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. 1992 Nov;63(5):1406–1411. doi: 10.1016/S0006-3495(92)81703-4

Tandem linkage of Shaker K+ channel subunits does not ensure the stoichiometry of expressed channels.

K McCormack 1, L Lin 1, L E Iverson 1, M A Tanouye 1, F J Sigworth 1
PMCID: PMC1261445  PMID: 1477286

Abstract

Shaker K+ channels are multimeric, probably tetrameric proteins. Substitution of a conserved leucine residue to valine (V2) at position 370 in the Drosophila Shaker 29-4 sequence results in large alterations in the voltage dependence of gating in the expressed channels. In order to determine the effects of this mutation in hybrid channels with a fixed stoichiometry of V2 and wild-type (WT) subunits we generated cDNA constructs of two linked-monomeric subunits similar to the tandem constructs previously reported by Isacoff, E. Y., Y. N. Jan, and L. Y. Jan. (1990. Nature (Lond.). 345:530-534). In addition, we constructed a tandem cDNA containing a wild-type subunit and a truncated nonfunctional subunit (Sh102) that suppresses channel expression. We report that the voltage-dependence of the channels produced with WT and V2 subunits varied significantly with the order of the subunits in the construct (WT-V2 or V2-WT), while the WT-Sh102 construct yielded currents that were much larger than expected. These results suggest that the tandem linkage of Shaker subunits does not guarantee the stoichiometry of the expressed channel proteins.

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Selected References

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