Activation of extracellular signal-regulated kinase signaling by epidermal growth factor mediates c-Jun activation and p300 recruitment in keratin 16 gene expression.
In studies of gene regulation of keratin 16, we reported previously that simian virus 40 promoter factor 1 shows a functional cooperation with c-Jun and coactivators p300/CBP in driving the transcriptional regulation of epidermal growth factor (EGF)-induced keratin 16 gene expression. In the present study, we found that the stimulated expression of keratin 16 by EGF was mediated mainly through the mitogen-activated protein kinase kinase-extracellular signal-regulated kinases 1 and 2 (ERK1/2) signaling pathway. Ser63 and Ser73 on the c-Jun NH(2)-terminal transactivation domain could be phosphorylated in cells treated with EGF; nevertheless, we found that the c-Jun COOH terminus played a pivotal role in EGF-induced expression of keratin 16. The activation of keratin 16 by EGF treatment could not be enhanced by the overexpression of myc-c-JunK3R, in which three putative acetylation lysine residues on the c-Jun COOH terminus were all mutated into arginines, suggesting that c-Jun acetylation on the COOH terminus might partially play a functional role in this system. In addition, by using a chromatin immunoprecipitation assay and a DNA affinity precipitation assay, EGF treatment up-regulated the p300 recruitment through ERK signaling to the promoter region in regulating keratin 16 transcriptional activity. Furthermore, the enhancement of acetyl-histone H3 to the keratin 16 chromatin promoter induced by EGF was also mediated via ERK activation. In conclusion, these results strongly suggest that both c-Jun induction and p300 recruitment to gene promoter, mediated through ERK activation, played an essential role in regulating keratin 16 gene expression by EGF. p300 mediated and regulated EGF-induced keratin 16 gene expression, at least in part, through multiple mechanisms, including a selective acetylation of c-Jun and histone H3.
Wang
Ying-Nai
YN
Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Chen
Yun-Ju
YJ
Chang
Wen-Chang
WC
D000107:Acetylation; D002461:Cell Line, Transformed; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D007633:Keratins / Q000235:genetics*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D050880:p300-CBP Transcription Factors / Q000378:metabolism*
D004791:Enzyme Inhibitors; D016755:Proto-Oncogene Proteins c-jun; D004815:Epidermal Growth Factor; D007633:Keratins; D050880:p300-CBP Transcription Factors; D048049:Extracellular Signal-Regulated MAP Kinases