This gene is a member of the Tyr protein kinase family and the epidermal growth factor receptor subfamily. It encodes a single-pass type I membrane protein with multiple cysteine rich domains, a transmembrane domain, a tyrosine kinase domain, a phosphotidylinositol-3 kinase binding site and a PDZ domain binding motif. The protein binds to and is activated by neuregulins and other factors and induces a variety of cellular responses including mitogenesis and differentiation. Multiple proteolytic events allow for the release of a cytoplasmic fragment and an extracellular fragment. Mutations in this gene have been associated with cancer. Alternatively spliced variants which encode different protein isoforms have been described, however, not all variants have been fully characterized.,ALS19,HER4,p180erbB4,ERBB4,HER4/ErbB4,Cancer,Tumor biomarkers,Signal Transduction,Kinase,Tyrosine kinases,ErbB-HER Signaling Pathway,Cell Biology & Developmental Biology,Growth factor,EGF,Immunology & Inflammation,ERBB4