Referenced in: none

Automatically associated channels: Cavβ4 , Slo1

Title: Cacnb4 directly couples electrical activity to gene expression, a process defective in juvenile epilepsy.

Authors: Abir Tadmouri, Shigeki Kiyonaka, Maud Barbado, Matthieu Rousset, Katell Fablet, Seishiro Sawamura, Eloi Bahembera, Karin Pernet-Gallay, Christophe Arnoult, Takafumi Miki, Karin Sadoul, Sylvie Gory-Faure, Caroline Lambrecht, Florian Lesage, Satoshi Akiyama, Saadi Khochbin, Sylvain Baulande, Veerle Janssens, Annie Andrieux, Ricardo Dolmetsch, Michel Ronjat, Yasuo Mori, Michel De Waard

Journal, date & volume: EMBO J., 2012 Sep 12 , 31, 3730-44

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/22892567

Abstract
Calcium current through voltage-gated calcium channels (VGCC) controls gene expression. Here, we describe a novel signalling pathway in which the VGCC Cacnb4 subunit directly couples neuronal excitability to transcription. Electrical activity induces Cacnb4 association to Ppp2r5d, a regulatory subunit of PP2A phosphatase, followed by (i) nuclear translocation of Cacnb4/Ppp2r5d/PP2A, (ii) association with the tyrosine hydroxylase (TH) gene promoter through the nuclear transcription factor thyroid hormone receptor alpha (TRα), and (iii) histone binding through association of Cacnb4 with HP1γ concomitantly with Ser(10) histone H3 dephosphorylation by PP2A. This signalling cascade leads to TH gene repression by Cacnb4 and is controlled by the state of interaction between the SH3 and guanylate kinase (GK) modules of Cacnb4. The human R482X CACNB4 mutation, responsible for a form of juvenile myoclonic epilepsy, prevents association with Ppp2r5 and nuclear targeting of the complex by altering Cacnb4 conformation. These findings demonstrate that an intact VGCC subunit acts as a repressor recruiting platform to control neuronal gene expression.