Referenced in: none

Automatically associated channels: Cav3.2

Title: A Ca(v)3.2/syntaxin-1A signaling complex controls T-type channel activity and low-threshold exocytosis.

Authors: Norbert Weiss, Shahid Hameed, José M Fernández-Fernández, Katell Fablet, Maria Karmazinova, Cathy Poillot, Juliane Proft, Lina Chen, Isabelle Bidaud, Arnaud Monteil, Sylvaine Huc-Brandt, Lubica Lacinova, Philippe Lory, Gerald W Zamponi, Michel De Waard

Journal, date & volume: J. Biol. Chem., 2012 Jan 20 , 287, 2810-8

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/22130660

Abstract
T-type calcium channels represent a key pathway for Ca(2+) entry near the resting membrane potential. Increasing evidence supports a unique role of these channels in fast and low-threshold exocytosis in an action potential-independent manner, but the underlying molecular mechanisms have remained unknown. Here, we report the existence of a syntaxin-1A/Ca(v)3.2 T-type calcium channel signaling complex that relies on molecular determinants that are distinct from the synaptic protein interaction site (synprint) found in synaptic high voltage-activated calcium channels. This interaction potently modulated Ca(v)3.2 channel activity, by reducing channel availability. Other members of the T-type calcium channel family were also regulated by syntaxin-1A, but to a smaller extent. Overexpression of Ca(v)3.2 channels in MPC 9/3L-AH chromaffin cells induced low-threshold secretion that could be prevented by uncoupling the channels from syntaxin-1A. Altogether, our findings provide compelling evidence for the existence of a syntaxin-1A/T-type Ca(2+) channel signaling complex and provide new insights into the molecular mechanism by which these channels control low-threshold exocytosis.