Tropomyosin, in association with the troponin complex, plays a central role in the calcium dependent regulation of muscle contraction. Homodimer (Probable). May interact with Unc-89 (via protein kinase domain 2) (PubMed:26251439). Additional isoforms seem to exist. Isoform 9A is expressed both maternally and zygotically during embryogenesis and mid pupal stages. Muscle isoform is expressed at late embryogenesis through to adulthood, highest expression level being late embryo and early larval stages. The molecule is in a coiled coil structure that is formed by 2 polypeptide chains. The sequence exhibits a prominent seven-residues periodicity. Belongs to the tropomyosin family.