FIGURE 4.

Catalytically inactive MK2 rescues K8-Ser⁷³ phosphorylation in MK2/3 DKO cells. MK2/3-deficient cells transduced retrovirally with MK2, MK2-K79R, or empty vector (GFP) were transfected with plasmids expressing human K8 and K18 or control vector. 24 h after transfection, cells were serum-starved for 10 h. Wherever indicated, cells were stimulated for 30 min with 10 μg/ml anisomycin. SB202190 (5 μm) pretreatment was given for 60 min where indicated. K8-Ser⁷³ and K18-Ser⁵² were analyzed by Western blotting. Rescue of p38 levels by MK2 or MK2-K79R is shown. Phospho-MSK-Thr⁵⁸¹, HSPB1-Ser⁸⁶, total K8/18, GAPDH, and MK2 were probed as controls.