High Temperature Requirement Factor A4 (HTRA4)

HTRA4 encodes a member of the HtrA family of proteases. The encoded protein contains a putative signal peptide, an insulin growth factor binding domain, a Kazal protease inhibitor domain, a conserved trypsin domain and a PDZ domain. Based on studies on other related family members, this enzyme may function as a secreted oligomeric chaperone protease to degrade misfolded secretory proteins. Other human HtrA proteins have been implicated in arthritis, tumor suppression, unfolded stress response, apoptosis, and aging.the deduced 445-amino acid HTRA4 protein contains an N-terminal signal sequence, followed by an insulin growth factor -binding domain, a Kazal protease inhibitor domain, a trypsin (PRSS1)-like domain, and a C-terminal PDZ domain.