Kopylova G V, Shchepkin D V, Borovkov D I, Matyushenko A M
Institute of Immunology and Physiology, Ural Division of the Russian Academy of Sciences, Moscow, Russia.
B. N. Yeltsin Ural Federal University, Ekaterinburg, Russia.
Bull Exp Biol Med. 2016 Nov;162(1):42-44. doi: 10.1007/s10517-016-3540-x. Epub 2016 Nov 23.
Tropomyosin plays an important role in the regulation of actin-myosin interaction in striated muscles. Mutations in the tropomyosin gene disrupt actin-myosin interaction and lead to myopathies and cardiomyopathies. Tropomyosin with mutations in the α-chain is expressed in both the myocardium and skeletal muscles. We studied the effect of mutations in the α-chain of tropomyosin related to hypertrophic (D175N and E180G) and dilated cardiomyopathies (E40K and E54K) on calcium regulation of the actin-myosin interaction in skeletal muscles. We analyzed the calcium-dependent sliding velocity of reconstructed thin filaments containing F-actin, troponin, and tropomyosin over myosin surface in an in vitro motility assay. Mutations D175N and E180G in tropomyosin increased the sliding velocity and its calcium sensitivity, while mutation E40K reduced both these parameters. E54K mutation increased the sliding velocity of thin filaments, but did not affect its calcium sensitivity.
原肌球蛋白在横纹肌中肌动蛋白 - 肌球蛋白相互作用的调节中起重要作用。原肌球蛋白基因突变会破坏肌动蛋白 - 肌球蛋白相互作用，并导致肌病和心肌病。α链发生突变的原肌球蛋白在心肌和骨骼肌中均有表达。我们研究了与肥厚型心肌病（D175N和E180G）和扩张型心肌病（E40K和E54K）相关的原肌球蛋白α链突变对骨骼肌中肌动蛋白 - 肌球蛋白相互作用的钙调节的影响。我们在体外运动分析中分析了含有F - 肌动蛋白、肌钙蛋白和原肌球蛋白的重建细肌丝在肌球蛋白表面上的钙依赖性滑动速度。原肌球蛋白中的D175N和E180G突变增加了滑动速度及其钙敏感性，而E40K突变降低了这两个参数。E54K突变增加了细肌丝的滑动速度，但不影响其钙敏感性。
