Binds to actin filaments in muscle and non-muscle cells (PubMed:7568216, PubMed:22812662). Plays a central role, in association with the troponin complex, in the calcium dependent regulation of vertebrate striated muscle contraction (PubMed:22812662). Smooth muscle contraction is regulated by interaction with caldesmon. In non-muscle cells is implicated in stabilizing cytoskeleton actin filaments. Homodimer (PubMed:7568216, PubMed:22812662). Heterodimer of an alpha (TPM1, TPM3 or TPM4) and a beta (TPM2) chain (PubMed:7568216, PubMed:22812662). Interacts with HRG (via the HRR domain); the interaction contributes to the antiangiogenic properties of the histidine/proline-rich region (HRR) of HRG (By similarity). Interacts (via N-terminus) with LMOD2 (via N-terminus) and TMOD1 (via N-terminus) (By similarity). Associates with F-actin stress fibers (PubMed:7568216). Additional isoforms seem to exist. The molecule is in a coiled coil structure that is formed by 2 polypeptide chains. The sequence exhibits a prominent seven-residues periodicity. Phosphorylated at Ser-283 by DAPK1 in response to oxidative stress and this phosphorylation enhances stress fiber formation in endothelial cells. Belongs to the tropomyosin family. miscellaneous discrepancy.