Mutations at residues Tyr771 and Tyr783 of phospholipase C‐γ1 have different effects on cell actin‐cytoskeleton organization and cell proliferation in CCL‐39 cells

Currently a central question that remains unresolved is the potential importance of phospholipase C (PLC)-γ1 in cell mitogenesis. In this study, we introduced wild-type PLC-γ1 plasmid and mutants Y771F and Y783F into CCL-39 fibroblasts and investigated their effect on host cell functions. To our surprise, Y771F and Y783F plasmids appeared to have opposite effects on CCL-39 cell actin-cytoskeleton organization and cell proliferation. Y771F transfectants increased cell proliferation by two-fold. Y783F transfectants showed much thicker actin filaments and decreased cell growth rate by 50%. These results suggest that PLC-γ1 mutations have an essential impact on cell mitogenesis.