Mice With AS160/TBC1D4-Thr649Ala Knockin Mutation Are Glucose Intolerant With Reduced Insulin Sensitivity and Altered GLUT4 Trafficking

Cell Metab. 2011 Jan 5;13(1):68-79. doi: 10.1016/j.cmet.2010.12.005.

Abstract

AS160 has emerged as a key player in insulin-mediated glucose transport through controlling GLUT4 trafficking, which is thought to be regulated by insulin-stimulated phosphorylation of sites including the 14-3-3 binding phospho-Thr649 (equivalent to Thr642 in human AS160). To define physiological roles of AS160-Thr649 phosphorylation and 14-3-3 binding in glucose homeostasis, we substituted this residue by a nonphosphorylatable alanine by knockin mutation in mice. The mutant protein was expressed at normal levels, while insulin-stimulated AS160 binding to 14-3-3s was abolished in homozygous knockin mice. These animals displayed impaired glucose disposal and insulin sensitivity, which were associated with decreased glucose uptake in vivo. Insulin-stimulated glucose transport and cell surface GLUT4 content were reduced in isolated muscles, but not in adipocytes. These results provide genetic evidence that insulin-induced AS160-Thr649 phosphorylation and/or its binding to 14-3-3 play an important role in regulating whole-body glucose homeostasis, at least in part through regulating GLUT4 trafficking in muscle.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 14-3-3 Proteins / metabolism
  • Adipocytes / metabolism
  • Animals
  • Biological Transport
  • Blood Glucose / metabolism
  • Cell Membrane / metabolism
  • Female
  • GTPase-Activating Proteins / genetics*
  • GTPase-Activating Proteins / metabolism
  • Gene Knock-In Techniques
  • Glucose / administration & dosage
  • Glucose / pharmacokinetics
  • Glucose Tolerance Test
  • Glucose Transporter Type 4 / metabolism*
  • In Vitro Techniques
  • Insulin / blood
  • Insulin / metabolism
  • Insulin / pharmacology*
  • Male
  • Mice
  • Mice, Transgenic
  • Muscle, Skeletal / metabolism
  • Mutation
  • Phosphorylation / drug effects
  • Protein Binding
  • Protein Transport

Substances

  • 14-3-3 Proteins
  • Blood Glucose
  • GTPase-Activating Proteins
  • Glucose Transporter Type 4
  • Insulin
  • Slc2a4 protein, mouse
  • Tbc1d4 protein, mouse
  • Glucose