TYROSINE PHOSPHORYLATION OF PHOSPHOLIPASE-C-GAMMA IN C-MET/HGF RECEPTOR-STIMULATED HEPATOCYTES - COMPARISON WITH HEPG2 HEPATOCARCINOMA CELLS

Hepatocyte growth factor (HGF) stimulates inositol 1,4,5-trisphosphate (InsP3) formation in rat primary cultured hepatocytes, which is inhibited by the pretreatment with a tyrosine kinase inhibitor, genistein. This lnsP3 production was coincident with tyrosine phosphorylation of phospholipase Cγ (PLCγ), detected in immunoprecipitates with anti-PLCγ, suggesting activation mechanism of PLCγ by tyrosine phosphorylation. However, in human hepatocarcinoma HepG2 cells, HGF, which suppresses cell growth, causes neither phosphorylation of PLCγ nor lnsP3 formation. The results suggests that PLCγ in normal hepatocytes was activated by HGF through tyrosine kinase of HGF receptor. © 1993 Academic Press.