References of "Musumeci, Lucia"
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See detailTargeting of C-type lectin-like receptor 2 or P2Y12 for the prevention of platelet activation by immunotherapeutic CpG oligodeoxynucleotides
Delierneux, Céline ULg; Donis, Nathalie ULg; servais, laurence et al

in Journal of Thrombosis and Haemostasis (in press)

Background: Synthetic phosphorothioate-modified CpG oligodeoxynucleotides (CpG ODNs) display potent immunostimulatory properties that are widely exploited in clinical trials of anticancer treatment ... [more ▼]

Background: Synthetic phosphorothioate-modified CpG oligodeoxynucleotides (CpG ODNs) display potent immunostimulatory properties that are widely exploited in clinical trials of anticancer treatment. Unexpectedly, a recent study indicates that CpG ODNs activate human platelets via the immunoreceptor tyrosine-based activation motif (ITAM)-coupled receptor glycoprotein VI. Objective: To further analyze the mechanisms of CpG ODN-induced platelet activation and identify potential inhibitory strategies. Methods: In vitro analyses were performed on human and mouse platelets, and on cell lines expressing platelet ITAM receptors. CpG ODN platelet activating effects were evaluated in a mouse model of thrombosis. Results: We demonstrated platelet uptake of CpG ODNs, resulting in platelet activation and aggregation. The C-type lectin-like receptor 2 (CLEC-2) expressed in DT40 cells bound CpG ODNs. CpG ODN uptake did not occur in CLEC-2-deficient mouse platelets. Inhibition of human CLEC-2 with a blocking antibody inhibited CpG ODN-induced platelet aggregation. CpG ODNs caused CLEC-2 dimerization, and provoked its internalization. They induced dense granule release before the onset of aggregation. Accordingly, pretreating platelets with apyrase, or inhibiting P2Y12 with cangrelor or clopidogrel prevented CpG ODN platelet activating effect. In vivo, intravenously injected CpG ODN interacted with platelets adhered to mouse injured endothelium, and promoted thrombus growth, which was inhibited by CLEC-2 deficiency or by clopidogrel. Conclusions: CLEC-2 and P2Y12 are required for CpG ODN-induced platelet activation and thrombosis and might be targeted to prevent adverse events in patients at risk. [less ▲]

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See detailInvolvement of Ikbζ in glioblastomas and its potential implication in radioresistance
Dubois, Nadège; Willems, Marie; Kroonen, Jérôme et al

Poster (2016, September 09)

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See detailFunctional analysis of protein tyrosine phosphatases in thrombosis and haemostasis
Rahmouni, Souad ULg; Hego, Alexandre ULg; Delierneux, Céline ULg et al

in Protein Tyrosine Phosphatases: Methods and Protocols (2016)

Platelets are small blood cells derived from cytoplasmic fragments of megakaryocytes and play an essential role in thrombosis and haemostasis. Platelet activation depends on the rapid phosphorylation and ... [more ▼]

Platelets are small blood cells derived from cytoplasmic fragments of megakaryocytes and play an essential role in thrombosis and haemostasis. Platelet activation depends on the rapid phosphorylation and dephosphorylation of key signaling molecules, and a number of kinases and phosphatases have been identified as major regulators of platelet function. However, the investigation of novel signaling proteins has suffered from technical limitations due to the anucleate nature of platelets and their very limited levels of mRNA and de novo protein synthesis. In the past, experimental methods were restricted to the generation of genetically modified mice and the development of specific antibodies. More recently, novel (phospho)proteomic technologies and pharmacological approaches using specific small-molecule inhibitors have added additional capabilities to investigate specific platelet proteins. In this chapter, we report methods for using genetic and pharmacological approaches to investigate the function of platelet signaling proteins. While the described experiments focus on the role of the dual-specificity phosphatase 3 (DUSP3) in platelet signaling, the presented methods are applicable to any signaling enzyme. Specifically, we describe a testing strategy that includes 1) aggregation and secretion experiments with mouse and human platelets, 2) immunoprecipitation and immunoblot assays to study platelet signaling events, 3) detailed protocols to use selected animal models in order to investigate thrombosis and haemostasis in vivo, and 4) strategies for utilizing pharmacological inhibitors on human platelets. [less ▲]

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See detailIkappaBzeta: an emerging player in cancer.
Willems, Marie; Dubois, Nadege; Musumeci, Lucia ULg et al

in Oncotarget (2016), 7(40), 66310-66322

IkappaBzeta, an atypical member of the nuclear IkappaB family of proteins, is expressed at low levels in most resting cells, but is induced upon stimulation of Toll-like/IL-1 receptors through an IRAK1 ... [more ▼]

