Essential for the organization of sarcomeric actin thin filaments in skeletal muscle (PubMed:25250574). Increases the rate of actin polymerization (PubMed:25250574). May interact with tropomyosin alpha (TPM1/2) N-terminus (PubMed:25250574). Interacts with KLHL40; leading to stabilization (By similarity). Highly expressed in nonstriated areas of developing myotubes, where it shows a granular cytoplasmic pattern. In sarcomeres, highly expressed in the M band region and, at lower levels, along actin thin filaments. Not detected in Z-disks. In sarcomeres, may be located near, but not at, actin thin filament pointed end. Expressed in cardiac and at higher levels in skeletal muscles (at protein level). Expressed soon after the start of myoblast differentiation and in skeletal muscle throughout life from at least 14 weeks gestation (at protein level). Ubiquitinated, leading to its degradation. Interaction with KLHL40 negatively regulates ubiquitination and degradation. The disease is caused by variants affecting the gene represented in this entry. Belongs to the tropomodulin family.