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See detailLa membrane du globule gras du lait (MFGM) : une composition et une structure originale.
Bodson, Pascal; Vanderghem, Caroline ULg; Danthine, Sabine ULg et al

Poster (2008, January 23)

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See detailThe membrane form of the DNA repair protein Ku interacts at the cell surface with metalloproteinase 9.
Monferran, Sylvie; Paupert, Jenny ULg; Dauvillier, Stephanie et al

in The EMBO journal (2004), 23(19), 3758-68

The Ku heterodimer (Ku70/Ku80) plays a central role in DNA double-strand breaks repair. Ku is also expressed on the cell surface of different types of cells where its function remains poorly understood ... [more ▼]

The Ku heterodimer (Ku70/Ku80) plays a central role in DNA double-strand breaks repair. Ku is also expressed on the cell surface of different types of cells where its function remains poorly understood. From a yeast two-hybrid screen, we have identified a specific interaction between the core region of Ku80 and the hemopexin domain of metalloproteinase 9 (MMP-9), a key enzyme involved in the degradation of extracellular matrix (ECM) components. Ku associates with MMP-9 on the surface of leukemic cells as demonstrated by co-immunoprecipitation experiments in membrane extracts and double-label immunofluorescence studies. In normal and tumoral migratory cells, Ku80 and MMP-9 colocalize at the periphery of leading edge of cells and cellular invasion of collagen IV matrices was blocked by antibodies directed against Ku70 or Ku80 subunits as well as by Ku80-specific antisense oligonucleotides. Our results indicate that Ku and MMP-9 interact at the cell membrane of highly invasive hematopoietic cells of normal and tumoral origin and document the unexpected importance of the membrane-associated form of Ku in the regulation of ECM remodelling. [less ▲]

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See detailMembrane interactions of cyclic lipodepsipeptides from the viscosin group
Geudens, Niels; Feher, Krisztina; De Vleeschouwer et al

Poster (2014, June)

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See detailMembrane topology of the Escherichia coli AmpG permease required for recycling of cell wall anhydromuropeptides and AmpC beta-lactamase induction.
Chahboune, Aicha; Decaffmeyer, Marc; Brasseur, Robert ULg et al

in Antimicrobial Agents and Chemotherapy (2005), 49(3), 1145-9

Escherichia coli, and presumably most other gram-negative bacteria, possesses an efficient protein machinery for recycling its peptidoglycan during cell growth. The major recycled peptidoglycan product is ... [more ▼]

Escherichia coli, and presumably most other gram-negative bacteria, possesses an efficient protein machinery for recycling its peptidoglycan during cell growth. The major recycled peptidoglycan product is N-acetylglucosamine-1,6-anhydro-N-acetylmuramic acid-tetrapeptide. Its uptake from the periplasm into the cytoplasm is carried out via the AmpG protein, an intrinsic membrane protein. In gram-negative bacteria carrying an ampC beta-lactamase-inducible gene on their chromosomes, the induction mechanism is directly linked to peptidoglycan recycling. After identification of the different putative hydrophobic segments by computing, the AmpG topology was experimentally determined by using beta-lactamase fusion. In the proposed model, AmpG contains 10 transmembrane segments and two large cytoplasmic loops. [less ▲]

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See detailMembrane Topology, Structure, and Functions of the Penicillin-Interactive Proteins
Ghuysen, Jean-Marie ULg

in Biotechnology & Applied Biochemistry (1990, October), 12(5), 468-472

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See detailMembrane Translocation and Relationship with MHC Class I of a Human Thymic Neurophysin-Like Protein
Geenen, Vincent ULg; Vandersmissen, E.; Cormann-Goffin, N. et al

in Thymus (1993), 22(1), 55-66

Thymic epithelial and nurse cells (TEC/TNC) synthesize an oxytocin (OT)-like peptide in association with a neurophysin (NP)-related protein in a way similar to in the hypothalamo-neurohypophysial (NHP ... [more ▼]

