NRG1, acting through the phosphorylation of Dock7 at Tyr-1118, regulates Schwann cell migration. (A) After stimulation with vehicle or 20 ng/ml of NRG1, NT3, or IGF-I for 30 min, Schwann cells were lysed, immunoprecipitated with an anti-Dock7 antibody, and immunoblotted with an anti-(pTyr¹¹¹⁸)Dock7 antibody. In some experiments, cells were treated with or without AG825 or ErbB3-Fc. The cell lysates were also immunoblotted with an anti-Dock7 antibody. (B) After stimulation with vehicle or NRG1, immunoprecipitated Dock7 was immunoblotted with an anti-ErbB2 antibody. Immunoblots for ErbB2, ErbB3, and Dock7 are shown. (C) After stimulation with vehicle or NRG1, Schwann cells were costained with the following antibodies: anti-(pTyr¹¹¹⁸)Dock7 (green; top) and anti-(pTyr¹¹¹²)ErbB2 (red; top), anti-(pTyr¹¹¹⁸)Dock7 (green; middle) and anti-ErbB2 (red; middle), and anti-Dock7 (green; bottom) and anti-ErbB2 (red; bottom). After stimulation with vehicle or NRG1, increased colocalization (indicated by arrows) was observed (Bar, 25 μm). a–d are magnifications of the boxed areas as indicated (Bar, 10 μm). Dotted lines indicate the outlines of cells. (D and E) Affinity precipitation with GST-Rac1G15A or Cdc42G15A was performed and immunoblotted with an anti-Dock7 antibody. Immunoblots for Dock7 are shown.