Human Matriptase/ST14 Catalytic Domain Antibody

Human Matriptase, encoded by the ST14 (suppression of tumorogenicity 14) gene, is also known as tumor associated differentially expressed gene 15 protein/TADG‑15), epithin, and membrane-type serine protease 1/MT-SP1 (1). Predicted to have a significant role in tumor biology, Matriptase may be a novel target for anti-cancer therapy (2). However, expressed in most human epithelia, Matriptase is also important in several physiological processes (1). For example, it activates prostasin to initiate a protease cascade that is essential for epidermal differentiation (3), and it converts a single-chain IGFBP-rp1 into the two-chain form (4). Matriptase is a type II transmembrane serine protease with a complex modular structure (1). The 855 amino acid (aa) sequence of human Matriptase consists of a cytoplasmic tail (aa 1‑55), a transmembrane domain (aa 56‑76), and an extracellular portion (aa 77‑855). The latter contains the following domains: SEA (aa 86‑201), two CUBs (aa 214‑334 and 340‑447), four LDLRAs (aa 452‑486, 487‑523, 524‑560, and 566‑603), and a serine protease (aa 615‑855). The physiological activation of the single-chain zymogen requires the cleavage at the SEA domain within the ER or Golgi, association with HAI-1, which facilitates the transport of the protease to the cell surface, and auto-cleavage at QAR-V(615)VGG (1). The activated Matriptase is inhibited by HAI-1, and the resulting HAI-1 complex can be shed from the cell surface (1).