Fig. 3.

Flow chart of receptor tyrosine kinase-mediated cell signaling in human cells. Binding of ligand to receptor tyrosine kinases causes dimerization and autophosphorylation. Signaling proteins such as GRB2 and SOS associate with phosphorylated tyrosine receptor kinases, triggering signaling cascades involving kinases such as RAS, RAF, MEK, and MAPK. Ultimately, the transcription factors Fos and Jun are phosphorylated and translocate to the nucleus, where they activate AP1-dependent genes.