Thymic epithelial and nurse cells (TEC/TNC) synthesize an oxytocin (OT)-like peptide in association with a neurophysin (NP)-related protein in a way similar to in the hypothalamo-neurohypophysial (NHP) system. The central T-cell tolerance of the NHP neuroendocrine functions have been proposed to be mediated through these thymic NHP-related peptides due to their close homology with the NHP neurohormones OT and vasopressin (VP). In order to investigate their putative presentation by proteins of the major histocompatibility complex (MHC), human thymic membranes were purified and passed through an immunoaffinity column using mAb B9.12 directed to the monomorphic determinant of human MHC class I proteins. This methodology provided the following observations: (1) a NP-like protein is translocated in human thymic membranes and is retained by B9.12 on the column; (2) the MW of this NP-like material (50-55 kD) is quite different from the MW of hypothalamic NP proteins (10 kD), and (3) this thymic NP-like protein could be identified on Western blots with mAb B9.12. The precise extent of this relationship between the thymic NP-like protein and the Ig/MHC superfamily is actually investigated through the characterization of the genetic mechanisms responsible for the thymic expression of NHP-related peptides. Given the physiological importance of OT and of its binding to NP for transport along the axonal processes of the NHP tract, we postulate that, somewhat analogously, the thymic NP-/MHC class I-related protein could be involved in the presentation of the OT-like peptide to immature T-cells. [less ▲]

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See detailMembrane type 1 matrix metalloproteinase detection in tumors, using the iodinated endogenous [123I]-tissue inhibitor 2 of metalloproteinases as imaging agent.
Van Steenkiste, Magali; Oltenfreiter, Ruth; Frankenne, Francis et al

in Cancer Biotherapy & Radiopharmaceuticals (2010), 25(5), 511-20

Matrix metalloproteinases (MMPs) are principal participants in tumor development. In addition to serve as a useful biochemical marker, MMP expression may also provide a target for the diagnostic in vivo ... [more ▼]

Matrix metalloproteinases (MMPs) are principal participants in tumor development. In addition to serve as a useful biochemical marker, MMP expression may also provide a target for the diagnostic in vivo imaging of tumors, using a radiolabeled inhibitor. This study investigates the use of membrane type 1 (MT1)-MMP as target for in vivo tumor diagnosis. Specific binding of the endogenous tissue inhibitor of metalloproteinase-2 (TIMP-2) to MT1-MMP has been previously described. In this study, biodistribution and imaging experiments were performed on MT1-MMP-overexpressing (S.1.5) and control (C.IV.3) tumor-inoculated mice using [(123)I]-recombinant human TIMP-2 (rhTIMP-2) as radioligand and [(123)I]-rhTIMP-1 as control. The expression profile was controlled in vitro and on tumor extracts. rhTIMP-2 as well as rhTIMP-1 were labeled using the Iodogen method and characterized. Biodistribution of [(123)I]-rhTIMP-2 showed a tumor uptake of 2.87% +/- 1.58% ID/g at 3 hours postinjection in S.1.5. Tumor values of [(123)I]-rhTIMP-1 and [(123)I]-rhTIMP-2 evaluated in S.1.5 and C.IV.3, respectively, were significantly lower. Planar imaging revealed significant uptake of [(123)I]-rhTIMP-2 in S.1.5 compared with contralateral background areas. This could not be observed in C.IV.3 and with [(123)I]-rhTIMP-1 in S.1.5. All tumors were well established (200-800 mg). These results suggest that rhTIMP-2 holds potential for development of radiotracers for in vivo imaging in overexpressing MT1-MMP but not in similar tumors that do not express this protease. [less ▲]

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See detailMembrane Type 1 Matrix Metalloproteinase-Associated Degradation of Tissue Inhibitor of Metalloproteinase 2 in Human Tumor Cell Lines
Maquoi, Erik ULg; Frankenne, Francis ULg; Baramova, Eugénia et al

in Journal of Biological Chemistry (2000), 275(15), 11368-78

Tissue inhibitor of metalloproteinase 2 (TIMP-2) is required for the membrane type 1 matrix metalloproteinase (MT1-MMP)-dependent activation of pro-MMP-2 on the cell surface. MT1-MMP-bound TIMP-2 has been ... [more ▼]

