49 results on '"Boonen M"'
Search Results
2. Sustainable Botrytis disease management in Rubus
- Author
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Vanwalleghem, T., primary, Smets, T., additional, Mata, C.I., additional, Van Hemelrijck, W., additional, Holtappels, M., additional, Beliën, T., additional, Geeraerd Ameryckx, A., additional, Michiels, F., additional, Demaître, N., additional, Boonen, M., additional, and Bylemans, D., additional
- Published
- 2024
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3. Papineau-irrigation technique: an alternative treatment of fracture-related infectious soft tissue defects
- Author
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BOONEN, M, primary, GINCKELS, L, additional, TUERLINCKX, G, additional, and LAMMENS, J, additional
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- 2023
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4. Optimization of the irrigation schedule in field-grown strawberry results in higher water use efficiency and improved taste quality
- Author
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Janssens, P., primary, Boonen, M., additional, Bylemans, D., additional, Melis, P., additional, Van Delm, T., additional, Vendel, I., additional, Hertog, M., additional, and Vandendriessche, H., additional
- Published
- 2022
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5. Year round production of primocane ‘Kwanza’ raspberry as an ultimate goal
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Putzeys, P., primary, Boonen, M., additional, and Bylemans, D., additional
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- 2020
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6. A well-balanced nutrient solution for raspberries
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Boonen, M., primary, Putzeys, P., additional, and Bylemans, D., additional
- Published
- 2020
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7. Year round production of the primocane raspberry ‘Kwanza’
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Herckens, K., primary, Boonen, M., additional, and Bylemans, D., additional
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- 2019
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8. A well-balanced nutrient solution for raspberries
- Author
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Boonen, M., primary, Herckens, K., additional, and Bylemans, D., additional
- Published
- 2019
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9. FloodCitiSense: An early warning service for urban pluvial flooding
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Verbeiren, B., Dagnachew Seyoum, S., Lubbad, I., Xin, T., ten Veldhuis, M.-C., Onof, C., Wang, L.-P., Ochoa-Rodriguez, S., Veeckman, C., Boonen, M., See, L., Nalpas, D., O'Brien, B., Johnston, A., and Willems, P.
- Published
- 2018
10. Nurses in Space. A qualitative empirical and conceptual study into the use of a drug safety system by nurses in an orthopaedic ward of a general hospital
- Author
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Boonen, M., Vosman, F.J.H., Lensvelt-Mulders, G.J.L.M., University of Humanistic Studies, and A just and caring society
- Published
- 2017
11. Electrical conductivity of the nutrient solution: implications for flowering and yield in day-neutral cultivars
- Author
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Gallace, N., primary, Boonen, M., additional, Lieten, P., additional, and Bylemans, D., additional
- Published
- 2017
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12. Remote sensing as a useful tool in strawberry cultivation
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Boonen, M., primary, Gallace, N., additional, Delalieux, S., additional, Sima, A., additional, Delauré, B., additional, and Bylemans, D., additional
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- 2017
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13. Matching commercial thrips predating phytoseids with the highly diversified climatic conditions of different strawberry production systems
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Clymans, R., primary, Trekels, H., additional, Boonen, M., additional, Craeye, S., additional, Hanssens, J., additional, Smagghe, G., additional, Vervoort, M., additional, Melis, P., additional, Bylemans, D., additional, and Beliën, T., additional
- Published
- 2017
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14. Covered soilless strawberry production in the field by raised substrate beds
- Author
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Boonen, M., primary, Gallace, N., additional, and Bylemans, D., additional
- Published
- 2017
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- View/download PDF
15. High resolution strawberry field monitoring using the compact hyperspectral imaging solution COSI
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Delalieux, S., primary, Delauré, B., additional, Tits, L., additional, Boonen, M., additional, Sima, A., additional, and Baeck, P.J., additional
- Published
- 2017
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16. COMPACT HYPERSPECTRAL IMAGING SYSTEM (COSI) FOR SMALL REMOTELY PILOTED AIRCRAFT SYSTEMS (RPAS) – SYSTEM OVERVIEW AND FIRST PERFORMANCE EVALUATION RESULTS
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Sima, A. A., primary, Baeck, P., additional, Nuyts, D., additional, Delalieux, S., additional, Livens, S., additional, Blommaert, J., additional, Delauré, B., additional, and Boonen, M., additional
- Published
- 2016
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17. De Bermudadriehoek van het inkoopproces
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Boonen, M., Olthuis, G.J., and Care and contested coherence
- Published
- 2011
18. Tinker, tailor, deliberate. An ethnographic inquiry into the institutionalized practice of bar-coded medication administration technology by nurses.
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Boonen, M. J. M. H., Vosman, Frans J. H., and Niemeijer, Alistair R.
- Abstract
Aim: Explore the practice of nurses working with bar-coded medication administration technology, to gain insight in the impact it has on their work. Background: The widespread presumption of using Barcoded Medication Administration Technology (BCMA) is that it will effectively reduce the number of errors in the dispensing of medication to patients. However, it remains unclear whether this is the case in actual practice. Method: Two distinct but overlapping research methodologies of Institutional Ethnography and Praxeology were combined as a means to uncover the highly complex practice of BCMA by nurses. Results: The implementation of BCMA creates a series of problems leading to nurses constantly tinkering with the technology. At the same time they are continuously deliberating the best ways of tailoring the BCMA to each of their patients. Conclusion: Although working with BCMA is often misconstrued as being mindless and automatic, conforming to the technology, this tinkering with BCMA in fact always entails thorough deliberation by nurses. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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19. Fast and accurate protocol specific bus modeling using TLM 2.0
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van Moll, H.W.M., primary, Corporaal, H., additional, Reyes, V., additional, and Boonen, M., additional
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- 2009
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20. Using SSDE for USB2.0 conformance co-verification
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Omnes, T.J.-F., primary, Postuma, G., additional, VerHaegh, J., additional, Boonen, M., additional, and Gatherer, N., additional
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- 2003
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21. Fast and accurate protocol specific bus modeling using TLM 2.0.
- Author
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van Moll, H. W. M., Corporaal, H., Reyes, V., and Boonen, M.
- Published
- 2009
22. Using SSDE for USB2.0 conformance co-verification.
- Author
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Omnes, T.J.-F., Postuma, G., VerHaegh, J., Boonen, M., and Gatherer, N.
- Published
- 2003
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23. De Esso aromatenfabriek; g-groep verslag
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Van Acker, W.P., Van den Berg, P., Boonen, M., Van den brekel, L., Brink, L., Ten Feld, B., Jansen, F., Krop, J., Nijdam, E., Peeters, J.P., Roza, M., Versendaal, R., Viets, N., and Vorst, F.
