Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumor necrosis factor-alpha (TNF-alpha) is a pleiotropic cytokine that elicits a large number of biological effects. However, the intracellular signaling mechanisms that are responsible for the TNF-alpha effects remain largely unknown. We have previously demonstrated that cultured mouse Sertoli cells, after TNF-alpha treatment, increase the surface expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and interleukin-6 (IL-6) production (Riccioli, A., Filippini, A., De Cesaris, P., Barbacci, E., Stefanini, M., Starace, G., and Ziparo, E. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 5808-5812). Here, we show that, in cultured Sertoli cells, TNF-alpha activates the mitogen-activated protein kinase pathway (p38, c-Jun N-terminal protein kinase/stress-activated protein kinase, and the p42/p44 mitogen-activated protein kinases) as revealed by an increased phosphorylation of p38, activating transcription factor-2, c-Jun, and Elk-1. Furthermore, our data indicate that the biological effects induced by TNF-alpha in Sertoli cells (enhancement of ICAM-1, VCAM-1, and IL-6 expression) depend on the activation of different signaling pathways. SB203580, a highly specific p38 inhibitor, does not affect ICAM-1 and VCAM-1 expression, but strongly inhibits IL-6 production. Moreover, interferon-gamma, which up-regulates adhesion molecule expression and reduces IL-6 production, does not induce phosphorylation of p38. Our data strongly support the hypothesis that, in response to TNF-alpha, activation of p38 leads to IL-6 production, whereas ICAM-1 and VCAM-1 expression could be induced by activation of the c-Jun N-terminal protein kinase/stress-activated protein kinase pathway.
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PMID:Tumor necrosis factor-alpha induces interleukin-6 production and integrin ligand expression by distinct transduction pathways. 951 59

Activation and infection by HIV-1 of glial cells and infiltrating macrophages are cardinal features of AIDS-related neurological disease. Tumor necrosis factor-alpha (TNF-alpha) is released by these cell types, and increased TNF-alpha mRNA and protein levels are associated with the development and severity of HIV-induced neurological disease. HIV-1 proteins have been implicated in HIV neuropathogenesis including Tat which has been shown to be a potent inducer of TNF-alpha. We review our data showing the induction of TNF-alpha by Tat in primary human fetal astrocytes, human peripheral blood mononuclear cells, macrophages, and astrocytic and macrophage cell lines. TNF-alpha induction was NF-kappaB dependent and was eliminated by inhibiting protein kinase A, phospholipase C and protein tyrosine kinase activity. In addition, we examined the molecular diversity of the tat genome in the brains of HIV-infected patients from different HIV-1 clades. Comparison of matched brain- and spleen-derived tat sequences indicated that homology among brain-derived clones was greater than that between the brain- and spleen-derived clones. The brain-derived tat sequences were markedly heterogeneous in regions which influence viral replication and intracellular transport. Future studies using Tat, encoded by different sequences, will be necessary to determine the functional significance of tat molecular diversity. Nonetheless, these studies suggest that Tat is an important inducer of TNF-alpha production and thus may play a key role in the pathogenesis of HIV-related neurological disease.
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PMID:HIV-1 tat molecular diversity and induction of TNF-alpha: implications for HIV-induced neurological disease. 973 Jun 85

The Rel/nuclear factor (NF)-kappaB family of transcription factors are important intracellular conveyors of extracellular signals in a number of systems. However, little is known of their roles in the specialized, hormonally regulated environment of the mammalian testis. In this study NF-kappaB p50 and p65 proteins were found to be constitutively present and active in the nucleus of Sertoli cells cultured from rat testis. In vivo, NF-kappaB proteins are present in the nucleus of Sertoli cells during all 14 (I-XIV) cyclical stages of spermatogenesis; however, nuclear NF-kappaB expression was elevated in stage XIV and remained high in stages I-VII. In contrast, NF-kappaB p50 and p65 subunits are transiently expressed in the nuclei of germ cells with peak levels found in pachytene spermatocytes during stages VII-XI and lower levels in stage I-VII spermatids. Tumor necrosis factor-alpha, which is produced by round spermatids in the testis, increased nuclear NF-kappaB binding activity when added to Sertoli cells. Stimulation of Sertoli cells with activators of the cAMP-protein kinase A (PKA) signaling pathway such as forskolin or FSH also increased NF-kappaB DNA binding activity. Consistent with the cellular localization studies, NF-kappaB was found to be activated as high basal levels of NF-kappaB-stimulated reporter gene expression were detected in transient transfection studies of Sertoli cells. Addition of tumor necrosis factor-alpha to Sertoli cells further stimulated kappaB enhancer-mediated transcription. These findings suggest that NF-kappaB proteins are stage specifically localized to Sertoli cell and spermatocyte nuclei and may play a role in the regulation of stage-specific gene expression during the process of spermatogenesis.
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PMID:Stage-specific nuclear expression of NF-kappaB in mammalian testis. 981 96

