Global effects of fluvastatin on the prothrombotic status of patients with antiphospholipid syndrome

2010 ◽  
Vol 70 (4) ◽  
pp. 675-682 ◽  
Author(s):  
Chary López-Pedrera ◽  
Patricia Ruiz-Limón ◽  
Maria Ángeles Aguirre ◽  
Nuria Barbarroja ◽  
Carlos Pérez-Sánchez ◽  
...  
Keyword(s):  
Antiphospholipid Syndrome ◽  
Binding Activity ◽  
Significant Inhibition ◽  
Mitogen Activated Protein Kinase ◽  
Protein Prenylation ◽  
Altered Expression ◽  
Dna Binding Activity ◽  
Healthy Donors ◽  
Mitogen Activated Protein

ObjectiveNumerous mechanisms have been proposed to explain the thrombotic/proinflammatory tendency of antiphospholipid syndrome (APS) patients. Prothrombotic monocyte activation by antiphospholipid antibodies involves numerous proteins and intracellular pathways. The anti-inflammatory, anticoagulant and immunoregulatory effects of statins have been aimed as a therapeutic tool in APS patients. This study delineates the global effects of fluvastatin on the prothrombotic tendency of monocytes from APS patients.MethodsForty-two APS patients with thrombosis and 35 healthy donors were included in the study. APS patients received 20 mg/day fluvastatin for 1 month. Blood samples were obtained before the start, at the end and 2 months after the end of treatment.ResultsAfter 1 month of treatment, monocytes showed a significant inhibition of tissue factor, protein activator receptors 1 and 2, vascular endothelial growth factor and Flt1 expression that was related to the inhibition of p38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa B/Rel DNA-binding activity. Proteomic analysis showed proteins involved in thrombotic development (annexin II, RhoA and protein disulphide isomerase) with altered expression after fluvastatin administration. In-vitro studies indicated that the inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase by fluvastatin might inhibit protein prenylation and MAPK activation.ConclusionThe data from this study support the belief that fluvastatin has multiple profound effects in monocyte activity, which might contribute to thrombosis prevention in APS patients.

scholarly journals Acetylation-Mediated Transcriptional Activation of the ETS Protein ER81 by p300, P/CAF, and HER2/Neu

2003 ◽  
Vol 23 (17) ◽  
pp. 6243-6254 ◽  
Author(s):  
Apollina Goel ◽  
Ralf Janknecht
Keyword(s):  
Protein Kinase ◽  
Transcriptional Activation ◽  
Binding Activity ◽  
Tumor Formation ◽  
Mitogen Activated Protein Kinase ◽  
Transactivation Domain ◽  
Dna Binding Activity ◽  
Mitogen Activated Protein

ABSTRACT The regulated expression of the ETS transcription factor ER81 is a prerequisite for normal development, and its dysregulation contributes to neoplasia. Here, we demonstrate that ER81 is acetylated by two coactivators/acetyltransferases, p300 and p300- and CBP-associated factor (P/CAF) in vitro and in vivo. Whereas p300 acetylates two lysine residues (K33 and K116) within the ER81 N-terminal transactivation domain, P/CAF targets only K116. Acetylation of ER81 not only enhances its ability to transactivate but also increases its DNA binding activity and in vivo half-life. Furthermore, oncogenic HER2/Neu, which induces phosphorylation and thereby activation of ER81, was less able to activate acetylation-deficient ER81 mutants, indicating that both acetyltransferase and protein kinase-specific regulatory mechanisms control ER81 activity. Importantly, HER2/Neu overexpression stimulates the ability of p300 to acetylate ER81, likely by inducing phosphorylation of p300 through the Ras→Raf→mitogen-activated protein kinase pathway. This represents a novel mechanism by which oncogenic HER2/Neu, Ras, or Raf may promote tumor formation by enhancing acetylation not only of ER81 but also of other downstream effector transcription factors as well as histones.

scholarly journals Cytokine-Responsive Induction of SAF-1 Activity Is Mediated by a Mitogen-Activated Protein Kinase Signaling Pathway

2002 ◽  
Vol 22 (4) ◽  
pp. 1027-1035 ◽  
Author(s):  
Alpana Ray ◽  
Guang-Yao Yu ◽  
Bimal K. Ray
Keyword(s):  
Map Kinase ◽  
Phosphorylation Site ◽  
Binding Activity ◽  
Mutant Proteins ◽  
Dna Binding Activity ◽  
Transactivation Potential ◽  
Mitogen Activated Protein ◽  
Kinase Phosphorylation ◽  
Kinase Signaling Pathway

