细丝蛋白对平滑肌肌球蛋白ATP酶活性的双向调节。
The bi-directional regulation of filamin on the ATPase activity of smooth muscle myosin.
作者信息
Lin Y, Sun H, Dai S, Tang Z, He X, Chen H
机构信息
Department of Pharmacology, Dalian Medical University, Dalian 116027.
出版信息
Chin Med Sci J. 2000 Sep;15(3):162-4.
OBJECTIVE
The aim of this study is to investigate the functional relationship between filamin, a known actin binding protein, and myosin and the effects of filamin on the interaction between myosin and actin.
METHODS
Ultra-centrifugation method was used to investigate the binding of filamin to both phosphorylated and unphosphorylated myosins. Mg-ATPase activities of both phosphorylated and unphosphorylated myosins in the presence and absence of actin were measured to observe the effects resulted from filamin-actin and filamin-myosin interactions.
RESULTS
It was found that filamin is also a myosin binding protein. Filamin inhibited the actin activated Mg-ATPase activity of phosphorylated myosin and stimulated Mg-ATPase of phosphorylated myosin in the absence of actin; in addition, filamin stimulated Mg-ATPase activity of unphosphorylated myosin in both the presence or absence of actin.
CONCLUSION
The result suggest that the effects of filamin on the myosin Mg-ATPase activities are bi-directional, i.e., stimulatory via binding to myosin and inhibitory via binding to actin.
目的
本研究旨在探讨已知的肌动蛋白结合蛋白细丝蛋白与肌球蛋白之间的功能关系，以及细丝蛋白对肌球蛋白与肌动蛋白相互作用的影响。
方法
采用超速离心法研究细丝蛋白与磷酸化和非磷酸化肌球蛋白的结合。测量存在和不存在肌动蛋白时磷酸化和非磷酸化肌球蛋白的镁 - ATP酶活性，以观察细丝蛋白 - 肌动蛋白和细丝蛋白 - 肌球蛋白相互作用产生的影响。
结果
发现细丝蛋白也是一种肌球蛋白结合蛋白。细丝蛋白抑制磷酸化肌球蛋白的肌动蛋白激活的镁 - ATP酶活性，并在不存在肌动蛋白的情况下刺激磷酸化肌球蛋白的镁 - ATP酶活性；此外，细丝蛋白在存在或不存在肌动蛋白的情况下均刺激非磷酸化肌球蛋白的镁 - ATP酶活性。
结论
结果表明细丝蛋白对肌球蛋白镁 - ATP酶活性的影响是双向的，即通过与肌球蛋白结合起刺激作用，通过与肌动蛋白结合起抑制作用。
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