ERB4/HER4 (C-term)

erbB4/HER4 is a receptor tyrosine kinase that belongs to the human epidermal growth factor receptor (EGFR) family. erbB4/HER4 is most predominantly expressed in several breast carcinoma cell lines, and in normal skeletal muscle, heart, pituitary, brain, and cerebellum (1). erbB4/HER4 is activated by neuregulins (NRG), betacellulin (BTC), and heparin-binding EGF-like growth factor (2). Neuregulins regulate the expression of ligand- and voltage-gated channels in neurons and skeletal muscle by the activation of ErbB 1-4. The erbB4/HER4 receptor is unique among these receptors because its C-terminal tail binds to a protein motif known as the PDZ domain (3).