADP.sup.+]. The observations from NMR spectra of pa-FPR and the pa-FPR-NADP complex provided insights into the C'-terminal sequence residues, which does not undergo conformational exchange in the presence or absence of [NADP.sup.+] and the stepwise-electron-proton transfer of hydride in the oxidation of NADPH by FPR enzymes.

Published
2008

45. Differential inhibition of class I and class II 5-enolpyruvylshikimate-3-phosphate synthases by tetrahedral reaction intermediate analogues

Author

Funke, Todd, Healy-Fried, Martha L., Huijong Han, Alberg, David G., Bartlett, Paul A., and Schonbrunn, Ernst

Subjects
Crystallography -- Technology application, Glyphosate -- Chemical properties, Shikimate pathway -- Research, Technology application, Biological sciences, Chemistry
Abstract

The differential inhibition of class I (glyphosate-sensitive) and class II (glyphosate-tolerant) 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) enzymes by analogues of tetrahedral reaction intermediate (TI) is examined. Results reveal that class II EPSPS are generally less susceptible to inhibition by these TI analogues.

Published
2007

46. Biochemical and structural characterization of pseudomonas aeruginosa Bfd and FPR: Ferredoxin [NADP.sup.+] reductase and not ferredoxin is the redox partner of heme oxygenase under iron-starvation conditions

Author

An Wang, Yuhong Zeng, Huijong Han, Weeratunga, Saroja, Morgan, Bailey N., Moenne-Loccoz, Pierre, Schonbrunn, Ernst, and Rivera, Mario

Subjects
Ferredoxins -- Structure, Ferredoxins -- Chemical properties, Pseudomonas aeruginosa -- Physiological aspects, Pseudomonas aeruginosa -- Research, Electron transport -- Research, Electron paramagnetic resonance spectroscopy -- Analysis, Biological sciences, Chemistry
Abstract

The products of the two genes encoding electron transfer proteins upregulated by Pseudomonas aeruginosa in response to iron starvation are identified as the redox partners of the heme oxygenase expressed under low-iron stress conditions.

Published
2007

47. Molecular mode of action of a covalently inhibiting peptidomimetic on the human calpain protease core

Author

Qingshan Li, Hanzlik, Robert P., Weaver, Robert F., and Schonbrunn, Ernst

Subjects
Calpain -- Structure, Calpain -- Research, Hydrogen bonding -- Research, Proteases -- Research, Biological sciences, Chemistry
Abstract

Calpain is ubiquitous Ca(super 2+) activated proteolytic enzyme, where a crystal structure of the human mu-calpain protease core (hmuI-II) containing a Gly213Ala mutation and covalently inactivated by a peptidomimetic (ZLLYCH2F). The hydrogen bonding and hydrophobic interaction between active site residues and the inhibitor where the terminal ZL portion of the inhibitor is solvent based in recognition of calpain's natural protein.

Published
2006

48. Interaction of phosphonate analogues of the tetrahedral reaction intermediate with 5-enolpyruvylshikimate-3-phosphate synthase in atomic detail

Author

Priestman, Melanie A., Healy, Martha L., Becker, Andreas, Alberg, David G., Lushington, Gerald H., Bartlett, Paul A., and Schonbrunn, Ernst

Subjects
Escherichia coli -- Structure, Escherichia coli -- Research, Phosphonates -- Atomic properties, Phosphonates -- Research, Biological sciences, Chemistry
Abstract

The high-resolution structures of Escherichia coli 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) inhibited by (R)- and (S)-configured phosphonate analogues of the tetrahedral reaction intermediate are determined. The results suggest that the structural events during open-closed transition of EPSPS are changed as a result of inhibitor action.

Published
2005

49. Editorial: Reproducibility in Research: A Cautionary Tale and Lessons Not Learned

Author

Agnes Schonbrunn

Subjects
medicine.medical_specialty, Biomedical Research, Low dose, Reproducibility of Results, General Medicine, Neuroendocrinology, Biology, Growth hormone secretion, Endocrinology, Editorial, Internal medicine, Pituitary hormones, medicine, High doses, Gh release, Humans, Molecular Biology
Abstract

The 1970s and 1980s were a transformative period for neuroendocrine research. During these 2 decades, many of the hypothalamic peptides regulating pituitary hormone secretion were identified and the field exploded with studies characterizing the spectrum of their biological activities. In the race to these exciting discoveries, discordant results were published regarding the central actions of the newly discovered GH-releasing factor (GRF). Two groups reported a biphasic effect of central administration of human GRF with low doses suppressing and high doses stimulating GH release in rats (1, 2). In contrast, a third group reported that administration of both low and high doses of human GRF inhibited GH secretion (3). Through meticulous scientific detective work, the source of the discrepancy was uncovered and, in the best scientific tradition, promptly published (4). Chemical characterization of the peptide that produced GH inhibition at all doses demonstrated that the putative GRF peptide consisted predominantly of corticotropin-releasing factor. Furthermore, use of new GRF samples reproduced the previously reported stimulatory effect on GH. Although how the original sample became contaminated is not known (4, 5), the source of this error is irrelevant for the purpose of scientific progress: the truth was discovered and revealed.

Published
2015

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