Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activator protein-1 (AP-1) and nuclear factor-kappa B (NF-kappa B), two transcription factors that respond to a wide range of signals, have been shown to be activated by H2O2 in several cell lines. Since H2O2 and related oxidants are implicated in reperfusion injury to the heart, we wished to know if NF-kappa B is present in the myocardium and if cardiac AP-1 and NF-kappa B also respond to oxidants. Rat neonatal cardiac myocytes were exposed to H2O2, and changes in c-fos and c-jun mRNAs, immunoreactive c-Fos and c-Jun proteins (components of AP-1), and immunoreactive p50 subunit of NF-kappa B were determined. Changes in nuclear activities of AP-1 and NF-kappa B were also measured by electrophoretic mobility shift assays. When myocytes were exposed to nonlethal concentrations of H2O2, c-fos and c-jun mRNAs were rapidly induced, reaching peak values at 30-60 min. The levels of c-Fos and c-Jun proteins increased in nuclei as revealed by immunostaining, and DNA binding activity of nuclear AP-1 increased. The presence of p50 subunit of NF-kappa B and its H2O2-induced shift from cytoplasm to nucleus were shown by immunostaining. H2O2-induced myocyte nuclear proteins capable of binding to a DNA probe containing the NF-kappa B element were also demonstrated. The findings suggest that altered expressions of cardiac genes regulated by AP-1 and NF-kappa B may be components of oxidant-induced injury to the heart or a part of the heart's adaptive response to oxidative stress.
Cell Mol Biol Res 1995
PMID:Oxidant-induced activations of nuclear factor-kappa B and activator protein-1 in cardiac myocytes. 858 59

In addition to biophysical properties, pulmonary surfactant has immunomodulatory activity. We previously demonstrated that both synthetic (Exosurf) and modified natural surfactant (Survanta) downregulated endotoxin-stimulated inflammatory c ytokine mRNA levels and protein products (tumor necrosis factor-alpha [TNF], interleukin-1-beta [IL-1], interleukin-6 [IL-6]) in human alveolar macrophages. In this study, we report that both Exosurf and Survanta suppress TNF mRNA and secretion (85 +/- 4% mean percent inhibition +/- SEM by Exosurf; 71 +/- 6% by Survanta) by endotoxin-stimulated THP-1, a human monocytic cell line. Because surfactant downregulated inflammatory cytokine production similarly in both normal human alveolar macrophages and the THP-1 cell line, we used this cell line to investigate whether surfactant affected transcriptional mechanisms. Specifically, we examined nuclear factor-kappa B (NF-kappa B) activation because it is crucial in transcriptional regulation of many inflammatory cytokine genes including TNF, IL-1, and IL-6. Electrophoretic mobility shift assays showed that both surfactants decreased activation of NF-kappa B. The presence of both p65 and p50 NF-kappa B components in LPS-activated THP-1 cells was confirmed by specific antibody induction of supershifts in mobility assays. These results are the first to suggest that surfactant's suppressive effects on inflammatory cytokine production may involve transcriptional regulation through inhibition of NF-kappa B activation.
Am J Respir Cell Mol Biol 1996 Apr
PMID:Surfactant suppresses NF-kappa B activation in human monocytic cells. 860 Sep 42