- Abstract
Document uit de collectie Chemische Procestechnologie
- Published
- 1982
24. Studie van de vaccinatiegraad bij jonge kinderen en adolescenten in Vlaanderen in 2008
- Author
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Hoppenbrouwers, K., Vandermeulen, C., Roelants, M., Boonen, M., pierre van damme, Heidi Theeten, Depoorter, A. M., and Maatschappelijke Gezondheidszorg
- Subjects
vaccination coverage ,Flanders ,Human medicine - Abstract
In 1999 en in 2005 werd, in opdracht van het Agentschap Zorg en Gezondheid, via een representatieve steekproef de vaccinatiestatus van jonge kinderen (18-24 maanden) in Vlaanderen onderzocht. In 2005 werd voor het eerst dezelfde methode gebruikt om ook bij adolescenten (14-jarigen) de vaccinatiestatus te bepalen. Om de evolutie van de vaccinatiegraad en beïnvloedende factoren te kunnen meten, werd de studie van 2005 herhaald. Specifieke doelstellingen waaraan deze studie diende te voldoen, waren: 1. Het bepalen van de vaccinatiegraad bij kinderen tussen de leeftijd van 18 en 24 maanden in het Vlaamse Gewest voor vaccins tegen de volgende infecties: - poliomyelitis - difterie - tetanus - pertussis - Haemophilus influenzae type b - hepatitis B - mazelen-bof-tubella - pneumokokken - Neisseria meningitidis serogroep C - varicella (op eigen initiatief) - rota (op eigen initiatief) 2. Het bepalen van de vaccinatiegraad bij adolescenten van het tweede jaar secundair onderwijs in het Vlaamse Gewest voor vaccins tegen de volgende infecties: - mazelen-bof-rubella (1e en 2e dosis, peiling naar de twee vaccinatiemomenten) - hepatitis B - Neisseria meningitidis serogroep C - difterie-tetanus-polio herhalingsinenting voorzien op de leeftijd van 6 jaar (1e leerjaar) - humaan papillomavirus (op eigen initiatief) 3. Per vaccin de vaccinatiegraad bepalen en vergelijken enerzijds met de bereikte vaccinatiegraad in de studie van 1999 en 2005 en anderzijds met de noodzakelijke vaccinatiegraad om groepsimmuniteit te bekomen. 4. Definiëren van subpopulaties die niet bereikt worden door het huidige vaccinatieprogramma. 5. Het nagaan van redenen van niet of onvolledig vaccineren. 6. Een vergelijking maken tussen de gegevens genoteerd tijdens de bevraging thuis en de vaccinatiegegevens die beschikbaar zijn in Vaccinnet van alle personen voor wie schriftelijke toestemming tot deelname aan de studie werd verkregen. 7. Het bepalen van het aandeel van de belangrijkste vaccinatoren in het vaccinatiebeleid eventueel gespecificeerd in functie van de doelgroep en/of het vaccin. 8. Het formuleren van voorstellen die leiden tot de verbetering van de vaccinatiegraad
25. A 0.4 W mixed-signal digital storage oscilloscope processor with Moire prevention, embedded 393 kb RAM and 50 M sample/s 8b ADC
- Author
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Vertregt, M., primary, Rey, W., additional, Boonen, M., additional, Verhaegh, J., additional, and Wiertsema, W., additional
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26. A 0.4 W mixed-signal digital storage oscilloscope processor with Moire prevention, embedded 393 kb RAM and 50 M sample/s 8b ADC.
- Author
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Vertregt, M., Rey, W., Boonen, M., Verhaegh, J., and Wiertsema, W.
- Published
- 1998
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27. Residence of the Nucleotide Sugar Transporter Family Members SLC35F1 and SLC35F6 in the Endosomal/Lysosomal Pathway.
- Author
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Van den Bossche F, Tevel V, Gilis F, Gaussin JF, Boonen M, and Jadot M
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- Humans, Amino Acid Sequence, Cell Membrane metabolism, Golgi Apparatus metabolism, HEK293 Cells, HeLa Cells, Nucleotide Transport Proteins metabolism, Nucleotide Transport Proteins genetics, Protein Sorting Signals, Protein Transport, Endosomes metabolism, Lysosomes metabolism
- Abstract
The SLC35 (Solute Carrier 35) family members acting as nucleotide sugar transporters are typically localized in the endoplasmic reticulum or Golgi apparatus. It is, therefore, intriguing that some reports document the presence of orphan transporters SLC35F1 and SLC35F6 within the endosomal and lysosomal system. Here, we compared the subcellular distribution of these proteins and found that they are concentrated in separate compartments; i.e., recycling endosomes for SLC35F1 and lysosomes for SLC35F6. Swapping the C-terminal tail of these proteins resulted in a switch of localization, with SLC35F1 being trafficked to lysosomes while SLC35F6 remained in endosomes. This suggested the presence of specific sorting signals in these C-terminal regions. Using site-directed mutagenesis, fluorescence microscopy, and cell surface biotinylation assays, we found that the EQERLL
360 signal located in the cytoplasmic tail of human SLC35F6 is involved in its lysosomal sorting (as previously shown for this conserved sequence in mouse SLC35F6), and that SLC35F1 localization in the recycling pathway depends on two YXXΦ-type signals: a Y367 KQF sequence facilitates its internalization from the plasma membrane, while a Y392 TSL motif prevents its transport to lysosomes, likely by promoting SLC35F1 recycling to the cell surface. Taken together, these results support that some SLC35 members may function at different levels of the endosomal and lysosomal system.- Published
- 2024
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28. The β Isoform of Human ATP-Binding Cassette B5 Transporter, ABCB5β, Localizes to the Endoplasmic Reticulum.
- Author
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Díaz-Anaya AM, Gerard L, Albert M, Gaussin JF, Boonen M, and Gillet JP
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- Humans, Molecular Chaperones metabolism, HeLa Cells, Protein Isoforms metabolism, Adenosine Triphosphate metabolism, ATP-Binding Cassette Transporters metabolism, Endoplasmic Reticulum metabolism
- Abstract
ABCB5β is a member of the ABC transporter superfamily cloned from melanocytes. It has been reported as a marker of skin progenitor cells and melanoma stem cells. ABCB5β has also been shown to exert an oncogenic activity and promote cancer metastasis. However, this protein remains poorly characterized. To elucidate its subcellular localization, we tested several anti-ABCB5 antibodies and prepared several tagged ABCB5β cDNA constructs. We then used a combination of immunofluorescence and biochemical analyses to investigate the presence of ABCB5β in different subcellular compartments of HeLa and MelJuSo cell lines. Treatment of the cells with the proteasome inhibitor MG132 showed that part of the population of newly synthesized ABCB5β is degraded by the proteasome system. Interestingly, treatment with SAHA, a molecule that promotes chaperone-assisted folding, largely increased the expression of ABCB5β. Nevertheless, the overall protein distribution in the cells remained similar to that of control conditions; the protein extensively colocalized with the endoplasmic reticulum marker calnexin. Taken together with cell surface biotinylation studies demonstrating that the protein does not reach the plasma membrane (even after SAHA treatment), the data indicate that ABCB5β is a microsomal protein predominantly localized to the ER.
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- 2023
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29. Hyaluronidase 1 deficiency decreases bone mineral density in mice.
