176 results on '"Horejsí V"'
Search Results
2. CD43 ligation mediates dendritic cell activation
- Author
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Corinti, S., primary, Fanales-Belasio, E., additional, Albanesi, C., additional, Cavani, A., additional, Horejsí, V., additional, and Girolomoni, G., additional
- Published
- 1998
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3. Lowering cellular cholesterol inhibits signal transduction via glycosyl phosphatidyl-inositol(GPI)-anchored proteins
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Stulnig, T.M., primary, Berger, M., additional, Stockinger, H., additional, Horejsí, V., additional, and Waldhǎusl, W., additional
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- 1997
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4. Supramolecular complexes of MHC class I, MHC class II, CD20, and tetraspan molecules (CD53, CD81, and CD82) at the surface of a B cell line JY.
- Author
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Szöllósi, J, primary, Horejsí, V, additional, Bene, L, additional, Angelisová, P, additional, and Damjanovich, S, additional
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- 1996
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5. Urokinase plasminogen activator receptor, beta 2-integrins, and Src-kinases within a single receptor complex of human monocytes.
- Author
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Bohuslav, J, primary, Horejsí, V, additional, Hansmann, C, additional, Stöckl, J, additional, Weidle, U H, additional, Majdic, O, additional, Bartke, I, additional, Knapp, W, additional, and Stockinger, H, additional
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- 1995
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6. The nature of large noncovalent complexes containing glycosyl-phosphatidylinositol-anchored membrane glycoproteins and protein tyrosine kinases.
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Cinek, T, primary and Horejsí, V, additional
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- 1992
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7. Shedding of the CD44 adhesion molecule from leukocytes induced by anti-CD44 monoclonal antibody simulating the effect of a natural receptor ligand.
- Author
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Bazil, V, primary and Horejsí, V, additional
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- 1992
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8. Association of the CD59 and CD55 cell surface glycoproteins with other membrane molecules.
- Author
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Stefanová, I, primary and Horejsí, V, additional
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- 1991
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9. The nature of the subset of MHC class II molecules carrying the CDw78 epitopes.
- Author
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Drbal, K, Angelisová, P, Rasmussen, A-M, Hilgert, I, Funderud, S, and Horejsí, V
- Abstract
A CDw78 mAb FN1 was shown to recognize DP and/or DR molecules under the conditions of Western blotting. DP molecules were specifically retarded on a column of the FN1 immunosorbent; binding of FITC-labeled FN1 to B cell lines was completely blocked by excess of mAb to DR/DP β chains, partially by several mAb to DP and weakly by some mAb to DR. The binding of two other CDw78 mAb, FN4 and MR11, to the B cell surface was most strongly inhibited by excess of different mAb to DR. Kinetics of stable binding of the CDw78 mAb indicated that their monovalent binding is of low affinity and that the stable binding to the surface is due to bivalent binding to two spatially close MHC class II molecules. FN-1 based immunosorbent effectively immunoisolated complexes of MHC class II proteins with several tetraspanin molecules from a mild detergent lysate of a B cell line. It is concluded that FN1 and most likely also the other two CDw78 mAb recognized with low affinity determinants on MHC class II molecules. Such dimers or aggregates may either exist as preformed on the cell surface or may be gradually formed and stabilized by bivalent interaction with mAb. These structures may be related to the previously described 'superdimers' of MHC class II and/or 'MHC-tetraspanin complexes'. CDw78 mAb may be valuable tools targeting such aggregated fraction of MHC class II molecules which can exhibit important signalling and antigen-presenting properties. [ABSTRACT FROM PUBLISHER]
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- 1999
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10. CD antigens 2001.
- Author
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Mason, D, André, P, Bensussan, A, Buckley, C, Civin, C, Clark, E, de Haas, M, Goyert, S, Hadam, M, Hart, D, Horejsí, V, Meuer, S, Morrissey, J, Schwartz-Albiez, R, Shaw, S, Simmons, D, Uguccioni, M, van der Schoot, E, Vivier, E, and Zola, H
- Published
- 2001
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11. Release from tonic inhibition of T cell activation through transient displacement of C-terminal Src kinase (Csk) from lipid rafts.
