Modification of the Na+ current conducted by the rat skeletal muscle alpha subunit by coexpression with a human brain beta subunit.
Sodium channels are multimeric structures composed of alpha and beta subunits. Oocytes injected with RNA encoding only the alpha subunit express voltage-gated Na+ currents. The kinetics of inactivation, however, are abnormal. Co-injection of rat brain alpha and beta subunits modifies inactivation of INa such that it closely resembles endogenous currents. Here we show that a beta subunit derived from human brain directs the same functional modification of INa expressed by a rat skeletal muscle alpha subunit. This implies that functional domains for the interaction of alpha and beta subunits are highly conserved across both tissues and species.
Cannon
S C
SC
Howard Hughes Medical Institute, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
McClatchey
A I
AI
Gusella
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JF
D000818:Animals; D001923:Brain Chemistry; D015870:Gene Expression; D006801:Humans; D007700:Kinetics; D046911:Macromolecular Substances; D008564:Membrane Potentials; D009132:Muscles / Q000737:chemistry*; D009865:Oocytes / Q000378:metabolism; D012313:RNA / Q000235:genetics; D018075:RNA, Complementary; D051381:Rats; D015222:Sodium Channels / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D014162:Transfection
D046911:Macromolecular Substances; D018075:RNA, Complementary; D015222:Sodium Channels; D012313:RNA