ABSTRACT SAF-1, a zinc finger transcription factor, is activated by a number of inflammatory agents, including interleukin-1 (IL-1) and IL-6. It is involved in the cytokine-mediated transcriptional induction of serum amyloid A, an acute-phase plasma protein that is associated with the pathogenesis of reactive amyloidosis, rheumatoid arthritis, and atherosclerosis. Here, we show that the mitogen-activated protein (MAP) kinase signaling pathway regulates cytokine-mediated induction of the DNA-binding activity and transactivation potential of SAF-1. Phosphorylation of endogenous SAF-1 in response to IL-1 and IL-6 was markedly inhibited by the addition of MAP kinase inhibitors. Consistent with this finding, we show that a consensus MAP kinase phosphorylation site, PPTP, within SAF-1 could be phosphorylated by MAP kinase in vitro. To analyze the contribution of MAP kinase in the activation of SAF-1, we prepared two independent mutant proteins in which the threonine residue of the PPTP motif was altered to either valine or alanine. These mutant proteins lost the ability to be phosphorylated by MAP kinase both in vivo and in vitro and exhibited a significantly reduced ability to promote expression of the SAF-1-regulated promoter. While the DNA-binding activity of wild-type SAF-1 protein was markedly increased upon phosphorylation with MAP kinase, no such increase could be detected with the mutant SAF-1 proteins. Further analysis with the GAL-4 reporter system showed that mutation of the MAP kinase phosphorylation site considerably lowers the transactivation potential of SAF-1. Together, these results show that activation of SAF-1 in response to IL-1 and -6 is mediated via MAP kinase-regulated phosphorylation.

scholarly journals Tobacco Transcription Factor WRKY1 Is Phosphorylated by the MAP Kinase SIPK and Mediates HR-Like Cell Death in Tobacco

2005 ◽  
Vol 18 (10) ◽  
pp. 1027-1034 ◽  
Author(s):  
Frank L. H. Menke ◽  
Hong-Gu Kang ◽  
Zhixiang Chen ◽  
Jeong Mee Park ◽  
Dhirendra Kumar ◽  
...  
Keyword(s):  
Cell Death ◽  
Transcription Factor ◽  
Protein Kinase ◽  
Dna Binding ◽  
Kinase Inhibitor ◽  
Hybrid Approach ◽  
Binding Activity ◽  
Mitogen Activated Protein Kinase ◽  
Dna Binding Activity ◽  
Mitogen Activated Protein

The salicylic acid-induced protein kinase (SIPK) of tobacco, which is a mitogen-activated protein kinase (MAPK), is activated by various biotic and abiotic treatments. Overexpression of SIPK has been shown to trigger cell death. In this study, a targeted yeast two-hybrid approach identified the tobacco transcription factor WRKY1 as a potential substrate. SIPK phosphorylated WRKY1, which resulted in enhanced DNA-binding activity of WRKY1 to its cognate binding site, a W box sequence from the tobacco chitinase gene CHN50. SIPK-mediated enhancement of WRKY1 DNA-binding activity was inhibited by staurosporine, a general kinase inhibitor. Co-expression of SIPK and WRKY1 in Nicotiana benthamiana led to more rapid cell death than expression of SIPK alone, suggesting that WRKY1 is involved in the formation of hypersensitive response-like cell death and may be a component of the signaling cascade downstream of SIPK.

scholarly journals C-Terminal Deletions Can Suppress Temperature-Sensitive Mutations and Change Dominance in the Phage Mu Repressor

Genetics ◽  
1996 ◽  
Vol 142 (3) ◽  
pp. 661-672 ◽  
Author(s):  
Jodi L Vogel ◽  
Vincent Geuskens ◽  
Lucie Desmet ◽  
N Patrick Higgins ◽  
Ariane Toussaint
Keyword(s):  
Binding Activity ◽  
Temperature Sensitive ◽  
Dna Binding Activity ◽  
Heat Stable ◽  
C Terminus ◽  
Acid Domain ◽  
Mutant Forms ◽  
Amino Acid Domain

Abstract Mutations in an N-terminal 70-amino acid domain of bacteriophage Mu's repressor cause temperature-sensitive DNA-binding activity. Surprisingly, amber mutations can conditionally correct the heat-sensitive defect in three mutant forms of the repressor gene, cts25 (D43-G), cts62 (R47-Q and cts71 (M28-I), and in the appropriate bacterial host produce a heat-stable Sts phenotype (for survival of temperature shifts). Sts repressor mutants are heat sensitive when in supE or supF hosts and heat resistant when in Sup° hosts. Mutants with an Sts phenotype have amber mutations at one of three codons, Q179, Q187, or Q190. The Sts phenotype relates to the repressor size: in Sup° hosts sts repressors are shorter by seven, 10, or 18 amino acids compared to repressors in supE or supF hosts. The truncated form of the sts62-1 repressor, which lacks 18 residues (Q179–V196), binds Mu operator DNA more stably at 42° in vitro compared to its full-length counterpart (cts62 repressor). In addition to influencing temperature sensitivity, the C-terminus appears to control the susceptibility to in vivo Clp proteolysis by influencing the multimeric structure of repressor.

