Caveolin-associated filamentous actin (Cav-actin) defines a novel F-actin structure in adipocytes

Makoto Kanzaki, Jeffrey E. Pessin

Research output: Contribution to journalArticle

84 Scopus citations

Abstract

Dynamic actin remodeling has been implicated in the translocation of the insulin-responsive glucose transporter 4 (GLUT4) to the plasma membrane in adipocytes. Here we show that fully differentiated 3T3L1 adipocytes have unique cortical filamentous actin structure, designated Cav-actin (caveolae-associated F-actin). During 3T3L1 adipocyte differentiation, rhodamine-phalloidin staining demonstrated the formation of a cortical actin cytoskeleton that is composed of small dot-like F-actin spikes lining the inside of the plasma membrane. Double labeling with a caveolin antibody indicated that these F-actin spikes emanate from organized rosette-like clusters of caveolae/lipid raft microdomains. In contrast, there was no obvious relationship between F-actin and caveolin localization and/or organization in 3T3L1 preadipocytes (fibroblasts). Treatments of differentiated adipocytes with latrunculin B, Clostridium difficile toxin B or a dominant-interfering TC10 mutant (TC10/T31N) disrupted the Cav-actin structure without significantly affecting the organization of clustered caveolae. Similarly, disruption of the clustered caveolae with methyl-β-cyclodextrin also dispersed the Cav-actin structure. These data demonstrate that this novel Cav-actin structure is organized through clustered caveolae but that the formation of caveolae-rosettes are not dependent upon F-actin.

Original languageEnglish (US)
Pages (from-to)25867-25869
Number of pages3
JournalJournal of Biological Chemistry
Volume277
Issue number29
DOIs
StatePublished - Jul 19 2002
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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