scholarly journals Role of Apoptosis Signal-Regulating Kinase in Regulation of the c-Jun N-Terminal Kinase Pathway and Apoptosis in Sympathetic Neurons

2000 ◽  
Vol 20 (1) ◽  
pp. 196-204 ◽  
Author(s):  
Takashi Kanamoto ◽  
Monica Mota ◽  
Kohsuke Takeda ◽  
Lee L. Rubin ◽  
Kohei Miyazono ◽  
...  

ABSTRACT We have previously shown that nerve growth factor (NGF) withdrawal-induced death requires the activity of the small GTP-binding protein Cdc42 and that overexpression of an active form of Cdc42 is sufficient to mediate neuronal apoptosis via activation of the c-Jun pathway. Recently, a new mitogen-activated protein (MAP) kinase kinase kinase, apoptosis signal-regulating kinase 1 (ASK1) which activates both the c-Jun N-terminal kinase (JNK) and p38 MAP kinase pathways and plays pivotal roles in tumor necrosis factor- and Fas-induced apoptosis, has been identified. Therefore, we investigated the role of ASK1 in neuronal apoptosis by using rat pheochromocytoma (PC12) neuronal cells and primary rat sympathetic neurons (SCGs). Overexpression of ASK1-ΔN, a constitutively active mutant of ASK1, activated JNK and induced apoptosis in differentiated PC12 cells and SCG neurons. Moreover, in differentiated PC12 cells, NGF withdrawal induced a four- to fivefold increase in the activity of endogenous ASK1. Finally, expression of a kinase-inactive ASK1 significantly blocked both NGF withdrawal- and Cdc42-induced death and activation of c-jun. Taken together, these results demonstrate that ASK1 is a crucial element of NGF withdrawal-induced activation of the Cdc42–c-Jun pathway and neuronal apoptosis.

2004 ◽  
Vol 49 (1) ◽  
pp. 69-80 ◽  
Author(s):  
Youn Sook Song ◽  
Hye Ji Park ◽  
Soo Yeon Kim ◽  
Seung Ho Lee ◽  
Hwan Soo Yoo ◽  
...  

2001 ◽  
Vol 281 (1) ◽  
pp. C350-C360 ◽  
Author(s):  
David J. Elzi ◽  
A. Jason Bjornsen ◽  
Todd MacKenzie ◽  
Travis H. Wyman ◽  
Christopher C. Silliman

Many receptor-linked agents that prime or activate the NADPH oxidase in polymorphonuclear neutrophils (PMNs) elicit changes in cytosolic Ca2+concentration and activate mitogen-activated protein (MAP) kinases. To investigate the role of Ca2+in the activation of p38 and p42/44 MAP kinases, we examined the effects of the Ca2+-selective ionophore ionomycin on priming and activation of the PMN oxidase. Ionomycin caused a rapid rise in cytosolic Ca2+that was due to both a release of cytosolic Ca2+stores and Ca2+influx. Ionomycin also activated (2 μM) and primed (20–200 nM) the PMN oxidase. Dual phosphorylation of p38 MAP kinase and phosphorylation of its substrate activating transcription factor-2 were detected at ionomycin concentrations that prime or activate the PMN oxidase, while dual phosphorylation of p42/44 MAP kinase and phosphorylation of its substrate Elk-1 were elicited at 0.2–2 μM. SB-203580, a p38 MAP kinase antagonist, inhibited ionomycin-induced activation of the oxidase (68 ± 8%, P < 0.05) and tyrosine phosphorylation of 105- and 72-kDa proteins; conversely, PD-98059, an inhibitor of MAP/extracellular signal-related kinase 1, had no effect. Treatment of PMNs with thapsigargin resulted in priming of the oxidase and activation of p38 MAP kinase. Chelation of cytosolic but not extracellular Ca2+completely inhibited ionomycin activation of p38 MAP kinase, whereas chelation of extracellular Ca2+abrogated activation of p42/44 MAP kinase. These results demonstrate the importance of changes in cytosolic Ca2+for MAP kinase activation in PMNs.


2002 ◽  
Vol 368 (3) ◽  
pp. 705-720 ◽  
Author(s):  
Koichi SAEKI ◽  
Norihiko KOBAYASHI ◽  
Yuko INAZAWA ◽  
Hong ZHANG ◽  
Hideki NISHITOH ◽  
...  

