TPM3 Human

Tropomyosin-3 exists as a heterodimer consisting of an alpha and a beta chain. This structural organization serves as a gatekeeper, controlling the recruitment and activity of several actin-binding partners such as myosin, non-muscle myosin, troponin, tropomodulin, Arp2/3, ADF/cofilin, and gelsolin . The TPM3 gene has been recognized as an indispensable regulator of muscle contraction in slow muscle fibers since its discovery in 1988 .

In vertebrate striated muscle, Tropomyosin-3, in association with the troponin complex, plays a central role in the calcium-dependent regulation of muscle contraction . The tropomyosin genes (TPM1-4) contribute to the functional diversity of skeletal muscle fibers. For instance, the α-tropomyosin isoform (Tpm1.1) encoded by the TPM1 gene is exclusively expressed in fast muscle fibers (type 2), while the striated β-tropomyosin isoform (Tpm2.2) encoded by the TPM2 gene is expressed in both slow (type 1) and fast muscle fibers .

Mutations in the TPM3 gene are associated with various congenital myopathies, including autosomal dominant nemaline myopathy . These mutations can lead to muscle dysfunction, although the precise mechanisms remain unclear . Additionally, defects in TPM3 are linked to thyroid papillary carcinoma and oncogenes formed by chromosomal translocations involving this locus are associated with cancer .

Recombinant human Tropomyosin-3 is typically expressed in E. coli and purified for research purposes. It is often used to study the protein’s role in muscle contraction and its involvement in various myopathies. The recombinant protein is usually lyophilized and can be reconstituted for experimental use .