- Author
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Torgersen, K M, Vang, T, Abrahamsen, H, Yaqub, S, Horejsí, V, Schraven, B, Rolstad, B, Mustelin, T, and Taskén, K
- Abstract
In resting peripheral T cells, Csk is constitutively present in lipid rafts through an interaction with the Csk SH2-binding protein, PAG, also known as Cbp. Upon triggering of the T cell antigen receptor (TCR), PAG/Cbp is rapidly dephosphorylated leading to dissociation of Csk from lipid rafts. However, tyrosine phosphorylation of PAG/Cbp resumes after 3--5 min, at which time Csk reassociates with the rafts. Cells overexpressing a mutant Csk that lacks the catalytic domain, but displaces endogenous Csk from lipid rafts, have elevated basal levels of TCR-zeta-chain phosphorylation and spontaneous activation of an NFAT-AP1 reporter from the proximal interleukin-2 promoter as well as stronger and more sustained responses to TCR triggering than controls. We suggest that a transient release from Csk-mediated inhibition by displacement of Csk from lipid rafts is important for normal T cell activation.
- Published
- 2001
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12. The nature of the subset of MHC class II molecules carrying the CDw78 epitopes
- Author
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Rasmussen, A-M., Funderud, S., Horejsí, V., Drbal, K., Angelisová, P., and Hilgert, I.
- Abstract
A CDw78 mAb FN1 was shown to recognize DP and/or DR molecules under the conditions of Western blotting. DP molecules were specifically retarded on a column of the FN1 immunosorbent; binding of FITC-labeled FN1 to B cell lines was completely blocked by excess of mAb to DR/DP β chains, partially by several mAb to DP and weakly by some mAb to DR. The binding of two other CDw78 mAb, FN4 and MR11, to the B cell surface was most strongly inhibited by excess of different mAb to DR. Kinetics of stable binding of the CDw78 mAb indicated that their monovalent binding is of low affinity and that the stable binding to the surface is due to bivalent binding to two spatially close MHC class II molecules. FN-1 based immunosorbent effectively immunoisolated complexes of MHC class II proteins with several tetraspanin molecules from a mild detergent lysate of a B cell line. It is concluded that FN1 and most likely also the other two CDw78 mAb recognized with low affinity determinants on MHC class II molecules. Such dimers or aggregates may either exist as preformed on the cell surface or may be gradually formed and stabilized by bivalent interaction with mAb. These structures may be related to the previously described 'superdimers' of MHC class II and/or 'MHC-tetraspanin complexes'. CDw78 mAb may be valuable tools targeting such aggregated fraction of MHC class II molecules which can exhibit important signalling and antigen-presenting properties.
- Published
- 1999
13. T cell activation-associated epitopes of CD147 in regulation of the T cell response, and their definition by antibody affinity and antigen density.
- Author
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Koch, C, Staffler, G, Hüttinger, R, Hilgert, I, Prager, E, Cerný, J, Steinlein, P, Majdic, O, Horejsí, V, and Stockinger, H
- Abstract
CD147 is a broadly expressed cell surface glycoprotein of the Ig superfamily whose expression is up-regulated upon T cell activation. In order to elucidate a possible role of CD147 in T cell biology, we established 15 specific mAb. Seven distinct epitopes were defined by the mAb panel. Most of the mAb bound only to phytohemagglutinin (PHA)-activated but not resting T cells. We demonstrate that this was not because of true expression of activation-dependent neoepitopes but rather due to bivalent binding of the relatively low-affinity mAb (affinity constant KA values between 2.25 x 10(8) and 7 x 10(9) M-1) to the more densely expressed and/or more clustered CD147 molecules on the activated T cells. In contrast, the mAb with higher affinity (KA > 7 x 10(9) M-1) could stably bind in a monovalent fashion even to the relatively low dense CD147 molecules on resting T cells. This model might more generally explain the nature of 'activation epitopes' described previously in other leukocyte surface molecules. Finally, we provide evidence that induction of ordered dimerization of CD147 by a mAb directed to a unique epitope results in strong inhibition of CD3-mediated T cell activation.
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- 1999
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14. Signal transduction via glycosyl phosphatidylinositol-anchored proteins in T cells is inhibited by lowering cellular cholesterol.
- Author
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Stulnig, T M, Berger, M, Sigmund, T, Stockinger, H, Horejsí, V, and Waldhäusl, W
- Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins can deliver costimulatory signals to lymphocytes, but the exact pathway of signal transduction involved is not yet characterized. GPI-anchored proteins are fixed to the cell surface solely by a phospholipid moiety and are clustered in distinct membrane domains that are formed by an unique lipid composition requiring cholesterol. To elucidate the role of membrane lipids for signal transduction via GPI-anchored proteins, we studied the influence of reduced cellular cholesterol content on calcium signaling via GPI-anchored CD59 and CD48 in Jurkat T cells. Lowering cholesterol by different inhibitors of cellular cholesterol synthesis suppressed calcium response via GPI-anchored proteins by about 50%, whereas stimulation via CD3 was only minimally affected (<10%). The decrease in overall calcium response via GPI-anchored proteins was reflected by inhibition of calcium release from intracellular stores. Cell surface expression of GPI-anchored proteins was not changed quantitatively by lowering cellular cholesterol, and neither was the pattern of immunofluorescence in microscopic examination. In addition, the distribution of GPI-anchored proteins in detergent-insoluble complexes remained unaltered. These results suggest that cellular cholesterol is an important prerequisite for signal transduction via GPI-anchored proteins beyond formation of membrane domains.
