title: Neuregulin-1 only induces trans-phosphorylation between ErbB receptor heterodimer partners.
abstract: ErbB2, ErbB3 and ErbB4 are members of the Epidermal Growth Factor Receptor (EGFR) sub-family of Receptor Tyrosine Kinases (RTKs). Neuregulin-1 (NRG-1) is a ligand of ErbB3 and ErbB4 receptors. NRG-1-induced ErbB2/ErbB3 or ErbB2/ErbB4 heterodimerization, followed by receptor phosphorylation, plays multiple biological roles. To precisely determine the phosphorylation status of each ErbB receptor in ErbB2/ErbB3 and ErbB2/ErbB4 heterodimers, an immunoprecipitation-recapture of the ErbB receptors was performed to exclude any co-immunoprecipitated heterodimer partners from cells with co-expression of ErbB2/ErbB3, ErbB2/ErbB4, or ErbB2/ErbB4D843N, a kinase-inactive ErbB4 mutant, in which the aspartic acid at 843 (D843) was replaced by an asparagine (N). Here, we provide direct biochemical evidence that ErbB2 was only trans-phosphorylated by ErbB4, but not by ErbB3 or ErbB4D843N. By contrast, ErbB3, ErbB4 and ErbB4D843N were trans-phosphorylated by ErbB2 in the co-transfected cells. Therefore, we conclude that trans-phosphorylation, but not cis-phosphorylation occurred between ErbB2/ErbB3 and ErbB2/ErbB4 heterodimer partners by NRG-1 stimulation.
authors.affiliation: Fudan-Zensun Cellular Signaling Research Laboratory, School of Life Science, Fudan University, No. 220 Handan Road, Shanghai 200433, PR China.
authors.forename: Zhaomin
authors.initials: Z
authors.lastname: Li
authors.forename: Yanai
authors.initials: Y
authors.lastname: Mei
authors.forename: Xifu
authors.initials: X
authors.lastname: Liu
authors.forename: Mingdong
authors.initials: M
authors.lastname: Zhou
mesh_terms: D000818:Animals; D019281:Dimerization; D066246:ErbB Receptors; D051379:Mice; D041681:NIH 3T3 Cells; D020890:Neuregulin-1 / Q000494:pharmacology*; D010766:Phosphorylation; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D020893:Receptor, ErbB-3 / Q000235:genetics / Q000378:metabolism*; D066247:Receptor, ErbB-4
chemical_list: D066246:ErbB Receptors; D020890:Neuregulin-1; D018719:Erb-b2 Receptor Tyrosine Kinases; D020893:Receptor, ErbB-3; D066247:Receptor, ErbB-4; C587690:Erbb4 protein, mouse