FIGURE 4.

D₂ and D₃ dopamine receptors bind GASP-1. A, recombinant cGASP produced by in vitro translation was incubated with GST alone or GST fusion protein containing the cytoplasmic tails of the dopamine receptors. Radiolabeled GASP-1 eluted from the GST resin was detected (upper panel). The lower panel shows the Coomassie stain of the input protein. B, cells stably expressing D₂, D₃, or D₄ were lysed, and the receptors were immunoprecipitated (IP) using M2 anti-FLAG antibody. Precipitates were immunoblotted (IB) for GASP (upper panel) and receptor (middle panel). Lower panels show lysate samples immunoblotted for GASP and β-actin.