Subunit stoichiometry of a mammalian K+ channel determined by construction of multimeric cDNAs

Neuron. 1992 Nov;9(5):861-71. doi: 10.1016/0896-6273(92)90239-a.

Abstract

The subunit stoichiometry of the mammalian K+ channel KV1.1 (RCK1) was examined by linking together the coding sequences of 2-5 K+ channel subunits in a single open reading frame and tagging the expression of individual subunits with a mutation (Y379K or Y379R) that altered the sensitivity of the channel to block by external tetraethylammonium ion. Two lines of evidence argue that these constructs lead to K+ channel expression only through the formation of functional tetramers. First, currents expressed by tetrameric constructs containing a single mutant subunit have a sensitivity to tetraethylammonium that is well fitted by a single site binding isotherm. Second, a mutant subunit (Y379K) that expresses only as part of a heteromultimer contributes to the expression of functional channels when coexpressed with a trimeric construct but not a tetrameric construct.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • DNA / chemistry*
  • DNA / genetics
  • Electric Conductivity
  • Gene Expression
  • Genetic Vectors
  • Macromolecular Substances
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Oocytes / metabolism
  • Potassium Channels / chemistry*
  • Potassium Channels / genetics
  • Potassium Channels / physiology
  • Tetraethylammonium
  • Tetraethylammonium Compounds / pharmacology
  • Thermodynamics
  • Xenopus

Substances

  • Macromolecular Substances
  • Potassium Channels
  • Tetraethylammonium Compounds
  • Tetraethylammonium
  • DNA