- Author
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Puissant E, Gilis F, Tevel V, Vandeweerd JM, Flamion B, Jadot M, and Boonen M
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- Animals, Bone Density, Cell Differentiation, Hyaluronic Acid metabolism, Hyaluronoglucosaminidase deficiency, Hyaluronoglucosaminidase genetics, Hyaluronoglucosaminidase metabolism, Mice, Mice, Knockout, Osteoblasts metabolism, Osteoclasts metabolism, Bone Resorption genetics, Bone Resorption metabolism, Mucopolysaccharidoses
- Abstract
Mucopolysaccharidosis IX is a lysosomal storage disorder caused by a deficiency in HYAL1, an enzyme that degrades hyaluronic acid at acidic pH. This disease causes juvenile arthritis in humans and osteoarthritis in the Hyal1 knockout mouse model. Our past research revealed that HYAL1 is strikingly upregulated (~ 25x) upon differentiation of bone marrow monocytes into osteoclasts. To investigate whether HYAL1 is involved in the differentiation and/or resorption activity of osteoclasts, and in bone remodeling in general, we analyzed several bone parameters in Hyal1 -/- mice and studied the differentiation and activity of their osteoclasts and osteoblasts when differentiated in vitro. These experiments revealed that, upon aging, HYAL1 deficient mice exhibit reduced femur length and a ~ 15% decrease in bone mineral density compared to wild-type mice. We found elevated osteoclast numbers in the femurs of these mice as well as an increase of the bone resorbing activity of Hyal1 -/- osteoclasts. Moreover, we detected decreased mineralization by Hyal1 -/- osteoblasts. Taken together with the observed accumulation of hyaluronic acid in Hyal1 -/- bones, these results support the premise that the catabolism of hyaluronic acid by osteoclasts and osteoblasts is an intrinsic part of bone remodeling., (© 2022. The Author(s).)
- Published
- 2022
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30. Nurses' knowledge and deliberations crucial to Barcoded Medication Administration technology in a Dutch hospital: Discovering nurses' agency inside ruling.
- Author
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Boonen M, Rankin J, Vosman F, and Niemeijer A
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- Anthropology, Cultural, Biomedical Technology, Humans, Medication Errors nursing, Netherlands, Qualitative Research, Workflow, Decision Making, Medication Adherence, Medication Errors prevention & control, Medication Systems, Hospital, Nursing Staff, Hospital psychology
- Abstract
This article shows how Barcoded Medication Administration technology institutionally organizes and rules the daily actions of nurses. Although it is widely assumed that Barcoded Medication Administration technology improves quality and safety by reducing the risk of human error, little research has been done on how this technology alters the work of nurses. Drawing on empirical and conceptual strategies of analysis, this qualitative study used certain tools of institutional ethnography to provide a view of how nurses negotiate Barcoded Medication Administration technology. The approach also uses elements from practice theory in order to discern how technology operates as a player on the field instead of being viewed as a 'mere' tool. A literature review preceded participant observation, whereby 17 nurses were followed and data on an orthopaedic ward were collected over a period of 9 months in 2011 and 2012. Barcoded Medication Administration technology relies on nurses' knowledge to mediate between the embedded logics of its design and the unpredictable needs of patients. Nurses negotiate their own professional logic of care in the form of moment-to-moment deliberations which subvert the ruling frame of the barcoded system and its objectified model of patient safety. The logic of Barcoded Medication Administration technology differs from the logic of nursing care, as this technology presumes medication distribution to be linear, even though nurses follow another line of actor-bound safety practices that we characterize as 'deliberations'.
- Published
- 2020
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31. Comparative Analysis of Quantitative Mass Spectrometric Methods for Subcellular Proteomics.
- Author
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Tannous A, Boonen M, Zheng H, Zhao C, Germain CJ, Moore DF, Sleat DE, Jadot M, and Lobel P
- Subjects
- Animals, Ions, Mass Spectrometry, Rats, Proteome, Proteomics
- Abstract
Knowledge of intracellular location can provide important insights into the function of proteins and their respective organelles, and there is interest in combining classical subcellular fractionation with quantitative mass spectrometry to create global cellular maps. To evaluate mass spectrometric approaches specifically for this application, we analyzed rat liver differential centrifugation and Nycodenz density gradient subcellular fractions by tandem mass tag (TMT) isobaric labeling with reporter ion measurement at the MS2 and MS3 level and with two different label-free peak integration approaches, MS1 and data independent acquisition (DIA). TMT-MS2 provided the greatest proteome coverage, but ratio compression from contaminating background ions resulted in a narrower accurate dynamic range compared to TMT-MS3, MS1, and DIA, which were similar. Using a protein clustering approach to evaluate data quality by assignment of reference proteins to their correct compartments, all methods performed well, with isobaric labeling approaches providing the highest quality localization. Finally, TMT-MS2 gave the lowest percentage of missing quantifiable data when analyzing orthogonal fractionation methods containing overlapping proteomes. In summary, despite inaccuracies resulting from ratio compression, data obtained by TMT-MS2 assigned protein localization as well as other methods but achieved the highest proteome coverage with the lowest proportion of missing values.
- Published
- 2020
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32. HOW BAR CODED MEDICATION ADMINISTRATION TECHNOLOGY AFFECTS THE NURSE-PATIENT RELATIONSHIPS: AN ETHNOGRAPHIC STUDY.
- Author
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Boonen M, Vosman FJH, and Niemeijer A
- Subjects
- Adult, Humans, Middle Aged, Netherlands, Observation, Pharmacy Service, Hospital, Qualitative Research, Young Adult, Electronic Data Processing, Medication Systems, Hospital, Nurse-Patient Relations
- Abstract
Objectives: This study aims to assess how care is mediated through technology by analyzing the interaction between nurses, patients, and a Bar Coded Medication Administration (BCMA) system. The objective is to explore how patients experience care through medication technology, with the main focus of our observations and interviews on nurses rather than patients., Methods: A qualitative ethnographic study was conducted in an orthopedic ward of a Dutch general hospital., Results: After analyses, the following two themes were discerned: (i) the use of bar code medication technology organizes double institutionalization, and (ii) nurses frequently need to work around the BCMA, as the system is not always supportive of patient needs., Conclusions: The results of this study indicate that BCMA is not merely a neutral tool, but an active component within the nurse-patient relationship, as it influences medication administration and profoundly affects patient participation in the care process.
- Published
- 2018
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- View/download PDF
33. SNAT7 is the primary lysosomal glutamine exporter required for extracellular protein-dependent growth of cancer cells.
