<p>These proteins are non-peptidase homologues belonging to MEROPS peptidase family S1 (chymotrypsin family, clan PA(S)), subfamily S1A.</p> <p>This family contains two mammalian proteins, hepatocyte growth factor (HGF; also called scatter factor), and macrophage stimulating protein 1 (MST1; also called hepatocyte growth factor-like protein). HGF is essential for placental, liver, and muscle development, whereas MST1 is not required for embryogenesis, fertility, or wound healing. Genes for HGF and its receptor, the Met tyrosine kinase, are close together on chromosome 7, so that polysomy of chromosome 7 may contribute to malignancy through overproduction of both molecules. MST1 and its receptor, the Ron tyrosine kinase (<db_xref db="PIRSF" dbkey="PIRSF000617"/>), are close together on chromosome 3. HGF and MST1 are closely related to plasminogen (<db_xref db="PIRSF" dbkey="PIRSF001150"/>), having similar domain architecture: signal sequence followed by a PAN (formerly apple) domain, four (rather than five) kringle domains, and a trypsin domain, which appears to lack any peptidase activity.</p> <p>For additional information please see [<cite idref="PUB00014576"/>, <cite idref="PUB00014577"/>].</p>