Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mitogen-activated protein kinase (MAPK) or extracellular signal-regulated kinase are ubiquitous kinases conserved from fungi to mammals. Their activity is regulated by phosphorylation on both threonine and tyrosine, and they play a crucial role in the regulation of proliferation and differentiation. We report here the cloning of the murine p44 MAP kinase (extracellular signal-regulated kinase 1) gene, the determination of its intron/exon boundaries, and the characterization of its promoter. The gene spans approximately eight kilobases (kb) and can be divided into nine exons and eight introns, each coding region exon containing from one to three of the highly conserved protein kinase domains. Primer extension analysis reveals the existence of two major start sites of transcription located at -183 and -186 base pairs (bp) as well as four discrete start sites for transcription located at -178, -192, -273, and -292 bp of the initiation of translation. However, the start site region lacks TATA-like sequences but does contain initiator-like sequences proximal to the major start sites obtained by primer extension. 1 kb of the promoter region has been sequenced. It contains three putative TATA boxes far upstream of the main start sites region, one AP-1 box, one AP-2 box, one Malt box, one GAGA box, one half serum-responsive element, and putative binding sites for Sp1 (five), GC-rich binding factor (five), CTF-NF1 (one), Myb (one), p53 (two), Ets-1 (one), NF-IL6 (two), MyoD (two), Zeste (one), and hepatocyte nuclear factor-5 (one). To determine the sites critical for the function of the p44 MAPK promoter, we constructed a series of chimeric genes containing variable regions of the 5'-flanking sequence of p44 MAPK gene and the coding region for luciferase. Activity of the promoter, measured by its capacity to direct expression of a luciferase reporter gene, is strong, being comparable with the activity of the Rous sarcoma virus promoter. Progressive deletions of the approximately 1 kb (-1200/-78) promoter region allowed us to define a minimal region of 186 bp (-284/-78) that has maximal promoter activity. Within this context, deletion of the AP-2 binding site reduces by 30-40% the activity of the promoter. Further deletion of this minimal promoter that removes the major start sites (-167/-78) surprisingly preserves promoter activity. This result implicates a major role of this region that contains the Sp1 sites.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:The mouse p44 mitogen-activated protein kinase (extracellular signal-regulated kinase 1) gene. Genomic organization and structure of the 5'-flanking regulatory region. 759 46

The p53 tumour suppressor protein is tightly regulated by protein-protein association, protein turnover and a variety of post-translational modifications. Multisite phosphorylation plays a major role in activating and in finely tuning p53 function. The proline rich domain of murine p53 is a substrate for phosphorylation, in vitro and in cultured cells, by the p42ERK2 and p44ERK1 mitogen-activated protein (MAP) kinases. However, to date there have been no reports of attempts to determine whether p53 from any other species is a substrate for MAP kinase. In this paper we confirm that murine p53 is targeted by recombinant MAP kinase and by MAP kinases in extracts of both murine and human cells. In contrast, human p53 is not a substrate for recombinant MAP kinase nor are there any detectable levels of protein kinase activity in stimulated human cell extracts which phosphorylate the proline rich domain of human p53 in vitro. Finally, although stimulation of murine fibroblasts with o-tetradecanolylphorbol 13-acetate (TPA), an indirect activator of the MAP kinase pathway, leads to site-specific phosphorylation of murine p53, similar treatment of human fibroblasts and epithelial cells showed no significant changes in the phosphorylation pattern. These data are consistent with accumulating evidence that significant species-dependent differences exist in the post-translational modification of p53.
 ...
PMID:Phosphorylation of murine p53, but not human p53, by MAP kinase in vitro and in cultured cells highlights species-dependent variation in post-translational modification. 1060 21