- Author
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Verdon Q, Boonen M, Ribes C, Jadot M, Gasnier B, and Sagné C
- Subjects
- Amino Acid Transport Systems, Neutral genetics, Glutamine genetics, HeLa Cells, Humans, Lysosomes genetics, Lysosomes pathology, Neoplasm Proteins genetics, Neoplasms genetics, Neoplasms pathology, Tumor Microenvironment, Amino Acid Transport Systems, Neutral metabolism, Glutamine metabolism, Intracellular Membranes metabolism, Lysosomes metabolism, Neoplasm Proteins metabolism, Neoplasms metabolism
- Abstract
Lysosomes degrade cellular components sequestered by autophagy or extracellular material internalized by endocytosis and phagocytosis. The macromolecule building blocks released by lysosomal hydrolysis are then exported to the cytosol by lysosomal transporters, which remain undercharacterized. In this study, we designed an in situ assay of lysosomal amino acid export based on the transcription factor EB (TFEB), a master regulator of lysosomal biogenesis that detects lysosomal storage. This assay was used to screen candidate lysosomal transporters, leading to the identification of sodium-coupled neutral amino acid transporter 7 (SNAT7), encoded by the SLC38A7 gene, as a lysosomal transporter highly selective for glutamine and asparagine. Cell fractionation confirmed the lysosomal localization of SNAT7, and flux measurements confirmed its substrate selectivity and showed a strong activation by the lysosomal pH gradient. Interestingly, gene silencing or editing experiments revealed that SNAT7 is the primary permeation pathway for glutamine across the lysosomal membrane and it is required for growth of cancer cells in a low free-glutamine environment, when macropinocytosis and lysosomal degradation of extracellular proteins are used as an alternative source of amino acids. SNAT7 may, thus, represent a novel target for glutamine-related anticancer therapies., Competing Interests: Conflict of interest statement: The authors have filed a European patent application on potential therapeutic uses of SNAT7-directed tools.
- Published
- 2017
- Full Text
- View/download PDF
34. Accounting for Protein Subcellular Localization: A Compartmental Map of the Rat Liver Proteome.
- Author
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Jadot M, Boonen M, Thirion J, Wang N, Xing J, Zhao C, Tannous A, Qian M, Zheng H, Everett JK, Moore DF, Sleat DE, and Lobel P
- Subjects
- Amino Acid Transport Systems, Basic genetics, Amino Acid Transport Systems, Basic metabolism, Amino Acid Transport Systems, Neutral genetics, Amino Acid Transport Systems, Neutral metabolism, Animals, Databases, Protein, Humans, Infant, Lysosomal Storage Diseases genetics, Lysosomes metabolism, Mass Spectrometry, Mutation, Neurodegenerative Diseases genetics, Rats, Sequence Analysis, DNA, Subcellular Fractions metabolism, Liver metabolism, Lysosomal Storage Diseases metabolism, Neurodegenerative Diseases metabolism, Proteome analysis, Proteomics methods
- Abstract
Accurate knowledge of the intracellular location of proteins is important for numerous areas of biomedical research including assessing fidelity of putative protein-protein interactions, modeling cellular processes at a system-wide level and investigating metabolic and disease pathways. Many proteins have not been localized, or have been incompletely localized, partly because most studies do not account for entire subcellular distribution. Thus, proteins are frequently assigned to one organelle whereas a significant fraction may reside elsewhere. As a step toward a comprehensive cellular map, we used subcellular fractionation with classic balance sheet analysis and isobaric labeling/quantitative mass spectrometry to assign locations to >6000 rat liver proteins. We provide quantitative data and error estimates describing the distribution of each protein among the eight major cellular compartments: nucleus, mitochondria, lysosomes, peroxisomes, endoplasmic reticulum, Golgi, plasma membrane and cytosol. Accounting for total intracellular distribution improves quality of organelle assignments and assigns proteins with multiple locations. Protein assignments and supporting data are available online through the Prolocate website (http://prolocate.cabm.rutgers.edu). As an example of the utility of this data set, we have used organelle assignments to help analyze whole exome sequencing data from an infant dying at 6 months of age from a suspected neurodegenerative lysosomal storage disorder of unknown etiology. Sequencing data was prioritized using lists of lysosomal proteins comprising well-established residents of this organelle as well as novel candidates identified in this study. The latter included copper transporter 1, encoded by SLC31A1, which we localized to both the plasma membrane and lysosome. The patient harbors two predicted loss of function mutations in SLC31A1, suggesting that this may represent a heretofore undescribed recessive lysosomal storage disease gene., (© 2017 by The American Society for Biochemistry and Molecular Biology, Inc.)
- Published
- 2017
- Full Text
- View/download PDF
35. Subcellular Trafficking of Mammalian Lysosomal Proteins: An Extended View.
- Author
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Staudt C, Puissant E, and Boonen M
- Subjects
- Animals, Humans, Hydrolases chemistry, Hydrolases metabolism, Mammals, Membrane Proteins chemistry, Protein Processing, Post-Translational, Protein Transport, Lysosomes metabolism, Membrane Proteins metabolism, Protein Sorting Signals
- Abstract
Lysosomes clear macromolecules, maintain nutrient and cholesterol homeostasis, participate in tissue repair, and in many other cellular functions. To assume these tasks, lysosomes rely on their large arsenal of acid hydrolases, transmembrane proteins and membrane-associated proteins. It is therefore imperative that, post-synthesis, these proteins are specifically recognized as lysosomal components and are correctly sorted to this organelle through the endosomes. Lysosomal transmembrane proteins contain consensus motifs in their cytosolic regions (tyrosine- or dileucine-based) that serve as sorting signals to the endosomes, whereas most lysosomal acid hydrolases acquire mannose 6-phosphate (Man-6-P) moieties that mediate binding to two membrane receptors with endosomal sorting motifs in their cytosolic tails. These tyrosine- and dileucine-based motifs are tickets for boarding in clathrin-coated carriers that transport their cargo from the trans-Golgi network and plasma membrane to the endosomes. However, increasing evidence points to additional mechanisms participating in the biogenesis of lysosomes. In some cell types, for example, there are alternatives to the Man-6-P receptors for the transport of some acid hydrolases. In addition, several "non-consensus" sorting motifs have been identified, and atypical transport routes to endolysosomes have been brought to light. These "unconventional" or "less known" transport mechanisms are the focus of this review., Competing Interests: The authors declare no conflict of interest.
- Published
- 2016
- Full Text
- View/download PDF
36. Monocytes/Macrophages Upregulate the Hyaluronidase HYAL1 and Adapt Its Subcellular Trafficking to Promote Extracellular Residency upon Differentiation into Osteoclasts.
