Ca2+ sensors of L‐type Ca2+ channel

[摘要]

Ca²⁺-induced inactivation of L-type Ca²⁺ is differentially mediated by two C-terminal motifs of the α_1C subunit, L (1572–1587) and K (1599–1651) implicated for calmodulin binding. We found that motif L is composed of a highly selective Ca²⁺ sensor and an adjacent Ca²⁺-independent tethering site for calmodulin. The Ca²⁺ sensor contributes to higher Ca²⁺ sensitivity of the motif L complex with calmodulin. Since only combined mutation of both sites removes Ca²⁺-dependent current decay, the two-site modulation by Ca²⁺ and calmodulin may underlie Ca²⁺-induced inactivation of the channel.

[学科分类] 生物化学/生物物理

[关键词] Heart;Calcium channel;Calmodulin;Ca2+ sensor;Inactivation;CaM;calmodulin;GST;glutathione S-transferase;PAGE;polyacrylamide gel electrophoresis