%0 Journal Article
%T Ca2+ Channels Mediate Bidirectional Signaling between Sarcolemma and Sarcoplasmic Reticulum in Muscle Cells.
%A Avila G
%A de la Rosa JA
%A Monsalvo-Villegas A
%A Montiel-Jaen MG
%J Cells
%V 9
%N 1
%D Dec 2019 24
%M 31878335
%F 7.666
%R 10.3390/cells9010055
%X The skeletal muscle and myocardial cells present highly specialized structures; for example, the close interaction between the sarcoplasmic reticulum (SR) and mitochondria-responsible for excitation-metabolism coupling-and the junction that connects the SR with T-tubules, critical for excitation-contraction (EC) coupling. The mechanisms that underlie EC coupling in these two cell types, however, are fundamentally distinct. They involve the differential expression of Ca2+ channel subtypes: CaV1.1 and RyR1 (skeletal), vs. CaV1.2 and RyR2 (cardiac). The CaV channels transform action potentials into elevations of cytosolic Ca2+, by activating RyRs and thus promoting SR Ca2+ release. The high levels of Ca2+, in turn, stimulate not only the contractile machinery but also the generation of mitochondrial reactive oxygen species (ROS). This forward signaling is reciprocally regulated by the following feedback mechanisms: Ca2+-dependent inactivation (of Ca2+ channels), the recruitment of Na+/Ca2+ exchanger activity, and oxidative changes in ion channels and transporters. Here, we summarize both well-established concepts and recent advances that have contributed to a better understanding of the molecular mechanisms involved in this bidirectional signaling.