Figure 2.

Heterodimerization modulates ErbB signaling. Ligand binding triggers ErbB dimerization and kinase activation, leading to phosphorylation of carboxy-terminal tyrosine residues in trans. When ErbB2 is expressed, mainly ErbB2-containing heterodimers are formed that, when compared with their homodimeric counterparts, possess altered signaling properties. EGF, epidermal growth factor; NRG, neuregulin; P, phosphotyrosine.