Molecular mechanisms of disease-causing mutations in the first voltage-sensing domain of Cav1.1

Voltage-gated calcium channels (CaV) control most activity-dependent functions of excitable cells. However, the molecular mechanisms by which different CaV's respond to membrane depolarization with specific gating properties remain unknown. Voltage-dependent gating of CaV channels is determined by four distinct voltage-sensing domains (VSD I-IV) linked to a common channel pore. Each VSD consists of four transmembrane helices (S1-S4) containing four to five positive gating charges. These arginines and lysines interact with negative countercharges in the helices S2 and S3, thus facilitating the outward movement of the S4 helix upon depolarization.