Claim: PLCG1's catalytic function can be activated by non-receptor tyrosine kinases, cytosolic enzymes responsible for catalyzing the transfer of phosphate groups.
Evidence: Phospholipase C, gamma 1, also known as PLCG1,is a protein that in humans involved in cell growth, migration, apoptosis, and proliferation. PLCG1 can be activated by receptor tyrosine kinases (RTKs) and non-receptor tyrosine kinases. Different preferred sequences around Tyr in Src and Abl suggest that these two types of nRTKs phosphorylates different targets. These PH domains bind to phosphatidylinositol lipids that have been phosphorylated at particular positions on the head group. Catalysis (/kəˈtæləsɪs/) is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (/ˈkætəlɪst/). Catalysts are not consumed in the catalyzed reaction but can act repeatedly. Often only very small amounts of catalyst are required. In general, chemical reactions occur faster in the presence of a catalyst because the catalyst provides an alternative reaction pathway - or mechanism - with a lower activation energy than the non-catalyzed mechanism. In catalyzed mechanisms, the catalyst usually reacts to form an intermediate, which then regenerates the original catalyst in a process. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process regenerating the catalyst. The protein encoded by this gene catalyzes the formation of inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG) from phosphatidylinositol 4,5-bisphosphate. This reaction uses calcium as a cofactor and plays an important role in the intracellular transduction of receptor-mediated tyrosine kinase activators. For example, when activated by SRC, the encoded protein causes the Ras guanine nucleotide exchange factor RASGRP1 to translocate to the Golgi apparatus, where it activates Ras. Also, this protein has been shown to be a major substrate for heparin-binding growth factor 1 (acidic fibroblast growth factor)-activated tyrosine kinase. The receptor protein tyrosine phosphatase PTPmu (PTPRM) is capable of dephosphorylating PLCG1. 
Receptor tyrosine kinases (RTKs) are the high-affinity cell surface receptors for many polypeptide growth factors, cytokines, and hormones. Of the 90 unique tyrosine kinase genes identified in the human genome, 58 encode receptor tyrosine kinase proteins. 
In chemistry, phosphorylation (a phosphate group is added to a molecule) of a molecule is the attachment of a phosphoryl group. Protein phosphorylation is especially important for their function; for example, this modification activates (or deactivates) almost half of the enzymes present in Saccharomyces cerevisiae, thereby regulating their function. Protein phosphorylation is considered the most abundant post-translational modification in eukaryotes. Recent work demonstrates widespread human protein phosphorylation on multiple non-canonical amino acids, including motifs containing phosphorylated histidine, aspartate, glutamate, cysteine, arginine and lysine in HeLa cell extracts. However, due to the chemical lability of these phosphorylated residues, and in marked contrast to Ser, Thr and Tyr phosphorylation, the analysis of phosphorylated histidine (and other non-canonical amino acids) using standard biochemical and mass spectrometric approaches is much more challenging and special procedures and separation techniques are required for their preservation alongside classical Ser, Thr and Tyr phosphorylation.