| Rab8A and Rab13 are activated by insulin and regulate GLUT4 translocation in muscle cells. | |
| | |
MedLine Citation:
|
PMID: 21041651 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Skeletal muscle is the primary site of dietary glucose disposal, a function that depends on insulin-mediated exocytosis of GLUT4 vesicles to its cell surface. In skeletal muscle and adipocytes, this response involves Akt signaling to the Rab-GAP (GTPase-activating protein) AS160/TBC1D4. Intriguingly, the AS160-targeted Rabs appear to differ, with Rab8A participating in GLUT4 exocytosis in muscle cells and Rab10 in adipocytes, and their activation by insulin is unknown. Rabs 8A, 10, and 13 belong to the same subfamily of Rab-GTPases. Here we show that insulin promotes GTP loading of Rab13 and Rab8A but not Rab10 in rat L6 muscle cells, Rab8A activation preceding that of Rab13. siRNA-mediated Rab13 knockdown blocked the insulin-induced increase of GLUT4 at the muscle cell surface that was rescued by a Rab13 ortholog but not by Rab8A. Constitutively active AS160 lowered basal and insulin-stimulated levels of surface GLUT4, effects that were reversed by overexpressing Rab8A or Rab13, suggesting that both Rabs are targets of AS160-GAP activity in the context of GLUT4 traffic. Rab13 had a broader intracellular distribution compared with the perinuclear restriction of Rab8A, and insulin promoted Rab13 colocalization with GLUT4 at the cell periphery. We conclude that Rab13 and Rab8A are Rab-GTPases activated by insulin, and that downstream of AS160 they regulate traffic of GLUT4 vesicles, possibly acting at distinct steps and sites. These findings close in on the series of events regulating muscle GLUT4 traffic in response to insulin, crucial for whole-body glucose homeostasis. |
| | |
Authors:
|
Yi Sun; Philip J Bilan; Zhi Liu; Amira Klip |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-11-01 |
Journal Detail:
|
Title: Proceedings of the National Academy of Sciences of the United States of America Volume: 107 ISSN: 1091-6490 ISO Abbreviation: Proc. Natl. Acad. Sci. U.S.A. Publication Date: 2010 Nov |
Date Detail:
|
Created Date: 2010-11-18 Completed Date: 2010-12-21 Revised Date: 2011-11-04 |
Medline Journal Info:
|
Nlm Unique ID: 7505876 Medline TA: Proc Natl Acad Sci U S A Country: United States |
Other Details:
|
Languages: eng Pagination: 19909-14 Citation Subset: IM |
Affiliation:
|
Program in Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada M5G 1X8. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Adipose Tissue
/
drug effects,
enzymology Animals Cell Line Cell Membrane / drug effects, metabolism Cell Nucleus / drug effects, metabolism Enzyme Activation / drug effects GTP Phosphohydrolases / genetics, metabolism* GTPase-Activating Proteins / metabolism Gene Expression Regulation / drug effects Gene Knockdown Techniques Glucose Transporter Type 4 / metabolism* Humans Insulin / pharmacology* Mice Muscle Cells / drug effects, metabolism* Protein Transport / drug effects Rats rab GTP-Binding Proteins / genetics, metabolism* |
| Grant Support | |
ID/Acronym/Agency:
|
MT 7307//Canadian Institutes of Health Research |
| Chemical | |
Reg. No./Substance:
|
0/GTPase-Activating Proteins; 0/Glucose Transporter Type 4; 0/LOC686547 protein, rat; 0/Rab8 protein, mouse; 11061-68-0/Insulin; EC 3.6.1.-/GTP Phosphohydrolases; EC 3.6.1.-/Rab13 protein, mouse; EC 3.6.1.-/Rab13 protein, rat; EC 3.6.1.-/Rab8 protein, rat; EC 3.6.1.-/rab GTP-Binding Proteins |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Uncoupling the Warburg effect from cancer.
Next Document: Nonstimulated early visual areas carry information about surrounding context.