ErbB receptors are activated through ligand binding, which induces receptor dimerization. This can occur as homodimers (e.g., EGFR-EGFR) or heterodimers (e.g., EGFR-HER2). The dimerization leads to the activation of the intracellular kinase domain, resulting in autophosphorylation of specific tyrosine residues. These phosphorylated residues serve as docking sites for signaling molecules, initiating various downstream pathways such as the PI3K/AKT and RAS/RAF/MEK/ERK pathways.
