FIGURE 2.

Parts of the arrestin-3 C-terminal domain confer lower activity than the complete C-terminal domain. A, COS-7 cells were transfected with HA-ASK1, HA-JNK3, and the indicated arrestins with a C-terminal FLAG tag. The amount of active phosphorylated JNK3 (PP-JNK3) 48 h post-transfection and the expression of ASK1, JNK3, and arrestins were determined by Western blotting. B, quantification of the level of JNK3 phosphorylation in cells expressing the indicated arrestins. Phosphorylated JNK3 bands from three independent experiments were quantified. The data were analyzed by ANOVA with arrestin as a main factor, followed by the Bonferroni-Dunn post-hoc test. The significance of the difference from arrestin-2 is shown. **, p < 0.01; ****, p < 0.0001. Band intensity is expressed as a percent of the difference between phosphorylated JNK3 in arrestin-3- and arrestin-2-expressing cells. Arr2, arrestin-2; Arr3, arrestin-3; 2N3C, Arr2N3C; 2-3AX, Arr2-3AX; 2-3AB, Arr2-3AB (detailed chimera descriptions are in the legend to Fig. 1).