Receptor tyrosine-protein kinase erbB-2 kinase domain (HER2 kinase domain)

The HER2 kinase domain is the intracellular catalytic domain of the receptor tyrosine-protein kinase erbB-2 (commonly known as HER2 or ERBB2), a member of the EGFR/ErbB family of receptor tyrosine kinases. This domain is responsible for ATP-dependent phosphorylation of tyrosine residues on substrate proteins, a critical step in activating downstream signal transduction pathways that regulate cell proliferation, growth, and survival[1][5][7]. HER2 does not bind ligand directly but functions as a coreceptor, forming heterodimers with other family members (especially EGFR/erbB-1 and HER3/erbB-3), resulting in activation and trans-autophosphorylation within the kinase domain[1][4][6]. Overexpression and hyperactivation of HER2—often due to gene amplification—is a major oncogenic driver in cancers, particularly breast and gastric cancers. The kinase domain is the target of several approved therapeutics, including small molecule inhibitors and monoclonal antibodies, which disrupt signaling by inhibiting kinase activity or receptor dimerization[2][3][5]. HER2 status is a key biomarker for patient selection in cancer therapy, but therapeutic targeting is challenged by issues such as resistance and cardiotoxicity[5].

Other names

HER2ERBB2NeuCD340HER-2/neuHER2/ERBB2 kinase domainerbB-2 kinase domain

Inhibition of kinase activity (small molecules such as lapatinib, neratinib); Antibody-mediated receptor blockade (trastuzumab, pertuzumab); Disruption of dimerization (pertuzumab); Antibody-dependent cellular cytotoxicity (trastuzumab)