Sequestration of Gβγ with βARKct-CD8 or coexpression of dominant negative Sar1(H79G) attenuate heterologous sensitization of AC5. Cells expressing Gα _s-CFP, D₂R and (a and c) AC5 or (b) ΔAC5 in combination with either empty vector (ctrl), (a-b) βARKct-CD8, or (c) indicated Sar1 construct. Data shown represent the fold-increase of cAMP accumulation observed in quinpirole-treated cells. (a-b) *=, using a paired, one-tailed t-test. (c) **=, using a one-way ANOVA and Dunnett’s post hoc test, comparing ctrl to Sar1(wt) or Sar1(H79G).