Cardiac ATP-sensitive K+ channel associates with the glycolytic enzyme complex

FASEB J. 2011 Jul;25(7):2456-67. doi: 10.1096/fj.10-176669. Epub 2011 Apr 11.

Abstract

Being gated by high-energy nucleotides, cardiac ATP-sensitive potassium (K(ATP)) channels are exquisitely sensitive to changes in cellular energy metabolism. An emerging view is that proteins associated with the K(ATP) channel provide an additional layer of regulation. Using putative sulfonylurea receptor (SUR) coiled-coil domains as baits in a 2-hybrid screen against a rat cardiac cDNA library, we identified glycolytic enzymes (GAPDH and aldolase A) as putative interacting proteins. Interaction between aldolase and SUR was confirmed using GST pulldown assays and coimmunoprecipitation assays. Mass spectrometry of proteins from K(ATP) channel immunoprecipitates of rat cardiac membranes identified glycolysis as the most enriched biological process. Coimmunoprecipitation assays confirmed interaction for several glycolytic enzymes throughout the glycolytic pathway. Immunocytochemistry colocalized many of these enzymes with K(ATP) channel subunits in rat cardiac myocytes. The catalytic activities of aldolase and pyruvate kinase functionally modulate K(ATP) channels in patch-clamp experiments, whereas D-glucose was without effect. Overall, our data demonstrate close physical association and functional interaction of the glycolytic process (particularly the distal ATP-generating steps) with cardiac K(ATP) channels.

Publication types

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

MeSH terms

  • ATP-Binding Cassette Transporters / genetics
  • ATP-Binding Cassette Transporters / metabolism
  • Animals
  • COS Cells
  • Cell Membrane / metabolism
  • Chlorocebus aethiops
  • Fructose-Bisphosphate Aldolase / genetics
  • Fructose-Bisphosphate Aldolase / metabolism*
  • Gene Library
  • Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) / genetics
  • Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) / metabolism*
  • Glycolysis
  • HEK293 Cells
  • Humans
  • Immunoblotting
  • Immunoprecipitation
  • KATP Channels / genetics
  • KATP Channels / metabolism*
  • Male
  • Myocardium / metabolism*
  • Potassium Channels, Inwardly Rectifying / genetics
  • Potassium Channels, Inwardly Rectifying / metabolism
  • Protein Binding
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Drug / genetics
  • Receptors, Drug / metabolism
  • Sulfonylurea Receptors
  • Tandem Mass Spectrometry
  • Two-Hybrid System Techniques

Substances

  • ATP-Binding Cassette Transporters
  • KATP Channels
  • Kir6.2 channel
  • Potassium Channels, Inwardly Rectifying
  • Receptors, Drug
  • Sulfonylurea Receptors
  • uK-ATP-1 potassium channel
  • Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating)
  • Fructose-Bisphosphate Aldolase