(2E)-3-[5-(2,3-Dimethoxy-6-methyl-1,4-benzoquinoyl)]-2-nonyl-2- propenoic acid (E3330), is a novel agent with hepatoprotective activity. We report the effect of E3330 on transcriptional activation of tumor necrosis factor (TNF)-alpha gene and on nuclear factor (NF)-kappa B activation. Nuclear run-on experiments showed that E3330 decreases transcriptional activation of TNF-alpha gene induced by lipopolysaccharide (LPS) stimulation in human peripheral monocytes. To investigate the inhibitory mechanisms, we constructed a secreted-type placental alkaline phosphatase (PLAP) reporter gene whose transcription is controlled by a 1.4-kb human TNF-alpha promoter. A stable transformant of the PLAP reporter gene derived from human monocytic cell line showed very little activity on the promoter before stimulation, whereas LPS stimulation led to a dramatic increase in PLAP activity. E3330 inhibited this induced promoter activity in a dose-dependent manner. There are four putative NF-kappa B binding sites (kappa B-1, kappa B-2, kappa B-3, kappa B-4) in human TNF-alpha promoter. By using mutated promoter-PLAP plasmids, we established that these NF-kappa B sites were necessary for induction of TNF-alpha transcription on stimulation with LPS. A gel retardation experiment with synthetic double-stranded oligonucleotides showed that activated NF-kappa B consisting of p50/p65 heterodimer bound to all four putative NF-kappa B DNA probes, suggesting that all four putative NF-kappa B recognition sites play an important role in inducible TNF-alpha expression. E3330 decreased activated NF-kappa B in nuclei, suggesting that E3330 inhibits NF-kappa B activation and/or translocation of the nuclei. Western blotting analysis with anti-I kappa B-alpha antibody indicated that E3330 inhibited degradation of I kappa B-alpha, which is an inhibitory protein of NF-kappa B, in LPS-stimulated monocytes. E3330 may suppress the production of active oxygen species serving as common messengers to activate NF-kappa B.
Mol Pharmacol 1996 May
PMID:Inhibitory effect of E3330, a novel quinone derivative able to suppress tumor necrosis factor-alpha generation, on activation of nuclear factor-kappa B. 862 36

The phosphoprotein I kappa B alpha exists in the cytoplasm of resting cells bound to the ubiquitous transcription factor NF-kappa B (p50-p65). In response to specific cellular stimulation, I kappa B alpha is further phosphorylated and subsequently degraded, allowing NF-kappa B to translocate to the nucleus and transactivate target genes. To identify the kinase(s) involved in I kappa B alpha phosphorylation, we first performed an I kappa B alpha in-gel kinase assay. Two kinase activities of 35 and 42 kDa were identified in cellular extracts from Jurkat T and U937 promonocytic cell lines. Specific inhibitors and immunodepletion studies identified the I kappa B alpha kinase activities as those of the alpha and alpha' subunits of casein kinase II (CKII). Immunoprecipitation studies demonstrated that CKII and I kappa B alpha physically associate in vivo. Moreover, phosphopeptide maps of I kappa B alpha phosphorylated in vitro by cellular extracts and in vivo in resting Jurkat T cells contained the same pattern of phosphopeptides as observed in maps of I kappa B alpha phosphorylated in vitro by purified CKII. Sequence analysis revealed that purified CKII and the kinase activity within cell extracts phosphorylated I kappa B alpha at its C terminus at S-283, S-288, S-293, and T-291. The functional role of CKII was tested in an in vitro I kappa B alpha degradation assay with extracts from uninfected and human immunodeficiency virus (HIV)-infected U937 cells. Immunodepletion of CKII from these extracts abrogated both the basal and enhanced HIV-induced degradation of I kappa B alpha. These studies provide new evidence that the protein kinase CKII physically associates with I kappa B alpha in vivo, induces multisite (serine/threonine) phosphorylation, and is required for the basal and HIV-induced degradation of I kappa B alpha in vitro.
Mol Cell Biol 1996 Mar
PMID:Casein kinase II phosphorylates I kappa B alpha at S-283, S-289, S-293, and T-291 and is required for its degradation. 862 92

Transcription factor NF-kappaB is generally considered to be a heterodimer with two subunits, p50 and p65. The p50 subunit has been suggested to be generated from its precursor, p105, via the ubiquitin-proteasome pathway. During processing, the C-terminal portion of p105 is rapidly degraded whereas the N-terminal portion (p50) is left intact. We report here that a 23-amino-acid, glycine-rich region (GRR) in p105 functions as a processing signal for the generation of p50. A GRR-dependent endoproteolytic cleavage downstream of the GRR releases p50 from p105, and this cleavage does not require any specific downstream sequences. p50 can be generated from chimeric precursor p105N-GRR-IkappaBalpha, while the C-terminal portion (IkappaBalpha) can also be recovered, suggesting that p105 processing includes two steps: a GRR-dependent endoproteolytic cleavage and the subsequent degradation of the C-terminal portion. We have also demonstrated that the GRR can direct a similar processing event when it is inserted into a protein unrelated to the NF-kappaB family and that it is therefore an independent signal for processing.
Mol Cell Biol 1996 May
PMID:A glycine-rich region in NF-kappaB p105 functions as a processing signal for the generation of the p50 subunit. 862 91