IkappaBzeta, an atypical member of the nuclear IkappaB family of proteins, is expressed at low levels in most resting cells, but is induced upon stimulation of Toll-like/IL-1 receptors through an IRAK1/IRAK4/NFkappaB-dependent pathway. Like its homolog Bcl3, IkappaBzeta can regulate the transcription of a set of inflamatory genes through its association with the p50 or p52 subunits of NF-kappaB. Long studied as a key component of the immune response, IkappaBzeta emerges as an important regulator of inflammation, cell proliferation and survival. As a result, growing evidence support the role of this transcription factor in the pathogenesis number of human hematological and solid malignancies. [less ▲]

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See detailInvolvement of Ikbζ in glioblastomas and its potential implication in radioresistance
Dubois, Nadège ULg; Willems, Marie; Kroonen, Jérôme et al

Poster (2016)

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See detailDUSP3 Phosphatase Deficiency or Inhibition Limits Platelet Activation and Arterial Thrombosis
Rahmouni, Souad ULg; MUSUMECI, Lucia ULg; Kuijpers, Marijke J et al

Conference (2015, June 24)

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See detailCLEC-2 is required for the activation of mouseplatelets by bacterial DNA mimetics
Delierneux, Céline ULg; Hego, Alexandre ULg; LECUT, Christelle ULg et al

Conference (2015, June 22)

Background: Short nuclease-resistant phosphorothioate synthetic CpG motif-bearing oligonucleotides (CpG ODNs) mimicking bacterial DNA display potent immunostimulatory activity and are therefore being used ... [more ▼]

Background: Short nuclease-resistant phosphorothioate synthetic CpG motif-bearing oligonucleotides (CpG ODNs) mimicking bacterial DNA display potent immunostimulatory activity and are therefore being used in clinical trials as vaccine adjuvants. Cellular uptake and activation depends on the interaction of CpG ODNs with the C-type lectin receptor DEC-205 and subsequent stimulation of the Toll-like receptor 9 (TLR9) and myeloid differentiation primary response 88 (MyD88) signaling cascade. Platelets express TLR9, MyD88, and the C-type lectin-like receptor 2 (CLEC-2). However, the impacts of CpG ODNs on platelet function have been elusive. Aims: To evaluate whether CpG ODNs affect platelet activation and thrombus formation via CLEC-2 and TLR9. Methods: We incubated washed platelets or whole blood from TLR9-, MyD88- or CLEC-2- deficient mice with CpG ODNs. We performed platelet aggregometry, flow cytometric binding and platelet activation assays as well as signal transduction analyses. Thrombus formation and fibrin generation were also analyzed by intravital microscopy in mouse microcirculation upon intravenous injection of CpG ODNs. Results: We show that CpG ODNs bind on platelet surface and are internalized. They activate platelets and induce their aggregation. TLR9- or MyD88-deficient platelets aggregated normally in response to CpG ODN. Interestingly, platelets deficient for the C-type lectin receptor CLEC-2 were unable to capture and internalize CpG ODN. CLEC-2 deficiencyabolished CpG ODN-induced platelet activation and aggregation. CpG ODN stimulated CLEC-2 dependent tyrosine kinase pathway and Syk phosphorylation. In vivo, intravenously injected CpG ODN interacted with platelets adhered to laser injured arteriolar endothelia and promoted fibrin generation and thrombus growth. Conclusion: CLEC-2 mediates CpG ODN uptake and subsequent platelet activation, independently of TLR9, which may serve an important role in the interplay between platelets and immunity. [less ▲]

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See detailCLEC-2 is required for the activation of mouse platelets by bacterial DNA mimetics
Delierneux, Céline ULg; Hego, Alexandre ULg; LECUT, Christelle ULg et al

Conference (2015, June 22)

Aims: To evaluate whether CpG ODNs affect platelet activation and thrombus formation via CLEC-2 and TLR9. Methods: We incubated washed platelets or whole blood from TLR9-, MyD88- or CLEC-2- deficient mice ... [more ▼]

