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Susceptibility of Glucokinase-MODY Mutants to Inactivation by Oxidative Stress in Pancreatic β-Cells
OBJECTIVE: The posttranslational regulation of glucokinase (GK) differs in hepatocytes and pancreatic β-cells. We tested the hypothesis that GK mutants that cause maturity-onset diabetes of the young (GK-MODY) show compromised activity and posttranslational regulation in β-cells. RESEARCH DESIGN AND...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Diabetes Association
2011
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3219952/ https://www.ncbi.nlm.nih.gov/pubmed/22028181 http://dx.doi.org/10.2337/db11-0423 |
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author | Cullen, Kirsty S. Matschinsky, Franz M. Agius, Loranne Arden, Catherine |
author_facet | Cullen, Kirsty S. Matschinsky, Franz M. Agius, Loranne Arden, Catherine |
author_sort | Cullen, Kirsty S. |
collection | PubMed |
description | OBJECTIVE: The posttranslational regulation of glucokinase (GK) differs in hepatocytes and pancreatic β-cells. We tested the hypothesis that GK mutants that cause maturity-onset diabetes of the young (GK-MODY) show compromised activity and posttranslational regulation in β-cells. RESEARCH DESIGN AND METHODS: Activity and protein expression of GK-MODY and persistent hyperinsulinemic hypoglycemia of infancy (PHHI) mutants were studied in β-cell (MIN6) and non–β-cell (H4IIE) models. Binding of GK to phosphofructo-2-kinase, fructose-2,6-bisphosphatase (PFK2/FBPase2) was studied by bimolecular fluorescence complementation in cell-based models. RESULTS: Nine of 11 GK-MODY mutants that have minimal effect on enzyme kinetics in vitro showed decreased specific activity relative to wild type when expressed in β-cells. A subset of these were stable in non–β-cells but showed increased inactivation in conditions of oxidative stress and partial reversal of inactivation by dithiothreitol. Unlike the GK-MODY mutants, four of five GK-PHHI mutants had similar specific activity to wild type and Y214C had higher activity than wild type. The GK-binding protein PFK2/FBPase2 protected wild-type GK from oxidative inactivation and the decreased stability of GK-MODY mutants correlated with decreased interaction with PFK2/FBPase2. CONCLUSIONS: Several GK-MODY mutants show posttranslational defects in β-cells characterized by increased susceptibility to oxidative stress and/or protein instability. Regulation of GK activity through modulation of thiol status may be a physiological regulatory mechanism for the control of GK activity in β-cells. |
format | Online Article Text |
id | pubmed-3219952 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2011 |
publisher | American Diabetes Association |
record_format | MEDLINE/PubMed |
spelling | pubmed-32199522012-12-01 Susceptibility of Glucokinase-MODY Mutants to Inactivation by Oxidative Stress in Pancreatic β-Cells Cullen, Kirsty S. Matschinsky, Franz M. Agius, Loranne Arden, Catherine Diabetes Islet Studies OBJECTIVE: The posttranslational regulation of glucokinase (GK) differs in hepatocytes and pancreatic β-cells. We tested the hypothesis that GK mutants that cause maturity-onset diabetes of the young (GK-MODY) show compromised activity and posttranslational regulation in β-cells. RESEARCH DESIGN AND METHODS: Activity and protein expression of GK-MODY and persistent hyperinsulinemic hypoglycemia of infancy (PHHI) mutants were studied in β-cell (MIN6) and non–β-cell (H4IIE) models. Binding of GK to phosphofructo-2-kinase, fructose-2,6-bisphosphatase (PFK2/FBPase2) was studied by bimolecular fluorescence complementation in cell-based models. RESULTS: Nine of 11 GK-MODY mutants that have minimal effect on enzyme kinetics in vitro showed decreased specific activity relative to wild type when expressed in β-cells. A subset of these were stable in non–β-cells but showed increased inactivation in conditions of oxidative stress and partial reversal of inactivation by dithiothreitol. Unlike the GK-MODY mutants, four of five GK-PHHI mutants had similar specific activity to wild type and Y214C had higher activity than wild type. The GK-binding protein PFK2/FBPase2 protected wild-type GK from oxidative inactivation and the decreased stability of GK-MODY mutants correlated with decreased interaction with PFK2/FBPase2. CONCLUSIONS: Several GK-MODY mutants show posttranslational defects in β-cells characterized by increased susceptibility to oxidative stress and/or protein instability. Regulation of GK activity through modulation of thiol status may be a physiological regulatory mechanism for the control of GK activity in β-cells. American Diabetes Association 2011-12 2011-11-13 /pmc/articles/PMC3219952/ /pubmed/22028181 http://dx.doi.org/10.2337/db11-0423 Text en © 2011 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details. |
spellingShingle | Islet Studies Cullen, Kirsty S. Matschinsky, Franz M. Agius, Loranne Arden, Catherine Susceptibility of Glucokinase-MODY Mutants to Inactivation by Oxidative Stress in Pancreatic β-Cells |
title | Susceptibility of Glucokinase-MODY Mutants to Inactivation by Oxidative Stress in Pancreatic β-Cells |
title_full | Susceptibility of Glucokinase-MODY Mutants to Inactivation by Oxidative Stress in Pancreatic β-Cells |
title_fullStr | Susceptibility of Glucokinase-MODY Mutants to Inactivation by Oxidative Stress in Pancreatic β-Cells |
title_full_unstemmed | Susceptibility of Glucokinase-MODY Mutants to Inactivation by Oxidative Stress in Pancreatic β-Cells |
title_short | Susceptibility of Glucokinase-MODY Mutants to Inactivation by Oxidative Stress in Pancreatic β-Cells |
title_sort | susceptibility of glucokinase-mody mutants to inactivation by oxidative stress in pancreatic β-cells |
topic | Islet Studies |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3219952/ https://www.ncbi.nlm.nih.gov/pubmed/22028181 http://dx.doi.org/10.2337/db11-0423 |
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