Differential use of SCL/TAL-1 DNA-binding domain in developmental hematopoiesis

Blood ◽  
2008 ◽  
Vol 112 (4) ◽  
pp. 1056-1067 ◽  
Author(s):  
Mira T. Kassouf ◽  
Hedia Chagraoui ◽  
Paresh Vyas ◽  
Catherine Porcher
Keyword(s):  
Dna Binding ◽  
Molecular Mechanisms ◽  
Binding Activity ◽  
Hematopoietic Stem ◽  
Helix Loop Helix ◽  
Experimental Systems ◽  
Dna Binding Activity ◽  
Independent Functions

Abstract Dissecting the molecular mechanisms used by developmental regulators is essential to understand tissue specification/differentiation. SCL/TAL-1 is a basic helix-loop-helix transcription factor absolutely critical for hematopoietic stem/progenitor cell specification and lineage maturation. Using in vitro and forced expression experimental systems, we previously suggested that SCL might have DNA-binding–independent functions. Here, to assess the requirements for SCL DNA-binding activity in vivo, we examined hematopoietic development in mice carrying a germline DNA-binding mutation. Remarkably, in contrast to complete absence of hematopoiesis and early lethality in scl-null embryos, specification of hematopoietic cells occurred in homozygous mutant embryos, indicating that direct DNA binding is dispensable for this process. Lethality was forestalled to later in development, although some mice survived to adulthood. Anemia was documented throughout development and in adulthood. Cellular and molecular studies showed requirements for SCL direct DNA binding in red cell maturation and indicated that scl expression is positively autoregulated in terminally differentiating erythroid cells. Thus, different mechanisms of SCL's action predominate depending on the developmental/cellular context: indirect DNA binding activities and/or sequestration of other nuclear regulators are sufficient in specification processes, whereas direct DNA binding functions with transcriptional autoregulation are critically required in terminal maturation processes.

scholarly journals Cross-talk between IRAK-4 and the NADPH oxidase1

2007 ◽  
Vol 403 (3) ◽  
pp. 451-461 ◽  
Author(s):  
Sandrine Pacquelet ◽  
Jennifer L. Johnson ◽  
Beverly A. Ellis ◽  
Agnieszka A. Brzezinska ◽  
William S. Lane ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Nadph Oxidase ◽  
P38 Mapk ◽  
Interleukin 1 ◽  
Mitogen Activated Protein Kinase ◽  
Free System ◽  
Mitogen Activated Protein ◽  
A Cell ◽  
Tlr4 Activation

Exposure of neutrophils to LPS (lipopolysaccharide) triggers their oxidative response. However, the relationship between the signalling downstream of TLR4 (Toll-like receptor 4) after LPS stimulation and the activation of the oxidase remains elusive. Phosphorylation of the cytosolic factor p47phox is essential for activation of the NADPH oxidase. In the present study, we examined the hypothesis that IRAK-4 (interleukin-1 receptor-associated kinase-4), the main regulatory kinase downstream of TLR4 activation, regulates the NADPH oxidase through phosphorylation of p47phox. We show that p47phox is a substrate for IRAK-4. Unlike PKC (protein kinase C), IRAK-4 phosphorylates p47phox not only at serine residues, but also at threonine residues. Target residues were identified by tandem MS, revealing a novel threonine-rich regulatory domain. We also show that p47phox is phosphorylated in granulocytes in response to LPS stimulation. LPS-dependent phosphorylation of p47phox was enhanced by the inhibition of p38 MAPK (mitogen-activated protein kinase), confirming that the kinase operates upstream of p38 MAPK. IRAK-4-phosphorylated p47phox activated the NADPH oxidase in a cell-free system, and IRAK-4 overexpression increased NADPH oxidase activity in response to LPS. We have shown that endogenous IRAK-4 interacts with p47phox and they co-localize at the plasma membrane after LPS stimulation, using immunoprecipitation assays and immunofluorescence microscopy respectively. IRAK-4 was activated in neutrophils in response to LPS stimulation. We found that Thr133, Ser288 and Thr356, targets for IRAK-4 phosphorylation in vitro, are also phosphorylated in endogenous p47phox after LPS stimulation. We conclude that IRAK-4 phosphorylates p47phox and regulates NADPH oxidase activation after LPS stimulation.

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