Tissue inhibitor of metalloproteinase 2 (TIMP-2) is required for the membrane type 1 matrix metalloproteinase (MT1-MMP)-dependent activation of pro-MMP-2 on the cell surface. MT1-MMP-bound TIMP-2 has been shown to function as a receptor for secreted pro-MMP-2, resulting in the formation of a trimolecular complex. In the presence of uncomplexed active MT1-MMP, the prodomain of cell surface-associated MMP-2 is cleaved, and activated MMP-2 is released. However, the behavior of MT1-MMP-bound TIMP-2 during MMP-2 activation is currently unknown. In this study, (125)I-labeled recombinant TIMP-2 ((125)I-rTIMP-2) was used to investigate the fate of TIMP-2 during pro-MMP-2 activation by HT1080 and transfected A2058 cells. HT1080 and A2058 cells transfected with MT1-MMP cDNA (but not vector-transfected A2058 cells) were able to bind (125)I-rTIMP-2, to activate pro-MMP-2, and to process MT1-MMP into an inactive 43-kDa form. Under these conditions, (125)I-rTIMP-2 bound to the cell surface was rapidly internalized and degraded in intracellular organelles through a bafilomycin A(1)-sensitive mechanism, and (125)I-bearing low molecular mass fragment(s) were released in the culture medium. These different processes were inhibited by hydroxamic acid-based synthetic MMP inhibitors and rTIMP-2, but not by rTIMP-1 or cysteine, serine, or aspartic proteinase inhibitors. These results support the concept that the MT1-MMP-dependent internalization and degradation of TIMP-2 by some tumor cells might be involved in the regulation of pericellular proteolysis. [less ▲]

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See detailMembrane Type Matrix Metalloproreases in tumor angiogenesis
Sounni, Nor Eddine ULg

Conference (2005, January)

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See detailMembrane type-1 matrix metalloproteinase and TIMP-2 in tumor angiogenesis
Sounni, Nor Eddine ULg; Janssen, M.; Foidart, Jean-Michel ULg et al

in Matrix Biology (2003), 22(1), 55-61

The matrix metalloproteinases (MMPs) constitute a multigene family of over 23 secreted and cell-surface associated enzymes that cleave or degrade various pericellular substrates. In addition to virtually ... [more ▼]

The matrix metalloproteinases (MMPs) constitute a multigene family of over 23 secreted and cell-surface associated enzymes that cleave or degrade various pericellular substrates. In addition to virtually all extracellular matrix (ECM) compounds, their targets include other proteinases, chemotactic molecules, latent growth factors, growth factor-binding proteins and cell surface molecules. The MMP activity is controlled by the physiological tissue inhibitors of MMPs (TIMPs). There is much evidence that MMPs and their inhibitors play a key role during extracellular remodeling in physiological situations and in cancer progression. They have other functions that promoting tumor invasion. Indeed, they regulate early stages of tumor progression such as tumor growth and angiogenesis. Membrane type MMPs (MT-MMPs) constitute a new subset of cell surface-associated MMPs. The present review will focus on MT1-MMP which plays a major role at least, in the ECM remodeling, directly by degrading several of its components, and indirectly by activating pro-MMP2. As our knowledge on the field of MT1-MMP biology has grown, the unforeseen complexities of this enzyme and its interaction with its inhibitor TIMP-2 have emerged, often revealing unexpected mechanisms of action. (C) 2003 Elsevier Science B.V/Intemational Society of Matrix Biology. All rights reserved. [less ▲]

