S100 calcium-binding protein A13 (S100A13)

S100 calcium-binding protein A13 (S100A13) is a small, cytoplasmic and nuclear protein within the S100 family, characterized by two EF-hand calcium-binding motifs[1][2][5]. It forms homodimers, binds calcium and copper ions, and is widely expressed in diverse tissues with high levels in the thyroid gland[1][2][3]. S100A13 is essential for the non-classical (ER-Golgi-independent) export/secretion of proteins lacking a signal peptide, including acidic fibroblast growth factor-1 (FGF-1) and interleukin-1alpha[2][3][5]. Through facilitating the extracellular release of these proangiogenic and inflammatory factors, S100A13 is implicated in tumor angiogenesis and progression, particularly in melanoma and glioma, where its expression correlates strongly with microvessel density and tumor aggressiveness[4][5]. Evidence indicates S100A13 may be associated with chemotherapy resistance in melanoma and is upregulated in several cancers[1][4]. No approved drugs are known to directly target S100A13, though it is a potential marker and mediator for anti-angiogenic therapies and as an indicator of aggressive tumor phenotypes[4][5].

Other names

Protein S100-A13S100 calcium-binding protein A13S100A13S100-A13

Not directly targeted by approved small molecule drugs or biologics, but plays a role as a mediator in the unconventional export of angiogenic factors (e.g., FGF-1) and inflammatory cytokines (e.g., IL-1alpha)[2][4][5].