Biogenesis of insulin-responsive GLUT4 vesicles is independent of brefeldin a-sensitive trafficking

Martin, S, Ramm, G, Lyttle, CT, Stoorvogel, W and James, DE (2000) Biogenesis of insulin-responsive GLUT4 vesicles is independent of brefeldin a-sensitive trafficking. Traffic, 1 8: 652-660. doi:10.1034/j.1600-0854.2000.010809.x


Author Martin, S
Ramm, G
Lyttle, CT
Stoorvogel, W
James, DE
Title Biogenesis of insulin-responsive GLUT4 vesicles is independent of brefeldin a-sensitive trafficking
Journal name Traffic   Check publisher's open access policy
ISSN 1398-9219
Publication date 2000
Sub-type Article (original research)
DOI 10.1034/j.1600-0854.2000.010809.x
Volume 1
Issue 8
Start page 652
End page 660
Total pages 9
Place of publication Edinburgh
Publisher Munksgaard International Publishers/Blackwell Science Ltd.
Collection year 2000
Language eng
Subject C1
780105 Biological sciences
270103 Protein Targeting and Signal Transduction
Abstract Insulin stimulates translocation of GLUT4 from an intracellular compartment to the plasma membrane in adipocytes. As a significant amount of GLUT4 is localised to the TGN, independently of the biosynthetic pathway, one possibility is that trafficking via the TGN is important in either intracellular sequestration or insulin-dependent movement to the cell surface. In this study we have used immune-electron microscopy to show that GLUT4 is localised to AP-1 vesicles in the TGN region in 3T3-L1 adipocytes. To dissect the role of this trafficking pathway we used brefeldin A (BFA) to disrupt AP-1 association with membranes. Despite a reorganisation of GLUT4 compartments following BFA treatment, the intracellular sequestration of GLUT4, and its insulin-dependent movement to the cell surface, was unaffected. BFA increased the half time of reversal of insulin-stimulated glucose transport from 17 to 30 min but did not prevent complete reversal. Furthermore, following reversal restimulation of glucose transport activity by insulin was not compromised. We conclude that under basal conditions GLUT4 cycles between the TGN and endosomes via the AP-1 pathway. However, neither this pathway, nor any other BFA-sensitive pathway, appears to play a major role in insulin-dependent recruitment of GLUT4 to the cell surface.
Keyword Cell Biology
Ap-1
Bfa
Glut4
Insulin
Mpr
Tgn
Glucose-transporter Glut4
Trans-golgi Network
Mannose 6-phosphate Receptors
Rat Adipose-cells
High-affinity Interaction
3t3-l1 Adipocytes
Subcellular Trafficking
Secretory Granules
Assembly Proteins
Coated Vesicles
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Chemistry and Molecular Biosciences
 
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Created: Tue, 10 Jun 2008, 12:25:31 EST