Mediates the production of the second messenger molecules diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP3). Plays an important role in the regulation of intracellular signaling cascades. Becomes activated in response to ligand-mediated activation of receptor-type tyrosine kinases, such as PDGFRA, PDGFRB, EGFR, FGFR1, FGFR2, FGFR3 and FGFR4 (By similarity). Plays a role in actin reorganization and cell migration (PubMed:17229814). a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-4,5-bisphosphate) + H2O = 1D-myo-inositol 1,4,5-trisphosphate + a 1,2-diacyl-sn-glycerol + H(+) a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol) + H2O = 1D-myo-inositol 1-phosphate + a 1,2-diacyl-sn-glycerol + H(+) Activated by phosphorylation on tyrosine residues. Interacts with AGAP2 via its SH3 domain. Interacts (via SH2 domain) with RET. Interacts with FLT1 (tyrosine-phosphorylated) (By similarity). Interacts (via SH2 domain) with FGFR1, FGFR2, FGFR3 and FGFR4 (phosphorylated). Interacts with LAT (phosphorylated) upon TCR activation. Interacts (via SH3 domain) with the Pro-rich domain of TNK1. Associates with BLNK, VAV1, GRB2 and NCK1 in a B-cell antigen receptor-dependent fashion. Interacts with CBLB in activated T-cells; which inhibits phosphorylation. Interacts with SHB. Interacts (via SH3 domain) with the Arg/Gly-rich-flanked Pro-rich domains of KHDRBS1/SAM68. This interaction is selectively regulated by arginine methylation of KHDRBS1/SAM68. Interacts with INPP5D/SHIP1, THEMIS and CLNK (By similarity). Interacts with AXL, FLT4 and KIT. Interacts with RALGPS1. Interacts (via the SH2 domains) with VIL1 (phosphorylated at C-terminus tyrosine phosphorylation sites). Interacts (via SH2 domain) with PDGFRA and PDGFRB (tyrosine phosphorylated). Interacts with PIP5K1C (By similarity). Interacts with NTRK1 and NTRK2 (phosphorylated upon ligand-binding). Interacts with SYK; activates PLCG1. Interacts with GRB2, LAT and THEMIS upon TCR activation in thymocytes (By similarity). Interacts with TESPA1; the association is increased with prolonged stimulation of the TCR and may facilitate the assembly of the LAT signalosome. (Microbial infection) Interacts (via SH3 domain) with HEV ORF3 protein. Rapidly redistributed to ruffles and lamellipodia structures in response to epidermal growth factor (EGF) treatment. The SH3 domain mediates interaction with CLNK (By similarity). The SH3 domain also mediates interaction with RALGPS1 (PubMed:10747847). Tyrosine phosphorylated in response to signaling via activated FLT3, KIT and PDGFRA (By similarity). Tyrosine phosphorylated by activated FGFR1, FGFR2, FGFR3 and FGFR4. Tyrosine phosphorylated by activated FLT1 and KDR. Tyrosine phosphorylated by activated PDGFRB. The receptor-mediated activation of PLCG1 involves its phosphorylation by tyrosine kinases, in response to ligation of a variety of growth factor receptors and immune system receptors. For instance, SYK phosphorylates and activates PLCG1 in response to ligation of the B-cell receptor. May be dephosphorylated by PTPRJ. Phosphorylated by ITK and TXK on Tyr-783 upon TCR activation in T-cells. Ubiquitinated by CBLB in activated T-cells.