Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.24 (mitogen-activated protein kinase)
 95,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peroxisome proliferator-activated receptor gamma (PPARgamma) coactivator-1alpha (PGC-1alpha) is a highly regulated transcriptional coactivator that coordinates energy metabolism in mammals. Misregulation of PGC-1alpha has been implicated in the pathogenesis of several human diseases, including diabetes, obesity, and neurological disorders. We identified SCF(Cdc4) as an E3 ubiquitin ligase that regulates PGC-1alpha through ubiquitin-mediated proteolysis. PGC-1alpha contains two Cdc4 phosphodegrons that bind Cdc4 when phosphorylated by Glycogen Synthase Kinase 3beta (GSK3beta) and p38 MAPK, leading to SCF(Cdc4)-dependent ubiquitylation and proteasomal degradation of PGC-1alpha. Furthermore, SCF(Cdc4) negatively regulates PGC-1alpha-dependent transcription. We demonstrate that RNAi-mediated reduction of Cdc4 in primary neurons results in an increase of endogenous PGC-1alpha protein, while ectopic expression of Cdc4 leads to a reduction of endogenous PGC-1alpha protein. Finally, under conditions of oxidative stress in neurons, Cdc4 levels are decreased, leading to an increase in PGC-1alpha protein and PGC-1alpha-dependent transcription. These results suggest that attenuation of SCF(Cdc4)-dependent proteasomal degradation of PGC-1alpha has a role in mediating the PGC-1alpha-dependent transcriptional response to oxidative stress.
 ...
PMID:SCFCdc4 acts antagonistically to the PGC-1alpha transcriptional coactivator by targeting it for ubiquitin-mediated proteolysis. 1819 41

Tumor expression of inducible nitric oxide synthase (iNOS) predicts poor outcomes for melanoma patients. We have reported the regulation of melanoma iNOS by the mitogen-activated protein kinase (MAPK) pathway. In this study, we test the hypothesis that NF-kappaB mediates this regulation. Western blotting of melanoma cell lysates confirmed the constitutive expression of iNOS. Western blot detected baseline levels of activated nuclear extracellular signal-regulated kinase and NF-kappaB. Indirect immunofluorescence confirmed the presence of NF-kappaB p50 and p65 in melanoma cell nuclei, with p50 being more prevalent. Electrophoretic mobility shift assay demonstrated baseline NF-kappaB activity, the findings confirmed by supershift analysis. Treatment of melanoma cells with the MEK inhibitor U0126 decreased NF-kappaB binding to its DNA recognition sequence, implicating the MAPK pathway in NF-kappaB activation. Two specific NF-kappaB inhibitors suppressed iNOS expression, demonstrating regulation of iNOS by NF-kappaB. Several experiments indicated the presence of p50 homodimers, which lack a transactivation domain and rely on the transcriptional coactivator Bcl-3 to carry out this function. Bcl-3 was detected in melanoma cells and co-immunoprecipitated with p50. These data suggest that the constitutively activated melanoma MAPK pathway stimulates activation of NF-kappaB hetero- and homodimers, which, in turn, drive iNOS expression and support melanoma tumorigenesis.
 ...
PMID:NF-kappaB mediates mitogen-activated protein kinase pathway-dependent iNOS expression in human melanoma. 1866 40

The OTT-MAL/RBM15-MKL1 fusion protein is the result of the recurrent translocation t(1;22) in acute megakaryocytic leukemia in infants. How it contributes to the malignancy is unknown. The 3' fusion partner, MAL/MKL1/MRTF-A, is a transcriptional coactivator of serum response factor (SRF). MAL plays a key role in regulated gene expression depending on Rho family GTPases and G-actin. Here we demonstrate that OTT-MAL is a constitutive activator of SRF and target gene expression. This requires the SRF-binding motif and the MAL-derived transactivation domain. OTT-MAL localizes to the nucleus and is not regulated by upstream signaling. OTT-MAL deregulation reflects its independence from control by G-actin, which fails to interact with OTT-MAL in coimmunoprecipitation experiments. Regulation cannot be restored by reintroduction of the entire MAL N terminus into the fusion protein. OTT-MAL also caused a delayed induction of the MAL-independent, ternary complex factor-dependent target genes c-fos and egr-1 and the mitogen-activated protein kinase/Erk pathway. With testing in heterologous tissue culture systems, however, we observed considerable antiproliferative effects of OTT-MAL. Our data suggest that the deregulated activation of MAL-dependent and -independent promoters results in tissue-specific functions of OTT-MAL.
 ...
PMID:OTT-MAL is a deregulated activator of serum response factor-dependent gene expression. 1871 Sep 51

