Year: 2004
Type: article
Abstract: Identifying which processes and proteins control glucose transport could provide important clues to understanding and treating a number of clinical entities including diabetes and some cancers.Glucose transport across the plasma membrane occurs by either sodium-dependent or independent glucose transporters.In order to study the mechanisms which control acute changes in glucose transport by sodium-independent glucose transporters, we use the non-transformed rat liver -derived Clone 9 cell line.These cells respond to the acute inhibition of oxidative phosphorylation by azide with a 4-6 fold stimulation of glucose transport and a 1.8 fold increase in the amount of glucose transporter 1 (Glut1) in the plasma membrane.In Clone 9 cells under basal conditions, ~38 % of Glut1 in the post-nuclear lysate is localized to the detergent-resistant membrane (DRM) microdomains.Acute exposure to azide decreased this figure by ~40 %.In order to examine the effects of azide on Glut1 localization to the plasma membrane of the Clone 9 cell, we performed subcellular fractionation of the post-nuclear homogenates.Approximately 30 % of the Glut1 in the post-nuclear homogenate was recovered in the plasma membrane (PM) compartment and 50 % of this PM Glut1 localized to the DRM fraction.Acute inhibition of oxidative phosphorylation with azide xii resulted in a 1.6-fold increase in the total abundance of Glut1 in the PM and was associated with a 2.9 fold increase in the abundance of Glut1 in the non-DRM fraction but no significant change in the content of Glut1 in the DRM fraction.We conclude that in the Clone 9 cell Glut1 localizes to detergent-resistant membrane microdomains in the plasma membrane.Moreover, in these cells the azide -induced increase in glucose transport is associated with an increase of Glut1 abundance in the non -DRM fraction of the plasma membrane and a decrease of Glut1 association with the DRM fraction of a membrane compartment other than the plasma membrane.These findings indicate that the distribution of Glut1 to the DRM and non-DRM domains of the cellular membrane compartments contribute, in part, to the mechanisms of glucose transport regulation in response to the acute inhibition of oxidative phosphorylation.
Author: Darrell Rubin
Institution: Case Western Reserve University
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
Funder: National Institutes of Health
OpenAlex ID: W2515666387