Phospho-ErbB3/HER3 (Tyr1289) Recombinant antibody

V-erb-b2 erythroblastic leukemia viral oncogene homolog 3 (ErbB-3, HER3) is a member of the EGF receptor tyrosine kinase family including EGFR (HER1), Neu (ErbB-2, HER2), ErbB-3 (HER3), and ErbB-4 (HER4) that are frequently overexpressed in a variety of carcinomas. Unlike EGFR and HER2, their paralogue HER3 does not possess intrinsic kinase activity due to substitutions at critical positions in the kinase domain. To phosphorylate tyrosine residues in the HER3 cytoplasmic tail to recruit and activate intracellular signaling molecules, it must interact with another functional tyrosine kinase. HER3 exhibits this crosstalk preferentially with HER2 and EGFR, with which it can form heterodimers. Ligand-induced hetero-dimerization with EGFR or HER2 promotes HER3-tyrosine phosphorylation at 6 positions (1054, 1197, 1222, 1260, 1276, and 1289) in the C-terminal tail capable of recruiting of the SH2-domain-containing p85 activator of phosphatidyl-inositol-3 kinase (PI3K) and promoting activation of the downstream Akt signaling pathway. (PMID: 35249128)