ERK2-mediated C-terminal Serine Phosphorylation of p300 Is Vital to the Regulation of Epidermal Growth Factor-induced Keratin 16 Gene Expression

Department of Pharmacology, Institute of Basic Medical Sciences, College of Medicine, Center for Gene Regulation and Signal Transduction Research, National Cheng Kung University, Tainan 701, Taiwan.
Journal of Biological Chemistry (Impact Factor: 4.57). 10/2007; 282(37):27215-28. DOI: 10.1074/jbc.M700264200
Source: PubMed


We previously reported that the epidermal growth factor (EGF) regulates the gene expression of keratin 16 by activating the extracellular signal-regulated kinase 1 and 2 (ERK1/2) signaling which in turn enhances the recruitment of p300 to the keratin 16 promoter. The recruited p300 functionally cooperates with Sp1 and c-Jun to regulate the gene expression of keratin 16. This study investigated in detail the molecular events incurred upon p300 whereby EGF caused an enhanced interaction between p300 and Sp1. EGF apparently induced time- and dose-dependent phosphorylation of p300, both in vitro and in vivo, through the activation of ERK2. The six potential ERK2 phosphorylation sites, including three threonine and three serine residues as revealed by sequential analysis, were first identified in vitro. Confirmation of these six sites in vivo indicated that these three serine residues (Ser-2279, Ser-2315, and Ser-2366) on the C terminus of p300 were the major signaling targets of EGF. Furthermore, the C-terminal serine phosphorylation of p300 stimulated its histone acetyltransferase activity and enhanced its interaction with Sp1. These serine phosphorylation sites on p300 controlled the p300 recruitment to the keratin 16 promoter. When all three serine residues on p300 were replaced by alanine, EGF could no longer induce the gene expression of keratin 16. Taken together, these results strongly suggested that the ERK2-mediated C-terminal serine phosphorylation of p300 was a key event in the regulation of EGF-induced keratin 16 expression. These results also constituted the first report identifying the unique p300 phosphorylation sites induced by ERK2 in vivo.

