Title: Determination of the subunit stoichiometry of a voltage-activated potassium channel.

Authors: R MacKinnon

Journal, date & volume: Nature, 1991 Mar 21 , 350, 232-5

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/1706481

Abstract
The voltage-activated K+, Na+ and Ca2+ channels are responsible for the generation and propagation of electrical signals in cell membranes. The K+ channels are multimeric membrane proteins formed by the aggregation of an unknown number of independent subunits. By studying the interaction of a scorpion toxin with coexpressed wild-type and toxin-insensitive mutant Shaker K+ channels, the subunit stoichiometry can be determined. The Shaker K+ channel is found to have a tetrameric structure. This is consistent with the sequence relationship between a K+ channel and each of the four internally homologous repeats of Na+ and Ca2+ channels.