In Vitro Tyrosine Phosphorylation of PLC-γ1 and PLC-γ2 by SRC-Family Protein Tyrosine Kinases

The phosphorylation of purified phospholipase C-γ1 (PLC-γ1) and PLC-γ2 by src-family-protein tyrosine kinases (PTKs) p56lck p53/56lyn, p59hck, p59fyn, and p60src was studied in vitro. All five PTKs phosphorylated PLC-γ1 and PLC-γ2, suggesting that both PLC-γ isozymes can be phosphorylated in cells by any of the src-fami1y PTKs in response to the activation of cell surface receptors. Comparison of the in vitro phosphorylation rates revealed no distinct specificity between PLC-γ1 and PLC-γ2, or between the five PTKs.