Referenced in: none

Automatically associated channels: Kv2.1

Title: Non-conducting function of the Kv2.1 channel enables it to recruit vesicles for release in neuroendocrine and nerve cells.

Authors: Lori Feinshreiber, Dafna Singer-Lahat, Reut Friedrich, Ulf Matti, Anton Sheinin, Ofer Yizhar, Rachel Nachman, Dodo Chikvashvili, Jens Rettig, Uri Ashery, Ilana Lotan

Journal, date & volume: J. Cell. Sci., 2010 Jun 1 , 123, 1940-7

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/20484665

Abstract
Regulation of exocytosis by voltage-gated K(+) channels has classically been viewed as inhibition mediated by K(+) fluxes. We recently identified a new role for Kv2.1 in facilitating vesicle release from neuroendocrine cells, which is independent of K(+) flux. Here, we show that Kv2.1-induced facilitation of release is not restricted to neuroendocrine cells, but also occurs in the somatic-vesicle release from dorsal-root-ganglion neurons and is mediated by direct association of Kv2.1 with syntaxin. We further show in adrenal chromaffin cells that facilitation induced by both wild-type and non-conducting mutant Kv2.1 channels in response to long stimulation persists during successive stimulation, and can be attributed to an increased number of exocytotic events and not to changes in single-spike kinetics. Moreover, rigorous analysis of the pools of released vesicles reveals that Kv2.1 enhances the rate of vesicle recruitment during stimulation with high Ca(2+), without affecting the size of the readily releasable vesicle pool. These findings place a voltage-gated K(+) channel among the syntaxin-binding proteins that directly regulate pre-fusion steps in exocytosis.