Regulation of cardiac inwardly rectifying potassium channels by membrane lipid metabolism.
Types and distributions of inwardly rectifying potassium (Kir) channels are one of the major determinants of the electrophysiological properties of cardiac myocytes. Kir2.1 (classical inward rectifier K(+) channel), Kir6.2/SUR2A (ATP-sensitive K(+) channel) and Kir3.1/3.4 (muscarinic K(+) channels) in cardiac myocytes are commonly upregulated by a membrane lipid, phosphatidylinositol 4,5-bisphosphates (PIP(2)). PIP(2) interaction sites appear to be conserved by positively charged amino acid residues and the putative alpha-helix in the C-terminals of Kir channels. PIP(2) level in the plasma membrane is regulated by the agonist stimulation. Kir channels in the cardiac myocytes seem to be actively regulated by means of the change in PIP(2) level rather than by downstream signal transduction pathways.
Takano
Makoto
M
Department of Physiology and Biophysics, Graduate School of Medicine, Kyoto University, Japan. takanom@card.med.kyoto-u.ac.jp
Kuratomi
Shinobu
S
D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D004594:Electrophysiology; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D006801:Humans; D050356:Lipid Metabolism; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism; D015221:Potassium Channels / Q000502:physiology; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism / Q000502:physiology*; D017434:Protein Structure, Tertiary; D011976:Receptors, Muscarinic / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013997:Time Factors; D015854:Up-Regulation
D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D019269:Phosphatidylinositol 4,5-Diphosphate; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D011976:Receptors, Muscarinic