Upon infection with Plasmodium berghei ANKA (PbA), various inbred strains of mice exhibit different susceptibility to the development of cerebral malaria (CM). Tumor necrosis factor-alpha (TNF) and interferon-gamma (IFN-gamma) have been shown to be crucial mediators in the pathogenesis of this neurovascular complication. Brain microvascular endothelial cells (MVEC) represent an important target of both cytokines. In the present study, we show that brain MVEC purified from CM-susceptible (CM-S) CBA/J mice and CM-resistant (CM-R) BALB/c mice exhibit a different sensitivity to TNF. CBA/J brain MVEC displayed a higher capacity to produce IL-6 and to up-regulate intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in response to TNF than BALB/c brain MVEC. In contrast, no difference was found in the induction of E-selectin after TNF challenge. CM-S brain MVEC were also significantly more sensitive to TNF-induced lysis. This differential reactivity to TNF was further substantiated by comparing TNF receptor expression on CM-S and CM-R brain MVEC. Although the constitutive expression of TNF receptors was comparable on cells from the two origins, TNF induced an up-regulation of both p55 and p75 TNF receptors in CM-S, but not in CM-R brain MVEC. A similar regulation was found at the level of TNF receptor mRNA, but not for receptor shedding. Although a protein kinase C inhibitor blocked the response to TNF in both the brain MVEC, an inhibitor of protein kinase A selectively abolished the response to TNF in CM-R, but not CM-S brain MVEC, suggesting a differential protein kinase involvement in TNF-induced activation of CM-S and CM-R brain MVEC. These results indicate that brain MVEC purified from CM-S and CM-R mice exhibit distinctive sensitivity to TNF This difference may be partly due to a differential regulation of TNF receptors and via distinct protein kinase pathways.
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PMID:Differential reactivity of brain microvascular endothelial cells to TNF reflects the genetic susceptibility to cerebral malaria. 986 35

Tumor necrosis factor (TNF)-alpha, a pluripotent cytokine implicated in the pathogenesis of airway inflammation, has been shown to provoke hypersecretion of mucin by airway epithelial cells in vitro. In this study, we investigated potential signaling pathways mediating TNF-alpha-induced mucin secretion using guinea pig tracheal epithelial (GPTE) cells in air-liquid interface culture. Exogenously applied TNF-alpha (human recombinant) stimulated mucin secretion in a concentration-dependent manner, with maximal effects at 10 to 15 ng/ml (286 to 429 U/ml). The pathway of stimulated secretion appeared to involve generation of intracellular nitric oxide (NO), activation of soluble guanylate cyclase (GC-S), production of cyclic guanosine monophosphate (cGMP), and activation of cGMP-dependent protein kinase (PKG). TNF-alpha increased production of nitrite and nitrate by GPTE cells; both mucin secretion and cGMP production were attenuated by NG-monomethyl-L-arginine (1 mM), a competitive inhibitor of nitric oxide synthase (NOS), or by the GC-S inhibitor LY83583 (50 microM); and mucin secretion in response to TNF-alpha or to the cGMP analogue dibutyryl cGMP (100 and 500 microM) was attenuated by the specific PKG inhibitor KT5823 (1 microM). Increased mucin secretion and increased cGMP production in response to TNF-alpha both appeared to be mediated by a phospholipase C that hydrolyzes phosphatidylcholine (PC-PLC), and by protein kinase C (PKC), since both responses were attenuated by either D609 (10 and 20 microg/ml), a specific PC-PLC inhibitor, or by each of three PKC inhibitors: Calphostin C (0.3 and 0.5 microM), bisindoylmaleimide (GF 109203X, Go 6850; 20 nM), or Ro31-8220 (10 microM). Collectively, the results suggest that TNF-alpha stimulates secretion of mucin by GPTE cells via a mechanism(s) dependent on PC-PLC and PKC, and involving activation of NOS, generation of NO, production of cGMP, and activation of PKG.
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PMID:Tumor necrosis factor-alpha stimulates mucin secretion and cyclic GMP production by guinea pig tracheal epithelial cells in vitro. 1003 Aug 39

