Phospholipase C–γ1: A Phospholipase and Guanine Nucleotide Exchange Factor

Two pathways depicting the molecular mechanisms by which PLC-γ1 mediates GF-induced cell mitogenesis. The red arrow indicates a guanosine nucleotide exchange factor (GEF) model [supported by (2)], and our speculation concerning methylation. The black arrow indicates a conventional phospholipase model that involves the PLC-γ1-dependent generation of DAG and IP3. GFs, growth factors; PM, plasma membrane; PI3K, phosphatidylinositol-3′ kinase; MAPK, mitogen-activated protein kinase.