Human HER4 kinase, also known as Erb-B4, Proto-Oncogene-Like Protein C-ErbB-4, and Tyrosine Kinase-Type Cell Surface Receptor HER4, GenBank Accession No. NM_005235, a.a. 708-993, with an N-terminal GST-tag, expressed in a Baculovirus infected Sf9 cell expression system. MW=59.5 kDa.