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See detailMembrane type-matrix metalloproteinases and tumor progression
Sounni, Nor Eddine ULg; Noël, Agnès ULg

in Biochimie (2005), 87

Matrix metalloproteinases (MMPs) are a family of zinc endopeptidases that process growth factors, growth factor binding proteins, cell surface proteins, degrade extracellular matrix (ECM) components and ... [more ▼]

Matrix metalloproteinases (MMPs) are a family of zinc endopeptidases that process growth factors, growth factor binding proteins, cell surface proteins, degrade extracellular matrix (ECM) components and thereby play a central role in tissue remodeling and tumor progression. Membrane-type matrix metalloproteinases (MT-MMPs) are a recently discovered subgroup of intrinsic plasma membrane proteins. Their functions have been extended from pericellular proteolysis and control of cell migration to cell signaling, control of cell proliferation and regulation of multiple stages of tumor progression including growth and angiogenesis. This review sheds light on the new functions of MT-MMPs and their inhibitors in tumor development and angiogenesis, and presents recent investigations that document their influence on various cell functions. [less ▲]

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See detailMembrane-bound DD-carboxypeptidase and LD-transpeptidase of Streptococcus faecalis ATCC 9790
Coyette, Jacques; Perkins, Harnold R.; Polacheck, Itzhack et al

in European Journal of Biochemistry (1974), 44(2), 459-468

Isolated membranes of Streptococcus faecalis ATCC 9790 exhibit DD-carboxypeptidase activity (standard reaction: Ac2-l-Lys-d-Ala-d-Ala →d-alanine + Ac2-l-Lys-d-Ala) and ld-trans-peptidase activity ... [more ▼]

Isolated membranes of Streptococcus faecalis ATCC 9790 exhibit DD-carboxypeptidase activity (standard reaction: Ac2-l-Lys-d-Ala-d-Ala →d-alanine + Ac2-l-Lys-d-Ala) and ld-trans-peptidase activity (standard reaction: Ac2-l-Lys-d-Ala + acceptor →d-alanine + Ac2-l-Lys-acceptor). The DD-carboxypeptidase activity has a considerable specificity for peptides with a C-terminal l-R3-d-Ala-d-Ala sequence where R3 is an amino acid residue and a long side-chain at the l-R3 position. A corresponding DD-transpeptidation reaction yielding the product Ac2-l-Lys-d-Ala-d-[14C]Ala from the system Ac2-l-Lys-d-Ala-d-Ala-f-d-[14C] alanine was not detected. The ld-transpeptidase activity has a considerable specificity for peptide donors that have an Nα-substituted, C-terminal l-R3-d-Ala sequence with a free ω-amino group at the end of a long side-chain at the l-R3 position, and a considerable specificity for amino group acceptors that are located on a d-carbon in α-position to a free carboxyl group. In the absence of acceptor, hydrolysis of the dipeptide Ac2-l-Lys-d-Ala (ld-carboxypeptidase activity) was not observed. Both DD-carboxypeptidase and ld-transpeptidase activities are inhibited by β-lactam antibiotics, but their relative sensitivity differs according to the particular antibiotic used. [less ▲]

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See detailMembrane-bound transpeptidase and penicillin binding sites in Streptomyces strain R61
Marquet, Alberto; Dusart, Jean; Ghuysen, Jean-Marie ULg et al

in European Journal of Biochemistry (1974), 46(3), 515-523

High-affinity penicillin binding sites from which the antibiotic could not be removed by washings at 4°C in 0.017 M K2HPO4 or 0.05 M Tris-HCl pH 7.5, were shown to occur in the isolated membranes of ... [more ▼]

