Referenced in: none

Automatically associated channels: Kv1.1

Title: Direct interaction of a brain voltage-gated K+ channel with syntaxin 1A: functional impact on channel gating.

Authors: O Fili, I Michaelevski, Y Bledi, D Chikvashvili, D Singer-Lahat, H Boshwitz, M Linial, I Lotan

Journal, date & volume: J. Neurosci., 2001 Mar 15 , 21, 1964-74

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/11245681

Abstract
Presynaptic voltage-gated K(+) (Kv) channels play a physiological role in the regulation of transmitter release by virtue of their ability to shape presynaptic action potentials. However, the possibility of a direct interaction of these channels with the exocytotic apparatus has never been examined. We report the existence of a physical interaction in brain synaptosomes between Kvalpha1.1 and Kvbeta subunits with syntaxin 1A, occurring, at least partially, within the context of a macromolecular complex containing syntaxin, synaptotagmin, and SNAP-25. The interaction was altered after stimulation of neurotransmitter release. The interaction with syntaxin was further characterized in Xenopus oocytes by both overexpression and antisense knock-down of syntaxin. Direct physical interaction of syntaxin with the channel protein resulted in an increase in the extent of fast inactivation of the Kv1.1/Kvbeta1.1 channel. Syntaxin also affected the channel amplitude in a biphasic manner, depending on its concentration. At low syntaxin concentrations there was a significant increase in amplitudes, with no detectable change in cell-surface channel expression. At higher concentrations, however, the amplitudes decreased, probably because of a concomitant decrease in cell-surface channel expression, consistent with the role of syntaxin in regulation of vesicle trafficking. The observed physical and functional interactions between syntaxin 1A and a Kv channel may play a role in synaptic efficacy and neuronal excitability.