FIGURE 2.

HuR cleavage does not depend on the activities of JNK, p38, or PP2A. HeLa cells were treated with inhibitors against JNK (25 μm SP600125 for 1 h), p38 (20 μm SB203580 for 1 h), or PP2A (100 nm okadaic acid for 1 h), then with 1 μm STS for 3 h. Extracts were analyzed by Western blotting, probing for G3BP or α-tubulin (as loading controls), HuR, and either p-c-Jun (Ser⁷³) to validate efficacy of JNK inhibition (A), p-MAPKAPK-2 (Thr³³⁴) to validate efficacy of p38 inhibition (B), or p-ERK1/2 (Thr²⁰²/Tyr²⁰⁴) to validate efficacy of PP2A inhibition (C). All blots shown are representative of at least three independent experiments.