GLUT4 is retained by an intracellular cycle of vesicle formation and fusion with endosomes. Academic Article uri icon

Overview

abstract

  • The intracellularly stored GLUT4 glucose transporter is rapidly translocated to the cell surface upon insulin stimulation. Regulation of GLUT4 distribution is key for the maintenance of whole body glucose homeostasis. We find that GLUT4 is excluded from the plasma membrane of adipocytes by a dynamic retention/retrieval mechanism. Our kinetic studies indicate that GLUT4-containing vesicles continually bud and fuse with endosomes in the absence of insulin and that these GLUT4 vesicles are 5 times as likely to fuse with an endosome as with the plasma membrane. We hypothesize that this intracellular cycle of vesicle budding and fusion is an element of the active mechanism by which GLUT4 is retained. The GLUT4 trafficking pathway does not extensively overlap with that of furin, indicating that the trans-Golgi network, a compartment in which furin accumulates, is not a significant storage reservoir of GLUT4. An intact microtubule cytoskeleton is required for insulin-stimulated recruitment to the cell surface, although it is not required for the basal budding/fusion cycle. Nocodazole disruption of the microtubule cytoskeleton reduces the insulin-stimulated exocytosis of GLUT4, accounting for the reduced insulin-stimulated translocation of GLUT4 to the cell surface.

publication date

  • October 31, 2003

Research

keywords

  • Adipocytes
  • Cell Membrane
  • Cytoskeleton
  • Endosomes
  • Monosaccharide Transport Proteins
  • Muscle Proteins

Identity

PubMed Central ID

  • PMC329400

Scopus Document Identifier

  • 0742288016

Digital Object Identifier (DOI)

  • 10.1091/mbc.e03-07-0517

PubMed ID

  • 14595108

Additional Document Info

volume

  • 15

issue

  • 2