Insulin stimulation of GLUT4 exocytosis, but not its inhibition of endocytosis, is dependent on RabGAP AS160. Academic Article uri icon

Overview

abstract

  • Insulin maintains whole body blood glucose homeostasis, in part, by regulating the amount of the GLUT4 glucose transporter on the cell surface of fat and muscle cells. Insulin induces the redistribution of GLUT4 from intracellular compartments to the plasma membrane, by stimulating a large increase in exocytosis and a smaller inhibition of endocytosis. A considerable amount is known about the molecular events of insulin signaling and the complex itinerary of GLUT4 trafficking, but less is known about how insulin signaling is transmitted to GLUT4 trafficking. Here, we show that the AS160 RabGAP, a substrate of Akt, is required for insulin stimulation of GLUT4 exocytosis. A dominant-inhibitory mutant of AS160 blocks insulin stimulation of exocytosis at a step before the fusion of GLUT4-containing vesicles with the plasma membrane. This mutant, however, does not block insulin-induced inhibition of GLUT4 endocytosis. These data support a model in which insulin signaling to the exocytosis machinery (AS160 dependent) is distinct from its signaling to the internalization machinery (AS160 independent).

publication date

  • July 14, 2004

Research

keywords

  • Endocytosis
  • Exocytosis
  • GTPase-Activating Proteins
  • Insulin
  • Monosaccharide Transport Proteins
  • Muscle Proteins
  • rab GTP-Binding Proteins

Identity

PubMed Central ID

  • PMC519136

Scopus Document Identifier

  • 4644300287

Digital Object Identifier (DOI)

  • 10.1091/mbc.e04-04-0333

PubMed ID

  • 15254270

Additional Document Info

volume

  • 15

issue

  • 10