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Rapid activation of Akt2 is sufficient to stimulate GLUT4 translocation in 3T3-L1 adipocytes

Yvonne Ng1, Georg Ramm, Jamie A Lopez

  • 1Diabetes and Obesity Research Program, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia.

Cell Metabolism
|April 9, 2008
PubMed

Insights

Activation of Akt2 is sufficient to stimulate glucose uptake in fat cells. This finding clarifies the role of Akt2 in insulin signaling and glucose transporter 4 (GLUT4) translocation.

Area of Science:

  • Cell biology
  • Molecular signaling
  • Metabolic research

Background:

  • The serine/threonine kinase Akt2 is involved in insulin-regulated glucose uptake.
  • Its sufficiency in this process is debated due to proposed alternate signaling pathways.

Purpose of the Study:

  • To determine if Akt2 activation alone is sufficient for glucose uptake and GLUT4 translocation.
  • To investigate the physiological range of Akt2 activity.

Main Methods:

  • Engineered 3T3-L1 adipocytes for rapid, drug-inducible Akt2 activation using heterodimerization.
  • Utilized a rapalog dimerizer to activate Akt2 and measured downstream substrate phosphorylation.

Main Results:

  • Rapalog addition induced Akt2 activation within 5 minutes, phosphorylating AS160 and GSK3.
  • Akt2 activation levels were within the physiological range, comparable to insulin stimulation.
  • Transient Akt2 activation increased glucose transport and GLUT4 translocation to the plasma membrane.

Conclusions:

  • Akt2 activation is sufficient to stimulate GLUT4 translocation in 3T3-L1 adipocytes.
  • This effect is comparable in magnitude to insulin stimulation.
  • Provides strong evidence for Akt2's central role in regulating glucose uptake.

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