Fig. 7. Mutation of the RRR motif in Nav1.8 disrupts β3-subunit-promoted surface expression of the channel. (A) TM+β3C-GFP was co-expressed with either Nav1.8-Myc or Nav1.8m-Myc in HEK293 cells. Proteins were immunoprecipitated with Myc antibody and cell lysates subjected to immunoblotting with antibodies against GFP or Myc as indicated. The experiment was repeated three times. (B-D) Nav1.8-Myc was co-transfected with β3-GFP or TM+β3C-GFP (B), and Nav1.8m-Myc was co-transfected with TM+β3C-GFP (C) in HEK293 cells. Cultured DRG neurons were incubated with GST-Tat or GST-Tat-β3C (D). Cells were subjected to cell-surface biotinylation/immunoblotting. Representative immunoblot and quantitative analyses are shown. Actin served as an internal control for protein loading. Data were plotted as a percentage of controls. *P<0.05 versus cells transfected with Nav1.8-Myc or Nav1.8m-Myc, or treated with GST-Tat (n=3).