Activation of RTK signal transduction. (a) Inactive RTK are monomeric but after ligand binding dimerization of the extracellular domain occurs (b) and since cytoplasmic domains are juxtaposed, phosphorylation of tyrosine residues (ovals with Tyr labels) is facilitated. Phosphorylation allows inactive proteins to interact with the tyrosine residues and elicit appropriate cellular responses. Adapted from [50] Hubbard, 2004.
