Co‐expression of slow‐twitch/cardiac muscle Ca2+‐ATPase (SERCA2) and phospholamban

[摘要]

Full length cDNAs encoding both slow-twitch/cardiac (SERCA2) and fast-twitch skeletal muscle (SERCA1) Ca²⁺-ATPases were expressed by transient transfection of COS-1 cells. Studies of the Ca²⁺-dependency of Ca²⁺-transport in microsomes isolated from these cells showed that both isoforms had an affinity for Ca²⁺ of about 0.2 μM. The Ca²⁺-affinity of SERCA2 was lowered when phospholamban was co-expressed with it, demonstrating that the two proteins interact in this expression system. These studies support the view that phospholamban inhibition accounts for the low Ca²⁺-amnity and low activity of SERCA2 in cardiac muscle sarcoplasmic reticulum.

[学科分类] 生物化学/生物物理

[关键词] Ca2+-ATPase;Phospholamban;Co-expression;Ca2+-affinity