Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P05412 (c-Jun)
 11,453 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The stress activated protein kinase pathway culminates in c-Jun phosphorylation mediated by the Jun Kinases (JNKs). The role of the JNK pathway in sympathetic neuronal death is unclear in that apoptosis is not inhibited by a dominant negative protein of one JNK kinase, SEK1, but is inhibited by CEP-1347, a compound known to inhibit this overall pathway but not JNKs per se. To evaluate directly the apoptotic role of the JNK isoform that is selectively expressed in neurons, JNK3, we isolated sympathetic neurons from JNK3-deficient mice and quantified nerve growth factor (NGF) deprivation-induced neuronal death, oxidative stress, c-Jun phosphorylation, and c-jun induction. Here, we report that oxidative stress in neurons from JNK3-deficient mice is normal after NGF deprivation. In contrast, NGF-deprivation-induced increases in the levels of phosphorylated c-Jun, c-jun, and apoptosis are each inhibited in JNK3-deficient mice. Overall, these results indicate that JNK3 plays a critical role in activation of c-Jun and apoptosis in a classic model of cell-autonomous programmed neuron death.
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PMID:JNK3 contributes to c-Jun activation and apoptosis but not oxidative stress in nerve growth factor-deprived sympathetic neurons. 1146 65

Mice lacking expression of the p66 isoform of the ShcA adaptor protein (p66(ShcA)) are less susceptible to oxidative stress and have an extended life span. Specifically, phosphorylation of p66(ShcA) at serine 36 is critical for the cell death response elicited by oxidative damage. We sought to identify the kinase(s) responsible for this phosphorylation. Utilizing the SH-SY5Y human neuroblastoma cell model, it is demonstrated that p66(ShcA) is phosphorylated on serine/threonine residues in response to UV irradiation. Both c-Jun N-terminal kinases (JNKs) and p38 mitogen-activated protein kinases are activated by UV irradiation, and we show that both are capable of phosphorylating serine 36 of p66(ShcA) in vitro. However, treatment of cells with a multiple lineage kinase inhibitor, CEP-1347, that blocks UV-induced JNK activation, but not p38, phosphatidylinositol 3-kinase, or MEK1 inhibitors, prevented p66(ShcA) phosphorylation in SH-SY5Y cells. Consistent with this finding, transfected activated JNK1, but not the kinase-dead JNK1, leads to phosphorylation of serine 36 of p66(ShcA) in Chinese hamster ovary cells. In conclusion, JNKs are the kinases that phosphorylate serine 36 of p66(ShcA) in response to UV irradiation in SH-SY5Y cells, and blocking p66(ShcA) phosphorylation by intervening in the JNK pathway may prevent cellular damage due to light-induced oxidative stress.
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PMID:c-Jun N-terminal kinase specifically phosphorylates p66ShcA at serine 36 in response to ultraviolet irradiation. 1160 89

A stress-activated protein kinase pathway comprising mitogen-activated protein kinase kinases (MKKs), c-Jun N-terminal kinase (JNK) and the transcription factor c-Jun is implicated in neuronal apoptosis. Using an immune-complex kinase assay, we measured the activation of MKK4 and MKK7 in low potassium (LK)-induced apoptosis of rat cerebellar granule neurons (CGN). MKK7, but not MKK4, was activated within the first 4-6 h in four independent sets of 14-h CGN apoptosis time-courses. CEP-1347 (500 nM), an mixed-lineage kinase 3 inhibitor, prevented MKK7 activation and cell death following exposure of CGN cultures to LK-induced apoptosis. Western blot analysis revealed that levels of phosphorylated c-Jun were elevated between 30 min and 10 h of CGN apoptosis, temporally consistent with MKK7 activation. These data suggest that MKK7 is responsible for activating the JNK pathway during LK-induced CGN apoptosis.
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PMID:Mitogen-activated protein kinase kinase 7 is activated during low potassium-induced apoptosis in rat cerebellar granule neurons. 1184 56

