CAP (cysteine-rich secretory proteins, antigen 5, and pathogenesis-related 1 proteins) domain of peptidase inhibitor 16 and HrTT-1 protein
Human peptidase inhibitor 16 (PI16) is also called cysteine-rich secretory protein 9 (CRISP-9) or PSP94-binding protein. Mouse PI16 is also called cysteine-rich protease inhibitor. PI16 is predominantly expressed by cardiac fibroblasts and is exposed to the interstitium via a glycophosphatidylinositol (-GPI) membrane anchor. It suppresses the activation of the chemokine chemerin in the myocardium, which may be a part of the cardiac stress response. At high endothelial shear stress, PI16 is an inflammation-regulated inhibitor of matrix metalloproteinase 2 (MMP2). Also included in this subfamily is the HrTT-1 protein, a tail-tip epidermis marker in ascidians. The wider family of CAP domain containing proteins includes plant pathogenesis-related protein 1 (PR-1), cysteine-rich secretory proteins (CRISPs), and allergen 5 from vespid venom, among others.
Jiyao W et al.(2023). "The conserved domain database in 2023.",