The inactivation behaviour of voltage-gated K-channels may be determined by association of alpha- and beta-subunits.
Voltage-gated K-channels of the Shaker related subfamily have two subunits, membrane integrated alpha- and peripheral beta-subunits. alpha-Subunits may assemble as tetramers and form in in vitro expression systems functional K-channels. beta-Subunits cannot from channels by themselves. Like for alpha-subunits, the rat nervous system apparently expresses a family of beta-subunit proteins. We have demonstrated that one rat K-channel beta-subunit, Kv beta 1, contains an inactivating domain. Upon association of alpha- and Kv beta 1-subunits, delayed-rectifier type K-channels are converted to rapidly inactivating A-type K-channels. The beta-subunit inactivation domain acts via a ball and chain type mechanism previously proposed for N-type inactivation of alpha-subunits. The association of alpha- and beta-subunits endows the nervous system with an unprecedented flexibility and diversity of K-channels which may play an important role in the regulation of nervous excitability.
Max-Planck-Institut für biophysikalische Chemie, Abteilung Membranbiophysik, Göttingen, Germany.
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Heinemann
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Rettig
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D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D004546:Elapid Venoms / Q000494:pharmacology; D004594:Electrophysiology; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D008954:Models, Biological; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism; D015221:Potassium Channels / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D051381:Rats; D014982:Xenopus laevis
D004546:Elapid Venoms; D009498:Neurotoxins; D015221:Potassium Channels; C020273:dendrotoxin