We investigated intracellular signalling pathways for apoptosis induced by epigallocatechin-3-gallate (EGCG) as compared with those induced by a toxic chemical substance (etoposide, VP16) or the death receptor ligand [tumour necrosis factor (TNF)]. EGCG as well as VP16 and TNF induced activation of two apoptosis-regulating mitogen-activated protein (MAP) kinases, namely c-Jun N-terminal kinase (JNK) and p38 MAP kinase, in both human leukaemic U937 and OCI-AML1a cells. In U937 cells, the apoptosis and activation of caspases-3 and −9 induced by EGCG but not VP16 and TNF were inhibited with SB203580, a specific inhibitor of p38, while those induced by EGCG and VP16 but not TNF were inhibited with SB202190, a rather broad inhibitor of JNK and p38. In contrast, the EGCG-induced apoptosis in OCI-AML1a cells was resistant to SB203580 but not to SB202190. Unlike TNF, EGCG did not induce the activation of nuclear factor-κB but rather induced the primary activation of caspase-9. N-Acetyl-l-cysteine (NAC) almost completely abolished apoptosis induced by EGCG under conditions in which the apoptosis induced by VP16 or TNF was not affected. The JNK/p38 activation by EGCG was also potently inhibited by NAC, whereas those by VP16 and TNF were either not or only minimally affected by NAC. In addition, dithiothreitol also suppressed both apoptosis and JNK/p38 activation by EGCG, and EGCG-induced activation of MAP kinase kinase (MKK) 3/6, MKK4 and apoptosis-regulating kinase 1 (ASK1) was suppressed by NAC. Dominant negative ASK1, MKK6, MKK4 and JNK1 potently inhibited EGCG-induced cell death. EGCG induced an intracellular increase in reactive oxygen species and GSSG, both of which were also inhibited by NAC, and the decreased synthesis of glutathione rendered the cell susceptible to EGCG-induced apoptosis. Taken together these results strongly suggest that EGCG executed apoptotic cell death via an ASK1, MKK and JNK/p38 cascade which is triggered by NAC-sensitive intracellular oxidative events in a manner distinct from chemically induced or receptor-mediated apoptosis.


1999 ◽  
Vol 19 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Ming Zhao ◽  
Liguo New ◽  
Vladimir V. Kravchenko ◽  
Yutaka Kato ◽  
Hermann Gram ◽  
...  

ABSTRACT Members of the MEF2 family of transcription factors bind as homo- and heterodimers to the MEF2 site found in the promoter regions of numerous muscle-specific, growth- or stress-induced genes. We showed previously that the transactivation activity of MEF2C is stimulated by p38 mitogen-activated protein (MAP) kinase. In this study, we examined the potential role of the p38 MAP kinase pathway in regulating the other MEF2 family members. We found that MEF2A, but not MEF2B or MEF2D, is a substrate for p38. Among the four p38 group members, p38 is the most potent kinase for MEF2A. Threonines 312 and 319 within the transcription activation domain of MEF2A are the regulatory sites phosphorylated by p38. Phosphorylation of MEF2A in a MEF2A-MEF2D heterodimer enhances MEF2-dependent gene expression. These results demonstrate that the MAP kinase signaling pathway can discriminate between different MEF2 isoforms and can regulate MEF2-dependent genes through posttranslational activation of preexisting MEF2 protein.


1996 ◽  
Vol 319 (1) ◽  
pp. 17-20 ◽  
Author(s):  
Waltraut H WATERMAN ◽  
Thaddeus F. P. MOLSKI ◽  
Chi-Kuang HUANG ◽  
Jerry L. ADAMS ◽  
Ramadan I. SHA'AFI

The role of the newly identified p38 mitogen-activated protein kinase (MAP kinase) in terminally differentiated cells, such as human neutrophils, is totally unknown. In order to examine the possible role of this MAP kinase in the phosphorylation and activation of cytoplasmic phospholipase A2 (cPLA2), we tested the effect of the recently synthesized inhibitor of p38 MAP kinase, SB 203580, on the phosphorylation and activation of both p38 MAP kinase and cPLA2. We found that while tumour necrosis factor-α (TNF-α)-stimulated tyrosine phosphorylation of p38 MAP kinase is affected only slightly by SB 203580, its stimulated kinase activity is greatly reduced in human neutrophils in suspension treated with this inhibitor. Furthermore, the TNF-α-stimulated phosphorylation and activation of cPLA2 are completely abolished in cells treated with SB 203580. Based on these data, it is reasonable to conclude that an SB 203580-sensitive kinase, or kinases and/or phosphatases, are involved in the phosphorylation and activation of cPLA2 in intact human neutrophils in suspension stimulated by TNF-α. The possible role of the p38 MAP kinase cascade in the phosphorylation and activation of cPLA2 is discussed.


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