- Published
- 1997
15. Purification and characterization of class II histocompatibility antigens from a homozygous human B cell line.
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Gorga, J C, Horejsí, V, Johnson, D R, Raghupathy, R, and Strominger, J L
- Abstract
Human class II histocompatibility antigens were purified from the Epstein-Barr virus-transformed human B lymphoblastoid cell line LG-2 by immunoaffinity chromatography. This is the first time all three subsets have been prepared as nonradioactive materials on a milligram scale. The yields of DR, DQ, and DP from 10 g of cells were approximately 12, 2, and 0.2 mg, respectively. Cross-contamination of the subsets was found to be less than 2% when assayed by measuring the binding of antigen-specific monoclonal antibodies to antigen immobilized on fixed erythrocytes. The three purified subsets were extensively characterized. They contained no detectable invariant chain. The three proteins were distinguished by their migration on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing. The denatured antigens were susceptible to partial removal of carbohydrate by endoglycosidase H and apparently complete removal of carbohydrate by endoglycosidase F. The isolated, denatured chains differed in their affinities for radiolabeled lectins, suggesting differences in carbohydrate structures. A water-soluble form of each antigen was prepared by a controlled papain digestion of the native antigen. Both native and denatured antigens were analyzed for their reactivities with a panel of class II antigen-specific monoclonal antibodies, allowing a precise definition of the specificities of the antibodies.
- Published
- 1987
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16. Surface proteins and glycoproteins of human leucocytes
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Horejsí, V and Bazil, V
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- 1988
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17. Theory of affinity electrophoresis : Evaluation of the effects of protein multivalency, immobilized ligand heterogeneity and microdistribution and determination of effective concentration of immobilized ligand
- Author
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Hořejší, V. and Tichá, Marie
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- 1981
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18. The use of lectins for determination of absolute configurations of small amounts of sugars eluted from chromatograms
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Hořejší, V., Tichá, Marie, and Trnka, T.
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- 1984
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19. Affinity isoelectric focusing in polyacrylamide gel—A method to detect ligand-binding proteins
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Hořejs̆í, V. and Tichá, Marie
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- 1981
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20. Equilibrium in the protein-immobilized-ligand-soluble-ligand system: Estimation of dissociation constants of protein-soluble-ligand complexes from binding-inhibition data
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Hořejší, V. and Matoušek, V.
- Published
- 1985
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21. GPI-microdomains: a role in signalling via immunoreceptors
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Horejsí, V
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- 1999
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22. A clustered subset of MHC class II molecules
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Horejsí, V
- Published
- 1998
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23. Separation of Ricinus communis lectins by affinity chromatography
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Hořejší, V.
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- 1979
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24. A CD3 antibody distinguishes Vγ9Vδ2-T cells from other T cells
- Author
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Drbal, K., Černý, J., Hilgert, I., and Hor̆ejší, V.
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- 1997
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25. Association of human NK cell surface receptors NKR-P1 and CD94 with Src-family protein kinases
- Author
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Černý, J., Fišerová, A., Horváth, O., Bezouška, K., Pospíšil, M., and Hořejší, V.
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- 1997
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26. Association of urokinase plasminogen activator receptor with a novel plasminogen binding molecule in monocytes
- Author
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Godar, S., Hansmann, C., Weidle, U., Hořejší, V., and Stockinger, H.
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- 1997
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27. Transmembrane adaptor molecules: A new category of lymphoid cell markers
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Jennifer C. Paterson, David Y. Mason, Giovanna Roncador, Helen Roberton, Michela Pozzobon, Pavla Angelisova, Richard Barry, Teresa Marafioti, Lydia Sánchez, Noraidah Masir, Sara Tedoldi, Stefano Pileri, Thomas Rüdiger, Martin-Leo Hansmann, Ming Q. Du, Yasodha Natkunam, Vaclav Horejsi, Tedoldi S., Paterson J.C., Hansmann M.-L., Natkunam Y., Rüdiger T., Angelisova P., Du M.Q., Roberton H., Roncador G., Sanchez L., Pozzobon M., Masir N., Barry R., Pileri S., Mason D.Y., and Horejsí V.
