title: Cardiac ATP-sensitive K+ channel associates with the glycolytic enzyme complex.
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.
authors.affiliation: Department of Pediatrics, New York University School of Medicine, New York, NY 10016, USA.
authors.forename: Miyoun
authors.initials: M
authors.lastname: Hong
authors.forename: Eirini
authors.initials: E
authors.lastname: Kefaloyianni
authors.forename: Li
authors.initials: L
authors.lastname: Bao
authors.forename: Brian
authors.initials: B
authors.lastname: Malester
authors.forename: Diane
authors.initials: D
authors.lastname: Delaroche
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Neubert
authors.forename: William A
authors.initials: WA
authors.lastname: Coetzee
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D000818:Animals; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism; D002522:Chlorocebus aethiops; D005634:Fructose-Bisphosphate Aldolase / Q000235:genetics / Q000378:metabolism*; D015723:Gene Library; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) / Q000235:genetics / Q000378:metabolism*; D006019:Glycolysis; D057809:HEK293 Cells; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D054086:KATP Channels / Q000235:genetics / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D017207:Rats, Sprague-Dawley; D011955:Receptors, Drug / Q000235:genetics / Q000378:metabolism; D064233:Sulfonylurea Receptors; D053719:Tandem Mass Spectrometry; D020798:Two-Hybrid System Techniques; D000099161:Kcnj11 Channel
chemical_list: D018528:ATP-Binding Cassette Transporters; D005634:Fructose-Bisphosphate Aldolase; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating); D054086:KATP Channels; D024661:Potassium Channels, Inwardly Rectifying; D011955:Receptors, Drug; D064233:Sulfonylurea Receptors; D000099161:Kcnj11 Channel; C092520:uK-ATP-1 potassium channel