- Author
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Puissant E and Boonen M
- Subjects
- Animals, Bone Marrow Cells cytology, Cathepsin K metabolism, Cell Differentiation, Cells, Cultured, Chondroitin Sulfates metabolism, Endosomes metabolism, Exocytosis, GPI-Linked Proteins genetics, GPI-Linked Proteins metabolism, Hyaluronic Acid metabolism, Hyaluronoglucosaminidase deficiency, Hyaluronoglucosaminidase genetics, Lectins, C-Type metabolism, Lysosomes metabolism, Macrophages cytology, Macrophages metabolism, Mannose Receptor, Mannose-Binding Lectins metabolism, Mice, Mice, Knockout, Monocytes cytology, Osteoclasts cytology, Osteoclasts metabolism, Osteogenesis, RANK Ligand metabolism, RAW 264.7 Cells, Receptors, Cell Surface metabolism, Tartrate-Resistant Acid Phosphatase metabolism, Up-Regulation, Hyaluronoglucosaminidase metabolism, Monocytes metabolism
- Abstract
Osteoclasts are giant bone-resorbing cells originating from monocytes/macrophages. During their differentiation, they overexpress two lysosomal enzymes, cathepsin K and TRAP, which are secreted into the resorption lacuna, an acidified sealed area in contact with bone matrix where bone degradation takes place. Here we report that the acid hydrolase HYAL1, a hyaluronidase able to degrade the glycosaminoglycans hyaluronic acid (HA) and chondroitin sulfate, is also upregulated upon osteoclastogenesis. The mRNA expression and protein level of HYAL1 are markedly increased in osteoclasts differentiated from RAW264.7 mouse macrophages or primary mouse bone marrow monocytes compared to these precursor cells. As a result, the HYAL1-mediated HA hydrolysis ability of osteoclasts is strongly enhanced. Using subcellular fractionation, we demonstrate that HYAL1 proteins are sorted to the osteoclast lysosomes even though, in contrast to cathepsin K and TRAP, HYAL1 is poorly mannose 6-phosphorylated. We reported previously that macrophages secrete HYAL1 proforms by constitutive secretion, and that these are recaptured by the cell surface mannose receptor, processed in endosomes and sorted to lysosomes. Present work highlights that osteoclasts secrete HYAL1 in two ways, through lysosomal exocytosis and constitutive secretion, and that these cells promote the extracellular residency of HYAL1 through downregulation of the mannose receptor. Interestingly, the expression of the other main hyaluronidase, HYAL2, and of lysosomal exoglycosidases involved in HA degradation, does not increase similarly to HYAL1 upon osteoclastogenesis. Taken together, these findings point out the predominant involvement of HYAL1 in bone HA metabolism and perhaps bone remodeling via the resorption lacuna., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2016
- Full Text
- View/download PDF
37. A conserved glycine residue in the C-terminal region of human ATG9A is required for its transport from the endoplasmic reticulum to the Golgi apparatus.
- Author
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Staudt C, Gilis F, Tevel V, Jadot M, and Boonen M
- Subjects
- Alanine chemistry, Amino Acid Motifs, Autophagy-Related Proteins genetics, Cell Membrane metabolism, Cysteine chemistry, Endoplasmic Reticulum metabolism, Gene Deletion, Golgi Apparatus metabolism, HeLa Cells, Humans, Membrane Proteins genetics, Microscopy, Fluorescence, Protein Domains, Protein Transport, Vesicular Transport Proteins genetics, Autophagy-Related Proteins metabolism, Glycine chemistry, Membrane Proteins metabolism, Vesicular Transport Proteins metabolism
- Abstract
ATG9A is the only polytopic protein of the mammalian autophagy-related protein family whose members regulate autophagosome formation during macroautophagy. At steady state, ATG9A localizes to several intracellular sites, including the Golgi apparatus, endosomes and the plasma membrane, and it redistributes towards autophagosomes upon autophagy induction. Interestingly, the transport of yeast Atg9 to the pre-autophagosomal structure depends on its self-association, which is mediated by a short amino acid motif located in the C-terminal region of the protein. Here, we investigated whether the residues that align with this motif in human ATG9A (V
515 -C519 ) are also required for its trafficking in mammalian cells. Interestingly, our findings support that human ATG9A self-interacts as well, and that this process promotes transport of ATG9A molecules through the Golgi apparatus. Furthermore, our data reveal that the transport of ATG9A out of the ER is severely impacted after mutation of the conserved V515 -C519 motif. Nevertheless, the mutated ATG9A molecules could still interact with each other, indicating that the molecular mechanism of self-interaction differs in mammalian cells compared to yeast. Using sequential amino acid substitutions of glycine 516 and cysteine 519, we found that the stability of ATG9A relies on both of these residues, but that only the former is required for efficient transport of human ATG9A from the endoplasmic reticulum to the Golgi apparatus., (Copyright © 2016 Elsevier Inc. All rights reserved.)- Published
- 2016
- Full Text
- View/download PDF
38. Molecular determinants that mediate the sorting of human ATG9A from the endoplasmic reticulum.
- Author
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Staudt C, Gilis F, Boonen M, and Jadot M
- Subjects
- Amino Acid Sequence, Autophagy-Related Proteins chemistry, Autophagy-Related Proteins genetics, Biosynthetic Pathways, Cell Compartmentation, Cell Membrane metabolism, Endosomes metabolism, Glycosylation, Golgi Apparatus metabolism, HeLa Cells, Humans, Membrane Proteins chemistry, Membrane Proteins genetics, Mutant Proteins metabolism, Mutation genetics, Polysaccharides metabolism, Proteasome Endopeptidase Complex metabolism, Protein Multimerization, Protein Stability, Protein Transport, Proteolysis, Vesicular Transport Proteins chemistry, Vesicular Transport Proteins genetics, Autophagy-Related Proteins metabolism, Endoplasmic Reticulum metabolism, Membrane Proteins metabolism, Vesicular Transport Proteins metabolism
- Abstract
ATG9A is a multispanning membrane protein required for autophagosome formation. Under basal conditions, neosynthesized ATG9A proteins travel to the Golgi apparatus and cycle between the trans-Golgi network and endosomes. In the present work, we searched for molecular determinants involved in the subcellular trafficking of human ATG9A in HeLa cells using sequential deletions and point mutations. Deletion of amino acids L(340) to L(354) resulted in the retention of ATG9A in the endoplasmic reticulum. In addition, we found that substitution of the L(711)YM(713) sequence (located in the C-terminal region of ATG9A) by alanine residues severely impaired its transport through the Golgi apparatus. This defect could be corrected by oligomerization of the mutant protein with co-transfected wild-type ATG9A, suggesting that ATG9A oligomerization may help its sorting through biosynthetic compartments. Lastly, the study of the consequences of the LYM/AAA mutation on the intracellular trafficking of ATG9A highlighted that some newly synthesized ATG9A can bypass the Golgi apparatus to reach the plasma membrane. Taken together, these findings provide new insights into the intracellular pathways followed by ATG9A to reach different subcellular compartments, and into the intramolecular determinants that drive the sorting of this protein., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2016