Aims: To evaluate whether CpG ODNs affect platelet activation and thrombus formation via CLEC-2 and TLR9. Methods: We incubated washed platelets or whole blood from TLR9-, MyD88- or CLEC-2- deficient mice with CpG ODNs. We performed platelet aggregometry, flow cytometric binding and platelet activation assays as well as signal transduction analyses. Thrombus formation and fibrin generation were also analyzed by intravital microscopy in mouse microcirculation upon intravenous injection of CpG ODNs. Results: We show that CpG ODNs bind on platelet surface and are internalized. They activate platelets and induce their aggregation. TLR9- or MyD88-deficient platelets aggregated normally in response to CpG ODN. Interestingly, platelets deficient for the C-type lectin receptor CLEC-2 were unable to capture and internalize CpG ODN. CLEC-2 deficiency abolished CpG ODN-induced platelet activation and aggregation. CpG ODN stimulated CLEC-2 dependent tyrosine kinase pathway and Syk phosphorylation. In vivo, intravenously injected CpG ODN interacted with platelets adhered to laser injured arteriolar endothelia and promoted fibrin generation and thrombus growth. Conclusion: CLEC-2 mediates CpG ODN uptake and subsequent platelet activation, independently of TLR9, which may serve an important role in the interplay between platelets and immunity. [less ▲]

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See detailDUSP3 genetic deletion confers M2-like−macrophage-dependent tolerance to septic shock
Singh, Pratibha; Dejager, Lien; Amand, Mathieu ULg et al

in Journal of Immunology (2015), 194(10), 4951-62

DUSP3 is a small dual-specificity protein phosphatase with an unknown physiological function. We report that DUSP3 is strongly expressed in human and mouse monocytes and macrophages and that its ... [more ▼]

DUSP3 is a small dual-specificity protein phosphatase with an unknown physiological function. We report that DUSP3 is strongly expressed in human and mouse monocytes and macrophages and that its deficiency in mice promotes tolerance to lipopolysaccharide (LPS)-induced endotoxin shock and to polymicrobial septic shock following cecal ligation and puncture. By using adoptive transfer experiments, we demonstrate that resistance to endotoxin is macrophage-dependent and transferable and that this protection is associated with a striking increase of M2-like macrophages in DUSP3-/- mice in both the LPS and cecal ligation and puncture models. We show that the altered response of DUSP3-/- mice to sepsis is reflected in decreased TNF production and impaired ERK1/2 activation. Our results demonstrate that DUSP3 plays a key and non-redundant role as a regulator of innate immune responses by mechanisms involving the control of ERK1/2 activation, TNF secretion and macrophage polarization. [less ▲]

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See detailDUSP3 Phosphatase Deficiency or Inhibition Limit Platelet Activation and Arterial Thrombosis
Musumeci, Lucia ULg; Kuijpers, Marijke; Gilio, Karen et al

in Circulation (2015), 131(7), 656-68

Background A limitation of current antiplatelet therapies is their inability to separate thrombotic events from bleeding occurrences. Better understanding of the molecular mechanisms leading to platelet ... [more ▼]

Background A limitation of current antiplatelet therapies is their inability to separate thrombotic events from bleeding occurrences. Better understanding of the molecular mechanisms leading to platelet activation is of importance for the development of improved therapies. Recently, protein tyrosine phosphatases (PTPs) have emerged as critical regulators of platelet function. Methods and Results This is the first report implicating the dual-specificity phosphatase 3 (DUSP3) in platelet signaling and thrombosis. This phosphatase is highly expressed in human and mouse platelets. Platelets from DUSP3-deficient mice displayed a selective impairment of aggregation and granule secretion mediated through the collagen receptor glycoprotein VI (GPVI) and the C-type lectin-like receptor 2 (CLEC-2). DUSP3-deficient mice were more resistant to collagen- and epinephrine-induced thromboembolism, compared to wild-type mice, and showed severely impaired thrombus formation upon ferric chloride-induced carotid artery injury. Intriguingly, bleeding times were not altered in DUSP3-deficient mice. At the molecular level, DUSP3 deficiency impaired Syk tyrosine phosphorylation, subsequently reducing phosphorylation of PLCγ2 and calcium fluxes. To investigate DUSP3 function in human platelets, a novel small-molecule inhibitor of DUSP3 was developed. This compound specifically inhibited collagen and CLEC-2-induced human platelet aggregation, thereby phenocopying the effect of DUSP3 deficiency in murine cells. Conclusions DUSP3 plays a selective and essential role in collagen- and CLEC-2-mediated platelet activation and thrombus formation in vivo. Inhibition of DUSP3 may prove therapeutic for arterial thrombosis. This is the first time a PTP, implicated in platelet signaling, has been targeted with a small-molecule drug. [less ▲]

