Tropomyosin is an alpha-helical, parallel, two-chain coiled coil which binds along the length of actin filaments in both muscle and non-muscle cells. This gene associates N-terminus to C-terminus to form a continuous strand along both sides of the actin filament and regulates its function. Tropomyosin contributes to most, if not all, functions of the actin cytoskeleton, and its role is essential for the viability of a wide range of organisms. The ability of tropomyosin to contribute to the many functions of the actin cytoskeleton is related to the temporal and spatial regulation of expression of tropomyosin isoforms.