- Full Text
- View/download PDF
39. Cathepsin D and its newly identified transport receptor SEZ6L2 can modulate neurite outgrowth.
- Author
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Boonen M, Staudt C, Gilis F, Oorschot V, Klumperman J, and Jadot M
- Subjects
- Animals, Brain metabolism, Brain physiology, Carrier Proteins metabolism, Cell Line, Cell Line, Tumor, Endosomes metabolism, Endosomes physiology, HeLa Cells, Humans, Lysosomes metabolism, Lysosomes physiology, Male, Mice, Mice, Inbred C57BL, Neurites physiology, Neuroblastoma metabolism, Neuroblastoma physiopathology, Protein Transport physiology, Transferases (Other Substituted Phosphate Groups) metabolism, Uridine Diphosphate metabolism, Cathepsin D metabolism, Membrane Proteins metabolism, Neurites metabolism
- Abstract
How, in the absence of a functional mannose 6-phosphate (Man-6-P)-signal-dependent transport pathway, some acid hydrolases remain sorted to endolysosomes in the brain is poorly understood. We demonstrate that cathepsin D binds to mouse SEZ6L2, a type 1 transmembrane protein predominantly expressed in the brain. Studies of the subcellular trafficking of SEZ6L2, and its silencing in a mouse neuroblastoma cell line reveal that SEZ6L2 is involved in the trafficking of cathepsin D to endosomes. Moreover, SEZ6L2 can partially correct the cathepsin D hypersecretion resulting from the knockdown of UDP-GlcNAc:lysosomal enzyme GlcNAc-1-phosphotransferase in HeLa cells (i.e. in cells that are unable to synthesize Man-6-P signals). Interestingly, cleavage of SEZ6L2 by cathepsin D generates an N-terminal soluble fragment that induces neurite outgrowth, whereas its membrane counterpart prevents this. Taken together, our findings highlight that SEZ6L2 can serve as receptor to mediate the sorting of cathepsin D to endosomes, and suggest that proteolytic cleavage of SEZ6L2 by cathepsin D modulates neuronal differentiation., (© 2016. Published by The Company of Biologists Ltd.)
- Published
- 2016
- Full Text
- View/download PDF
40. The Na+/K+-ATPase and the amyloid-beta peptide aβ1-40 control the cellular distribution, abundance and activity of TRPC6 channels.
- Author
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Chauvet S, Boonen M, Chevallet M, Jarvis L, Abebe A, Benharouga M, Faller P, Jadot M, and Bouron A
- Subjects
- Amyloid beta-Peptides pharmacology, Animals, HEK293 Cells, Humans, Mice, Peptide Fragments pharmacology, Protein Transport drug effects, Protein Transport genetics, Sodium-Potassium-Exchanging ATPase genetics, TRPC Cation Channels genetics, TRPC6 Cation Channel, Amyloid beta-Peptides metabolism, Calcium Signaling, Peptide Fragments metabolism, Sodium-Potassium-Exchanging ATPase metabolism, TRPC Cation Channels metabolism
- Abstract
The Na(+)/K(+)-ATPase interacts with the non-selective cation channels TRPC6 but the functional consequences of this association are unknown. Experiments performed with HEK cells over-expressing TRPC6 channels showed that inhibiting the activity of the Na(+)/K(+)-ATPase with ouabain reduced the amount of TRPC6 proteins and depressed Ca(2+) entry through TRPC6. This effect, not mimicked by membrane depolarization with KCl, was abolished by sucrose and bafilomycin-A, and was partially sensitive to the intracellular Ca(2+) chelator BAPTA/AM. Biotinylation and subcellular fractionation experiments showed that ouabain caused a multifaceted redistribution of TRPC6 to the plasma membrane and to an endo/lysosomal compartment where they were degraded. The amyloid beta peptide Aβ(1-40), another inhibitor of the Na(+)/K(+)-ATPase, but not the shorter peptide Aβ1-16, reduced TRPC6 protein levels and depressed TRPC6-mediated responses. In cortical neurons from embryonic mice, ouabain, veratridine (an opener of voltage-gated Na(+) channel), and Aβ(1-40) reduced TRPC6-mediated Ca(2+) responses whereas Aβ(1-16) was ineffective. Furthermore, when Aβ(1-40) was co-added together with zinc acetate it could no longer control TRPC6 activity. Altogether, this work shows the existence of a functional coupling between the Na(+)/K(+)-ATPase and TRPC6. It also suggests that the abundance, distribution and activity of TRPC6 can be regulated by cardiotonic steroids like ouabain and the naturally occurring peptide Aβ(1-40) which underlines the pathophysiological significance of these processes., (Copyright © 2015 Elsevier B.V. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
41. Subcellular trafficking and activity of Hyal-1 and its processed forms in murine macrophages.
- Author
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Puissant E, Gilis F, Dogné S, Flamion B, Jadot M, and Boonen M
- Subjects
- Animals, Endocytosis physiology, Endosomes metabolism, Glycosylation, Hydrolases metabolism, Lectins, C-Type metabolism, Lysosomes metabolism, Mannose Receptor, Mannose-Binding Lectins metabolism, Mannosephosphates metabolism, Mice, Receptors, Cell Surface metabolism, Sucrose metabolism, Hyaluronoglucosaminidase metabolism, Macrophages metabolism, Protein Transport physiology
- Abstract
The hyaluronidase Hyal-1 is an acid hydrolase that degrades hyaluronic acid (HA), a component of the extracellular matrix. It is often designated as a lysosomal protein. Yet few data are available on its intracellular localization and trafficking. We demonstrate here that in RAW264.7 murine macrophages, Hyal-1 is synthesized as a glycosylated precursor that is only weakly mannose 6-phosphorylated. Nevertheless, this precursor traffics to endosomes, via a mannose 6-phosphate-independent secretion/recapture mechanism that involves the mannose receptor. Once in endosomes, it is processed into a lower molecular mass form that is transported to lysosomes, where its activity could be detected using native gel zymography. Indeed, this activity co-distributed with lysosomal hydrolases in the densest fraction of a self-forming Percoll(TM) density gradient. Moreover, it shifted toward the lower density region, in parallel with those hydrolases, when a decrease of lysosomal density was induced by the endocytosis of sucrose. Interestingly, the activity of the processed form of Hyal-1 was largely underestimated when assayed by zymography after SDS-PAGE and subsequent renaturation of the proteins, by contrast to the full-length protein that could efficiently degrade HA in those conditions. These results suggest that noncovalent associations support the lysosomal activity of Hyal-1., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)
- Published
- 2014
- Full Text
- View/download PDF
42. Mouse liver lysosomes contain enzymatically active processed forms of Hyal-1.
- Author
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Boonen M, Puissant E, Gilis F, Flamion B, and Jadot M
- Subjects
- Animals, Gene Knockdown Techniques, Hyaluronic Acid metabolism, Hyaluronoglucosaminidase genetics, Liver enzymology, Liver metabolism, Lysosomes metabolism, Mice, Mice, Inbred C57BL, Hyaluronoglucosaminidase analysis, Hyaluronoglucosaminidase metabolism, Lysosomes enzymology
- Abstract
It has long been known that liver lysosomes contain an endoglycosidase activity able to degrade the high molecular mass glycosaminoglycan hyaluronic acid (HA). The identification and cloning of a hyaluronidase with an acidic pH optimum, Hyal-1, suggested it might be responsible for this activity. However, we previously reported that this hydrolase could only be detected in pre-lysosomal compartments of the mouse liver using a zymography technique that allows the detection of Hyal-1 activity after SDS-PAGE ("renatured protein zymography"). Present work reveals that the activity highlighted by this technique belongs to a precursor form of Hyal-1 and that the lysosomal HA endoglycosidase activity of the mouse liver is accounted for by a proteolytically processed form of Hyal-1 that can only be detected using "native protein zymography". Indeed, the distribution of this form follows the distribution of β-galactosidase, a well-established lysosomal marker, after fractionation of the mouse liver in a linear sucrose density gradient. In addition, both activities shift toward the lower density region of the gradient when a specific decrease of the lysosomal density is induced by Triton WR-1339 injection. The fact that only native protein zymography but not renatured protein zymography is able to detect Hyal-1 activity in lysosomes points to a non-covalent association of Hyal-1 proteolytic fragments or the existence of closely linked partners supporting Hyal-1 enzymatic activity. The knockdown of Hyal-1 results in an 80% decrease of total acid hyaluronidase activity in the mouse liver, confirming that Hyal-1 is a key actor of HA catabolism in this organ., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