- Subjects
Cell type ,Pathology ,medicine.medical_specialty ,Lymphoma ,T cell ,T-Lymphocytes ,Immunology ,Biology ,Stem cell marker ,Biochemistry ,Immunophenotyping ,medicine ,Humans ,Lymphocytes ,B cell ,Adaptor Proteins, Signal Transducing ,B-Lymphocytes ,Membrane Proteins ,Cell Biology ,Hematology ,medicine.disease ,Prognosis ,Molecular biology ,Immunohistochemistry ,Lymphatic system ,medicine.anatomical_structure ,Diffuse large B-cell lymphoma ,Biomarkers - Abstract
Transmembrane adaptor proteins (of which 7 have been identified so far) are involved in receptor signaling in immune cells. They have only a short extracellular region, with most of the molecule comprising a substantial intracytoplasmic region carrying multiple tyrosine residues that can be phosphorylated by Src- or Syk-family kinases. In this paper, we report an immunohistologic study of 6 of these molecules in normal and neoplastic human tissue sections and show that they are restricted to subpopulations of lymphoid cells, being present in either T cells (LAT, LIME, and TRIM), B cells (NTAL), or subsets of both cell types (PAG and SIT). Their expression in neoplastic lymphoid cells broadly reflects that of normal lymphoid tissue, including the positivity of plasma cells and myeloma/plasmacytoma for LIME, NTAL, PAG, and SIT. However, this study also revealed some reactions that may be of diagnostic/prognostic value. For example, lymphocytic lymphoma and mantle-cell lymphoma showed similar profiles but differed clearly from follicle-center lymphoma, whereas PAG tended to be selectively expressed in germinal center-derived subsets of diffuse large B-cell lymphoma. These molecules represent a potentially important addition to the panel of immunophenotypic markers detectable in routine biopsies that can be used in hematopathologic studies.
- Published
- 2006
28. Btk is a positive regulator in the TREM-1/DAP12 signaling pathway.
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Ormsby T, Schlecker E, Ferdin J, Tessarz AS, Angelisová P, Köprülü AD, Borte M, Warnatz K, Schulze I, Ellmeier W, Horejsí V, and Cerwenka A
- Subjects
- Adaptor Proteins, Signal Transducing immunology, Agammaglobulinaemia Tyrosine Kinase, Agammaglobulinemia metabolism, Animals, Cell Separation, Flow Cytometry, Genetic Diseases, X-Linked metabolism, Humans, Immunoblotting, Immunoprecipitation, Inflammation immunology, Male, Membrane Glycoproteins immunology, Membrane Proteins immunology, Mice, Mice, Inbred C57BL, Mice, Knockout, Myeloid Cells immunology, Myeloid Cells metabolism, Protein-Tyrosine Kinases immunology, Receptors, Immunologic immunology, Triggering Receptor Expressed on Myeloid Cells-1, Up-Regulation, Adaptor Proteins, Signal Transducing metabolism, Inflammation metabolism, Membrane Glycoproteins metabolism, Membrane Proteins metabolism, Protein-Tyrosine Kinases metabolism, Receptors, Immunologic metabolism, Signal Transduction immunology
- Abstract
The triggering receptor expressed on myeloid cells 1 (TREM-1) has been implicated in the production of proinflammatory cytokines and chemokines during bacterial infection and sepsis. For downstream signal transduction, TREM-1 is coupled to the ITAM-containing adaptor DAP12. Here, we demonstrate that Bruton tyrosine kinase (Btk), a member of the Tec kinases, becomes phosphorylated upon TREM-1 triggering. In U937-derived cell lines, in which expression of Btk was diminished by shRNA-mediated knockdown, phosphorylation of Erk1/2 and PLCγ1 and Ca²⁺ mobilization were reduced after TREM-1 stimulation. Importantly, TREM-1-induced production of the pro-inflammatory cytokines, TNF-α and IL-8, and up-regulation of activation/differentiation cell surface markers were impaired in Btk knockdown cells. Similar results were obtained upon TREM-1 stimulation of BMDCs of Btk(-/-) mice. The analysis of cells containing Btk mutants revealed that intact membrane localization and a functional kinase domain were required for TREM-1-mediated signaling. Finally, after TREM-1 engagement, TNF-α production by PBMCs was reduced in the majority of patients suffering from X-linked agammaglobulinemia (XLA), a rare hereditary disease caused by mutations in the BTK gene. In conclusion, our data identify Btk as a positive regulator in the ITAM-mediated TREM-1/DAP12 pathway and suggest its implication in inflammatory processes.
