Skeletal and cardiac ryanodine receptors bind to the Ca2+-sensor region ofdihydropyridine receptor alpha(1C) subunit

In striated muscles, excitation-contraction coupling is mediated by the fun ctional interplay between dihydropyridine receptor L-type calcium channels (DHPR) and ryanodine receptor calcium-release channel (RyR). Although signi ficantly different molecular mechanisms are involved in skeletal and cardia c muscles, bidirectional cross-talk between the two channels has been descr ibed in both tissues. In the present study using surface plasmon resonance spectroscopy, we demonstrate that both RyR(1) and RyR(2) can bind to struct ural elements of the C-terminal cytoplasmic domain of alpha (1C). The inter action is restricted to the CB and IQ motifs involved in the calmodulin-med iated Ca2+-dependent inactivation of the DHPR, suggesting functional intera ctions between the two channels. (C) 2001 Published by Elsevier Science B.V . on behalf of the Federation of European Biochemical Societies.