Tropomyosin 4 (TPM4)

Tropomyosin 4 is a member of the tropomyosin family of actin-binding proteins involved in the contractile system of striated and smooth muscles and the cytoskeleton of non-muscle cells.Vertebrates have at least 4 different tropomyosin genes; in humans, they are named TPM1 , TPM2 , TPM3, and TPM4. Both the muscle and nonmuscle isoforms of the tropomyosins are expressed through alternative splicing of each of the 4 genes. Tropomyosins are dimers of coiled-coil proteins that polymerize end-to-end along the major groove in most actin filaments. They provide stability to the filaments and regulate access of other actin-binding proteins. In muscle cells, they regulate muscle contraction by controlling the binding of myosin heads to the actin filament. Multiple transcript variants encoding different isoforms have been found for this gene.