scholarly journals Requirement of the p38 mitogen-activated protein kinase signalling pathway for the induction of the 78 kDa glucose-regulated protein/immunoglobulin heavy-chain binding protein by azetidine stress: activating transcription factor 6 as a target for stress-induced phosphorylation

2002 ◽  
Vol 366 (3) ◽  
pp. 787-795 ◽  
Author(s):  
Shengzhan LUO ◽  
Amy S. LEE
Keyword(s):  
Signal Transduction ◽  
Transcription Factor ◽  
Protein Kinase ◽  
Er Stress ◽  
P38 Mapk ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Grp78 Promoter ◽  
Activating Transcription Factor ◽  
Glucose Regulated Protein

Malfolded protein formation and perturbance of calcium homoeostasis results in the induction of the endoplasmic reticulum (ER) chaperone protein, namely the 78kDa glucose-regulated protein (GRP78)/immunoglobulin heavy-chain binding protein. Various ER stress inducers can activate grp78, but signal transduction mechanisms are not well understood. We report in the present study that the induction of endogenous grp78 mRNA by the amino acid analogue azetidine (AzC) requires the integrity of a signal transduction pathway mediated by p38 mitogen-activated protein kinase (p38 MAPK). In contrast, induction of grp78 by thapsigargin that depletes the ER calcium storage can occur even when the p38 MAPK pathway is blocked. Treatment of cells with AzC results in the sustained activation of p38 MAPK. We identified an ER transmembrane activating transcription factor 6 (ATF6) as a target of p38 MAPK phosphorylation in AzC-treated cells. ATF6 undergoes proteolytic cleavage on AzC treatment, releasing a nuclear form that is an activator of the grp78 promoter. We show here that constitutively active mitogen-activated protein kinase kinase 6, a selective p38 MAPK activator, enhances the ability of the nuclear form of ATF6 to transactivate the grp78 promoter. Our results provide direct evidence that different ER stress inducers use diverse pathways to activate grp78 and that in addition to activation by proteolytic cleavage, ATF6 undergoes specific ER stress-induced phosphorylation. We propose that phosphorylation of ATF6 is a novel mechanism for augmenting its potential as a transcription activator.

scholarly journals Helicobacter pylori VacA Enhances Prostaglandin E2 Production through Induction of Cyclooxygenase 2 Expression via a p38 Mitogen-Activated Protein Kinase/Activating Transcription Factor 2 Cascade in AZ-521 Cells

2007 ◽  
Vol 75 (9) ◽  
pp. 4472-4481 ◽  
Author(s):  
Junzo Hisatsune ◽  
Eiki Yamasaki ◽  
Masaaki Nakayama ◽  
Daisuke Shirasaka ◽  
Hisao Kurazono ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Transcription Factor ◽  
Protein Kinase ◽  
P38 Mapk ◽  
Cyclooxygenase 2 ◽  
Mitogen Activated Protein Kinase ◽  
Mrna Levels ◽  
Mitogen Activated Protein ◽  
Cox 2 ◽  
Activating Transcription Factor

ABSTRACT Treatment of AZ-521 cells with Helicobacter pylori VacA increased cyclooxygenase 2 (COX-2) mRNA in a time- and dose-dependent manner. A p38 mitogen-activated protein kinase (MAPK) inhibitor, SB203580, blocked elevation of COX-2 mRNA levels, whereas PD98059, which blocks the Erk1/2 cascade, partially suppressed the increase. Consistent with involvement of p38 MAPK, VacA-induced accumulation of COX-2 mRNA was reduced in AZ-521 cells overexpressing a dominant-negative p38 MAPK (DN-p38). Phosphatidylinositol-specific phospholipase C, which inhibits VacA-induced p38 MAPK activation, blocked VacA-induced COX-2 expression. In parallel with COX-2 expression, VacA increased prostaglandin E2 (PGE2) production, which was inhibited by SB203580 and NS-398, a COX-2 inhibitor. VacA-induced PGE2 production was markedly attenuated in AZ-521 cells stably expressing DN-p38. VacA increased transcription of a COX-2 promoter reporter gene and activated a COX-2 promoter containing mutated NF-κB or NF-interleukin-6 sites but not a mutated cis-acting replication element (CRE) site, suggesting direct involvement of the activating transcription factor 2 (ATF-2)/CREB-binding region in VacA-induced COX-2 promoter activation. The reduction of ATF-2 expression in AZ-521 cells transformed with ATF-2-small interfering RNA duplexes resulted in suppression of COX-2 expression. Thus, VacA enhances PGE2 production by AZ-521 cells through induction of COX-2 expression via the p38 MAPK/ATF-2 cascade, leading to activation of the CRE site in the COX-2 promoter.