43. Disruption of the Man-6-P targeting pathway in mice impairs osteoclast secretory lysosome biogenesis.
- Author
-
van Meel E, Boonen M, Zhao H, Oorschot V, Ross FP, Kornfeld S, and Klumperman J
- Subjects
- Acid Phosphatase metabolism, Animals, Cathepsin D metabolism, Cathepsin K metabolism, Cell Differentiation physiology, Cells, Cultured, Endosomes metabolism, Endosomes ultrastructure, Isoenzymes metabolism, Lysosomes ultrastructure, Macrophages cytology, Macrophages physiology, Mice, Mice, Knockout, Microscopy, Immunoelectron, Signal Transduction physiology, Tartrate-Resistant Acid Phosphatase, Transferases (Other Substituted Phosphate Groups) genetics, Transferases (Other Substituted Phosphate Groups) metabolism, trans-Golgi Network metabolism, trans-Golgi Network ultrastructure, Lysosomes metabolism, Mannosephosphates metabolism, Osteoclasts metabolism, Osteoclasts ultrastructure
- Abstract
Osteoclasts are specialized cells that secrete lysosomal acid hydrolases at the site of bone resorption, a process critical for skeletal formation and remodeling. However, the cellular mechanism underlying this secretion and the organization of the endo-lysosomal system of osteoclasts have remained unclear. We report that osteoclasts differentiated in vitro from murine bone marrow macrophages contain two types of lysosomes. The major species is a secretory lysosome containing cathepsin K and tartrate-resistant acid phosphatase (TRAP), two hydrolases critical for bone resorption. These secretory lysosomes are shown to fuse with the plasma membrane, allowing the regulated release of acid hydrolases at the site of bone resorption. The other type of lysosome contains cathepsin D, but little cathepsin K or TRAP. Osteoclasts from Gnptab(-/-) (gene encoding GlcNAc-1-phosphotransferase α, β-subunits) mice, which lack a functional mannose 6-phosphate (Man-6-P) targeting pathway, show increased secretion of cathepsin K and TRAP and impaired secretory lysosome formation. However, cathepsin D targeting was intact, showing that osteoclasts have a Man-6-P-independent pathway for selected acid hydrolases., (© 2011 John Wiley & Sons A/S.)
- Published
- 2011
- Full Text
- View/download PDF
44. Vacuolization of mucolipidosis type II mouse exocrine gland cells represents accumulation of autolysosomes.
- Author
-
Boonen M, van Meel E, Oorschot V, Klumperman J, and Kornfeld S
- Subjects
- Acid Anhydride Hydrolases metabolism, Animals, Exocrine Glands enzymology, Fibroblasts enzymology, Fibroblasts pathology, Gene Deletion, Humans, Lysosomes enzymology, Mannosephosphates metabolism, Mice, Mice, Knockout, Microscopy, Immunoelectron, Mucolipidoses enzymology, Organ Specificity, Secretory Vesicles enzymology, Secretory Vesicles pathology, Transferases (Other Substituted Phosphate Groups) genetics, Vacuoles enzymology, Exocrine Glands pathology, Lysosomes pathology, Mucolipidoses pathology, Transferases (Other Substituted Phosphate Groups) deficiency, Vacuoles pathology
- Abstract
We previously reported that mice deficient in UDP-GlcNAc:lysosomal enzyme GlcNAc-1-phosphotransferase (mucolipidosis type II or Gnptab -/- mice), the enzyme that initiates the addition of the mannose 6-phosphate lysosomal sorting signal on acid hydrolases, exhibited extensive vacuolization of their exocrine gland cells, while the liver, brain, and muscle appeared grossly unaffected. Similar pathological findings were observed in several exocrine glands of patients with mucolipidosis II. To understand the basis for this cell type-specific abnormality, we analyzed these tissues in Gnptab -/- mice using a combined immunoelectron microscopy and biochemical approach. We demonstrate that the vacuoles in the exocrine glands are enlarged autolysosomes containing undigested cytoplasmic material that accumulate secondary to deficient lysosomal function. Surprisingly, the acid hydrolase levels in these tissues ranged from normal to modestly decreased, in contrast to skin fibroblasts, which accumulate enlarged lysosomes and/or autolysosomes also but exhibit very low levels of acid hydrolases. We propose that the lysosomal defect in the exocrine cells is caused by the combination of increased secretion of the acid hydrolases via the constitutive pathway along with their entrapment in secretory granules. Taken together, our results provide new insights into the mechanisms of the tissue-specific abnormalities seen in mucolipidosis type II.
- Published
- 2011
- Full Text
- View/download PDF
45. Glycan microarray analysis of P-type lectins reveals distinct phosphomannose glycan recognition.
- Author
-
Song X, Lasanajak Y, Olson LJ, Boonen M, Dahms NM, Kornfeld S, Cummings RD, and Smith DF
- Subjects
- Animals, Carbohydrate Conformation, Carbohydrate Sequence, Molecular Sequence Data, Oligosaccharides chemistry, Oligosaccharides metabolism, Phosphorylation, Lectins chemistry, Microarray Analysis, Polysaccharides analysis, Protein Isoforms metabolism, Receptor, IGF Type 2 metabolism
- Abstract
The specificity of the cation-independent and -dependent mannose 6-phosphate receptors (CI-MPR and CD-MPR) for high mannose-type N-glycans of defined structure containing zero, one, or two Man-P-GlcNAc phosphodiester or Man-6-P phosphomonoester residues was determined by analysis on a phosphorylated glycan microarray. Amine-activated glycans were covalently printed on N-hydroxysuccinimide-activated glass slides and interrogated with different concentrations of recombinant CD-MPR or soluble CI-MPR. Neither receptor bound to non-phosphorylated glycans. The CD-MPR bound weakly or undetectably to the phosphodiester derivatives, but strongly to the phosphomonoester-containing glycans with the exception of a single Man7GlcNAc2-R isomer that contained a single Man-6-P residue. By contrast, the CI-MPR bound with high affinity to glycans containing either phospho-mono- or -diesters although, like the CD-MPR, it differentially recognized isomers of phosphorylated Man7GlcNAc2-R. This differential recognition of phosphorylated glycans by the CI- and CD-MPRs has implications for understanding the biosynthesis and targeting of lysosomal hydrolases.
- Published
- 2009
- Full Text
- View/download PDF
46. Mice lacking mannose 6-phosphate uncovering enzyme activity have a milder phenotype than mice deficient for N-acetylglucosamine-1-phosphotransferase activity.
