This study identifies the minimum set of five junctional proteins required to support Ca V 1.1–RyR1 conformational coupling for excitation-contraction coupling in skeletal muscle.
Significance Excitation–contraction coupling (ECC) in vertebrate skeletal muscle depends upon specialized junctions at which Ca V 1.1, a voltage-gated channel in the plasma membrane, interacts with RyR1, a calcium release channel in the sarcoplasmic reticulum. Because calcium flux via Ca V 1.1 is unnecessary for ECC, Ca V 1.1 is thought to “conformationally couple” to RyR1. Studies of muscle cells with gene knockouts have shown that additional, junctional proteins are also necessary, but are unable to reveal whether or not these complete the set of required proteins. Here, we show that conformational coupling can be conferred upon tsA201 cells by expressing five junctional proteins (Ca V 1.1, RyR1, β1a, Stac3, and junctophilin2), thus establishing a minimum set of proteins supporting Ca V 1.1–RyR1 conformational coupling in skeletal muscle.
Perni et al. (Mon,) studied this question.