Role of insulin-dependent cortical fodrin/spectrin remodeling in glucose transporter 4 translocation in rat adipocytes

Mol Biol Cell. 2006 Oct;17(10):4249-56. doi: 10.1091/mbc.e06-04-0278. Epub 2006 Jul 26.

Abstract

Fodrin or nonerythroid spectrin is an abundant component of the cortical cytoskeletal network in rat adipocytes. Fodrin has a highly punctate distribution in resting cells, and insulin causes a dramatic remodeling of fodrin to a more diffuse pattern. Insulin-mediated remodeling of actin occurs to a lesser extent than does that of fodrin. We show that fodrin interacts with the t-soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) syntaxin 4, and this interaction is increased by insulin stimulation and decreased by prior latrunculin A treatment. Latrunculin A disrupts all actin filaments, inhibits glucose transporter 4 (GLUT4) translocation, and causes fodrin to partially redistribute from the plasma membrane to the cytosol. In contrast, cytochalasin D disrupts only the short actin filament signal, and cytochalasin D neither inhibits GLUT4 translocation nor fodrin redistribution in adipocytes. Together, our data suggest that insulin induces remodeling of the fodrin-actin network, which is required for the fusion of GLUT4 storage vesicles with the plasma membrane by permitting their access to the t-SNARE syntaxin 4.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Actins / metabolism
  • Adipocytes / drug effects
  • Adipocytes / metabolism*
  • Animals
  • Bridged Bicyclo Compounds, Heterocyclic / pharmacology
  • Carrier Proteins / metabolism*
  • Cytochalasin D / pharmacology
  • Glucose Transporter Type 4 / metabolism*
  • Insulin / pharmacology*
  • Microfilament Proteins / metabolism*
  • Models, Biological
  • Protein Transport
  • Qa-SNARE Proteins / metabolism
  • Rats
  • Spectrin / physiology*
  • Thiazolidines / pharmacology

Substances

  • Actins
  • Bridged Bicyclo Compounds, Heterocyclic
  • Carrier Proteins
  • Glucose Transporter Type 4
  • Insulin
  • Microfilament Proteins
  • Qa-SNARE Proteins
  • Thiazolidines
  • fodrin
  • Spectrin
  • Cytochalasin D
  • latrunculin A