scholarly journals p38 Mitogen-Activated Protein Kinase Is the Central Regulator of Cyclic AMP-Dependent Transcription of the Brown Fat Uncoupling Protein 1 Gene

2004 ◽  
Vol 24 (7) ◽  
pp. 3057-3067 ◽  
Author(s):  
Wenhong Cao ◽  
Kiefer W. Daniel ◽  
Jacques Robidoux ◽  
Pere Puigserver ◽  
Alexander V. Medvedev ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
P38 Mapk ◽  
Uncoupling Protein ◽  
Brown Fat ◽  
Mitogen Activated Protein Kinase ◽  
Uncoupling Protein 1 ◽  
Response Element ◽  
Mitogen Activated Protein

ABSTRACT It is well established that catecholamine-stimulated thermogenesis in brown fat requires β-adrenergic elevations in cyclic AMP (cAMP) to increase expression of the uncoupling protein 1 (UCP1) gene. However, little is known about the downstream components of the signaling cascade or the relevant transcription factor targets thereof. Here we demonstrate that cAMP- and protein kinase A-dependent activation of p38 mitogen-activated protein kinase (MAPK) in brown adipocytes is an indispensable step in the transcription of the UCP1 gene in mice. By phosphorylating activating transcription factor 2 (ATF-2) and peroxisome proliferator-activated receptor gamma (PPARγ) coativator 1α (PGC-1α), members of two distinct nuclear factor families, p38 MAPK controls the expression of the UCP1 gene through their respective interactions with a cAMP response element and a PPAR response element that both reside within a critical enhancer motif of the UCP1 gene. Activation of ATF-2 by p38 MAPK additionally serves as the cAMP sensor that increases expression of the PGC-1α gene itself in brown adipose tissue. In conclusion, our findings illustrate that by orchestrating the activity of multiple transcription factors, p38 MAPK is a central mediator of the cAMP signaling mechanism of brown fat that promotes thermogenesis.

scholarly journals Hog1 Mitogen-Activated Protein Kinase (MAPK) Interrupts Signal Transduction between the Kss1 MAPK and the Tec1 Transcription Factor To Maintain Pathway Specificity

2009 ◽  
Vol 8 (4) ◽  
pp. 606-616 ◽  
Author(s):  
Teresa R. Shock ◽  
James Thompson ◽  
John R. Yates ◽  
Hiten D. Madhani
Keyword(s):  
Signal Transduction ◽  
Transcription Factor ◽  
Protein Kinase ◽  
Dna Binding ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Nuclear Accumulation ◽  
Hog Pathway ◽  
Pathway Activation ◽  
Mitogen Activated Protein

ABSTRACT In Saccharomyces cerevisiae, the mating, filamentous growth (FG), and high-osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) signaling pathways share components and yet mediate distinct responses to different extracellular signals. Cross talk is suppressed between the mating and FG pathways because mating signaling induces the destruction of the FG transcription factor Tec1. We show here that HOG pathway activation results in phosphorylation of the FG MAPK, Kss1, and the MAPKK, Ste7. However, FG transcription is not activated because HOG signaling prevents the activation of Tec1. In contrast to the mating pathway, we find that the mechanism involves the inhibition of DNA binding by Tec1 rather than its destruction. We also find that nuclear accumulation of Tec1 is not affected by HOG signaling. Inhibition by Hog1 is apparently indirect since it does not require any of the consensus S/TP MAPK phosphorylation sites on Tec1, its DNA-binding partner Ste12, or the associated regulators Dig1 or Dig2. It also does not require the consensus MAPK sites of the Ste11 activator Ste50, in contrast to a recent proposal for a role for negative feedback in specificity. Our results demonstrate that HOG signaling interrupts the FG pathway signal transduction between the phosphorylation of Kss1 and the activation of DNA binding by Tec1.

