Difference between GF (i.e. EGF, FGF) and Insulin Tyrosine kinase receptor activity?
Growth factor: ligan binds to R; R dimerizes and intracellular domains phosphorylate each other allowing other proteins (i.e. PLC-gamma, PI 3-kinase, etc.) to bind. All these proteins contain Src homology (SH2) meaning they allow other proteins to bind at docking site.
Insulin: A tetramer whose beta-subunits are phosphorylated via ligand binding. Then, Insulin Receptor Substrate 1 (IRS-1) binds to serve as a docking site for SH2-containing proteins like PLC-gamma, PI 3-kinase, GRB/SOS, others.