The p53 tumor suppressor protein is a transcription factor that plays a major role in the DNA damage response. After DNA damage, p53 levels increase due primarily to stabilization of the protein. The molecular mechanisms leading to stabilization of p53 after DNA damage have not been completely elucidated. Recently we reported that cisplatin treatment activated extracellular signal-regulated kinase 1 and 2 (ERK1/2) and that inhibition of ERK1/2 resulted in enhanced sensitivity to cisplatin. In the present study, we examined the potential role of ERK1/2 activation in regulation of the p53 response to cisplatin. In the ovarian carcinoma cell line A2780, inhibition of ERK1/2 activation with the mitogen-activated protein kinase/ERK kinase 1 (MEK1) inhibitor PD98059 resulted in decreased p53 protein half-life and diminished accumulation of p53 protein during exposure to cisplatin. We also demonstrated that p53 protein co-immunoprecipitated with ERK1/2 protein and was phosphorylated by activated recombinant murine ERK2 in vitro. Furthermore, PD98059 decreased the phosphorylation of p53 at serine 15 during cisplatin exposure, suggesting that ERK1/2 mediates in part phosphorylation of p53 during the cisplatin DNA response. These results strongly suggest that cisplatin-induced ERK activation is an up-stream regulator of the p53 response to DNA damage caused by cisplatin.
 ...
PMID:Effect of extracellular signal-regulated kinase on p53 accumulation in response to cisplatin. 1095 92

Bcl-2 has been reported to inhibit neurotoxicity induced by cisplatin. However, neither the mechanism of cisplatin-induced neurotoxicity nor the mechanism by which Bcl-2 confers neuroprotection is clear. In this study, the signaling pathways involved in cisplatin-induced neurotoxicity were examined using a rat neuroblastoma cell line, B104. Treatment of B104 cells with cisplatin induced apoptosis, accompanying the accumulation of p53 and Bax protein. Interestingly, extracellular signal-regulated kinase 1/2 (ERK1/2) activities of MAP kinases were markedly enhanced prior to cisplatin-induced accumulation of p53 and Bax. Inhibition of ERK1/2 activities using PD98059, a selective MEK inhibitor, blocked the apoptotic cell death preventing cisplatin-induced accumulation of p53 and Bax. These results suggest that ERK mediates cisplatin-induced p53 activation to trigger apoptosis in B104 cells. Overexpression of Bcl-2 in B104 cells resulted in the complete resistance to cisplatin-induced apoptosis blocking ERK activation and the subsequent signaling pathway of p53. Our study clearly demonstrates that the action site of Bcl-2 localizes upstream of ERK in cisplatin-induced apoptotic signaling pathway.
 ...
PMID:Bcl-2 blocks cisplatin-induced apoptosis by suppression of ERK-mediated p53 accumulation in B104 cells. 1153 34

Two papillary thyroid carcinoma (PTC) and two follicular thyroid carcinoma (FTC) cell lines treated with resveratrol (RV), 1-10 microM, showed activation and nuclear translocation of MAPK (extracellular signal-regulated kinase 1/2). Cellular abundance of the oncogene suppressor protein p53, serine phosphorylation of p53, and abundance of c-fos, c-jun, and p21 mRNAs were also increased by RV. Inhibition of the MAPK pathway by either H-ras antisense transfection or PD 98059, an MAPK kinase inhibitor, blocked these RV-induced effects. Addition of pifithrin-alpha, a specific inhibitor of p53, or transfection of p53 antisense oligonucleotides caused decreased RV-induced p53 and p21 expression in PTC and FTC cells. Studies of nucleosome levels estimated by ELISA and of DNA fragmentation showed that RV induced apoptosis in both papillary and follicular thyroid cancer cell lines; these effects were inhibited by pifithrin-alpha and by p53 antisense oligonucleotide transfection. PD 98059 and H-ras antisense transfection also blocked induction of apoptosis by RV. Thus, RV acts via a Ras-MAPK kinase-MAPK signal transduction pathway to increase p53 expression, serine phosphorylation of p53, and p53-dependent apoptosis in PTC and FTC cell lines.
 ...
PMID:Resveratrol induces apoptosis in thyroid cancer cell lines via a MAPK- and p53-dependent mechanism. 1188 92