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See detailDUSP3/VHR is a pro-angiogenic atypical dual-specificity phosphatase
Amand, Mathieu ULg; Erpicum, Charlotte ULg; BAJOU, Khalid ULg et al

Poster (2014, January 27)

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See detailDUSP3/VHR is a pro-angiogenic atypical dual-specificity phosphatase
Amand, Mathieu ULg; Erpicum, Charlotte ULg; BAJOU, Khalid ULg et al

in Molecular Cancer (2014)

Background DUSP3 phosphatase, also known as Vaccinia-H1 Related (VHR) phosphatase, encoded by DUSP3/Dusp3 gene, is a relatively small member of the dual-specificity protein phosphatases. In vitro studies ... [more ▼]

Background DUSP3 phosphatase, also known as Vaccinia-H1 Related (VHR) phosphatase, encoded by DUSP3/Dusp3 gene, is a relatively small member of the dual-specificity protein phosphatases. In vitro studies showed that DUSP3 is a negative regulator of ERK and JNK pathways in several cell lines. On the other hand, DUSP3 is implicated in human cancer. It has been alternatively described as having tumor suppressive and oncogenic properties. Thus, the available data suggest that DUSP3 plays complex and contradictory roles in tumorigenesis that could be cell type-dependent. Since most of these studies were performed using recombinant proteins or in cell-transfection based assays, the physiological function of DUSP3 has remained elusive. Results Using immunohistochemistry on human cervical sections, we observed a strong expression of DUSP3 in endothelial cells (EC) suggesting a contribution for this phosphatase to EC functions. DUSP3 downregulation, using RNA interference, in human EC reduced significantly in vitro tube formation on Matrigel and spheroid angiogenic sprouting. However, this defect was not associated with an altered phosphorylation of the documented in vitro DUSP3 substrates, ERK1/2, JNK1/2 and EGFR but was associated with an increased PKC phosphorylation. To investigate the physiological function of DUSP3, we generated Dusp3-deficient mice by homologous recombination. The obtained DUSP3-/- mice were healthy, fertile, with no spontaneous phenotype and no vascular defect. However, DUSP3 deficiency prevented neo-vascularization of transplanted b-FGF containing Matrigel and LLC xenograft tumors as evidenced by hemoglobin (Hb) and FITC-dextran quantifications. Furthermore, we found that DUSP3 is required for b-FGF-induced microvessel outgrowth in the aortic ring assay. Conclusions All together, our data identify DUSP3 as a new important player in angiogenesis. [less ▲]

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See detailDual-specificity phosphatase 3 knockout female mice are resistant to LPS and to polymicrobial induced septic shock in TNF dependent manner.
Rahmouni, Souad ULg; Singh; Dejager, Lien et al

in Journal of Immunology (2013, May)

We report the generation of dual-specificity phosphatase 3 (DUSP3) deficient mice. These mice develop normally and do not exhibit any spontaneous phenotype. However, VHR-/- females, but not males, are ... [more ▼]

We report the generation of dual-specificity phosphatase 3 (DUSP3) deficient mice. These mice develop normally and do not exhibit any spontaneous phenotype. However, VHR-/- females, but not males, are resistant to LPS- and to polymicrobial infection-induced septic shock. After LPS injection, while VHR-/- males and VHR+/+ mice of both genders, displayed an increased serum levels of TNF-α and IFN, the levels of these cytokines remained significantly low in the VHR-/- females. In vitro experiments using peritoneal macrophages showed the same results suggesting that the systemic cytokines profiles observed are macrophages-dependent. Adoptive transfer of VHR-/- females bone marrow to irradiated VHR+/+ female mice, but not to VHR-/- or VHR+/+ males, protected them from death after administration of LPS. Interestingly, VHR-/- females were sensitive to TNF-α- induced lethality. We also report that the decrease of TNF-α production observed in VHR-/- female’s macrophages after LPS activation was associated with a decreased ERK1/2, but not MEK1/2, activation. Interestingly, pervanadate (PTP pan inhibitor) treatment prior to LPS activation restored ERK1/2 activation in the VHR-deficient macrophages, suggesting that VHR is targeting one of the ERK1/2 PTPs or DUSPs. These results, together with our observation that DUSP3 is the most highly expressed phosphatase in macrophages, suggest a key non-redundant role of VHR as positive regulator of TNF-α in innate immune response in females. [less ▲]

