Functional characterization of MODY2 mutations highlights the importance of the fine-tuning of glucokinase and its role in glucose sensing.

Glucokinase (GK) acts as a glucose sensor in the pancreatic beta-cell and regulates insulin secretion. Heterozygous mutations in the human GK-encoding GCK gene that reduce the activity index increase the glucose-stimulated insulin secretion threshold and cause familial, mild fasting hyperglycaemia,...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Carmen-María García-Herrero, Oscar Rubio-Cabezas, Sharona Azriel, Angel Gutierrez-Nogués, Angel Aragonés, Olivier Vincent, Angel Campos-Barros, Jesús Argente, María-Angeles Navas
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2012
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/922a1fa58b42429c864ff12388c797d1
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:922a1fa58b42429c864ff12388c797d1
record_format	dspace
spelling	oai:doaj.org-article:922a1fa58b42429c864ff12388c797d12021-11-18T07:29:28ZFunctional characterization of MODY2 mutations highlights the importance of the fine-tuning of glucokinase and its role in glucose sensing.1932-620310.1371/journal.pone.0030518https://doaj.org/article/922a1fa58b42429c864ff12388c797d12012-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22291974/?tool=EBIhttps://doaj.org/toc/1932-6203Glucokinase (GK) acts as a glucose sensor in the pancreatic beta-cell and regulates insulin secretion. Heterozygous mutations in the human GK-encoding GCK gene that reduce the activity index increase the glucose-stimulated insulin secretion threshold and cause familial, mild fasting hyperglycaemia, also known as Maturity Onset Diabetes of the Young type 2 (MODY2). Here we describe the biochemical characterization of five missense GK mutations: p.Ile130Thr, p.Asp205His, p.Gly223Ser, p.His416Arg and p.Ala449Thr. The enzymatic analysis of the corresponding bacterially expressed GST-GK mutant proteins show that all of them impair the kinetic characteristics of the enzyme. In keeping with their position within the protein, mutations p.Ile130Thr, p.Asp205His, p.Gly223Ser, and p.His416Arg strongly decrease the activity index of GK, affecting to one or more kinetic parameters. In contrast, the p.Ala449Thr mutation, which is located in the allosteric activator site, does not affect significantly the activity index of GK, but dramatically modifies the main kinetic parameters responsible for the function of this enzyme as a glucose sensor. The reduced Kcat of the mutant (3.21±0.28 s(-1) vs 47.86±2.78 s(-1)) is balanced by an increased glucose affinity (S(0.5) = 1.33±0.08 mM vs 7.86±0.09 mM) and loss of cooperativity for this substrate. We further studied the mechanism by which this mutation impaired GK kinetics by measuring the differential effects of several competitive inhibitors and one allosteric activator on the mutant protein. Our results suggest that this mutation alters the equilibrium between the conformational states of glucokinase and highlights the importance of the fine-tuning of GK and its role in glucose sensing.Carmen-María García-HerreroOscar Rubio-CabezasSharona AzrielAngel Gutierrez-NoguésAngel AragonésOlivier VincentAngel Campos-BarrosJesús ArgenteMaría-Angeles NavasPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 7, Iss 1, p e30518 (2012)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Carmen-María García-Herrero Oscar Rubio-Cabezas Sharona Azriel Angel Gutierrez-Nogués Angel Aragonés Olivier Vincent Angel Campos-Barros Jesús Argente María-Angeles Navas Functional characterization of MODY2 mutations highlights the importance of the fine-tuning of glucokinase and its role in glucose sensing.