High-affinity penicillin binding sites from which the antibiotic could not be removed by washings at 4°C in 0.017 M K2HPO4 or 0.05 M Tris-HCl pH 7.5, were shown to occur in the isolated membranes of Streptomyces R61. These sites caused the attachment of 25 picomoles of [14C]benzylpenicillin per milligram membrane protein. Penicillins and cephalosporins competed for the same binding sites. The antibiotic concentrations which excluded [14C]benzylpenicillin from 50% of the binding sites were those which inhibited by 50% the membrane-bound transpeptidase. The same rate constant (about 1 × 10−4 s−1) for the dissociation of the benzylpenicillin membrane complex at 37°C and in 0.017 M K2HPO4, was calculated either from the release of the radioactivity (using [14C]benzylpenicillin) or from the recovery of the transpeptidase activity. These observations supported the conclusion that the high-affinity binding sites in the isolated membranes were the transpeptidase molecules. All the complexes formed between the membranes and the various penicillins and cephalosporins examined were reversible at 37°C and in 0.017 M K2HPO4 at least with regard to the transpeptidase. Depending upon the antibiotics, the rate constants for the dissociation of these complexes varied from 3.3 × 10−3 to 0.73 × 10−4 s−1. The radioactivity released through the dissociation of [14C]benzylpenicillin membrane complex occurred mainly in the form of a compound which behaved as [W]-benzylpenicilloic acid both by paper electrophoresis and thin-layer chromatography. It was impossible to choose between several possible mechanisms for the release of the antibiotic molecule. [less ▲]

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See detailMembrane-type 1 matrix metalloproteinase expression is regulated by zonula occludens-1 in human breast cancer cells
Polette, M.; Gilles, Christine ULg; Nawrocki-Raby, B. et al

in Cancer Research (2005), 65(17), 7691-7698

The acquisition of a migratory/invasive phenotype by tumor cells is characterized by the loss of cell-cell adhesion contacts and the expression of degradative properties. In this study, we examined the ... [more ▼]

The acquisition of a migratory/invasive phenotype by tumor cells is characterized by the loss of cell-cell adhesion contacts and the expression of degradative properties. In this study, we examined the effect of the disorganization of occludin/zomda occludens (ZO)-1 tight junction (TJ) complexes on the expression of membrane-type I matrix metalloproteinase (MT1-MMP). We first compared the expression of MT1-MMP and the localization of occludin/ZO-1 complexes in breast tumor cell lines displaying various degrees of invasiveness. We showed that the expression of MT1-MMP in invasive breast tumor cell lines correlates with the absence of occludin and with a cytoplasmic localization of ZO-1. In contrast, noninvasive cell lines displayed a membrane staining for both ZO-1 and occludin and did not express MT1-MMP. In vivo, cytoplasmic ZO-1 and MTI-MMP could be detected in invasive tumor clusters of human breast carcinomas. We then used RNA interference strategy to inhibit ZO-1 expression in invasive BT549 cells and to evaluate the effect of ZO-1 downregulation on MTI-MMP expression. We observed that ZO-1 small interfering RNA transfection down-regulates MT1-MMP mRNAs and proteins and subsequently decreases the ability of tumor cells to invade a reconstituted basement membrane in a Boyden chamber assay. Inversely, transfection of expression vectors encoding wild-type ZO-1 or the NH2-terminal fragment of ZO-1 comprising the PSD95/DLG/ZO-1 domains in BT549 activated a human MT1-MMP promoter luciferase reporter construct and increased cell invasiveness. Such transfections concomitantly activated the beta-catenin/TCF/LEF pathway. Our results therefore show that ZO-1, besides its structural role in TJ assembly, can intervene in signaling events promoting tumor cell invasion. [less ▲]

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See detailMembrane-Type 4 Matrix Metalloproteinase (MT4-MMP) induces lung metastasis by alteration of primary breast tumor vascular architecture
Chabottaux, Vincent; Ricaud, Stéphanie; Host, Lorin et al

in Journal of Cellular & Molecular Medicine (2009)

The present study aims at investigating the mechanism by which MT4-MMP, a membrane-anchored MMP expressed by human breast tumor cells promotes the metastatic dissemination into lung. We applied ... [more ▼]

