title: Neuregulin-increased expression of acetylcholine receptor epsilon-subunit gene requires ErbB interaction with Shc.
abstract: Selective transcription of acetylcholine receptor (AChR) subunit genes by neuregulin is one of the mechanisms involved in the synaptic localization of AChRs to the neuromuscular junction. Neuregulin stimulates ErbB receptor tyrosine kinases and subsequently activates the Ras/ERK pathway, which is required for neuregulin-mediated induction of AChR subunit genes in muscle cells and synapse-specific expression in vivo. Here we investigated the neuregulin transduction mechanism that leads to ERK activation after ErbB receptor tyrosine phosphorylation. Neuregulin increases the association of the adaptor proteins Grb2 and Shc with both ErbB2 and ErbB3 in C2C12 muscle cells. Dephosphorylation of the tyrosine-phosphorylated ErbB proteins abolished their association with both Grb2 and Shc, suggesting a tyrosine phosphorylation-dependent interaction. The interaction of Shc with the ErbB receptors is mediated by Shc's phosphotyrosine-binding domain. In addition, neuregulin increased tyrosine phosphorylation of Shc. Mutagenesis approaches demonstrated that tyrosine phosphorylation of Shc is required for neuregulin induction of AChR subunit gene expression. Taken together, these data indicate that the interaction of ErbB receptors with Grb2 alone is insufficient for neuregulin-activated transcription, but that ErbB receptor signaling via Shc is necessary and important.
authors.affiliation: Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, USA.
authors.forename: S
authors.initials: S
authors.lastname: Won
authors.forename: J
authors.initials: J
authors.lastname: Si
authors.forename: M
authors.initials: M
authors.lastname: Colledge
authors.forename: K S
authors.initials: KS
authors.lastname: Ravichandran
authors.forename: S C
authors.initials: SC
authors.lastname: Froehner
authors.forename: L
authors.initials: L
authors.lastname: Mei
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D019943:Amino Acid Substitution; D000818:Animals; D019556:COS Cells; D002478:Cells, Cultured / Q000187:drug effects; D002522:Chlorocebus aethiops; D019281:Dimerization; D051380:GRB2 Adaptor Protein; D017930:Genes, Reporter; D018734:Genes, erbB-2; D020935:MAP Kinase Signaling System / Q000187:drug effects; D046911:Macromolecular Substances; D051379:Mice; D018482:Muscle, Skeletal / Q000166:cytology / Q000187:drug effects*; D016297:Mutagenesis, Site-Directed; D020890:Neuregulin-1 / Q000494:pharmacology*; D009469:Neuromuscular Junction / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000737:chemistry / Q000502:physiology*; D020893:Receptor, ErbB-3 / Q000737:chemistry / Q000502:physiology*; D011950:Receptors, Cholinergic / Q000096:biosynthesis / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000494:pharmacology; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014162:Transfection
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D051380:GRB2 Adaptor Protein; D046911:Macromolecular Substances; D020890:Neuregulin-1; D011506:Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases; D020893:Receptor, ErbB-3; D011950:Receptors, Cholinergic; D011993:Recombinant Fusion Proteins; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; C495949:Grb2 protein, mouse; C528034:Shc1 protein, mouse