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See detailDynamic interaction between lymphoid tyrosine phosphatase and C-terminal Src kinase controls T cell activation
Tautz, Lutz; Vang, Torkel; Liu, Wallace et al

in FASEB Journal (2012, April), 26

Lymphoid tyrosine phosphatase (LYP) and C-terminal Src kinase (CSK) are negative regulators of signaling mediated through the T cell antigen receptor (TCR) and are thought to act in a cooperative manner ... [more ▼]

Lymphoid tyrosine phosphatase (LYP) and C-terminal Src kinase (CSK) are negative regulators of signaling mediated through the T cell antigen receptor (TCR) and are thought to act in a cooperative manner when forming a complex. Here, we show that dissociation of the LYP/CSK complex is necessary for recruitment of LYP to lipid rafts, where it down-modulates TCR-mediated signaling. Our findings may also explain the reduced TCR signaling associated with a single nucleotide polymorphism, which confers increased risk for autoimmunity and results in the expression of a LYP allele that can no longer bind CSK. Development of a potent and selective chemical probe of LYP allowed us to confirm that the observed down-modulation of TCR-induced signaling was due to the LYP catalytic activity. Our compound also represents a starting point for the development of a LYP-based treatment of autoimmunity. [less ▲]

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See detailAn improved protocol for efficient engraftment in NOD/LTSZ-SCIDIL-2Rgammanull mice allows HIV replication and development of anti-HIV immune responses.
Singh, Maneesh; Singh, Pratibha; Gaudray, Gilles et al

in PLoS ONE (2012), 7(6), 38491

Cord blood hematopoietic progenitor cells (CB-HPCs) transplanted immunodeficient NOD/LtsZ-scidIL2Rgamma(null) (NSG) and NOD/SCID/IL2Rgamma(null) (NOG) mice need efficient human cell engraftment for long ... [more ▼]

Cord blood hematopoietic progenitor cells (CB-HPCs) transplanted immunodeficient NOD/LtsZ-scidIL2Rgamma(null) (NSG) and NOD/SCID/IL2Rgamma(null) (NOG) mice need efficient human cell engraftment for long-term HIV-1 replication studies. Total body irradiation (TBI) is a classical myeloablation regimen used to improve engraftment levels of human cells in these humanized mice. Some recent reports suggest the use of busulfan as a myeloablation regimen to transplant HPCs in neonatal and adult NSG mice. In the present study, we further ameliorated the busulfan myeloablation regimen with fresh CB-CD34+cell transplantation in 3-4 week old NSG mice. In this CB-CD34+transplanted NSG mice engraftment efficiency of human CD45+cell is over 90% in peripheral blood. Optimal engraftment promoted early and increased CD3+T cell levels, with better lymphoid tissue development and prolonged human cell chimerism over 300 days. These humanized NSG mice have shown long-lasting viremia after HIV-1JRCSF and HIV-1Bal inoculation through intravenous and rectal routes. We also saw a gradual decline of the CD4+T cell count, widespread immune activation, up-regulation of inflammation marker and microbial translocation after HIV-1 infection. Humanized NSG mice reconstituted according to our new protocol produced, moderate cellular and humoral immune responses to HIV-1 postinfection. We believe that NSG mice reconstituted according to our easy to use protocol will provide a better in vivo model for HIV-1 replication and anti-HIV-1 therapy trials. [less ▲]

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See detailLYP inhibits T-cell activation when dissociated from CSK
Vang; Liu, Wallace H; Delacroix, Laurence ULg et al

in Nature Chemical Biology (2012)

Lymphoid tyrosine phosphatase (LYP) and C-terminal Src kinase (CSK) are negative regulators of signaling mediated through the T-cell antigen receptor (TCR) and are thought to act in a cooperative manner ... [more ▼]

Lymphoid tyrosine phosphatase (LYP) and C-terminal Src kinase (CSK) are negative regulators of signaling mediated through the T-cell antigen receptor (TCR) and are thought to act in a cooperative manner when forming a complex. Here we studied the spatiotemporal dynamics of the LYP–CSK complex in T cells. We demonstrate that dissociation of this complex is necessary for recruitment of LYP to the plasma membrane, where it downmodulates TCR signaling. Development of a potent and selective chemical probe of LYP confirmed that LYP inhibits T-cell activation when removed from CSK. Our findings may explain the reduced TCR-mediated signaling associated with a single-nucleotide polymorphism that confers increased risk for certain autoimmune diseases, including type 1 diabetes and rheumatoid arthritis, and results in expression of a mutant LYP that is unable to bind CSK. Our compound also represents a starting point for the development of a LYP-based treatment of autoimmunity. [less ▲]