The present study aims at investigating the mechanism by which MT4-MMP, a membrane-anchored MMP expressed by human breast tumor cells promotes the metastatic dissemination into lung. We applied experimental (intravenous) and spontaneous (subcutaneous) models of lung metastasis using human breast adenocarcinoma MDA-MB-231 cells overexpressing or not MT4-MMP. We found that MT4-MMP does not affect lymph node colonization nor extravasation of cells from the bloodstream, but increases the intravasation step leading to metastasis. Ultrastructural and fluorescent microscopic observations coupled with automatic computer-assisted quantifications revealed that MT4-MMP expression induces blood vessel enlargement and promotes the detachment of mural cells from the vascular tree, thus causing an increased tumor vascular leak. On this basis, we propose that MT4-MMP promotes lung metastasis by disturbing the tumor vessel integrity and thereby facilitating tumor cell intravasation. [less ▲]

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See detailMembrane-type 4 matrix metalloproteinase promotes breast cancer growth and metastases
Chabottaux, Vincent; Sounni, Nor Eddine ULg; Pennington, C. J. et al

in Cancer Research (2006), 66(10), 5165-5172

Membrane-type matrix metalloproteinases (MT-MMP) constitute a subfamily of six distinct membrane-associated MMPs. Although the contribution of MT1-MMP during different steps of cancer progression has been ... [more ▼]

Membrane-type matrix metalloproteinases (MT-MMP) constitute a subfamily of six distinct membrane-associated MMPs. Although the contribution of MT1-MMP during different steps of cancer progression has been well documented, the significance of other MT-MMPs is rather unknown. We have investigated the involvement of MT4-MMP, a glycosylphosphatidylinositol-anchored protease, in breast cancer progression. Interestingly, immunohistochemical analysis shows that MT4-MMP production at protein level is strongly increased in epithelial cancer cells of human breast carcinomas compared with normal epithelial cells. Positive staining for MT4-MMP is also detected in lymph node metastases. In contrast, quantitative reverse transcription-PCR analysis reveals similar MT4-MMP mRNA levels in human breast adenocarcinomas and normal breast tissues. Stable transfection of MT4-MMP cDNA in human breast adenocarcinoma MDA-MB-231 cells does not affect in vitro cell proliferation or invasion but strongly promotes primary tumor growth and associated metastases in RAG-1 immunodeficient mice. We provide for the first time evidence that MT4-MMP overproduction accelerates in vivo tumor growth, induces enlargement of i.t. blood vessels, and is associated with increased lung metastases. These results identify MT4-MMP as a new putative target to design anticancer strategies. [less ▲]

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See detailMembrane-type matrix metalloproteinase-1 expression at the site of human placentation
Nawrocki, B.; Polette, M. E.; Marchand, V. et al

in Placenta (1996), 17(8), 565-72

Human trophoblast implantation is a highly regulated process of invasion that requires action of proteolytic enzymes to degrade extracellular matrix components of the endometrium. Among these enzymes ... [more ▼]

Human trophoblast implantation is a highly regulated process of invasion that requires action of proteolytic enzymes to degrade extracellular matrix components of the endometrium. Among these enzymes, matrix metalloproteinases (MMPs) seem to be particularly important in this degradative process. We previously showed that gelatinase A is extensively expressed in vivo in the human placenta. A new MMP, MT-MMP-1 (membrane-type matrix metalloproteinase-1), which is thought to activate progelatinase A, has recently been described. In this study, we examined the expression of MT-MMP-1, by immunohistochemistry and in situ hybridization, in human placental bed biopsies taken during the first trimester of gestation. Human first trimester intermediate trophoblasts synthesized MT-MMP-1 mRNAs and the protein. The MT-MMP-1 pattern of distribution in placental beds was similar to that of gelatinase A, suggesting a pivotal role for MT-MMP-1 in placentation, perhaps by activating progelatinase A. [less ▲]

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See detailmembre rebelle
Claes, Hubert; Andrianne, Robert ULg

Book published by Roularta Books (2005)

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See detailMême galvaudé, le terme ‘politique’ ne suggère-t-il pas le pouvoir ?
Grandjean, Geoffrey ULg

Conference given outside the academic context (2012)

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