scholarly journals A new phosphospecific cell-based ELISA for p42/p44 mitogen-activated protein kinase (MAPK), p38 MAPK, protein kinase B and cAMP-response-element-binding protein

2000 ◽  
Vol 350 (3) ◽  
pp. 717-722 ◽  
Author(s):  
Henri H. VERSTEEG ◽  
Evert NIJHUIS ◽  
Gijs R. VAN DEN BRINK ◽  
Maaike EVERTZEN ◽  
Gwenda N. PYNAERT ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Protein Kinase ◽  
P38 Mapk ◽  
Protein Kinase B ◽  
Camp Response Element Binding ◽  
Mitogen Activated Protein Kinase ◽  
Camp Response Element ◽  
Response Element ◽  
Mitogen Activated Protein ◽  
Element Binding Protein

Assaying activation of signal transduction is laborious and does not allow the study of large numbers of samples, essential for high-throughput drug screens or for large groups of patients. Using phosphospecific antibodies, we have developed ELISA techniques enabling non-radioactive semi-quantitative assessment of the activation state of p42/p44 mitogen-activated protein kinase (MAPK), p38 MAPK, protein kinase B and the transcription factor cAMP-response-element-binding protein (CREB) in 96-well plates. This assay has been termed PACE (phosphospecific antibody cell-based ELISA) and was used successfully for both adherent and suspension cells. Various stimuli induced dose-dependent enzymic activity of which the kinetics closely correlated with those measured via classical methodology. Using PACE we have now characterized for the first time the concentration-dependent effects of various inflammatory prostaglandins on CREB phosphorylation in macrophages. PACE is a straightforward and novel technique enabling the large-scale analysis of signal transduction.

scholarly journals Combined De-Repression of Chemoresistance Associated Mitogen-Activated Protein Kinase 14 and Activating Transcription Factor 2 by Loss of microRNA-622 in Hepatocellular Carcinoma

Cancers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1183
Author(s):  
Valerie Fritz ◽  
Lara Malek ◽  
Anne Gaza ◽  
Laura Wormser ◽  
Majken Appel ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Transcription Factor ◽  
Protein Kinase ◽  
Target Genes ◽  
Resistant Cell ◽  
Mitogen Activated Protein Kinase ◽  
Erk Activation ◽  
Mitogen Activated Protein ◽  
Collateral Pathway ◽  
Activating Transcription Factor

Chemoresistance is a major hallmark driving the progression and poor prognosis of hepatocellular carcinoma (HCC). Limited chemoresponse of HCC was demonstrated to be mediated by mitogen-activated protein kinase 14 (MAPK14) and activating transcription factor 2 (ATF2). Recently, we have demonstrated loss of control of RAS-RAF-ERK-signaling as a consequence of miR-622 downregulation in HCC. However, the majority of target genes of this potent tumorsuppressive microRNA had remained elusive. The MAPK14-ATF2-axis represents a collateral pathway ensuring persisting ERK-activation in the presence of sorafenib-mediated RAF-inhibition. In contrast to the function of the MAPK14-ATF2-axis, both the expression and regulation of MAPK14 and ATF2 in human HCC remained to be clarified. We found combined overexpression of MAPK14 and ATF2 in human HCC cells, tissues and in sorafenib resistant cell lines. High expression of MAPK14 and ATF2 was associated with reduced overall survival in HCC patients. Deciphering the molecular mechanism promoting combined upregulation of MAPK14 and ATF2 in HCC, we revealed that miR-622 directly targets both genes, resulting in combined de-repression of the MAPK14-ATF2-axis. Together, miR-622 represents a superior regulator of both RAS-RAF-ERK as well as MAPK14-ATF2-signaling pathways in liver cancer.

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