FIGURE 1.

Arrestin3 is the only isoform that enhances ASK1-mediated JNK3 activation. COS-7 cells were transfected with HA-JNK3 alone, or with HA-ASK1, or together with FLAG-tagged arrestin3 (Arr3), arrestin2 (Arr2), arrestin1 (Rod), or arrestin4 (Cone). Cell lysates were immunoblotted for phospho-JNK (p-JNK3), HA, or FLAG. The intensity of the phospho-JNK band in three independent experiments was quantified and statistically analyzed. Means ± S.D. are shown. ^****, p < 0.0001, as compared with the basal level in cells co-expressing ASK1 and JNK3 without arrestin.