Tumor necrosis factor-alpha (TNFalpha, 10-100 ng/ml) provokes a dramatic cell death in differentiated PC12 cells (dPC12), but it does not affect the viability and the proliferation of naive PC12 cells (nPC12). We have analyzed the molecular alterations of the TNFalpha-signal cascade underlying this developmental switch toward propagation of apoptosis. The transcriptional inhibitor actinomycin D rendered nPC12 responsive for TNFalpha-induced death, but was hardly effective in dPC12, suggesting that TNFalpha evokes its harmful action in dPC12 predominantly by posttranslational modification of existing molecules. This suggestion was supported by the finding that differentiation of PC12 per se went along with the increased expression of the proapoptotic TNFalpha-receptor I (p55) and its adapter protein Traf-2, whereas expression and phosphorylation of the antiapoptotic Akt (PKB) declined. We could demonstrate that the c-Jun N-terminal kinases (JNKs) mediate this enhanced capacity of apoptotic signaling in dPC12. TNFalpha induced in dPC12, but not nPC12, a biphasic activation of JNKs with a rapid transient JNK1 activation and a second persistent activation of JNK1 and JNK2 paralleled by phosphorylation of c-Jun; in contrast, TNFalpha did not activate p38 kinase. Block of JNKs by CEP-11004, a MLK antagonist and subsequently indirect inhibitor of JNK activation, or L-JNK11, a direct peptidergic inhibitor of JNK activity, almost completely rescued dPC12. Summarizing, the NGF-triggered formation of neurites during differentiation of PC12 includes the reinforced propensity for apoptosis, with JNK2 as the effector in JNK3-negative PC12. These findings offer novel insights into the increased risk of neuronal death, which is linked to the potential to regenerate.
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PMID:Fatal shift of signal transduction is an integral part of neuronal differentiation: JNKs realize TNFalpha-mediated apoptosis in neuronlike, but not naive, PC12 cells. 1209 55

The c-Jun N-terminal kinases (JNKs) exert a pleiotrophy of physiological and pathological actions. This is also true for the immune system. Disruption of the JNK locus results in substantial functional deficits of peripheral T-cells. In contrast to circulating immune cells and the role of p38, the presence and function of JNKs in the immune cells of the brain remain to be defined. Here, we report on the expression and activation of JNKs in cultivated microglia from neonatal rats and from mice with targeted disruption of the JNK locus and the N-terminal mutation of c-Jun (c-JunAA), respectively. JNK1, 2 and 3 mRNA and proteins were all expressed in microglia. Following stimulation with LPS (100 ng/mL), a classical activator of microglia, JNKs were rapidly activated and this activation returns to basal levels within 4 hr. Following LPS and other stimuli such as thrombin (10-50 unit/mL), the activation of JNKs went along with the N-terminal phosphorylation of c-Jun which persisted for at least 8 hr. Indirect inhibition of JNK by CEP-11004 (0.5-2 microM), an inhibitor of mixed-lineage kinases (MLK), reduced the LPS-induced phosphorylation of both, JNK and c-Jun, by around 50%, and attentuated the LPS-induced the alterations in microglial morphology. Finally, JNKs are involved in the control of cytokine release since both, incubation with CEP-11004 and disruption of the JNK1 locus enhanced the release of TNFalpha, IL-6 and IL-12. Our findings provide insight in so far unknown functions of JNKs in cerebral immune cells. These observations are also important for the wide spread efforts to develop JNK-inhibitors as neuroprotective drugs which, however, might trigger pro-inflammatory processes.
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PMID:The c-Jun N-terminal kinases in cerebral microglia: immunological functions in the brain. 1221 70

The hair cells (HCs) are the most vulnerable elements in the cochlea and damage to them is the most common cause of sensorineural hearing loss (SNHL). Understanding the intracellular events that lead to the death of HCs is a key to developing protective strategies. Recently, it has been shown that the c-Jun-N-terminal kinase (JNK) pathway is activated in HCs in response to aminoglycosides and CEP-1347, an inhibitor of the JNK signaling pathway protected HCs from ototoxicity. We have studied another inhibitor (CEP-11 004) of this signaling pathway in its ability to protect HCs from aminoglycoside ototoxicity in vitro. Organ of Corti explants from p5 rat basal turns were maintained in tissue culture and treated with CEP-11 004 for 12 hours. They were then treated with CEP-11 004 plus gentamicin for 72 hours. Significantly less HC death was observed compared to gentamicin alone. CEP-11 004 alone had no effect on HCs. We conclude that the JNK signaling pathway plays a role in aminoglycoside ototoxicity signaling.
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PMID:[Rescue of auditory hair cells from ototoxicity by CEP-11 004, an inhibitor of the JNK signaling pathway]. 1248 21

Apoptosis has been proposed as a mechanism of cell death in Alzheimer's, Huntington's and Parkinson's diseases and the occurrence of apoptosis in these disorders suggests a common mechanism. Events such as oxidative stress, calcium toxicity, mitochondria defects, excitatory toxicity, and deficiency of survival factors are all postulated to play varying roles in the pathogenesis of the diseases. However, the transcription factor c-jun may play a role in the pathology and cell death processes that occur in Alzheimer's disease. Parkinson's disease (PD) is also a progressive disorder involving the specific degeneration and death of dopamine neurons in the nigrostriatal pathway. In Parkinson's disease, dopaminergic neurons in the substantia nigra are hypothesized to undergo cell death by apoptotic processes. The commonality of biochemical events and pathways leading to cell death in these diseases continues to be an area under intense investigation. The current therapy for PD and AD remains targeting replacement of lost transmitter, but the ultimate objective in neurodegenerative therapy is the functional restoration and/or cessation of progression of neuronal loss. This chapter will describe a novel approach for the treatment of neurodegenerative diseases through the development of kinase inhibitors that block the active cell death process at an early transcriptional independent step in the stress activated kinase cascade. In particular, preclinical data will be presented on the c-Jun Amino Kinase pathway inhibitor, CEP-1347/KT-7515, with respect to it's properties that make it a desirable clinical candidate for treatment of various neurodegenerative diseases.
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PMID:Discovery of CEP-1347/KT-7515, an inhibitor of the JNK/SAPK pathway for the treatment of neurodegenerative diseases. 1251 22

