Skeletal and cardiac ryanodine receptors bind to the Ca2+‐sensor region of dihydropyridine receptor α1C subunit

Abstract
In striated muscles, excitation–contraction coupling is mediated by the functional interplay between dihydropyridine receptor L-type calcium channels (DHPR) and ryanodine receptor calcium-release channel (RyR). Although significantly different molecular mechanisms are involved in skeletal and cardiac muscles, bidirectional cross-talk between the two channels has been described in both tissues. In the present study using surface plasmon resonance spectroscopy, we demonstrate that both RyR1 and RyR2 can bind to structural elements of the C-terminal cytoplasmic domain of α1C. The interaction is restricted to the CB and IQ motifs involved in the calmodulin-mediated Ca2+-dependent inactivation of the DHPR, suggesting functional interactions between the two channels.