Figure 1.

mGluR1a is constitutively associated with Ral and RalGDS. HEK 93 cell lysates transiently expressing either FLAG-mGluR1a or FLAG-β₂AR and GFP-RalA or GFP-RalGDS were immunoprecipitated using a monoclonal anti-FLAG antibody. a, Representative immunoblot showing the coimmunoprecipitation of endogenous Ral from cells coexpressing FLAG-mGluR1a (+) but not in cells lacking coexpressed receptors(-) or expressing Flag-β₂AR(+). The immunoblot is representative of three independent experiments. The bar graph shows the mean ± SE of the amount of endogenous Ral coimmunprecipitated expressed as a percentage of total Ral expression in the cell lysate. b, Coimmunoprecipitation of GFP-RalA with FLAG-mGluR1a in the absence and presence of agonist (30 μm quisqualate) stimulation for 0-15 min. The data shown are representative of three independent experiments, and the bar graph shows the mean ± SE of the amount of GFP-Ral coimmunprecipitated with FLAG-mGluR1a after agonist treatment relative to that coimmunprecipitated in the absence of agonist. c, Representative immunoblot showing the coimmunoprecipitation of GFP-Ral from cells coexpressing FLAG-mGluR5a (+) but not in cells lacking coexpressed receptors(-). The immunoblot is representative of three independent experiments. d, Coimmunoprecipitation of GFP-RalGDS with FLAG-mGluR1a and FLAG-mGluR5a in the presence and absence of agonist stimulation (30 μm quisqualate). The data shown are representative of three independent experiments. NT, Nontransfected. Lysates correspond to 100 μg of total HEK cell lysate.