Structure, G protein activation, and functional relevance of the cardiac G protein-gated K+ channel, IKACh.
The muscarinic-gated atrial potassium channel IKACh has been well characterized functionally, and has been an excellent model system for studying G protein/effector interactions. Complementary DNAs encoding the composite subunits of IKACh have been identified, allowing direct probing of structural and functional features of the channel. Here, we highlight recent approaches taken in our laboratory to determine the oligomeric structure of native cardiac IKACh, the mechanism of activation of IKACh by G proteins, and the relevance of IKACh to cardiac physiology.
Wickman
K
K
Department of Cardiology, Howard Hughes Medical Institute, Harvard Medical School, Children's Hospital, Boston, Massachusetts 02115, USA.
Krapivinsky
G
G
Corey
S
S
Kennedy
M
M
Nemec
J
J
Medina
I
I
Clapham
D E
DE
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003432:Cross-Linking Reagents / Q000737:chemistry; D004562:Electrocardiography; D004594:Electrophysiology; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006325:Heart Atria / Q000378:metabolism*; D006339:Heart Rate; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000494:pharmacology; D015221:Potassium Channels / Q000737:chemistry / Q000502:physiology*; D024661:Potassium Channels, Inwardly Rectifying; D011487:Protein Conformation; D014630:Vagus Nerve / Q000502:physiology
D003432:Cross-Linking Reagents; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D010446:Peptide Fragments; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D019204:GTP-Binding Proteins