The p38/MK2-Driven Exchange between Tristetraprolin and HuR Regulates AU–Rich Element–Dependent Translation (original) (raw)
Figure 2
MK2-dependent translational control of TNF mRNA detected by ribosomal profiling after ER/cytosol cell fractionation of MK2-rescued and GFP-transduced macrophages and of wild type, MK2-deficient, and MK2/MK3 double-deficient primary BMDM.
A) Polysome profile and fractions (1–12) within the profile. A schematic representation of the position of RNPs, ribosomal subunits, monosomes and polysomes is given above. Insert: TNF and ß-actin mRNA distibution (cytosol/ER ratio) after LPS-treatment of MK2-rescued (+MK2) or GFP-transduced (+GFP) macrophages. The difference in the TNF/18S is significant with p = 0.007. B) Distribution of TNF mRNA in the ER and cytosolic polysome profiles of MK2-rescued and GFP-transduced cells 1 h after LPS stimulation. An MK2-dependent redistribution of TNF mRNA to polysomal ER fractions (peaking in fraction 9) is observed. Rescue with the catalytic dead mutant MK2 K79R and block of MK2 activation by the p38 inhibitor SB202190 (MK2+SB202190) leads to a loss of the redistribution. C) MK2-independent distribution of ß-actin mRNA in the polysome profiles. D) MK2-independent distribution of the mRNA of the secreted cytokine KC/Cxcl1. E) Polysome profiles of total lysates of wild type, MK2-deficient and MK2/MK3 double-deficient primary BMDM. F,G) Distribution of TNF mRNA (F) and actin mRNA (G) in the polysome profile of WT, MK2-deficient and MK2/3-deficient primary macrophages.