The Axin/TNKS complex interacts with KIF3A and is required for insulin-stimulated GLUT4 translocation

Cell Res. 2012 Aug;22(8):1246-57. doi: 10.1038/cr.2012.52. Epub 2012 Apr 3.

Abstract

Insulin-stimulated glucose uptake by the glucose transporter GLUT4 plays a central role in whole-body glucose homeostasis, dysregulation of which leads to type 2 diabetes. However, the molecular components and mechanisms regulating insulin-stimulated glucose uptake remain largely unclear. Here, we demonstrate that Axin interacts with the ADP-ribosylase tankyrase 2 (TNKS2) and the kinesin motor protein KIF3A, forming a ternary complex crucial for GLUT4 translocation in response to insulin. Specific knockdown of the individual components of the complex attenuated insulin-stimulated GLUT4 translocation to the plasma membrane. Importantly, TNKS2(-/-) mice exhibit reduced insulin sensitivity and higher blood glucose levels when re-fed after fasting. Mechanistically, we demonstrate that in the absence of insulin, Axin, TNKS and KIF3A are co-localized with GLUT4 on the trans-Golgi network. Insulin treatment suppresses the ADP-ribosylase activity of TNKS, leading to a reduction in ADP ribosylation and ubiquitination of both Axin and TNKS, and a concurrent stabilization of the complex. Inhibition of Akt, the major effector kinase of insulin signaling, abrogates the insulin-mediated complex stabilization. We have thus elucidated a new protein complex that is directly associated with the motor protein kinesin in insulin-stimulated GLUT4 translocation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3-L1 Cells
  • Adipocytes / drug effects
  • Adipocytes / metabolism
  • Animals
  • Axin Protein / genetics
  • Axin Protein / metabolism*
  • Blood Glucose / analysis
  • Blood Glucose / drug effects
  • Blood Glucose / metabolism
  • Cell Membrane / genetics
  • Cell Membrane / metabolism
  • Enzyme Activation
  • Glucose Transporter Type 4 / genetics
  • Glucose Transporter Type 4 / metabolism*
  • HEK293 Cells
  • Humans
  • Insulin / administration & dosage
  • Insulin / pharmacology*
  • Insulin Resistance
  • Kinesins / genetics
  • Kinesins / metabolism*
  • Male
  • Mice
  • Microscopy, Fluorescence
  • Protein Interaction Mapping
  • Protein Stability
  • Protein Transport
  • RNA Interference
  • Signal Transduction
  • Tankyrases / genetics
  • Tankyrases / metabolism*
  • Two-Hybrid System Techniques
  • trans-Golgi Network / metabolism

Substances

  • Axin Protein
  • Blood Glucose
  • Glucose Transporter Type 4
  • Insulin
  • Kif3a protein, mouse
  • Slc2a4 protein, mouse
  • Tankyrases
  • tankyrase-2, mouse
  • Kinesins