Regulatory domains of C/EBP[delta] involved in P38 MAPK dependent transcriptional activation
We have previously shown that C/EBP[delta], a transcription factor implicated in various cellular processes, is involved in the intestinal inflammatory response. Indeed, C/EBP[delta] levels increase in the intestine during the acute phase response. Furthermore, C/EBP[delta] regulates several inflammatory response genes, such as haptoglobin and [alpha]-acid glycoprotein, in the rat intestinal epithelial cell line IEC-6. However, the different C/EBP[delta] domains involved in transcriptional activation and the kinases implicated in its regulation have not been properly defined. The IL-1 dependent induction of the haptoglobin-encoded acute phase protein in EEC-6 cells was decreased at the transcriptional level in response to the p38 MAP kinase inhibitor SB203580, as determined by Northern blot. The p38 MAPK inhibitor SB203580 also decreased C/EBP[delta] transactivation potential in transient transfections. The N-terminal region of C/EBP[delta] (amino acids 1 to 156), in contrast to the C-terminal region, mostly interacted with p38 MAP kinase through amino acids 70-108."--Résumé abrégé par UMI.