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- 2011
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29. PRR7 is a transmembrane adaptor protein expressed in activated T cells involved in regulation of T cell receptor signaling and apoptosis.
- Author
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Hrdinka M, Dráber P, Stepánek O, Ormsby T, Otáhal P, Angelisová P, Brdicka T, Paces J, Horejsí V, and Drbal K
- Subjects
- Adaptor Proteins, Signal Transducing genetics, Adaptor Proteins, Signal Transducing immunology, Amino Acid Motifs, Animals, Antigens, CD biosynthesis, Antigens, CD genetics, Antigens, CD immunology, Antigens, Differentiation, T-Lymphocyte biosynthesis, Antigens, Differentiation, T-Lymphocyte genetics, Antigens, Differentiation, T-Lymphocyte immunology, Apoptosis drug effects, Caco-2 Cells, Calcium Signaling drug effects, Carcinogens pharmacology, HEK293 Cells, Humans, Interleukin-2 biosynthesis, Interleukin-2 genetics, Interleukin-2 immunology, Ionomycin pharmacology, Ionophores pharmacology, Jurkat Cells, Lectins, C-Type biosynthesis, Lectins, C-Type genetics, Lectins, C-Type immunology, Phosphorylation drug effects, Phosphorylation physiology, Protein Structure, Tertiary, Proto-Oncogene Proteins c-jun genetics, Proto-Oncogene Proteins c-jun immunology, Proto-Oncogene Proteins c-jun metabolism, Rats, Receptors, Antigen, T-Cell genetics, Receptors, Antigen, T-Cell immunology, T-Lymphocytes immunology, Tetradecanoylphorbol Acetate pharmacology, U937 Cells, Adaptor Proteins, Signal Transducing biosynthesis, Apoptosis physiology, Calcium Signaling physiology, Gene Expression Regulation physiology, Receptors, Antigen, T-Cell metabolism, T-Lymphocytes metabolism
- Abstract
Transmembrane adaptor proteins (TRAPs) are important organizers and regulators of immunoreceptor-mediated signaling. A bioinformatic search revealed several potential novel TRAPs, including a highly conserved protein, proline rich 7 (PRR7), previously described as a component of the PSD-95/N-methyl-d-aspartate receptor protein complex in postsynaptic densities (PSD) of rat neurons. Our data demonstrate that PRR7 is weakly expressed in other tissues but is readily up-regulated in activated human peripheral blood lymphocytes. Transient overexpression of PRR7 in Jurkat T cell line led to gradual apoptotic death dependent on the WW domain binding motif surrounding Tyr-166 in the intracellular part of PRR7. To circumvent the pro-apoptotic effect of PRR7, we generated Jurkat clones with inducible expression of PRR7 (J-iPRR7). In these cells acute induction of PRR7 expression had a dual effect. It resulted in up-regulation of the transcription factor c-Jun and the activation marker CD69 as well as enhanced production of IL-2 after phorbol 12-myristate 13-acetate (PMA) and ionomycin treatment. On the other hand, expression of PRR7 inhibited general tyrosine phosphorylation and calcium influx after T cell receptor cross-linking by antibodies. Moreover, we found PRR7 constitutively tyrosine-phosphorylated and associated with Src. Collectively, these data indicate that PRR7 is a potential regulator of signaling and apoptosis in activated T cells.
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- 2011
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30. LAT--an important raft-associated transmembrane adaptor protein. Delivered on 6 July 2009 at the 34th FEBS Congress in Prague, Czech Republic.
- Author
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Horejsí V, Otáhal P, and Brdicka T
- Subjects
- Adaptor Proteins, Signal Transducing genetics, Animals, Humans, Membrane Proteins genetics, Models, Biological, Mutation, Protein Binding, Receptors, Antigen, T-Cell metabolism, Receptors, Cell Surface metabolism, Adaptor Proteins, Signal Transducing metabolism, Membrane Microdomains metabolism, Membrane Proteins metabolism, Signal Transduction
- Abstract
Membrane rafts are microdomains involved in a number of biologically important processes, including immunoreceptor signalling. Among the functionally important protein components of these microdomains are transmembrane adaptor proteins, containing in their intracellular domains tyrosine residues that can be phosphorylated and bind other cytoplasmic signalling proteins. The most important leukocyte transmembrane adaptor protein is LAT (linker for activation of T cells), which is critically involved in T cell receptor signalling, but also plays important roles in signal initiation by several other immunologically important receptors. Here we review recent progress in the elucidation of several aspects of this protein, e.g. the controversy concerning the importance of LAT being present in membrane rafts, the involvement in signalling through a number of receptors other than the T cell receptor and the puzzling phenotype of some LAT mutants., (© 2010 The Authors Journal compilation © 2010 FEBS.)
