Anti-Human ErbB3 (E231-GRP)

V-erb-b2 erythroblastic leukemia viral oncogene homolog 3 (avian), also known as ERBB3 is a member of the epidermal growth factor (EGF) receptor subfamily of receptor tyrosine kinases and is believed to be a receptor for an unknown ligand.1 ErbB3 has a heregulin (HRG) or neuregulin binding domain but lacks intrinsic protein tyrosine kinase activity.2 Therefore, it can bind to the ligand but not convey the signal into the cell through protein phosphorylation. However, it does form heterodimers with other EGF receptor family members which do have kinase activity. Heterodimerization leads to the activation of pathways which lead to cell proliferation or differentiation. Amplification of ErbB3 and/or over-expression of its protein have been reported in numerous cancers, including prostate, bladder, and breast tumors.