Referenced in: none

Automatically associated channels: Kv10.1 , Slo1

Title: A caveolae-targeted L-type Ca²+ channel antagonist inhibits hypertrophic signaling without reducing cardiac contractility.

Authors: Catherine A Makarewich, Robert N Correll, Hui Gao, Hongyu Zhang, Baohua Yang, Remus M Berretta, Victor Rizzo, Jeffery D Molkentin, Steven R Houser

Journal, date & volume: Circ. Res., 2012 Mar 2 , 110, 669-74

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/22302787

Abstract
The source of Ca(2+) to activate pathological cardiac hypertrophy is not clearly defined. Ca(2+) influx through the L-type Ca(2+) channels (LTCCs) determines "contractile" Ca(2+), which is not thought to be the source of "hypertrophic" Ca(2+). However, some LTCCs are housed in caveolin-3 (Cav-3)-enriched signaling microdomains and are not directly involved in contraction. The function of these LTCCs is unknown.To test the idea that LTCCs in Cav-3-containing signaling domains are a source of Ca(2+) to activate the calcineurin-nuclear factor of activated T-cell signaling cascade that promotes pathological hypertrophy.We developed reagents that targeted Ca(2+) channel-blocking Rem proteins to Cav-3-containing membranes, which house a small fraction of cardiac LTCCs. Blocking LTCCs within this Cav-3 membrane domain eliminated a small fraction of the LTCC current and almost all of the Ca(2+) influx-induced NFAT nuclear translocation, but it did not reduce myocyte contractility.We provide proof of concept that Ca(2+) influx through LTCCs within caveolae signaling domains can activate "hypertrophic" signaling, and this Ca(2+) influx can be selectively blocked without reducing cardiac contractility.