- Published
- 2010
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31. A new type of membrane raft-like microdomains and their possible involvement in TCR signaling.
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Otáhal P, Angelisová P, Hrdinka M, Brdicka T, Novák P, Drbal K, and Horejsí V
- Subjects
- Adaptor Proteins, Signal Transducing immunology, Adaptor Proteins, Signal Transducing metabolism, Humans, Jurkat Cells, Lymphocyte Activation immunology, Membrane Microdomains chemistry, Membrane Proteins chemistry, Membrane Proteins immunology, Membrane Proteins isolation & purification, Membrane Proteins metabolism, Receptors, Antigen, T-Cell metabolism, Signal Transduction immunology, T-Lymphocytes chemistry, T-Lymphocytes metabolism, Membrane Microdomains immunology, Receptors, Antigen, T-Cell immunology, T-Lymphocytes immunology
- Abstract
Membrane rafts and signaling molecules associated with them are thought to play important roles in immunoreceptor signaling. Rafts differ in their lipid and protein compositions from the rest of the membrane and are relatively resistant to solubilization by Triton X-100 or similar detergents, producing buoyant, detergent-resistant membranes (DRMs) that can be isolated by density gradient ultracentrifugation. One of the key signaling molecules present in T cell DRMs is the transmembrane adaptor protein LAT (linker for activation of T cells). In contrast to previous results, a recent study demonstrated that a LAT construct not present in the buoyant DRMs is fully able to support TCR signaling and development of T cells in vivo. This finding caused doubts about the real physiological role of rafts in TCR signaling. In this study, we demonstrate that these results can be explained by the existence of a novel type of membrane raft-like microdomains, producing upon detergent solubilization "heavy DRMs" containing a number of membrane molecules. At a moderate level of expression, LAT supported TCR signaling more efficiently than constructs targeted to the microdomains producing heavy DRMs or to nonraft membrane. We suggest that different types of membrane microdomains provide environments regulating the functional efficiencies of signaling molecules present therein.
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- 2010
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32. Czech bibliometric system fosters mediocre research.
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Konvalinka J, Illnerová H, Hobza P, Horejsí V, Holý A, Jungwirth P, Paces V, Martásek P, and Zlatuska J
- Subjects
- Czech Republic, Bibliometrics, Research economics, Research standards, Research Support as Topic economics
- Published
- 2009
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33. LFA-1-mediated leukocyte adhesion regulated by interaction of CD43 with LFA-1 and CD147.
- Author
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Khunkaewla P, Schiller HB, Paster W, Leksa V, Cermák L, Andera L, Horejsí V, and Stockinger H
- Subjects
- Animals, Cell Adhesion, Cell Line, Humans, Leukosialin genetics, Mice, Protein Binding, Basigin metabolism, Leukocytes physiology, Leukosialin metabolism, Lymphocyte Function-Associated Antigen-1 physiology
- Abstract
The activity of the lymphocyte-function associated antigen 1 (LFA-1; CD11a/CD18) must be tightly controlled during the onset of cellular immunity. It is well known that the sialoglycoprotein CD43 can influence LFA-1-mediated cell adhesion in an either anti- or pro-adhesive manner through mechanisms not well understood. By using a yeast-2-hybrid screen and co-immunoprecipitation we identified physical association of CD43 with two novel partners, LFA-1 itself and the Ig-family member CD147 (EMMPRIN, basigin), and characterized how these interactions are involved in LFA-1-mediated cell adhesion. Monoclonal antibodies (mAbs) to both CD43 and CD147 induced similar homotypic cell aggregation and adhesion of Jurkat T cells and U937 myeloid cells. Both CD43 and CD147 mAbs induced dynamic co-capping of LFA-1 together with the CD43 and the CD147 molecule to cell contact zones. However, in contrast to CD43, we were not able to co-immunoprecipitate LFA-1 with CD147, which indicates that CD43 interacts with CD147 and LFA-1 in two distinct but similarly reorganized complexes. Co-transfection of CD43 interfered with the CD147-induced cell adhesion and aggregation, and siRNA-mediated knock down of CD43 in human T cells resulted in enhanced LFA-1 activation induced via CD147 and also the T cell antigen receptor. These results indicate that triggering CD43 and the underlying signaling pathways enhance LFA-1 adhesiveness while CD43 also negatively regulates LFA-1 induction via other receptors by dynamic interaction with either LFA-1 or CD147.
