RT Journal Article
SR Electronic
T1 Modulation of gating of cloned rat and human K+ channels by micromolar Zn2+.
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 482
OP 486
VO 43
IS 3
A1 Harrison, N L
A1 Radke, H K
A1 Tamkun, M M
A1 Lovinger, D M
YR 1993
UL http://molpharm.aspetjournals.org/content/43/3/482.abstract
AB The actions of zinc ions on three species of K+ channels were studied using mouse fibroblasts stably transfected with a plasmid containing both the appropriate K+ channel gene and a steroid-inducible promotor. The channels studied were rKv1.1 and hKv1.5, delayed rectifiers cloned from rat and human tissue, respectively, and hKv1.4, an inactivating human K+ channel. Zn2+ shifted the activation curves for all three K+ currents in the depolarizing direction and also shifted the steady state inactivation curve for hKv1.4 in the depolarizing direction. The effect of Zn2+ was concentration dependent between 2 and 1000 microM. As a consequence of the modulation of gating, the activation kinetics of the K+ currents were slowed by Zn2+, an effect likely to delay repolarization of the neuronal action potential. The action of Zn2+ on these diverse K+ channels suggests the existence of a common Zn2+ binding domain, the occupation of which influences the voltage sensor. The resulting modulation of gating of hKv1.4 by Zn2+ may well be of physiological significance, in view of the localization of this channel in mossy fiber nerve terminals in the hippocampus, where Zn2+ is found in abundance.