Tumor necrosis factor-alpha (TNF alpha) can function as both an autocrine and a paracrine growth factor and may therefore play a role in ovarian tumor progression. TNF alpha initiates multiple cellular responses, many of which are mediated through the mitogen-activated protein kinase pathways, which transduce signals from the TNF alpha receptors through the cytoplasm to the nucleus, resulting in regulation of gene expression. We examined the role of c-jun N-terminal kinase 1 (JNK1) and extracellular signal-regulated protein kinase (ERK) 1 and 2 in the cellular growth response to TNF alpha in the ovarian carcinoma cell line UCI 101. JNK1 activity was increased to a maximum level ninefold above the basal level after 10-20 min of treatment with 10 ng/mL TNF alpha. A maximum threefold induction of ERK1/2 activity was observed after 1 min of treatment. At concentrations up to 100 ng/mL, TNF alpha had neither a stimulatory nor an inhibitory effect on growth of UCI 101 cells. However, inhibition of TNF alpha-induced ERK1/2 activity by the MAP/ERK kinase 1 inhibitor PD 98059 resulted in 60% inhibition of cell growth in TNF alpha-treated UCI 101 cells. This decrease in cell growth was accompanied by apoptosis, as demonstrated by the presence of a 180-bp DNA ladder. Thus, the inhibition of TNF alpha-induced ERK1/2 activity was associated with induction of apoptosis in the TNF alpha-resistant cell line UCI 101. Inhibition of TNF alpha-induced ERK1/2 activity was accompanied by a subsequent transient increase in TNF alpha-induced JNK1 activity. The significance of this increase with respect to apoptosis induction remains to be determined. These findings demonstrated that ERK1/2 activity can modulate cellular sensitivity to TNF alpha and suggested that the balance between the levels of ERK1/2 and JNK1 activation may be critical in the cellular growth response to TNF alpha.
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PMID:Association of apoptosis with the inhibition of extracellular signal-regulated protein kinase activity in the tumor necrosis factor alpha-resistant ovarian carcinoma cell line UCI 101. 1033 40

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF family that interacts with several receptors, including TRAIL-R1, TRAIL-R2, and TRAIL-R4. TRAIL-R1 and TRAIL-R2 can induce apoptosis of cancer cells and activate the transcription factor NF-kappaB. TRAIL-R4 can activate NF-kappaB and protect cells from TRAIL-induced apoptosis. Here we show that TRAIL-R1-, TRAIL-R2-, and TRAIL-R4-induced NF-kappaB activation are mediated by a TRAF2-NIK-IkappaB kinase alpha/beta signaling cascade but is MEKK1 independent. TRAIL receptors also activate the protein kinase JNK. JNK activation by TRAIL-R1 is mediated by a TRAF2-MEKK1-MKK4 but not the TRAF2-NIK/IkappaB kinase alpha/beta signaling pathway. We also show that activation of NF-kappaB or overexpression of TRAIL-R4 does not protect TRAIL-R1-induced apoptosis. Moreover, inhibition of NF-kappaB by IkappaBalpha sensitizes cells to tumor necrosis factor- but not TRAIL-induced apoptosis. These findings suggest that TRAIL receptors induce apoptosis, NF-kappaB and JNK activation through distinct signaling pathways, and activation of NF-kappaB is not sufficient for protecting cells from TRAIL-induced apoptosis.
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PMID:Tumor necrosis factor-related apoptosis-inducing ligand receptors signal NF-kappaB and JNK activation and apoptosis through distinct pathways. 1052 44