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See detailSingle nucleotide differences (SNDs) in the dbSNP database may lead to errors in genotyping and haplotyping studies.
Musumeci, Lucia ULg; Arthur, Jonathan; Cheung, Florence et al

in Human Mutation (2010), 31(1), 63-73

The creation of single nucleotide polymorphism (SNP) databases (such as NCBI dbSNP) has facilitated scientific research in many fields. SNP discovery and detection has improved to the extent that there ... [more ▼]

The creation of single nucleotide polymorphism (SNP) databases (such as NCBI dbSNP) has facilitated scientific research in many fields. SNP discovery and detection has improved to the extent that there are over 17 million human reference (rs) SNPs reported to date (Build 129 of dbSNP). SNP databases are unfortunately not always complete and/or accurate. In fact, half of the reported SNPs are still only candidate SNPs and are not validated in a population. We describe the identification of SNDs (single nucleotide differences) in humans, that may contaminate the dbSNP database. These SNDs, reported as real SNPs in the database, do not exist as such, but are merely artifacts due to the presence of a paralogue (highly similar duplicated) sequence in the genome. Using sequencing we showed how SNDs could originate in two paralogous genes and evaluated samples from a population of 100 individuals for the presence/absence of SNPs. Moreover, using bioinformatics, we predicted as many as 8.32% of the biallelic, coding SNPs in the dbSNP database to be SNDs. Our identification of SNDs in the database will allow researchers to not only select truly informative SNPs for association studies, but also aid in determining accurate SNP genotypes and haplotypes. [less ▲]

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See detailLow-Molecular-Weight Protein Tyrosine Phosphatases of Bacillus subtilis
Musumeci, Lucia ULg; Bongiorni, Cristina; Tautz, Lutz et al

in Journal of Bacteriology (2005), 187(14), 4945-4956

In gram-negative organisms, enzymes belonging to the low-molecular-weight protein tyrosine phosphatase (LMPTP) family are involved in the regulation of important physiological functions, including stress ... [more ▼]

In gram-negative organisms, enzymes belonging to the low-molecular-weight protein tyrosine phosphatase (LMPTP) family are involved in the regulation of important physiological functions, including stress resistance and synthesis of the polysaccharide capsule. LMPTPs have been identified also in gram-positive bacteria, but their functions in these organisms are presently unknown. We cloned two putative LMPTPs from Bacillus subtilis, YfkJ and YwlE, which are highly similar to each other in primary structure as well as to LMPTPs from gram-negative bacteria. When purified from overexpressing Escherichia coli strains, both enzymes were able to dephosphorylate p-nitrophenyl-phosphate and phosphotyrosine-containing substrates in vitro but showed significant differences in kinetic parameters and sensitivity to inhibitors. Transcriptional analyses showed that yfkJ was transcribed at a low level throughout the growth cycle and underwent a σB-dependent transcriptional upregulation in response to ethanol stress. The transcription of ywlE was growth dependent but stress insensitive. Genomic deletion of each phosphatase-encoding gene led to a phenotype of reduced bacterial resistance to ethanol stress, which was more marked in the ywlE deletion strain. Our study suggests that YfkJ and YwlE play roles in B. subtilis stress resistance. [less ▲]

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See detailIn vitro characterization of the Bacillus subtilis protein tyrosine phosphatase YwqE
Mijakovic, Ivan; Musumeci, Lucia ULg; Tautz, Lutz et al

in Journal of Bacteriology (2005), 187(10), 3384-90

Both gram-negative and gram-positive bacteria possess protein tyrosine phosphatases (PTPs) with a catalytic Cys residue. In addition, many gram-positive bacteria have acquired a new family of PTPs, whose ... [more ▼]

Both gram-negative and gram-positive bacteria possess protein tyrosine phosphatases (PTPs) with a catalytic Cys residue. In addition, many gram-positive bacteria have acquired a new family of PTPs, whose first characterized member was CpsB from Streptococcus pneumoniae. Bacillus subtilis contains one such CpsB-like PTP, YwqE, in addition to two class II Cys-based PTPs, YwlE and YfkJ. The substrates for both YwlE and YfkJ are presently unknown, while YwqE was shown to dephosphorylate two phosphotyrosine-containing proteins implicated in UDP-glucuronate biosynthesis, YwqD and YwqF. In this study, we characterize YwqE, compare the activities of the three B. subtilis PTPs (YwqE, YwlE, and YfkJ), and demonstrate that the two B. subtilis class II PTPs do not dephosphorylate the physiological substrates of YwqE. [less ▲]

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