description	Glucokinase (GK) acts as a glucose sensor in the pancreatic beta-cell and regulates insulin secretion. Heterozygous mutations in the human GK-encoding GCK gene that reduce the activity index increase the glucose-stimulated insulin secretion threshold and cause familial, mild fasting hyperglycaemia, also known as Maturity Onset Diabetes of the Young type 2 (MODY2). Here we describe the biochemical characterization of five missense GK mutations: p.Ile130Thr, p.Asp205His, p.Gly223Ser, p.His416Arg and p.Ala449Thr. The enzymatic analysis of the corresponding bacterially expressed GST-GK mutant proteins show that all of them impair the kinetic characteristics of the enzyme. In keeping with their position within the protein, mutations p.Ile130Thr, p.Asp205His, p.Gly223Ser, and p.His416Arg strongly decrease the activity index of GK, affecting to one or more kinetic parameters. In contrast, the p.Ala449Thr mutation, which is located in the allosteric activator site, does not affect significantly the activity index of GK, but dramatically modifies the main kinetic parameters responsible for the function of this enzyme as a glucose sensor. The reduced Kcat of the mutant (3.21±0.28 s(-1) vs 47.86±2.78 s(-1)) is balanced by an increased glucose affinity (S(0.5) = 1.33±0.08 mM vs 7.86±0.09 mM) and loss of cooperativity for this substrate. We further studied the mechanism by which this mutation impaired GK kinetics by measuring the differential effects of several competitive inhibitors and one allosteric activator on the mutant protein. Our results suggest that this mutation alters the equilibrium between the conformational states of glucokinase and highlights the importance of the fine-tuning of GK and its role in glucose sensing.
format	article
author	Carmen-María García-Herrero Oscar Rubio-Cabezas Sharona Azriel Angel Gutierrez-Nogués Angel Aragonés Olivier Vincent Angel Campos-Barros Jesús Argente María-Angeles Navas
author_facet	Carmen-María García-Herrero Oscar Rubio-Cabezas Sharona Azriel Angel Gutierrez-Nogués Angel Aragonés Olivier Vincent Angel Campos-Barros Jesús Argente María-Angeles Navas
author_sort	Carmen-María García-Herrero
title	Functional characterization of MODY2 mutations highlights the importance of the fine-tuning of glucokinase and its role in glucose sensing.
title_short	Functional characterization of MODY2 mutations highlights the importance of the fine-tuning of glucokinase and its role in glucose sensing.
title_full	Functional characterization of MODY2 mutations highlights the importance of the fine-tuning of glucokinase and its role in glucose sensing.
title_fullStr	Functional characterization of MODY2 mutations highlights the importance of the fine-tuning of glucokinase and its role in glucose sensing.
title_full_unstemmed	Functional characterization of MODY2 mutations highlights the importance of the fine-tuning of glucokinase and its role in glucose sensing.
title_sort	functional characterization of mody2 mutations highlights the importance of the fine-tuning of glucokinase and its role in glucose sensing.
publisher	Public Library of Science (PLoS)
publishDate	2012
url	https://doaj.org/article/922a1fa58b42429c864ff12388c797d1
work_keys_str_mv	AT carmenmariagarciaherrero functionalcharacterizationofmody2mutationshighlightstheimportanceofthefinetuningofglucokinaseanditsroleinglucosesensing AT oscarrubiocabezas functionalcharacterizationofmody2mutationshighlightstheimportanceofthefinetuningofglucokinaseanditsroleinglucosesensing AT sharonaazriel functionalcharacterizationofmody2mutationshighlightstheimportanceofthefinetuningofglucokinaseanditsroleinglucosesensing AT angelgutierreznogues functionalcharacterizationofmody2mutationshighlightstheimportanceofthefinetuningofglucokinaseanditsroleinglucosesensing AT angelaragones functionalcharacterizationofmody2mutationshighlightstheimportanceofthefinetuningofglucokinaseanditsroleinglucosesensing AT oliviervincent functionalcharacterizationofmody2mutationshighlightstheimportanceofthefinetuningofglucokinaseanditsroleinglucosesensing AT angelcamposbarros functionalcharacterizationofmody2mutationshighlightstheimportanceofthefinetuningofglucokinaseanditsroleinglucosesensing AT jesusargente functionalcharacterizationofmody2mutationshighlightstheimportanceofthefinetuningofglucokinaseanditsroleinglucosesensing AT mariaangelesnavas functionalcharacterizationofmody2mutationshighlightstheimportanceofthefinetuningofglucokinaseanditsroleinglucosesensing
_version_	1718423359978471424

Functional characterization of MODY2 mutations highlights the importance of the fine-tuning of glucokinase and its role in glucose sensing.

Ejemplares similares