Serine Peptidase Inhibitor Kunitz Type 1 (SPINT1)

SPINT1 is a potent inhibitor specific for HGF activator and is thought to be involved in the regulation of the proteolytic activation of HGF in injured tissues. Alternative splicing results in multiple variants encoding different isoforms.The protein contains an N-terminal putative signal peptide sequence, a hydrophobic, membrane-associated C-terminal region, and a central region that encodes the processed, cleaved protein. SPINT1 has 3 potential N-glycosylation sites. Two regions show extensive similarity to the Kunitz-type sequence of serine protease inhibitors, but only one of these regions is believed to be responsible for the inhibitory activity of SPINT1. Between the 2 Kunitz domains is a region similar to the cysteine-rich ligand-binding domain of the low density lipoprotein receptor (LDLR).