Fig. 8
Involvement of EGFR transactivation in the desensitization of β2 adrenoceptors. A HEK-293 cells expressing β2AR were pretreated with either vehicle or 200 nM of AG1478 for 30 min, followed by treatment with 10 μM of isoproterenol for 5 min and washed/rechallenged to induce desensitization. ISO/Veh group was significantly different from other groups at 10−8.5–10−5 M isoproterenol (n = 3). B HEK-293 cells expressing β2AR were pretreated with either vehicle or 200 nM of AG1478 for 30 min, followed by treatment with 10 μM of isoproterenol for 2 min to induce the ERK activation. *p < 0.05, **p < 0.01 compared with corresponding vehicle-treated groups (n = 3). C HEK-293 cells were transfected with EGFR-GFP together with either FLAG-tagged WT-β2AR or GRK2-KO-β2AR. Cells were treated with 10 ng/mL of EGF for 5 min and washed/rechallenged according to the desensitization protocol. The cell lysates were immunoprecipitated with FLAG beads. Co-IP/lysate and IP were immunoblotted with antibodies against GFP and FLAG. *p < 0.05 compared with other groups of the cells expressing WT-β2AR or GRK2-KO-β2AR (n = 3). D HEK-293 cells expressing β2AR were treated with either vehicle or 10 ng/mL of EGF for 20 min, followed by an increasing concentration of isoproterenol. ***p < 0.001 when compared between Veh- and EGF-treated groups at 10−8.5–10−5 M of isoproterenol (n = 3)