CREB is a prototypic bZIP transcription factor and a master regulator of glucose metabolism, synaptic plasticity, cell growth, apoptosis, and tumorigenesis. Transducers of regulated CREB activity (TORCs) are essential transcriptional coactivators of CREB and an important point of regulation on which various signals converge. In this study, we report on the activation of TORC1 through MEKK1-mediated phosphorylation. MEKK1 potently activated TORC1, and this activation was independent of downstream effectors MEK1/MEK2, ERK2, JNK, p38, protein kinase A, and calcineurin. MEKK1 induced phosphorylation of TORC1 both in vivo and in vitro. Expression of the catalytic domain of MEKK1 alone in cultured mammalian cells sufficiently caused phosphorylation and subsequent activation of TORC1. MEKK1 physically interacted with TORC1 and stimulated its nuclear translocation. An activation domain responsive to MEKK1 stimulation was mapped to amino acids 431-650 of TORC1. As a physiological activator of CREB, interleukin 1alpha triggered MEKK1-dependent phosphorylation of TORC1 and its consequent recruitment to the cAMP response elements in the interleukin 8 promoter. Taken together, our findings suggest a new mechanism for regulated activation of TORC1 transcriptional coactivator and CREB signaling.
 ...
PMID:Activation of TORC1 transcriptional coactivator through MEKK1-induced phosphorylation. 1878 53

The transcriptional corepressor SnoN is a critical regulator of axonal morphogenesis, but how SnoN drives axonal growth is unknown. Here, we report that gene-profiling analyses in cerebellar granule neurons reveal that the large majority of genes altered upon SnoN knockdown are surprisingly downregulated, suggesting that SnoN may activate transcription in neurons. Accordingly, we find that the transcriptional coactivator p300 interacts with SnoN, and p300 plays a critical role in SnoN-induced axon growth. We also identify the gene encoding the signaling scaffold protein Ccd1 as a critical target of SnoN in neurons. Ccd1 localizes to the actin cytoskeleton, is enriched at axon terminals in neurons, and activates the axon growth-promoting kinase JNK (c-Jun N-terminal protein kinase). Knockdown of Ccd1 in neurons reduces axonal length and suppresses the ability of SnoN to promote axonal growth. Importantly, Ccd1 knockdown in rat pups profoundly impairs the formation of granule neuron parallel fiber axons in the rat cerebellar cortex in vivo. These findings define a novel SnoN-Ccd1 link that promotes axonal growth in the mammalian brain, with important implications for axonal development and regeneration.
 ...
PMID:A SnoN-Ccd1 pathway promotes axonal morphogenesis in the mammalian brain. 1933 25

The peroxisome proliferator activated receptor coactivator 1 alpha (PGC-1alpha) is a nuclear transcriptional coactivator that is widely expressed in the brain areas. Over-expression of PGC-1alpha can protect neuronal cells from oxidant-induced injury. The purpose of the current study is to investigate the role of PGC-1alpha in the oxygen (anoxia) deprivation (OGD) neurons. The PGC-1alpha mRNA and protein level between control and OGD neurons were examined by real-time PCR and Western blot. More PGC-1alpha expression was found in the OGD neurons compared with the normal group. Over-expression of PGC-1alpha suppressed cell apoptosis while inhibition of the PGC-1alpha expression induced cell apoptosis in OGD neurons. Furthermore, increase of PGC-1alpha resulted in activation of N-methyl-D-aspartate (NMDA) receptor, p38, and ERK mitogen-activated protein kinase (MAPK) pathway. The blocking of the NMDA receptor by its antagonists MK-801 reduced PGC-1alpha mRNA expression in OGD neurons, while NMDA itself can directly induce the expression of PGC-1alpha in neuronal cells. At the same time, PD98059 (ERK MAPK inhibitor) and SB203580 (P38 MAPK inhibitor) also prevented the up-regulation of PGC-1alpha in OGD neurons and MK801 can inhibit the expression of P38 and ERK MAPK. These data suggested that the expression of PGC-1alpha was up-regulated in OGD mice cortical neurons, which protected the neurons against OGD injury. Moreover, this effect was correlated to the NMDA receptor and the ERK and P38 MAPK pathway. The protective effect of PGC-1alpha on OGD cortical neurons may be useful for stroke therapy.
 ...
PMID:NMDA receptor dependent PGC-1alpha up-regulation protects the cortical neuron against oxygen-glucose deprivation/reperfusion injury. 1934 77

Oxidative myofibers, also known as slow-twitch myofibers, help maintain the metabolic health of mammals, and it has been proposed that decreased numbers correlate with increased risk of obesity. The transcriptional coactivator PPARgamma coactivator 1alpha (PGC-1alpha) plays a central role in maintaining levels of oxidative myofibers in skeletal muscle. Indeed, loss of PGC-1alpha expression has been linked to a reduction in the proportion of oxidative myofibers in the skeletal muscle of obese mice. MAPK phosphatase-1 (MKP-1) is encoded by mkp-1, a stress-responsive immediate-early gene that dephosphorylates MAPKs in the nucleus. Previously we showed that mice deficient in MKP-1 have enhanced energy expenditure and are resistant to diet-induced obesity. Here we show in mice that excess dietary fat induced MKP-1 overexpression in skeletal muscle, and that this resulted in reduced p38 MAPK-mediated phosphorylation of PGC-1alpha on sites that promoted its stability. Consistent with this, MKP-1-deficient mice expressed higher levels of PGC-1alpha in skeletal muscle than did wild-type mice and were refractory to the loss of oxidative myofibers when fed a high-fat diet. Collectively, these data demonstrate an essential role for MKP-1 as a regulator of the myofiber composition of skeletal muscle and suggest a potential role for MKP-1 in metabolic syndrome.
 ...
PMID:MAPK phosphatase-1 facilitates the loss of oxidative myofibers associated with obesity in mice. 1992 Mar 56