- Author
-
Boonen M, Vogel P, Platt KA, Dahms N, and Kornfeld S
- Subjects
- Animals, Brain enzymology, Cathepsin D metabolism, Endocytosis, Female, Fibroblasts enzymology, Fibroblasts metabolism, Glycosylation, Golgi Apparatus enzymology, Hydrolases analysis, Hydrolases blood, L Cells metabolism, Liver enzymology, Lysosomes enzymology, Male, Mannosephosphates metabolism, Mice, Mice, Inbred C57BL, Mice, Knockout, Mutagenesis, Insertional, Phenotype, Phosphoric Diester Hydrolases genetics, Phosphoric Diester Hydrolases physiology, Protein Processing, Post-Translational, Receptor, IGF Type 2 metabolism, Transferases (Other Substituted Phosphate Groups) deficiency, Phosphoric Diester Hydrolases deficiency
- Abstract
The mannose 6-phosphate (Man-6-P) lysosomal targeting signal on acid hydrolases is synthesized by the sequential action of uridine 5'-diphosphate-N-acetylglucosamine: lysosomal enzyme N-acetylglucosamine-1-phosphotransferase (GlcNAc-1-phosphotransferase) and GlcNAc-1-phosphodiester alpha-N-acetylglucosaminidase ("uncovering enzyme" or UCE). Mutations in the two genes that encode GlcNAc-1-phosphotransferase give rise to lysosomal storage diseases (mucolipidosis type II and III), whereas no pathological conditions have been associated with the loss of UCE activity. To analyze the consequences of UCE deficiency, the UCE gene was inactivated via insertional mutagenesis in mice. The UCE -/- mice were viable, grew normally and lacked detectable histologic abnormalities. However, the plasma levels of six acid hydrolases were elevated 1.6- to 5.4-fold over wild-type levels. These values underestimate the degree of hydrolase hypersecretion as these enzymes were rapidly cleared from the plasma by the mannose receptor. The secreted hydrolases contained GlcNAc-P-Man diesters, exhibited a decreased affinity for the cation-independent mannose 6-phosphate receptor and failed to bind to the cation-dependent mannose 6-phosphate receptor. These data demonstrate that UCE accounts for all the uncovering activity in the Golgi. We propose that in the absence of UCE, the weak binding of the acid hydrolases to the cation-independent mannose 6-phosphate receptor allows sufficient sorting to lysosomes to prevent the tissue abnormalities seen with GlcNAc-1-phosphotranferase deficiency.
- Published
- 2009
- Full Text
- View/download PDF
47. A dileucine signal situated in the C-terminal tail of the lysosomal membrane protein p40 is responsible for its targeting to lysosomes.
- Author
-
Boonen M, Rezende de Castro R, Cuvelier G, Hamer I, and Jadot M
- Subjects
- Amino Acid Motifs, Amino Acid Sequence, Cell Membrane metabolism, HeLa Cells, Humans, Leucine genetics, Lysosomal Membrane Proteins genetics, Microscopy, Confocal, Molecular Sequence Data, Protein Sorting Signals, Recombinant Fusion Proteins chemistry, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Transfection, Leucine chemistry, Lysosomal Membrane Proteins chemistry, Lysosomal Membrane Proteins metabolism, Lysosomes metabolism
- Abstract
Transport of newly synthesized lysosomal membrane proteins from the TGN (trans-Golgi network) to the lysosomes is due to the presence of specific signals in their cytoplasmic domains that are recognized by cytosolic adaptors. p40, a hypothetical transporter of 372 amino acids localized in the lysosomal membrane, contains four putative lysosomal sorting motifs in its sequence: three of the YXXphi-type (Y(6)QLF, Y(106)VAL, Y(333)NGL) and one of the [D/E]XXXL[L/I]-type (EQERL(360)L(361)). To test the role of these motifs in the biosynthetic transport of p40, we replaced the most critical residues of these consensus sequences, the tyrosine residue or the leucine-leucine pair, by alanine or alanine-valine respectively. We analysed the subcellular localization of the mutated p40 proteins in transfected HeLa cells by confocal microscopy and by biochemical approaches (subcellular fractionation on self-forming Percoll density gradients and cell surface biotinylation). The results of the present study show that p40 is mistargeted to the plasma membrane when its dileucine motif is disrupted. No role of the tyrosine motifs could be put forward. Taken together, our results provide evidence that the sorting of p40 from the TGN to the lysosomes is directed by the dileucine EQERL(360)L(361) motif situated in its C-terminal tail.
- Published
- 2008
- Full Text
- View/download PDF
48. Intracellular localization of p40, a protein identified in a preparation of lysosomal membranes.
- Author
-
Boonen M, Hamer I, Boussac M, Delsaute AF, Flamion B, Garin J, and Jadot M
- Subjects
- Amino Acid Sequence, Animals, COS Cells, Cells, Cultured, Chlorocebus aethiops, Cricetinae, HeLa Cells, Humans, Intracellular Membranes chemistry, Liver metabolism, Male, Mass Spectrometry, Mice, Molecular Sequence Data, Molecular Weight, Protein Transport, Rats, Rats, Wistar, Recombinant Fusion Proteins metabolism, Transfection, Intracellular Membranes metabolism, Lysosomes metabolism, Proteins chemistry, Proteins metabolism
- Abstract
Unlike lysosomal soluble proteins, few lysosomal membrane proteins have been identified. Rat liver lysosomes were purified by centrifugation on a Nycodenz density gradient. The most hydrophobic proteins were extracted from the lysosome membrane preparation and were identified by MS. We focused our attention on a protein of approx. 40 kDa, p40, which contains seven to ten putative transmembrane domains and four lysosomal consensus sorting motifs in its sequence. Knowing that preparations of lysosomes obtained by centrifugation always contain contaminant membranes, we combined biochemical and morphological methods to analyse the subcellular localization of p40. The results of subcellular fractionation of mouse liver homogenates validate the lysosomal residence of p40. In particular, a density shift of lysosomes induced by Triton WR-1339 similarly affected the distributions of p40 and beta-galactosidase, a lysosomal marker protein. We confirmed by fluorescence microscopy on eukaryotic cells transfected with p40 or p40-GFP (green fluorescent protein) constructs that p40 is localized in lysosomes. A first molecular characterization of p40 in transfected Cos-7 cells revealed that it is an unglycosylated protein tightly associated with membranes. Taken together, our results strongly support the hypothesis that p40 is an authentic lysosomal membrane protein.
- Published
- 2006
- Full Text
- View/download PDF
49. [Treatment of schizophrenia in the family].
- Author
-
Boonen M and Bockhorn M
- Subjects
- Adult, Communication, Emotions, Family psychology, Female, Humans, Male, Recurrence, Social Support, Family Therapy methods, Schizophrenia rehabilitation, Schizophrenic Psychology
- Abstract
The Bonn project "Treatment of schizophrenia in Family" is in the tradition of behavioristic and psychoeducative family intervention studies in England and USA. Information about psychosis and its neuroleptical treatment, communication and problem solving training are provided to schizophrenic patients and to their relatives at home. Important results and experiences of the 2-year-study are presented.
- Published
- 1992
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