Activation of the JNK pathway and induction of the AP-1 transcription factor c-Jun are critical for neuronal apoptosis caused by a variety of insults. Ara-C-induced DNA damage caused rapid sympathetic neuronal death that was associated with an increase of c-jun expression. In addition, c-Jun was phosphorylated in its N-terminal transactivation domain, which is important for c-Jun-mediated gene transcription. Blocking c-Jun activation by JNK pathway inhibition prevented neuronal death after stress. In contrast, neither the JNK inhibitor SP600125 nor the mixed lineage kinase inhibitor CEP-1347 prevented cytosine arabinoside-induced neuronal death, demonstrating that the JNK pathway was not necessary for DNA damage-induced neuronal apoptosis. Surprisingly, SP600125 or CEP-1347 could not block c-Jun induction or phosphorylation after DNA damage. Pharmacological inhibitors of cyclin-dependent kinase (CDK) activity completely prevented c-Jun phosphorylation after DNA damage. These results demonstrate that c-Jun activation during DNA damage-induced neuronal apoptosis was independent of the classical JNK pathway and was mediated by a novel c-Jun kinase. Based on pharmacological criteria, DNA damage-induced neuronal c-Jun kinase may be a member of the CDK family or be activated by a CDK-like kinase. Activation of this novel kinase and subsequent phosphorylation of c-Jun may be important in neuronal death after DNA damage.
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PMID:JNK-independent activation of c-Jun during neuronal apoptosis induced by multiple DNA-damaging agents. 1268 20

The c-Jun N-terminal protein kinases (JNKs) form one subfamily of the mitogen-activated protein kinase (MAPK) group of serine/threonine protein kinases. The JNKs were first identified by their activation in response to a variety of extracellular stresses and their ability to phosphorylate the N-terminal transactivation domain of the transcription factor c-Jun. One approach to study the function of the JNKs has included in vivo gene knockouts of each of the three JNK genes. Whilst loss of either JNK1 or JNK2 alone appears to have no serious consequences, their combined knockout is embryonic lethal. In contrast, the loss of JNK3 is not embryonic lethal, but rather protects the adult brain from glutamate-induced excitotoxicity. This latter example has generated considerable enthusiasm with JNK3, considered an appropriate target for the treatment of diseases in which neuronal death should be prevented (e.g. stroke, Alzheimer's and Parkinson's diseases). More recently, these gene knockout animals have been used to demonstrate that JNK could provide a suitable target for the protection against obesity and diabetes and that JNKs may act as tumour suppressors. Considerable effort is being directed to the development of chemical inhibitors of the activators of JNKs (e.g. CEP-1347, an inhibitor of the MLK family of JNK pathway activators) or of the JNKs themselves (e.g. SP600125, a direct inhibitor of JNK activity). These most commonly used inhibitors have demonstrated efficacy for use in vivo, with the successful intervention to decrease brain damage in animal models (CEP-1347) or to ameliorate some of the symptoms of arthritis in other animal models (SP600125). Alternative peptide-based inhibitors of JNKs are now also in development. The possible identification of allosteric modifiers rather than direct ATP competitors could lead to inhibitors of unprecedented specificity and efficacy.
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PMID:Targeting the JNK MAPK cascade for inhibition: basic science and therapeutic potential. 1502 53

Environmental exposure to the oxidant-producing herbicide paraquat has been implicated as a risk factor in Parkinson's disease. Although intraperitoneal paraquat injections in mice cause a selective loss of dopaminergic neurons in the substantia nigra pars compacta, the exact mechanism involved is still poorly understood. Our data show that paraquat induces the sequential phosphorylation of c-Jun N-terminal kinase (JNK) and c-Jun and the activation of caspase-3 and sequential neuronal death both in vitro and in vivo. These effects are diminished by the specific JNK inhibitor SP600125 and the antioxidant manganese(III) tetrakis (4-benzoic acid) porphyrin in vitro. Furthermore, JNK pathway inhibitor CEP-11004 effectively blocks paraquat-induced dopaminergic neuronal death in vivo. These results suggest that the JNK signaling cascade is a direct activator of the paraquat-mediated nigral dopaminergic neuronal apoptotic machinery and provides a molecular linkage between oxidative stress and neuronal apoptosis.
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PMID:The herbicide paraquat induces dopaminergic nigral apoptosis through sustained activation of the JNK pathway. 1515 44


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