Figure 1.

Life cycle of the tyrosine kinase receptor. Ligand binding to RTK monomer mediates receptor dimerization, autophosphorylation, and various adapter protein binding. In turn, RTK interacting proteins mediate receptor internalization and downstream RAS/MAPK cascade activation including negative and positive feedback loops regulating ubiquitination and phosphorylation. Internalized RTK continues signaling and upon ubiquitination can be recycled to the cell surface.^95–98 Alternatively, RTK can be subjected to lysosomal degradation.^96,98

MAPK, mitogen-activated protein kinase; RTK, receptor tyrosine kinase.