Fig. 1.

Agonist-dependent ERK and PKA responses in HEK293 cells that heterologously overexpress S⁴⁹G³⁸⁹, G⁴⁹G³⁸⁹, S⁴⁹R³⁸⁹, and G⁴⁹R³⁸⁹ haplotypes of the β₁-adrenergic receptor (β₁AR). Cell lysates from cells treated for 5 min with vehicle, isoproterenol (Iso, 1 μM), forskolin (Forsk, 10 μM), or EGF (100 ng/ml) were subjected to immunoblot analysis for pERK and pPKA substrate, as well as ERK protein (to verify equal protein loading) and β₁AR (to track transgene expression) according to materials and methods. Results (means ± SE) from 3 separate experiments on separate culture preparations are quantified. *P < 0.05 vs. uninfected. #P < 0.05 vs. S⁴⁹R³⁸⁹ or G⁴⁹R³⁸⁹. S⁴⁹R³⁸⁹ and G⁴⁹R³⁸⁹ do not differ from each other.