ErbB4 (Erythroblastic Leukemia Viral Oncogene Homolog-4) is a 180-kDa transmembrane RTK (Receptor Tyrosine Kinase) that regulates cell proliferation and differentiation. The ErbB4 gene has been isolated as the fourth member of the human EGFR (Epidermal Growth Factor Receptor) subfamily of tyrosine kinases and has been reported to encode a receptor for Her (Heregulin) (Ref.1). ErbB4 is expressed in several tissues, mainly heart, neural tissue and various epithelia. ErbB4 and its ligands have important roles in normal cardiovascular and neural development, differentiation of the mammary gland, and in pathological conditions, such as heart diseases and cancer (Ref.2).
Four structurally different ErbB4 isoforms have been identified. Isoforms differ either within their extracellular juxtamembrane domains or within their C-terminal cytoplasmic tails. Juxtamembrane isoforms [...]