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    • "For example, while protein kinase C (PKC) and salt inducible kinase 2 mediated phosphorylation at serine-89 was reported to inhibit the HAT activity [38,39], Akt mediated phosphorylation at serine-1834, serine-2279, serine-2315, and serine-2366 was shown to enhance the HAT activity of p300 [40-42]. Along those lines, Akt and ERK2 mediated phosphorylation was shown to stabilize p300 protein levels, but phosphorylation by mitogen activated protein kinase (MAPK) resulted in degradation of the p300 protein [11,12,36,40,43]. However, none of the studies have so far focused on the effect of phosphorylation on intracellular distribution of p300. "
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    ABSTRACT: Background To date only a handful of drugs are available for the treatment of melanoma. Among them vemurafenib, a BrafV600E specific inhibitor, showed promising results in terms of response rate and increase in median survival time. However, its effectiveness is limited by development of resistance and the search for additional drugs for melanoma treatment is ongoing. The present study was performed to analyze the correlation between Braf expression and the expression of p300, a known down stream target of the mitogen activated protein kinase (MAPK) pathway, which was recently shown by us to be a prognostic marker for melanoma progression and patient survival. Methods The expression of Braf and p300 expression were correlated and analyzed by Chi-square test. A total of 327 melanoma patient cases (193 primary melanoma and 134 metastatic melanoma) were used for the study. Classification & regression tree (CRT), Kaplan-Meier, and multivariate Cox regression analysis were used to elucidate the significance of the combination of Braf and p300 expression in the diagnosis and prognosis of melanoma. Results Our results demonstrate that Braf expression is inversely correlated with nuclear p300 and positively correlated with cytoplasmic p300 expression. Braf and cytoplasmic p300 were found to be associated with melanoma progression, tumor size and ulceration status. CRT analysis revealed that a combination of Braf and p300 expression (nuclear and cytoplasmic), could be used to distinguish between nevi and melanoma, and primary from metastatic melanoma lesions. The combination of Braf and nuclear p300 was significantly associated with patient survival and nuclear p300 was found to be an independent predictor of patient survival. Conclusion Our results indicate a cross-talk between Braf and p300 in melanoma and demonstrate the importance Braf and p300 expression in the diagnosis and prognosis of melanoma.
    BMC Cancer 06/2014; 14(1):398. DOI:10.1186/1471-2407-14-398 · 3.36 Impact Factor
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    • "The stability of p300 protein is believed to be regulated by its phosphorylation [Reviewed in (37)]. Multiple site-specific serine/threonine phosphorylations have been identified in p300 and are linked to its pleiotropic potential (15,19,38–41). To discern the underlying basis of p300 phosphorylation in response to UV damage, we irradiated NHF cells and analyzed p300 phosphorylations at serine 89 and serine 1834 by western blots with antibodies against site-specifically phosphorylated p300. "
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    ABSTRACT: Besides the primary histone acetyltransferase (HAT)-mediated chromatin remodeling function, co-transcriptional factor, p300, is also known to play a distinct role in DNA repair. However, the exact mechanism of p300 function in DNA repair has remained unclear and difficult to discern due to the phosphorylation and degradation of p300 in response to DNA damage. Here, we have demonstrated that p300 is only degraded in the presence of specific DNA lesions, which are the substrates of nucleotide excision repair (NER) pathway. In contrast, DNA double-strand breaks fail to degrade p300. Degradation is initiated by phosphorylation of p300 at serine 1834, which is catalyzed by the cooperative action of p38 mitogen-activated protein kinases and Akt kinases. In depth, functional analysis revealed that (i) p300 and CBP act redundantly in repairing ultraviolet (UV) lesions, (ii) the phosphorylation of p300 at S1834 is critical for efficient removal of UV-induced cyclobutane pyrimidine dimers and (iii) p300 is recruited to DNA damage sites located within heterochromatin. Taken together, we conclude that phosphorylated p300 initially acetylates histones to relax heterochromatin to allow damage recognition factors access to damage DNA. Thereupon, p300 is promptly degraded to allow the sequential recruitment of downstream repair proteins for successful execution of NER.
    Nucleic Acids Research 12/2012; 41(3). DOI:10.1093/nar/gks1312 · 9.11 Impact Factor
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    • "Repression of miR-142 by p300 Both ERK/MAPK and p38MAPK phosphorylate and modulate the activity of p300 (Chen et al, 2007; Darieva et al, 2004; Gusterson et al, 2002; Poizat et al, 2005). To determine whether p300 also regulates miR-142, we transduced cardiac myocytes with an adenovirus expressing full-length human p300 (Ad- p300) or with an anti-p300 silencing RNA (siRNA). "
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    ABSTRACT: An increase in cardiac workload, ultimately resulting in hypertrophy, generates oxidative stress and therefore requires the activation of both survival and growth signal pathways. Here, we wanted to characterize the regulators, targets and mechanistic roles of miR-142, a microRNA (miRNA) negatively regulated during hypertrophy. We show that both miRNA-142-3p and -5p are repressed by serum-derived growth factors in cultured cardiac myocytes, in models of cardiac hypertrophy in vivo and in human cardiomyopathic hearts. Levels of miR-142 are inversely related to levels of acetyltransferase p300 and MAPK activity. When present, miR-142 inhibits both survival and growth pathways by directly targeting nodal regulators p300 and gp130. MiR-142 also potently represses multiple components of the NF-κB pathway, preventing cytokine-mediated NO production and blocks translation of α-actinin. Forced expression of miR-142 during hypertrophic growth induced extensive apoptosis and cardiac dysfunction; conversely, loss of miR-142 fully rescued cardiac function in a murine heart failure model. Downregulation of miR-142 is required to enable cytokine-mediated survival signalling during cardiac growth in response to haemodynamic stress and is a critical element of adaptive hypertrophy.
    EMBO Molecular Medicine 07/2012; 4(7):617-32. DOI:10.1002/emmm.201200234 · 8.67 Impact Factor
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