Tropomodulin-3 is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

that in humans is encoded by the ''TMOD3''

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

. 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 The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is compos ...

by capping the pointed (minus) ends of

actin Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of ...

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 The endothelium (: endothelia) is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the res ...

, 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.

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