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. 1990 Oct;87(19):7579–7582. doi: 10.1073/pnas.87.19.7579

Do voltage-dependent K+ channels require Ca2+? A critical test employing a heterologous expression system.

C M Armstrong 1, C Miller 1
PMCID: PMC54791  PMID: 2217187

Abstract

Removal of Ca2+ from the solution bathing neurons is known in many cases to alter the gating properties of voltage-dependent K+ channels and to induce a large, nonselective "leak" conductance. We used a heterologous expression system to test whether the leak conductance observed in neurons is mediated by voltage-dependent K+ channels in an altered, debased conformation. Voltage-dependent K+ channels were expressed in an insect cell line infected with a recombinant baculovirus carrying the cDNA for Drosophila Shaker "A-type" K+ channels. These expressed channels respond to low Ca2+ identically to voltage-dependent K+ channels in native neuronal membranes; upon removal of external Ca2+, Shaker K+ currents disappear and are replaced by a steady, nonselective leak conductance. However, control cells devoid of Shaker channels were free of any voltage-dependent conductances and did not generate a leak when external Ca2+ was removed. These results show that Ca2+ is essential for proper function of voltage-dependent K+ channels and is required to stabilize the native conformations of these membrane proteins.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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