The role of oxidative metabolism in the up-regulation/activation of stress-induciblesignaling pathways as well as induction of micronucleus formation in bystander cells was investigated. By immunoblotting and in situ immunofluorescence, active Cu-Zn superoxide dismutase (SOD) enzyme and active catalase enzyme were shown to inhibit the up-regulation of p21(Waf1) as well as the induction of micronucleus formation in bystander cells from confluent cultures of normal human diploid fibroblasts irradiated with 0.3-3 cGy of alpha-particles. Enzyme activity assays indicated that exogenous SOD became significantly associated with the cells. Reactive oxygen species apparently derived from a flavin-containing oxidase enzyme [presumably an NAD(P)H-oxidase] appeared to be major contributors to the bystander-induced up-regulation of p53 and p21(Waf1) as well as micronucleus formation, as evidenced by the inhibition of these effects with diphenyliodonium. Rapid activation of nuclear factor kappaB, Raf-1, extracellular signal-regulated kinase 1/2, c-Jun NH2-terminal kinase, and p38 mitogen-activated protein kinase and their downstream effectors activator protein 1, ELK-1, p90RSK, and activating transcription factor 2 was also observed in cultures exposed to very low fluences of alpha-particles. Significant attenuation in the activation of these kinases and transcription factors occurred in irradiated cultures treated with either SOD or catalase. Overall, these results support the hypothesis that superoxide and hydrogen peroxide produced by flavin-containing oxidase enzymes mediate the activation of several stress-inducible signaling pathways as well as micronucleus formation in bystander cells from cultures of human cells exposed to low fluences of alpha-particles.
 ...
PMID:Oxidative metabolism modulates signal transduction and micronucleus formation in bystander cells from alpha-particle-irradiated normal human fibroblast cultures. 1235 50

1,25-Dihydroxyvitamin D3 (1,25D3) exhibits potent antitumor activity in the murine squamous cell carcinoma (SCC) SCCVII/SF, and the combination of 1,25D3 with cisplatin (1,25D3/cisplatin) demonstrates even greater activity. Because these agents possess different mechanisms of cytotoxicity, studies were initiated to define the mechanism by which the combination displays enhanced activity. Median dose-effect analysis demonstrates that 1,25D3 and cisplatin act synergistically to inhibit SCC growth. When SCC cells were treated with 1,25D3 (10 nM) and/or cisplatin (0.5 microg/ml), greater caspase-3 activation was observed for the combination than for either agent alone. This suggests that the enhanced cytotoxicity is, at least in part, due to greater induction of apoptosis. No alterations in cellular platinum concentration or platinum-DNA adducts were observed for 1,25D3/cisplatin cotreatment compared with cisplatin treatment alone. Effects of the combination on cisplatin and 1,25D3 signaling pathways in adherent (nonapoptotic) and floating (apoptotic) cells were explored. Cisplatin induced p53 and its downstream targets, p21(Cip1) (p21) and Bax, in both cell populations. In contrast, 1,25D3 reduced p53, p21, and Bax to nearly undetectable levels in adherent cells. In the floating cells, 1,25D3 reduced levels of p53 and p21, but Bax expression was maintained at control levels. Expression of these proteins in cells treated with 1,25D3/cisplatin was similar to treatment with 1,25D3 alone. The two agents also had divergent effects on survival and stress signaling pathways. Phospho-extracellular signal-regulated kinase 1/2 and phospho-Jun levels increased after treatment with cisplatin but decreased after treatment with 1,25D3 and 1,25D3/cisplatin. Moreover, cisplatin decreased levels of mitogen-activated protein kinase kinase kinase (MEKK-1), whereas 1,25D3 up-regulated MEKK-1, and 1,25D3/cisplatin further up-regulated MEKK-1. We propose that the increased cytotoxicity for 1,25D3/cisplatin results from cisplatin enhancement of 1,25D3-induced apoptotic signaling through MEKK-1.
 ...
PMID:Cisplatin potentiates 1,25-dihydroxyvitamin D3-induced apoptosis in association with increased mitogen-activated protein kinase kinase kinase 1 (MEKK-1) expression. 1249 15

