Matriptase is an epithelial-derived, integral membrane serine
protease. This protease forms a complex with the
Kunitz-type serine protease inhibitor,
HAI-1, and is found to be activated by
sphingosine-1-phosphate. This protease has been shown to cleave and activate hepatocyte growth factor/scatter factor, and
urokinase plasminogen activator, which suggest the function of this protease as an epithelial membrane activator for other proteases and latent growth factors. Matriptase is a type II transmembrane serine protease expressed in most human
epithelia, where it is coexpressed with its cognate transmembrane inhibitor,
hepatocyte growth factor activator inhibitor (HAI)-1. Activation of the matriptase zymogen requires sequential
N-terminal cleavage, activation site autocleavage, and transient association with HAI-1. Matriptase has an essential physiological role in
profilaggrin processing,
corneocyte maturation, and lipid matrix formation associated with terminal differentiation of the oral
epithelium and the
epidermis, and is also critical for hair follicle growth. Matriptase is an 80- to 90-kDa cell surface glycoprotein with a complex modular structure that is common to all matriptases. == Clinical significance ==