Fig. 2.

S⁴⁹G³⁸⁹, G⁴⁹G³⁸⁹, and S⁴⁹R³⁸⁹ variants of β₁-AR recruit the cAMP and ERK pathways. A: HEK293 cell lines that stably expressing similar amounts of S⁴⁹G³⁸⁹-, G⁴⁹G³⁸⁹-, or S⁴⁹R³⁸⁹-β₁ARs were treated for the indicated times with Iso (1 μM). Cell lysates were subjected to immunoblot analysis for pERK and ERK protein according to materials and methods. The results are from a single experiment and are representative of data obtained in three separate experiments. B: cAMP and pERK responses were measured in HEK293 cells treated for 5 min with vehicle (Cont), Iso (1 μM), carvedilol (Carv, 1 μM), or forskolin (10 μM) according to materials and methods. The results (means ± SE) represent data from 5–7 (for cAMP) or 3 (for ERK) separate experiments performed on separate culture preparations. *P < 0.05 vs. response to cognate agonist in G⁴⁹G³⁸⁹ or S⁴⁹R³⁸⁹ cells.