Hepatocyte Growth Factor Activator 1 (HAI-1)

HAI-1 is one of two types of Kunitz-type serine protease inhibitors that was detected as an inhibitory factor of hepatocyte growth factor activator (HGFA), the factor that converts hepatocyte growth factor into the active form. It is said to act as a transmembrane protein having two Kunitz domains, and to inhibit HGFA also as a free form secreted from membrane. HAI-1 targets various other serine proteases such as matriptase and hepsin. It has been detected in the placenta, kidney, pancreas, prostate, and small intestine, and also reported to express in the liver cancer.