RNF20/40-mediated eEF1BδL monoubiquitylation stimulates transcription of heat shock-responsive genes.

RNF20/40 E3 ubiquitin ligase-mediated histone H2B monoubiquitylation plays important roles in many cellular processes, including transcriptional regulation. However, the multiple defects observed in RNF20-depleted cells suggest additional ubiquitylation targets of RNF20/40 beyond histone H2B. Here, using biochemically defined assays employing purified factors and cell-based analyses, we demonstrate that RNF20/40, in conjunction with its cognate E2 ubiquitin-conjugating enzyme RAD6, monoubiquitylates lysine 381 of eEF1BδL, a heat shock transcription factor.

MSK1 functions as a transcriptional coactivator of p53 in the regulation of p21 gene expression.

Mitogen- and stress-activated kinase 1 (MSK1) is a chromatin kinase that facilitates activator-dependent transcription by altering chromatin structure through histone H3 phosphorylation. The kinase activity of MSK1 is activated by intramolecular autophosphorylation, which is initially triggered by the activation of upstream mitogen-activated protein kinases (MAPKs), such as p38 and ERK1/2. MSK1 has been implicated in the expression of p21, a p53 target gene; however, the precise connection between MSK1 and p53 has not been clearly elucidated.