Roles of light chains in the activity and conformation of smooth muscle myosin
Roles of light chains in the activity and conformation of smooth muscle myosin
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DOI：
10.1074/jbc.271.17.9992
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发表时间：
1996-04-26
影响因子：
4.8
通讯作者：
Morita, F
中科院分区：
文献类型：
--
作者：
Katoh, T;Morita, F
用三氟拉嗪和氯化铵可从猪主动脉平滑肌肌球蛋白中去除20 kDa调控亚基(LC20)和17 kDa必需轻链亚基(LC17)。分离的重链反弹了两条轻链，导致天然性质的恢复。用Lc17和/或Lc20重组分离的重链的实验表明，这两条轻链都是折叠成10 S构象所必需的，从而也是肌球蛋白磷酸化依赖的细丝形成所必需的。然而，LC17对于肌动蛋白激活的ATPase活性和超沉淀的磷酸化依赖调节并不是必需的，但对于完全调节是必需的。Lc17和磷酸化的Lc20可作为激活剂，去磷酸化的Lc20可抑制肌球蛋白的运动活动。
The 20-kDa regulatory (LC20) and 17-kDa essential (LC17) light chain subunits could be removed from porcine aorta smooth muscle myosin by the use of trifluoperazine and ammonium chloride. The isolated heavy chain rebound both light chains, resulting in the restoration of native properties. Experiments on reconstitution of the isolated heavy chain with LC17 and/or LC20 showed that both light chains were required for folding into the 10 S conformation and thus for the phosphorylation dependent filament format-ion of smooth muscle myosin. However, LC17 was not essential for the phosphorylation-dependent regulation of actin-activated ATPase activity and superprecipitation but was required for full regulation. LC17 and phosphorylated LC20 were found to act as activators, and dephosphorylated LC20 was found to act as a repressor of the motor activities of smooth muscle myosin.