– TPM1, also known as tropomyosin-1, is a member of the tropomyosin family. Members of this family are highly conserved, widely distributed actin-binding proteins involved in the contractile system of striated and smooth muscles and the cytoskeleton of non-muscle cells. highly conserved, widely distributed actin-binding proteins involved in the contractile system of striated and smooth muscles and the cytoskeleton of non-muscle cells. TPM1 is one type of alpha-helical chain that forms the predominant tropomyosin of striated muscle. It binds to actin filaments in muscle and non-muscle cells. TPM1 plays a central role, in association with the troponin complex, in the calcium-dependent regulation of vertebrate striated muscle contraction.