Spinophilin and arrestin reciprocally regulate α_2BAR-induced ERK1/2 activation kinetics in MEFs.

Abstract

<p>(A) Arr2,3^-/- and corresponding WT (Arr2,3^+/+) MEFs expressing HA-α_2BAR were stimulated with 1μM clonidine for indicated time points. Phospho- and total-ERK1/2 were detected by Western blots. Representative blots from multiple independent experiments are shown. (B) Quantitation of ERK1/2 activation in Arr2,3^+/+ or Arr2,3^-/- MEFs at indicated time points. The relative ERK1/2 activation at each time point was expressed as a ratio to the peak level of ERK1/2 activation in the same experiment, which was arbitrarily defined as 1.0. Data were mean ± SEM. n = 4 for each condition. *, <i>p</i><0.05, Arr2,3^-/-<i>vs</i>. Arr2,3^+/+. (C) Sp^-/- and corresponding WT (Sp^+/+) MEFs expressing HA-α_2BAR were stimulated. Representative blots for phospho- and total ERK1/2 from multiple independent experiments are shown. (D) Quantitation of ERK1/2 activation in Sp^+/+ or Sp^-/- MEFs at indicated time points. Data were mean ± SEM. n = 7 for data collected in Sp^+/+ cells and n = 4 for Sp^-/- cells. *, <i>p</i><0.05; ***, <i>p</i><0.001, Sp^-/-<i>vs</i>. Sp^+/+.</p