Tropomodulin-3 is a protein that in humans is encoded by the TMOD3 gene.
Tropomodulin-3 (Tmod3) is a member of the tropomodulin family of actin-regulatory proteins that plays a key role in modulating the dynamics of the cytoskeleton by capping the pointed (minus) ends of actin filaments. Unlike some other tropomodulin isoforms, Tmod3 is widely expressed in non-muscle cells, where it contributes to essential cellular processes such as shape maintenance, motility, and adhesion. It regulates filament stability by preventing both polymerization and depolymerization at the pointed end, thus helping to define actin filament length and organization. In endothelial cells, Tmod3 has been shown to inhibit cell motility through its capping activity, highlighting its role as a negative regulator of actin-driven migration. Additionally, Tmod3 can bind not only to filamentous actin but also directly to actin monomers, suggesting a broader function in actin filament turnover and cytoskeletal remodeling.