Overexpression of the short isoform of p53 (p44) has unexpectedly uncovered a role for p53 in the regulation of size and life span in the mouse. Hyperactivation of the insulin-like growth factor (IGF) signaling axis by p44 sets in motion a kinase cascade that clamps potentially unimpeded growth through p21Cip1. This suggests that pathways of gene activity known to regulate longevity in lower organisms are linked in mammals via p53 to mechanisms for controlling cell proliferation. Thus, appropriate expression of the short and long p53 isoforms might maintain a balance between tumor suppression and tissue regeneration, a major requisite for long mammalian life span.
 ...
PMID:Modulation of mammalian life span by the short isoform of p53. 1487 29

FKHRL1 (FOXO3a) and p53 are two potent stress-response regulators. Here we show that these two transcription factors exhibit "crosstalk" in vivo. In response to DNA damage, p53 activation led to FKHRL1 phosphorylation and subcellular localization change, which resulted in inhibition of FKHRL1 transcription activity. AKT was dispensable for p53-dependent suppression of FKHRL1. By contrast, serum- and glucocorticoid-inducible kinase 1 (SGK1) was significantly induced in a p53-dependent manner after DNA damage, and this induction was through extracellular signal-regulated kinase 1/2-mediated posttranslational regulation. Furthermore, inhibition of SGK1 expression by a small interfering RNA knockdown experiment significantly decreased FKHRL1 phosphorylation in response to DNA damage. Taken together, our observations reveal previously unrecognized crosstalk between p53 and FKHRL1. Moreover, our findings suggest a new pathway for understanding aging and the age dependency of human diseases governed by these two transcription factors.
 ...
PMID:p53-dependent inhibition of FKHRL1 in response to DNA damage through protein kinase SGK1. 1538 58

Resveratrol, a naturally occurring stilbene with antitumor properties, caused mitogen-activated protein kinase [MAPK, extracellular signal-regulated kinase 1/2 (ERK1/2)] activation, nuclear translocation of Ser15-phosphorylated p53, and p53-dependent apoptosis in hormone-insensitive DU145 prostate cancer cells. Exposure of these cells to epidermal growth factor (EGF) for up to 4 hours resulted in brief activation of MAPK followed by inhibition of resveratrol-induced signal transduction, p53 phosphorylation, and apoptosis. Resveratrol stimulated c-fos and c-jun expression in DU145 cells, an effect also suppressed by EGF. An inhibitor of protein kinase C (PKC)-alpha, -beta, and -gamma (CGP41251) enhanced Ser15 phosphorylation of p53 by resveratrol in the absence of EGF and blocked EGF inhibition of the resveratrol effect. EGF caused PKC-alpha/beta phosphorylation in DU145 cells, an effect reversed by CGP41251. Activation of PKC by phorbol ester (phorbol 12-myristate 13-acetate) enhanced EGF action on ERK1/2 phosphorylation without significantly altering p53 phosphorylation by resveratrol. DU145 cells transfected with a dominant-negative PKC-alpha construct showed resveratrol-induced ERK1/2 phosphorylation and Ser15 phosphorylation of p53 but were unresponsive to EGF. Thus, resveratrol and EGF activate MAPK by discrete mechanisms in DU145 cells. The stilbene promoted p53-dependent apoptosis, whereas EGF opposed induction of apoptosis by resveratrol via a PKC-alpha-mediated mechanism. Resveratrol also induced p53 phosphorylation in LNCaP prostate cancer cells, an effect also inhibited by EGF. Inhibition of PKC activation in LNCaP cells, however, resulted in a reduction, rather than increase, in p53 activation and apoptosis, suggesting that resveratrol-induced apoptosis in these two cell lines occurs through different PKC-mediated and MAPK-dependent pathways.
 ...
PMID:Inhibitory effect of epidermal growth factor on resveratrol-induced apoptosis in prostate cancer cells is mediated by protein kinase C-alpha. 1554 74


1 2 3 4 5 6 7 8 Next >>