- Published
- 2008
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34. Non-T cell activation linker (NTAL) negatively regulates TREM-1/DAP12-induced inflammatory cytokine production in myeloid cells.
- Author
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Tessarz AS, Weiler S, Zanzinger K, Angelisová P, Horejsí V, and Cerwenka A
- Subjects
- Adaptor Proteins, Signal Transducing metabolism, Animals, Calcium Signaling drug effects, Calcium Signaling immunology, Gene Expression Regulation drug effects, Gene Expression Regulation immunology, Humans, Inflammation immunology, Inflammation metabolism, Interleukin-8 biosynthesis, Lipopolysaccharides pharmacology, MAP Kinase Signaling System drug effects, MAP Kinase Signaling System immunology, Membrane Glycoproteins metabolism, Membrane Proteins, Mice, Mitogen-Activated Protein Kinase 1 immunology, Mitogen-Activated Protein Kinase 1 metabolism, Mitogen-Activated Protein Kinase 3 immunology, Mitogen-Activated Protein Kinase 3 metabolism, Myeloid Cells metabolism, Phosphorylation drug effects, Protein Processing, Post-Translational drug effects, Protein Processing, Post-Translational immunology, RNA Interference immunology, Receptors, Immunologic metabolism, Triggering Receptor Expressed on Myeloid Cells-1, Tumor Necrosis Factor-alpha biosynthesis, U937 Cells, Adaptor Proteins, Signal Transducing immunology, Interleukin-8 immunology, Membrane Glycoproteins immunology, Myeloid Cells immunology, Receptors, Immunologic immunology, Tumor Necrosis Factor-alpha immunology
- Abstract
The engagement of triggering receptor expressed on myeloid cells 1 (TREM-1) on macrophages and neutrophils leads to TNF-alpha and IL-8 production and enhances inflammatory responses to microbial products. For signal transduction, TREM-1 couples to the ITAM-containing adapter DNAX activation protein of 12 kDa (DAP12). In general, ITAM-mediated signals lead to cell activation, although DAP12 was recently implicated in inhibitory signaling in mouse macrophages and dendritic cells. To date, signals downstream of the TREM-1 and DAP12 complex in myeloid cells are poorly defined. By analyzing receptor-induced tyrosine phosphorylation patterns, we discovered that the ligation of TREM-1 leads to tyrosine phosphorylation of the non-T cell activation linker (NTAL; also called linker of activation in B cells or LAB) in a myelomonocytic cell line and primary human granulocytes. Using RNA interference to decrease the expression levels of NTAL, we demonstrate that in NTAL knockdown cell lines the phosphorylation of ERK1/2 is enhanced. In addition, low levels of NTAL are correlated with decreased and delayed mobilization of Ca(2+) after TREM-1 triggering. Most importantly, we demonstrate that NTAL acts as a negative regulator of TNF-alpha and IL-8 production after stimulation via TREM-1. Our results show that activation signals delivered via DAP12 can be counterbalanced by the adaptor NTAL, identifying NTAL as gatekeeper of TREM-1/DAP12-induced signaling in myeloid cells.
- Published
- 2007
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35. Dendritic cells sensitize TCRs through self-MHC-mediated Src family kinase activation.
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Meraner P, Horejsí V, Wolpl A, Fischer GF, Stingl G, and Maurer D
- Subjects
- Antigen Presentation immunology, Antigen-Antibody Complex immunology, Antigen-Antibody Complex metabolism, Autoimmunity, Cell Line, Transformed, Dendritic Cells enzymology, Enzyme Activation immunology, Histocompatibility Antigens Class II metabolism, Humans, Lymphocyte Specific Protein Tyrosine Kinase p56(lck) metabolism, Peptides immunology, Peptides metabolism, Proto-Oncogene Proteins c-fyn metabolism, Receptors, Antigen, T-Cell metabolism, T-Lymphocytes metabolism, Dendritic Cells immunology, Histocompatibility Antigens Class II immunology, Lymphocyte Specific Protein Tyrosine Kinase p56(lck) immunology, Proto-Oncogene Proteins c-fyn immunology, Receptors, Antigen, T-Cell immunology, T-Lymphocytes immunology
- Abstract
It is unclear whether peptide-MHC class II (pMHC) complexes on distinct types of APCs differ in their capacity to trigger TCRs. In this study, we show that individual cognate pMHC complexes displayed by dendritic cells (DCs), as compared with nonprofessional APCs, are far better in productively triggering Ag-specific TCRs independently of conventional costimulation. As we further show, this is accomplished by the unique ability of DCs to robustly activate the Src family kinases (SFKs) Lck and Fyn in T cells even in the absence of cognate peptide. Instead, this form of SFK activation depends on interactions of DC-displayed MHC with TCRs of appropriate restriction, suggesting a central role of self-pMHC recognition. DC-mediated SFK activation leads to "TCR licensing," a process that dramatically increases sensitivity and magnitude of the TCR response to cognate pMHC. Thus, TCR licensing, besides costimulation, is a main mechanism of DCs to present Ag effectively.
