Insulin Antagonizes Ischemia-Induced Thr172 Phosphorylation of AMP-activated Protein Kinase Alpha-Subunits in Heart via Hierarchical Phosphorylation of Ser485/491

J Biol Chem. 2006 Mar 3;281(9):5335-40. doi: 10.1074/jbc.M506850200. Epub 2005 Dec 9.

Abstract

Previous studies showed that insulin antagonizes AMP-activated protein kinase activation by ischemia and that protein kinase B might be implicated. Here we investigated whether the direct phosphorylation of AMP-activated protein kinase by protein kinase B might participate in this effect. Protein kinase B phosphorylated recombinant bacterially expressed AMP-activated protein kinase heterotrimers at Ser(485) of the alpha1-subunits. In perfused rat hearts, phosphorylation of the alpha1/alpha2 AMP-activated protein kinase subunits on Ser(485)/Ser(491) was increased by insulin and insulin pretreatment decreased the phosphorylation of the alpha-subunits at Thr(172) in a subsequent ischemic episode. It is proposed that the effect of insulin to antagonize AMP-activated protein kinase activation involves a hierarchical mechanism whereby Ser(485)/Ser(491) phosphorylation by protein kinase B reduces subsequent phosphorylation of Thr(172) by LKB1 and the resulting activation of AMP-activated protein kinase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinases
  • Adenosine Monophosphate / metabolism
  • Animals
  • Enzyme Activation
  • In Vitro Techniques
  • Insulin / metabolism*
  • Male
  • Multienzyme Complexes / chemistry
  • Multienzyme Complexes / genetics
  • Multienzyme Complexes / metabolism*
  • Myocardial Ischemia*
  • Myocardium / enzymology*
  • Phosphorylation
  • Protein Subunits / genetics
  • Protein Subunits / metabolism*
  • Protein-Serine-Threonine Kinases / chemistry
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • Proto-Oncogene Proteins c-akt / genetics
  • Proto-Oncogene Proteins c-akt / metabolism
  • Rats
  • Rats, Wistar
  • Serine / metabolism*
  • Threonine / metabolism*

Substances

  • Insulin
  • Multienzyme Complexes
  • Protein Subunits
  • Threonine
  • Adenosine Monophosphate
  • Serine
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • Stk11 protein, rat
  • AMP-Activated Protein Kinases