Fig. 2.
Signal pathway of receptor-activated tyrosine kinase receptors. Cytokines, growth factors, and insulin activate receptor-linked tyrosine kinases that induce receptor autophosphorylation. The GRB2 and son of sevenless (SOS) guanine nucleotide-releasing protein is recruited to the plasma membrane. SOS activates raf kinase, which initiates a phosphorylation cascade resulting in effects on metabolism and growth.