The human epidermal growth factor (EGF) receptor HER4/erbB4 is part of the erbB family of receptor tyrosine kinases, including also EGFR, HER2/erbB2 and HER3/erbB3. Activation of ErbB receptors is initiated by ligand binding, either variants of heregulins (HRGs) or different EGF related proteins, to their extracellular domain, leading to the formation of both, homo- and heterodimeric ErbB receptor complexes. In contrast to HER-3, HER-4/erbB is ativated by both, HRGs and some of the EGF ligands, providing a considerable variability in receptor activation and a diversity of HER-4 monomers and heterodimers. Upon dimerization the receptor kinase undergo autophosphorylation at specific tyrosine residues within the intracellular domain, acting as binding sites for proteins e.g. Shc, Grb2, Src, PI3K, SHP1 and SHP2. This couples the ErbB receptor to downstream signaling pathways e.g. MAPK and the Akt pathway. HER4 is overexpressed in breast tumor. In cell line experiments, when HER-2 positive cancer cells were transfected to overexpress HER-4, a reduction in proliferation and an increase in apoptosis were observed. Thus, in contrast to HER-2 overexpression of HER-4 has been associated with a good outcome, might be explained by differences in the recruitment of signal transduction pathways and alternate apoptosis stimulation.
Protein: human ERBB4 amino acids R676-V1307 (as in GenBank entry NM_005235)*, N-terminally
fused to GST-HIS6-Thrombin cleavage site
Theoretical MW : 102.1 kDa (fusion proteins)
Expression system: Baculovirus infected Sf9 cells
Specific activity : 26.000 pmol/mg x min
Method for determination of Km value & specific activity: Filter binding assay MAFC membrane
Protein concentration: 0.232 mg/ml (Bradford method using BSA as standard protein)
Size: 10 µg
Ordering information: shipped on dry ice
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