Subunit composition of minK potassium channels.
Expression of minK protein in Xenopus oocytes induces a slowly activating, voltage-dependent, potassium-selective current. Point mutations in minK that alter current gating kinetics, ion selectivity, pharmacology, and response to protein kinase C all support the notion that minK is a structural protein for a channel-type transporter. Yet, minK has just 130 amino acids and a single transmembrane domain. Though larger cloned potassium channels form functional channels through tetrameric subunit association, the subunit composition of minK is unknown. Subunit stoichiometry was determined by coexpression of wild-type minK and a dominant lethal point mutant of minK, which reaches the plasma membrane but passes no current. The results support a model for complete minK potassium channels in which just two minK monomers are present, with other, as yet unidentified, non-minK subunits.
Wang
K W
KW
Department of Pediatrics, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA.
Goldstein
S A
SA
D000818:Animals; D004553:Electric Conductivity; D005260:Female; D015870:Gene Expression; D018014:Gene Transfer Techniques; D007700:Kinetics; D046911:Macromolecular Substances; D008433:Mathematics; D016296:Mutagenesis; D009865:Oocytes / Q000378:metabolism; D010641:Phenotype; D017354:Point Mutation; D015221:Potassium Channels / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D024642:Potassium Channels, Voltage-Gated; D018075:RNA, Complementary / Q000235:genetics; D051381:Rats; D013329:Structure-Activity Relationship; D014981:Xenopus
D046911:Macromolecular Substances; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D018075:RNA, Complementary; C059983:potassium channel protein I(sk)