Peroxisome proliferator-activated receptor gamma coactivator (PGC-1alpha) is a transcriptional coactivator that plays a key role in coordinating mitochondrial biogenesis. Recent evidence has linked p38 MAPK and AMPK with activation of PGC-1alpha. It was recently shown in rodent skeletal muscle that acute endurance exercise causes a shift in the subcellular localization of PGC-1alpha from the cytosol to the nucleus, allowing PGC-1alpha to coactivate transcription factors and increase mitochondrial gene expression, but human data are limited and equivocal in this regard. Our purpose was to examine p38 MAPK and AMPK activation, and PGC-1alpha protein content in whole muscle, cytosolic, and nuclear fractions of human skeletal muscle following an acute bout of endurance exercise. Eight trained men (29 +/- 3 yr; Vo(2peak) = 55 +/- 2 ml.kg(-1).min(-1)) cycled for 90 min at approximately 65% of Vo(2peak) and needle biopsy samples (vastus lateralis) were obtained before and immediately after exercise. At rest, the majority of PGC-1alpha was detected in cytosolic compared with the nuclear fractions. In response to exercise, nuclear PGC-1alpha protein increased by 54% (P < 0.05), yet whole muscle PGC-1alpha protein was unchanged compared with rest. Whole muscle and cytosolic p38 MAPK phosphorylation increased several-fold immediately after exercise compared with rest (P < 0.05). Acetyl CoA carboxylase (ACC) phosphorylation, a marker of AMPK activation, was increased by approximately 5-fold in cytosolic fractions following exercise (P < 0.05). These data provide evidence that, in human skeletal muscle, activation of cytosolic p38 MAPK and AMPK may be potential signals that lead to increased nuclear abundance and activation of PGC-1alpha in response to an acute bout of endurance exercise.
 ...
PMID:Acute endurance exercise increases the nuclear abundance of PGC-1alpha in trained human skeletal muscle. 2010 91

In eukaryotes, mitochondria are critical for cellular bioenergetics and mediating apoptosis. The transcriptional coactivator peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha) is an important regulator of mitochondrial biogenesis and function. However, the role of PGC-1alpha in neuronal apoptosis and its regulation by apoptotic pathway are still unknown. We demonstrated that PGC-1alpha expression was down-regulated in cerebellar granule neurons(CGNs) after activation of the JNK/c-Jun pathway by potassium deprivation. Overexpression of PGC-1alpha partially protected CGNs from potassium deprivation-induced apoptosis. JNK-specific inhibitors, SP600125 and CEP11004, partially blocked the inhibitory effects of JNK on PGC-1alpha expression and its promoter activity. Furthermore, ChIP assays revealed that c-Jun was able to bind to the CRE site (-188 to -180) in the PGC-1alpha promoter. In conclusion, these results suggest that down-expression of PGC-1alpha partially mediated by activation of JNK/c-Jun may be through the binding of c-Jun to the CRE site in the PGC-1alpha promoter, and it might be involved in potassium deprivation-induced apoptosis in CGNs.
 ...
PMID:Down-expression of PGC-1alpha partially mediated by JNK/c-Jun through binding to CRE site during apoptotic procedure in cerebellar granule neurons. 2014 20

In this study, we analysed the expression of the transcriptional coactivator TAZ (transcriptional co-activator with PDZ-binding motif), also named WWTR1, in a panel of papillary thyroid carcinoma samples and we observed a significant deregulation of its expression in such tumours. Specifically, by quantitative real-time PCR (qRT-PCR) we evaluated TAZ mRNA levels in tissue specimens (n=61) of papillary thyroid carcinoma (PTC) and herein we show that the PTC samples express much higher TAZ mRNA levels with respect to the normal thyroid tissue (p<0.001). TAZ expression was also evaluated in normal (n=10) and pathological human thyroids (n=17) by immunohistochemical analysis and the increase of TAZ protein levels in PTC was confirmed. To further analyse the molecular mechanisms underlying TAZ overexpression in PTC, we used an inducible system consisting of FRTL-5 rat thyroid cells expressing a conditional RAS oncoprotein and we show that the activation of the RAS signalling pathway is involved in TAZ deregulation. These observations suggest that the activated effectors of the RAS/RAF/MEK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) signalling pathway are involved in the increased expression of TAZ, supporting the idea that this may also occur in thyroid papillary carcinoma. Moreover, we demonstrated that the overexpression of TAZ is able to confer growth advantage to thyroid cells in culture and to induce epithelial-mesenchymal transition. In conclusion, these findings support a potential role for TAZ in the pathogenesis of papillary thyroid carcinomas.
 ...
PMID:TAZ/WWTR1 is overexpressed in papillary thyroid carcinoma. 2113 Nov 95


<< Previous 1 2 3 4 5 6 7 8 Next >>