Tumor necrosis factor-alpha (TNFalpha) critically regulates several cellular functions during monocyte/macrophage differentiation. We therefore investigated during the phorbol ester (phorbol 12-myristate 13-acetate (PMA))-induced monocyte/macrophage differentiation of the human HL-60 leukemia cells, if TNFalpha contributed to plasminogen activator inhibitor type-1 (PAI-1) synthesis that is initiated by a protein kinase Cbeta-extracellular signal-regulated kinase 2-dependent pathway (Lopez, S., Peiretti, F., Morange, P., Laouar, A., Fossat, C., Bonardo, B., Huberman, E., Juhan-Vague, I., and Nalbone, G. (1999) Thromb. Haemostasis 81, 415-422). Following PMA treatment, the level of TNFalpha mRNA strongly increased and appeared earlier than PAI-1 mRNA. An anti-TNFalpha antibody significantly inhibited the PMA-induced PAI-1 mRNA and protein levels. The recombinant human TNFalpha, which is inactive on native HL-60 cells in terms of PAI-1 synthesis, optimally potentiates it once HL-60 cells are committed into the differentiation process. The use of 1) the HL-525 cell line, a clone issued from HL-60 cells rendered resistant to PMA-induced differentiation, and 2) the transforming growth factorbeta-1/vitamin D3 differentiative mixture confirmed the relationships between the induction of differentiation and the potency of TNFalpha to up-regulate PAI-1 synthesis. In conclusion, we showed that during the induction of monocyte/macrophage differentiation, TNFalpha and PAI-1 gene expressions are activated and that synthesized TNFalpha up-regulates and prolongs, in an autocrine manner, the synthesis of PAI-1.
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PMID:Tumor necrosis factor alpha up-regulates in an autocrine manner the synthesis of plasminogen activator inhibitor type-1 during induction of monocytic differentiation of human HL-60 leukemia cells. 1065 89

Tumor necrosis factor-alpha (TNF-alpha) inhibits growth of normal cervical keratinocytes but stimulates proliferation of human papillomavirus (HPV)-immortalized and cervical carcinoma-derived cell lines when mitogens such as epidermal growth factor (EGF) or serum are depleted. Current work identifies the mechanism of growth stimulation. TNF-alpha promoted cell cycle progression by increasing expression of HPV-16 E6/E7 RNAs and enhancing activity of cyclin-dependent kinase (cdk)2 and cdc2 after 3 d. Increased kinase activity was mediated by upregulation of cyclins A and B and decreases in cdk inhibitors p21(waf) and p27(kip). TNF-alpha stimulated these changes in part by increasing transcription and stabilization of RNA for amphiregulin, an EGF receptor ligand, and amphiregulin directly increased HPV-16 E6/E7 and cyclin A RNAs. To define which components of the EGF receptor signaling pathway were important, HPV-immortalized cells were transfected with activated or dominant negative mutants of Ha-ras, raf, or MAPKK. Expression of activated Ha-ras maintained HPV-16 and cyclin gene expression and promoted rapid growth in the absence of EGF. Furthermore, ras activation was necessary for TNF-alpha mitogenesis as transfection with a dominant negative ras mutant (Asn-17) strongly inhibited growth. Thus, activation of ras promotes expression of HPV-16 E6/E7 RNAs, induces cyclins A and B, and mediates growth stimulation of immortal keratinocytes by TNF-alpha. These studies define a pathway by which ras mutations, which occur in a subset of cervical cancers, may contribute to pathogenesis. Mol. Carcinog. 27:97-109, 2000. Published by Wiley-Liss, Inc.
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PMID:Tumor necrosis factor-alpha promotes human papillomavirus (HPV) E6/E7 RNA expression and cyclin-dependent kinase activity in HPV-immortalized keratinocytes by a ras-dependent pathway. 1065 2

The c-Jun N-terminal kinase (JNK) signaling pathway plays a crucial role in cellular responses stimulated by stress-inducing agents and proinflammatory cytokines. The group I germinal center kinase family members selectively activate the JNK pathway. In this study, we have isolated a mouse cDNA encoding a protein kinase homologous to Nck-interacting kinase (NIK), a member of the group I germinal center kinase family. This protein kinase is expressed during the late stages of embryogenesis, but not in adult tissues, and thus named NESK (NIK-like embryo-specific kinase). NESK selectively activated the JNK pathway when overexpressed in HEK 293 cells but did not stimulate the p38 kinase or extracellular signal-regulated kinase (ERK) pathways. NESK-induced JNK activation was inhibited by the dominant negative mutants of MEKK1 and MKK4. Tumor necrosis factor (TNF)-alpha or TNF receptor-associated factor 2 (TRAF2) stimulated the NESK activity. Furthermore, the dominant negative NESK mutant inhibited the JNK activation induced by TNF-alpha or TRAF2. These results suggest that NESK, a novel activator of the JNK pathway, functions in coupling TRAF2 to the MEKK1 --> MKK4 --> JNK kinase cascade during the late stages of mammalian embryogenesis.
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PMID:NESK, a member of the germinal center kinase family that activates the c-Jun N-terminal kinase pathway and is expressed during the late stages of embryogenesis. 1080 98


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