Cargando…
Dynamic Localization of Glucokinase and Its Regulatory Protein in Hypothalamic Tanycytes
Glucokinase (GK), the hexokinase involved in glucose sensing in pancreatic β cells, is also expressed in hypothalamic tanycytes, which cover the ventricular walls of the basal hypothalamus and are implicated in an indirect control of neuronal activity by glucose. Previously, we demonstrated that GK...
Autores principales: | , , , , , , , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2014
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3989220/ https://www.ncbi.nlm.nih.gov/pubmed/24739934 http://dx.doi.org/10.1371/journal.pone.0094035 |
_version_ | 1782312128006324224 |
---|---|
author | Salgado, Magdiel Tarifeño-Saldivia, Estefanía Ordenes, Patricio Millán, Carola Yañez, María José Llanos, Paula Villagra, Marcos Elizondo-Vega, Roberto Martínez, Fernando Nualart, Francisco Uribe, Elena de los Angeles García-Robles, María |
author_facet | Salgado, Magdiel Tarifeño-Saldivia, Estefanía Ordenes, Patricio Millán, Carola Yañez, María José Llanos, Paula Villagra, Marcos Elizondo-Vega, Roberto Martínez, Fernando Nualart, Francisco Uribe, Elena de los Angeles García-Robles, María |
author_sort | Salgado, Magdiel |
collection | PubMed |
description | Glucokinase (GK), the hexokinase involved in glucose sensing in pancreatic β cells, is also expressed in hypothalamic tanycytes, which cover the ventricular walls of the basal hypothalamus and are implicated in an indirect control of neuronal activity by glucose. Previously, we demonstrated that GK was preferentially localized in tanycyte nuclei in euglycemic rats, which has been reported in hepatocytes and is suggestive of the presence of the GK regulatory protein, GKRP. In the present study, GK intracellular localization in hypothalamic and hepatic tissues of the same rats under several glycemic conditions was compared using confocal microscopy and Western blot analysis. In the hypothalamus, increased GK nuclear localization was observed in hyperglycemic conditions; however, it was primarily localized in the cytoplasm in hepatic tissue under the same conditions. Both GK and GKRP were next cloned from primary cultures of tanycytes. Expression of GK by Escherichia coli revealed a functional cooperative protein with a S(0.5) of 10 mM. GKRP, expressed in Saccharomyces cerevisiae, inhibited GK activity in vitro with a K(i) 0.2 µM. We also demonstrated increased nuclear reactivity of both GK and GKRP in response to high glucose concentrations in tanycyte cultures. These data were confirmed using Western blot analysis of nuclear extracts. Results indicate that GK undergoes short-term regulation by nuclear compartmentalization. Thus, in tanycytes, GK can act as a molecular switch to arrest cellular responses to increased glucose. |
format | Online Article Text |
id | pubmed-3989220 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-39892202014-04-21 Dynamic Localization of Glucokinase and Its Regulatory Protein in Hypothalamic Tanycytes Salgado, Magdiel Tarifeño-Saldivia, Estefanía Ordenes, Patricio Millán, Carola Yañez, María José Llanos, Paula Villagra, Marcos Elizondo-Vega, Roberto Martínez, Fernando Nualart, Francisco Uribe, Elena de los Angeles García-Robles, María PLoS One Research Article Glucokinase (GK), the hexokinase involved in glucose sensing in pancreatic β cells, is also expressed in hypothalamic tanycytes, which cover the ventricular walls of the basal hypothalamus and are implicated in an indirect control of neuronal activity by glucose. Previously, we demonstrated that GK was preferentially localized in tanycyte nuclei in euglycemic rats, which has been reported in hepatocytes and is suggestive of the presence of the GK regulatory protein, GKRP. In the present study, GK intracellular localization in hypothalamic and hepatic tissues of the same rats under several glycemic conditions was compared using confocal microscopy and Western blot analysis. In the hypothalamus, increased GK nuclear localization was observed in hyperglycemic conditions; however, it was primarily localized in the cytoplasm in hepatic tissue under the same conditions. Both GK and GKRP were next cloned from primary cultures of tanycytes. Expression of GK by Escherichia coli revealed a functional cooperative protein with a S(0.5) of 10 mM. GKRP, expressed in Saccharomyces cerevisiae, inhibited GK activity in vitro with a K(i) 0.2 µM. We also demonstrated increased nuclear reactivity of both GK and GKRP in response to high glucose concentrations in tanycyte cultures. These data were confirmed using Western blot analysis of nuclear extracts. Results indicate that GK undergoes short-term regulation by nuclear compartmentalization. Thus, in tanycytes, GK can act as a molecular switch to arrest cellular responses to increased glucose. Public Library of Science 2014-04-16 /pmc/articles/PMC3989220/ /pubmed/24739934 http://dx.doi.org/10.1371/journal.pone.0094035 Text en © 2014 Salgado et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Salgado, Magdiel Tarifeño-Saldivia, Estefanía Ordenes, Patricio Millán, Carola Yañez, María José Llanos, Paula Villagra, Marcos Elizondo-Vega, Roberto Martínez, Fernando Nualart, Francisco Uribe, Elena de los Angeles García-Robles, María Dynamic Localization of Glucokinase and Its Regulatory Protein in Hypothalamic Tanycytes |
title | Dynamic Localization of Glucokinase and Its Regulatory Protein in Hypothalamic Tanycytes |
title_full | Dynamic Localization of Glucokinase and Its Regulatory Protein in Hypothalamic Tanycytes |
title_fullStr | Dynamic Localization of Glucokinase and Its Regulatory Protein in Hypothalamic Tanycytes |
title_full_unstemmed | Dynamic Localization of Glucokinase and Its Regulatory Protein in Hypothalamic Tanycytes |
title_short | Dynamic Localization of Glucokinase and Its Regulatory Protein in Hypothalamic Tanycytes |
title_sort | dynamic localization of glucokinase and its regulatory protein in hypothalamic tanycytes |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3989220/ https://www.ncbi.nlm.nih.gov/pubmed/24739934 http://dx.doi.org/10.1371/journal.pone.0094035 |
work_keys_str_mv | AT salgadomagdiel dynamiclocalizationofglucokinaseanditsregulatoryproteininhypothalamictanycytes AT tarifenosaldiviaestefania dynamiclocalizationofglucokinaseanditsregulatoryproteininhypothalamictanycytes AT ordenespatricio dynamiclocalizationofglucokinaseanditsregulatoryproteininhypothalamictanycytes AT millancarola dynamiclocalizationofglucokinaseanditsregulatoryproteininhypothalamictanycytes AT yanezmariajose dynamiclocalizationofglucokinaseanditsregulatoryproteininhypothalamictanycytes AT llanospaula dynamiclocalizationofglucokinaseanditsregulatoryproteininhypothalamictanycytes AT villagramarcos dynamiclocalizationofglucokinaseanditsregulatoryproteininhypothalamictanycytes AT elizondovegaroberto dynamiclocalizationofglucokinaseanditsregulatoryproteininhypothalamictanycytes AT martinezfernando dynamiclocalizationofglucokinaseanditsregulatoryproteininhypothalamictanycytes AT nualartfrancisco dynamiclocalizationofglucokinaseanditsregulatoryproteininhypothalamictanycytes AT uribeelena dynamiclocalizationofglucokinaseanditsregulatoryproteininhypothalamictanycytes AT delosangelesgarciaroblesmaria dynamiclocalizationofglucokinaseanditsregulatoryproteininhypothalamictanycytes |