Previous studies have indicated that Bcl-3 interacts through its ankyrin repeats with the transcriptional factors NF-kappaB1 (p50) and NF-kappaB2 (p52), affecting their biological activities. To further investigate the role of Bcl-3 in vivo and its association with the NF-kappaB proteins, we have generated transgenic mice constitutively expressing Bcl-3 in thymocytes. The results indicate that Bcl-3 is associated with endogenous p50 and p52 in nuclear extracts from transgenic animals. Remarkably, constitutive expression of Bcl-3 in these cells augments the DNA binding activity of p52 homodimers. This effect could be reproduced in vitro and is blocked by anti-Bcl-3 antibodies. We have also shown that Bcl-3 is phosphorylated in thymocytes and that its dephosphorylation greatly decreases the effect on p50 homodimers.
Mol Cell Biol 1996 Apr
PMID:Constitutive expression of Bc1-3 in thymocytes increases the DNA binding of NF-kappaB1 (p50) homodimers in vivo. 865 7

GM-CSF is an important mediator of hematopoiesis and its dysregulation may play a role in neoplastic and inflammatory conditions. Previous studies have demonstrated that GM-CSF production depends upon the accumulation of specific mRNA, which occurs by transcriptional and post-transcriptional mechanisms. In order to dissect the cis-acting sequences responsible for its regulation, we performed an extensive mutagenesis study spanning 54 nucleotides 5' of the GM-CSF coding region. Our analysis suggests that the previously-described functional elements of the GM-CSF promoter, kappa B and a repetitive CATTT/A motif, the former co-exists with an overlapping 9 nucleotide site which silences promoter activity, and the CATTT/A complex binds multiple polypeptides which differentially contribute to basal and inducible promoter activity. These two sites interact to provide tissue-appropriate and stimulus-specific promoter function. Using DNA-protein cross-linking and co-transfection studies, we demonstrate that the c-rel-related proteins p65 and p50 bind to the GM-CSF promoter and that p65 binding is primarily responsible for the enhancing effects at this site. In addition, we show that the GM-CSF kappa B decanucleotide is inadequate to provide full binding affinity; mutation of nucleotides flanking this site affect promoter function by altering NF-kappa B binding affinity. Together these results suggest that the transcriptional response of GM-CSF is dependent on a complex interplay of multiple DNA binding proteins.
Mol Immunol
PMID:The regulation of GM-CSF is dependent on a complex interplay of multiple nuclear proteins. 867 97

Interaction between CD40 on B cells and CD40 ligand (CD40L) on T cells has been shown to mediate T-cell contact help for B-cell proliferation, differentiation, and immunoglobulin isotype switching. It has recently been shown that cross-linking CD40 on mouse B cells induces germ line gamma1 and epsilon transcripts and that interleukin-4 synergizes with CD40 signaling to further induce these germ line transcripts. Germ line transcripts have been shown to be required for class switch recombination. Here we show that signaling via CD40 increases expression of a transiently transfected luciferase reporter plasmid driven by the germ line Cgamma1 promoter in M12.4.1 B-lymphoma cells. By linker-scanning mutation analysis of the promoter, we have identified a CD40-responsive region (CD40RR) which is able to confer inducibility by CD40L to a minimal c-fos promoter. The CD40RR contains three binding sites for NF-kappaB/Rel proteins which are each required for maximal induction of CD40RR activity by CD40L. Binding of the NF-kappaB/Rel proteins p50, p65, c-Rel, and RelB to the CD40RR is induced by CD40 signaling in M12.4.1 cells and in splenic B cells. Cotransfection of expression plasmids for p50 and p65 or p50 and RelB, but not c-Rel, into M12.4.1 cells transactivates the CD40RR and the germ line gamma1 promoter. These data demonstrate that NF-kappaB Rel proteins activated by CD40 ligation play an important role in induction of the germ line Cgamma1 promoter.
Mol Cell Biol 1996 Sep
PMID:Activation of NF-kappaB/Rel by CD40 engagement induces the mouse germ line immunoglobulin Cgamma1 promoter. 875 15

