The beta gamma subunits of GTP-binding proteins activate the muscarinic K+ channel in heart.
Subunits of guanine nucleotide regulatory proteins purified from bovine cerebral cortex were used to perfuse the intracellular surface of excised patches of chick embryonic atrial cells. Single-channel current measurements unexpectedly indicate that the beta gamma, and not the alpha subunits, are responsible for activating the muscarinic-gated potassium channel.
D000818:Animals; D002642:Chick Embryo; D004553:Electric Conductivity; D019204:GTP-Binding Proteins / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D006321:Heart / Q000502:physiology*; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology*; D046911:Macromolecular Substances; D008274:Magnesium / Q000494:pharmacology; D011188:Potassium / Q000502:physiology*; D011976:Receptors, Muscarinic / Q000502:physiology*; D013329:Structure-Activity Relationship; D013873:Thionucleotides / Q000494:pharmacology
D007473:Ion Channels; D046911:Macromolecular Substances; D011976:Receptors, Muscarinic; D013873:Thionucleotides; D006165:Guanylyl Imidodiphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins; D008274:Magnesium; D011188:Potassium