ErbB 4 (Her-4, c-erbB-4, v-erbB-4) is a member of the class I receptor kinase family. With more than 500 gene products, the protein kinase family is one of the largest families of proteins in eukaryotes. The family has been classified in 8 major groups based on sequence comparison of their tyrosine (PTK) or serine/threonine (STK) kinase catalytic domains. ErbB 4 is activated by neuregulins and NTAK (neural and thymus derived activator for ErbB kinases). ErbB 4 is a receptor for heregulin and is capable of mediating HGL-stimulated tyrosine phosphorylation of itself. Like other protein kinases, ErbB 4 mediate most of the signal transduction in eukaryotic cells, regulating cellular metabolism, transcription, cell cycle progression, cytoskeletal rearrangement and cell movement, apoptosis, and differentiation. ErbB 4 is most predominantly expressed in several breast carcinoma cell lines, and in normal skeletal muscle, heart, pituitary, brain, and cerebellum. Breast tumor cell lines T47-D, MDA-MB-453, BT-474 and H3396 are found to have the highest levels of mRNA, and intermediate levels are seen in MCF-7, MDAMB-330 and MDA-MB-361. Expression of ErbB 4 is low or absent in some breast tumor cell lines such as MDA-MB-231, MDA-MB-157, MDA-MB-468, and SKBR-3. ErbB 4 levels have been found to be elevated in certain human tumor cell lines suggesting that it may play a role in some malignancies.
4ICD; avian erythroblastic leukemia viral (v-erb-b2) oncogene homolog 4; avian erythroblastosis oncogene B 4; c-erbB-4; ERBB4 intracellular domain; ERBB4 transcript variant I12DEL; ERBB4 transcript variant I20DEL; human epidermal growth factor receptor 4; OTTHUMP00000209432; p180erbB4; Proto-oncogene-like protein c-ErbB-4; receptor tyrosine kinase; Receptor tyrosine-protein kinase erbB-4; s80HER4; Tyrosine kinase-type cell surface receptor HER4; v-erb-a erythroblastic leukemia viral oncogene homolog 4; v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 4