Figure 3.

β₂-adrenoceptor internalization in cells inducibly overexpressing GRK5. Following treatment with ponasterone (Pon A, 5 μM) or ethanol (EtOH) for 72 h, ECR293:β₂-adrenoceptor:GRK5 cells were treated with 5 μM isoprenaline for varying times up to 30 min. Untransfected EcR293:β₂-adrenoceptor cells (control) were similarly treated. Each point represents the means±s.e.m. of three independent experiments. The fraction of receptors left on the surface was plotted as a function of time and the curves fitted as previously described (Morrison et al., 1996).