- The content on this page originated on Wikipedia and is yet to be significantly improved. Contributors are invited to replace and add material to make this an original article.
In biochemistry, erbB-2 (Human Epidermal growth factor Receptor 2, HER2, HER-2, HER2/neu) is a cell surface receptor that is a "protein-tyrosine kinase receptor that is found to be overexpressed in a significant number of adenocarcinomas including gastric, esophageal, salivary, colon, bladder and lung cancers (8-9). It has extensive homology to and can heterodimerize with the EGF receptor (epidermal growth factor receptor), the erbB-3 receptor and the erbB-4 receptor. " The ErbB-2 gene is located on chromosome 17q21 and encodes a protein of 1255 amino acids which weighs, when glycosylated, 185 kDa. The human ErbB-2 was cloned by homology screening with v-ErbB (3) and has the highest homology to the EGFR among ErbB family members. It is mostly related to EGFR in its kinase domain (82%) and mostly distinct in the C-terminus, which contains most of the autophosphorylation sites. ErbB-2 is the only orphan receptor of the ErbB family, since no ligand binding it has been found up to date. Activation of ErbB-2 is, therefore, highly dependent on the expression of other family members, to which it is recruited as a preferred heterodimeric partner (4). On the other hand, overexpression and/or mutation of ErbB-2 are thought to lead to spontaneous dimerisation and the stabilization of the receptor dimmers in a ligandindependent manner (5-7).