[Heterotrimeric G proteins and ion channels].
Direct G protein regulation of ion channels is one of the major mechanisms of the functional regulation of excitable cells by hormones and neurotransmitters. Recent extensive studies indicate that a number of channels are directly regulated by G proteins. In this short review, we focus on the molecular mechanism underlying G protein (GK) regulation fo cardiac muscarinic K+ channels. This channel was reported to be activated in the inside-out configuration by both exogenously applied alpha- and beta gamma-subunits of pertussis toxin-sensitive G proteins. There has been a longstanding controversy as to which of the subunits physiologically mediate the effect of GK on this channel. We have established the notion that GK physiologically activates cardiac muscarinic K+ channels through its beta gamma-subunit but not its alpha-subunit.
Mayo Clinic, Rochester, MN 55905.
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M
Yamada
Y
Y
Kurachi
D000818:Animals; D019204:GTP-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D009206:Myocardium / Q000378:metabolism; D037342:Pertussis Toxin; D015221:Potassium Channels / Q000378:metabolism*; D015290:Second Messenger Systems; D010566:Virulence Factors, Bordetella / Q000378:metabolism
D015221:Potassium Channels; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins