Figure 3.
A unique dual signaling mechanism by β3AR. (A) The receptor can couple to both Gs and Gi to activate PKA (step 1a) and ERK (step 1b). The shaded gray arrows point to subsequent downstream cellular effects. (B) Preadipocytes were transfected or not (NT) with hemagglutinin (HA)-tagged β3AR and differentiated. (a) Expression of aP2 and β3AR mRNA as a function of differentiation on the indicated days. Levels of aP2 are maximal by day 4. Cyclophilin RNA (Cyclo) is the internal control. (b) Phospho-ERK1/2 in cell lysates in response to the β3AR agonist CL316243 (CL) in the absence or presence of pertussis toxin (PTX; n = 3; mean ± SD). (c) Level of c-Src co-precipitated with β3AR (n = 3; mean ± SD). (Adapted from Cao et al., 2000).