Blocks the elongation and depolymerization of the actin filaments at the pointed end. The Tmod/TM complex contributes to the formation of the short actin protofilament, which in turn defines the geometry of the membrane skeleton (By similarity). Binds to the N-terminus of tropomyosin and to actin. In myofibrils with sarcomeric structure, localizes to the pointed end of actin thin filaments. Belongs to the tropomodulin family.