Document Detail


Identification of P-Rex1 as a novel Rac1-guanine nucleotide exchange factor (GEF) that promotes actin remodelling and GLUT4 trafficking in adipocytes.
MedLine Citation:
PMID:  22002247     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Phosphoinositide 3-kinase (PI3K) signaling promotes the translocation of the glucose transporter, GLUT4, to the plasma membrane in insulin-sensitive tissues to facilitate glucose uptake. In adipocytes insulin-stimulated reorganization of the actin cytoskeleton has been proposed to play a role in promoting GLUT4 translocation and glucose uptake, in a PI3K dependent manner. However, the PI3K effectors that promote GLUT4 translocation via regulation of the actin cytoskeleton in adipocytes remains to be fully elucidated. Here we demonstrate that the PI3K-dependent Rac exchange factor, P-Rex1, enhances membrane ruffling in 3T3-L1 adipocytes, and promotes GLUT4 trafficking to the plasma membrane at submaximal insulin concentrations. P-Rex1-facilitated GLUT4 trafficking requires a functional actin network and membrane ruffle formation, and occurs in a PI3K and Rac1-dependent manner. In contrast expression of other Rho GTPases, such as Cdc42 or Rho did not affect insulin-stimulated P-Rex1 mediated GLUT4 trafficking. P-Rex1 siRNA knockdown or expression of a P-Rex1 dominant negative mutant reduced but did not completely inhibit glucose uptake in response to insulin. Collectively these studies identify a novel RacGEF in adipocytes as P-Rex1 that, at physiological insulin concentrations, functions as an insulin-dependent regulator of the actin cytoskeleton that contributes to GLUT4 trafficking to the plasma membrane.
Authors:
Demis Balamatsias; Anne M Kong; Joanne E Waters; Absorn Sriratana; Rajendra Gurung; Charles G Bailey; John E J Rasko; Tony Tiganis; S Lance Macaulay; Christina A Mitchell
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-10-15
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  -     ISSN:  1083-351X     ISO Abbreviation:  -     Publication Date:  2011 Oct 
Date Detail:
Created Date:  2011-10-17     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Monash University, Australia;
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