NF-kappa B is a potent transcriptional activator that resides in latent form in the cytoplasm complexed to its inhibitor I kappa B. Phosphorylation of I kappa B by protein kinase C (PKC) releases NF-kappa B, enabling its translocation to the nucleus. Since PKC can activate NF-kappa B and PKC is activated by long-term potentiation (LTP), we investigated NF-kappa B expression after hippocampal LTP induced in vivo. We first described the expression of the NF-kappa B subunits, p50 and p65, and I kappa B alpha mRNAs, in each cell field of the hippocampus. In other brain locations I kappa B alpha mRNA exhibited a more selective expression than p50 and p65. We then demonstrated specific NF-kappa B-like DNA-binding activity in hippocampal whole-cell extracts and in synaptosomes using electrophoretic mobility shift assays by the following criteria: (1) latent binding was revealed after deoxycholate treatment; (2) binding was competed off by unlabeled kappa B oligonucleotides; and (3) antibodies to either p50 or p65 blocked binding. Since p50 gene expression is auto-regulated by NF-kappa B, we used its expression as a reporter for NF-kappa B activity using quantitative in situ hybridization. Both p50 and p65 increased their expression in response to either LTP-inducing or low-frequency control stimulation, although the increase in p65 mRNA levels was greater after LTP than control stimulation. In contrast to p50 and p65, I kappa B alpha hybridization levels were not increased, but were inversely correlated with the magnitude of LTP. Since NF-kappa B subunit gene expression in the hippocampus is increased by augmented synaptic activity, NF-kappa B activation may contribute to alterations in target gene expression that accompany activity-dependent synaptic plasticity, but only in a combinatorial fashion with other transcription factors.
Brain Res Mol Brain Res 1996 Jun
PMID:Gene expression of the transcription factor NF-kappa B in hippocampus: regulation by synaptic activity. 879 6

NF-(kappa)B is an inducible transcription factor that activates many cellular genes involved in stress and immune response and whose DNA binding activity and cellular distribution are regulated by I(kappa)B inhibitor proteins. The interaction between NF-(kappa)B p50 and DNA was investigated by protein footprinting using chemical modification and partial proteolysis. Both methods confirmed lysine-DNA contacts already found in the crystal structure (K-147, K-149, K-244, K-275, and K-278) but also revealed an additional contact in the lysine cluster K-77-K-78-K-80 which was made on an extended DNA. Molecular modelling of such a DNA-protein complex revealed that lysine 80 is ideally placed to make phosphate backbone contacts in the extended DNA. Thus, it seems likely that the entire AB loop, containing lysines 77, 78, and 80, forms a C-shaped clamp that closes around the DNA recognition site. The same protein footprinting approaches were used to probe the interaction of p50 with the ankyrin repeat containing proteins I(kappa)B(gamma) and I(kappa)B(alpha). Lysine residues in p50 that were protected from modification by DNA were also protected from modification by I(kappa)B(gamma) but not I(kappa)B(alpha). Similarly, proteolytic cleavage at p50 residues which contact DNA was inhibited by bound I(kappa)B(gamma) but was enhanced by the presence of I(kappa)B(alpha). Thus, I(kappa)B(gamma) inhibits the DNA binding activity of p50 by direct interactions with residues contacting DNA, whereas the same residues remain exposed in the presence of I(kappa)B(alpha), which binds to p50 but does not block DNA binding.
Mol Cell Biol 1996 Nov
PMID:I(kappa)B(gamma) inhibits DNA binding of NF-kappaB p50 homodimers by interacting with residues that contact DNA. 888 76


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>