In: Biology
Answer: PLC gamma is downstream for RTK's(Receptor tyrosine kinases) only. PLC beta is downstream for GPCR( G protein-coupled receptor).
Receptor tyrosine kinases is a transmembrane receptor. These receptors have intracellular tyrosine kinase moiety. These receptors include receptors for growth factors, insulin receptor and so on. When a specific ligand binds to these receptors dimerisation (association of two intracellular kinase domains) of receptor takes place. This facilitates the autophosphorylation of an intracellular tyrosine residue. Autophosphorylation facilitates the recruitment of adapter proteins(SH2 domain proteins). These adapter proteins attached to the intracellular tyrosine kinase domain. There are many SH2 proteins like Phospholipase C, protein kinases and enzymes. All of these SH2 proteins also known as downstream of RTK's. When receptor is RTK the isoform of PLC will be PLC-gamma. PLC-gamma facilitates the splitting of PIP2 into IP3 and DAG. IP3 pathway facilitates the calcium release and DAG pathway in combination with calcium facilitates the activation of Protein kinase C(PKc). PKc facilitates the phosphorylation of structural proteins and alters the activity of proteins(functional and structural).
During the course of GPCR activation PLC isoform- PLC beta is recruited as an adapter protein.
Hence the systemned statement(as question) is false.
PIP2- Phosphatidylinositol4,5-bisphosphate
DAG- Diacylglycerol
IP3- Inositol1,4,5 trisphosphate