S100A4 Human

S100 Calcium-Binding Protein A4 (S100A4), also known as metastasin, is a member of the S100 family of proteins. These proteins are characterized by their ability to bind calcium ions through EF-hand motifs, which are helix-loop-helix structural domains . S100A4 is encoded by the S100A4 gene located on chromosome 1q21 in humans .

S100A4 is a small protein consisting of 101 amino acids . It contains two EF-hand calcium-binding motifs, which are crucial for its function. The protein is localized in the cytoplasm and/or nucleus of various cell types and is involved in several cellular processes, including cell motility, invasion, and tubulin polymerization .

S100A4 plays a significant role in the regulation of the cell cycle, differentiation, and apoptosis. It is also involved in the epithelial to mesenchymal transition (EMT), a process critical for cancer metastasis . The protein interacts with non-muscle myosin heavy chain IIA (NMMHC IIA), enhancing cell motility and invasiveness .

The expression of S100A4 is often upregulated in various cancers, including breast, colorectal, and pancreatic cancers . Its overexpression is associated with poor prognosis and increased metastatic potential. S100A4 has been shown to interact with other proteins, such as S100A1, and is implicated in tumor progression and metastasis .

Given its role in cancer progression, S100A4 is considered a potential therapeutic target. Inhibiting its expression or function could potentially reduce tumor invasiveness and metastasis . Research is ongoing to develop specific inhibitors that can target S100A4 and its interactions with other proteins.