Hitchcock-DeGregori Sarah E, Barua Bipasha
Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, Rutgers University, 675 Hoes Lane West, Piscataway, NJ, 08854, USA.
Subcell Biochem. 2017;82:253-284. doi: 10.1007/978-3-319-49674-0_9.
Tropomyosin is the archetypal-coiled coil, yet studies of its structure and function have proven it to be a dynamic regulator of actin filament function in muscle and non-muscle cells. Here we review aspects of its structure that deviate from canonical leucine zipper coiled coils that allow tropomyosin to bind to actin, regulate myosin, and interact directly and indirectly with actin-binding proteins. Four genes encode tropomyosins in vertebrates, with additional diversity that results from alternate promoters and alternatively spliced exons. At the same time that periodic motifs for binding actin and regulating myosin are conserved, isoform-specific domains allow for specific interaction with myosins and actin filament regulatory proteins, including troponin. Tropomyosin can be viewed as a universal regulator of the actin cytoskeleton that specifies actin filaments for cellular and intracellular functions.
原肌球蛋白是典型的卷曲螺旋结构，但对其结构和功能的研究表明，它是肌肉和非肌肉细胞中肌动蛋白丝功能的动态调节因子。在此，我们综述其结构中偏离典型亮氨酸拉链卷曲螺旋的方面，正是这些方面使原肌球蛋白能够结合肌动蛋白、调节肌球蛋白，并直接或间接地与肌动蛋白结合蛋白相互作用。脊椎动物中有四个基因编码原肌球蛋白，另外由于可变启动子和可变剪接外显子，还存在额外的多样性。在结合肌动蛋白和调节肌球蛋白的周期性基序保守的同时，同工型特异性结构域允许与肌球蛋白和肌动蛋白丝调节蛋白（包括肌钙蛋白）进行特异性相互作用。原肌球蛋白可被视为肌动蛋白细胞骨架的通用调节因子，它为细胞和细胞内功能指定肌动蛋白丝。
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