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Regulation of p53 in NIH3T3 mouse fibroblasts following hyperosmotic stress

The aim of this project was to analyze the regulation of p53 expression in NIH3T3 fibroblasts under the influence of increasing hyperosmotic stress. Expression of p53 showed a biphasic response pattern in NIH3T3 cells under increasing osmotic stress (337 mOsm to 737 mOsm) with a maximum at 587 mOsm....

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Autores principales: Lambert, Ian Henry, Enghoff, Maria Stine, Brandi, Marie-Luise, Hoffmann, Else Kay
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley & Sons, Ltd 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4510620/
https://www.ncbi.nlm.nih.gov/pubmed/26056062
http://dx.doi.org/10.14814/phy2.12412
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author Lambert, Ian Henry
Enghoff, Maria Stine
Brandi, Marie-Luise
Hoffmann, Else Kay
author_facet Lambert, Ian Henry
Enghoff, Maria Stine
Brandi, Marie-Luise
Hoffmann, Else Kay
author_sort Lambert, Ian Henry
collection PubMed
description The aim of this project was to analyze the regulation of p53 expression in NIH3T3 fibroblasts under the influence of increasing hyperosmotic stress. Expression of p53 showed a biphasic response pattern in NIH3T3 cells under increasing osmotic stress (337 mOsm to 737 mOsm) with a maximum at 587 mOsm. Under isotonic conditions p53 expression increased after addition of the proteasome inhibitor MG132 indicating that cellular p53 levels in unperturbed cells is kept low by proteasomal degradation. However, under hypertonic conditions p53 synthesis as well as p53 degradation were significantly reduced and it is demonstrated that the increase in p53 expression observed when tonicity is increased from 337 to 587 mOsm reflects that degradation is more inhibited than synthesis, whereas the decrease in p53 expression at higher tonicities reflects that synthesis is more inhibited than degradation. The activity of the p53 regulating proteins p38 MAP kinase and the ubiquitin ligase MDM2 were studied as a function of increasing osmolarity. MDM2 protein expression was unchanged at all osmolarities, whereas MDM2 phosphorylation (Ser(166)) increased at osmolarities up to 537 mOsm and remained constant at higher osmolarities. Phosphorylation of p38 increased at osmolarities up to 687 mOsm which correlated with an increased phosphorylation of p53 (Ser(15)) and the decreased p53 degradation. Caspase-3 activity increased gradually with hypertonicity and at 737 mOsm both Caspase-3 activity and annexin V binding are high even though p53 expression and activity are low, indicating that initiation of apoptosis under severe hypertonic conditions is not strictly controlled by p53.
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spelling pubmed-45106202015-07-28 Regulation of p53 in NIH3T3 mouse fibroblasts following hyperosmotic stress Lambert, Ian Henry Enghoff, Maria Stine Brandi, Marie-Luise Hoffmann, Else Kay Physiol Rep Original Research The aim of this project was to analyze the regulation of p53 expression in NIH3T3 fibroblasts under the influence of increasing hyperosmotic stress. Expression of p53 showed a biphasic response pattern in NIH3T3 cells under increasing osmotic stress (337 mOsm to 737 mOsm) with a maximum at 587 mOsm. Under isotonic conditions p53 expression increased after addition of the proteasome inhibitor MG132 indicating that cellular p53 levels in unperturbed cells is kept low by proteasomal degradation. However, under hypertonic conditions p53 synthesis as well as p53 degradation were significantly reduced and it is demonstrated that the increase in p53 expression observed when tonicity is increased from 337 to 587 mOsm reflects that degradation is more inhibited than synthesis, whereas the decrease in p53 expression at higher tonicities reflects that synthesis is more inhibited than degradation. The activity of the p53 regulating proteins p38 MAP kinase and the ubiquitin ligase MDM2 were studied as a function of increasing osmolarity. MDM2 protein expression was unchanged at all osmolarities, whereas MDM2 phosphorylation (Ser(166)) increased at osmolarities up to 537 mOsm and remained constant at higher osmolarities. Phosphorylation of p38 increased at osmolarities up to 687 mOsm which correlated with an increased phosphorylation of p53 (Ser(15)) and the decreased p53 degradation. Caspase-3 activity increased gradually with hypertonicity and at 737 mOsm both Caspase-3 activity and annexin V binding are high even though p53 expression and activity are low, indicating that initiation of apoptosis under severe hypertonic conditions is not strictly controlled by p53. John Wiley & Sons, Ltd 2015-06-08 /pmc/articles/PMC4510620/ /pubmed/26056062 http://dx.doi.org/10.14814/phy2.12412 Text en © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society. http://creativecommons.org/licenses/by/4.0/ This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Research
Lambert, Ian Henry
Enghoff, Maria Stine
Brandi, Marie-Luise
Hoffmann, Else Kay
Regulation of p53 in NIH3T3 mouse fibroblasts following hyperosmotic stress
title Regulation of p53 in NIH3T3 mouse fibroblasts following hyperosmotic stress
title_full Regulation of p53 in NIH3T3 mouse fibroblasts following hyperosmotic stress
title_fullStr Regulation of p53 in NIH3T3 mouse fibroblasts following hyperosmotic stress
title_full_unstemmed Regulation of p53 in NIH3T3 mouse fibroblasts following hyperosmotic stress
title_short Regulation of p53 in NIH3T3 mouse fibroblasts following hyperosmotic stress
title_sort regulation of p53 in nih3t3 mouse fibroblasts following hyperosmotic stress
topic Original Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4510620/
https://www.ncbi.nlm.nih.gov/pubmed/26056062
http://dx.doi.org/10.14814/phy2.12412
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