- Published
- 2007
- Full Text
- View/download PDF
36. Transmembrane adaptor molecules: a new category of lymphoid-cell markers.
- Author
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Tedoldi S, Paterson JC, Hansmann ML, Natkunam Y, Rüdiger T, Angelisova P, Du MQ, Roberton H, Roncador G, Sanchez L, Pozzobon M, Masir N, Barry R, Pileri S, Mason DY, Marafioti T, and Horejsí V
- Subjects
- B-Lymphocytes chemistry, B-Lymphocytes pathology, Biomarkers analysis, Humans, Immunohistochemistry, Immunophenotyping, Lymphocytes pathology, Lymphoma diagnosis, Prognosis, T-Lymphocytes chemistry, T-Lymphocytes pathology, Adaptor Proteins, Signal Transducing analysis, Lymphocytes chemistry, Lymphoma chemistry, Lymphoma classification, Membrane Proteins analysis
- Abstract
Transmembrane adaptor proteins (of which 7 have been identified so far) are involved in receptor signaling in immune cells. They have only a short extracellular region, with most of the molecule comprising a substantial intracytoplasmic region carrying multiple tyrosine residues that can be phosphorylated by Src- or Syk-family kinases. In this paper, we report an immunohistologic study of 6 of these molecules in normal and neoplastic human tissue sections and show that they are restricted to subpopulations of lymphoid cells, being present in either T cells (LAT, LIME, and TRIM), B cells (NTAL), or subsets of both cell types (PAG and SIT). Their expression in neoplastic lymphoid cells broadly reflects that of normal lymphoid tissue, including the positivity of plasma cells and myeloma/plasmacytoma for LIME, NTAL, PAG, and SIT. However, this study also revealed some reactions that may be of diagnostic/prognostic value. For example, lymphocytic lymphoma and mantle-cell lymphoma showed similar profiles but differed clearly from follicle-center lymphoma, whereas PAG tended to be selectively expressed in germinal center-derived subsets of diffuse large B-cell lymphoma. These molecules represent a potentially important addition to the panel of immunophenotypic markers detectable in routine biopsies that can be used in hematopathologic studies.
- Published
- 2006
- Full Text
- View/download PDF
37. CD molecules 2005: human cell differentiation molecules.
- Author
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Zola H, Swart B, Nicholson I, Aasted B, Bensussan A, Boumsell L, Buckley C, Clark G, Drbal K, Engel P, Hart D, Horejsí V, Isacke C, Macardle P, Malavasi F, Mason D, Olive D, Saalmueller A, Schlossman SF, Schwartz-Albiez R, Simmons P, Tedder TF, Uguccioni M, and Warren H
- Subjects
- Antigens, CD immunology, Cell Differentiation, Humans, Reproducibility of Results, Antigens, CD classification, Terminology as Topic
- Abstract
The immune system works through leukocytes interacting with each other, with other cells, with tissue matrices, with infectious agents, and with other antigens. These interactions are mediated by cell-surface glycoproteins and glycolipids. Antibodies against these leukocyte molecules have provided powerful tools for analysis of their structure, function, and distribution. Antibodies have been used widely in hematology, immunology, and pathology, and in research, diagnosis, and therapy. The associated CD nomenclature is commonly used when referring to leukocyte surface molecules and antibodies against them. It provides an essential classification for diagnostic and therapeutic purposes. The most recent (8th) Workshop and Conference on Human Leukocyte Differentiation Antigens (HLDA), held in Adelaide, Australia, in December 2004, allocated 95 new CD designations and made radical changes to its aims and future operational strategy in order to maintain its relevance to modern human biology and clinical practice.
- Published
- 2005
- Full Text
- View/download PDF
38. The CD85J/leukocyte inhibitory receptor-1 distinguishes between conformed and beta 2-microglobulin-free HLA-G molecules.
- Author
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Gonen-Gross T, Achdout H, Arnon TI, Gazit R, Stern N, Horejsí V, Goldman-Wohl D, Yagel S, and Mandelboim O
- Subjects
- Cell Line, Transformed, Cell Line, Tumor, HLA-G Antigens, Humans, Killer Cells, Natural physiology, Leukocyte Immunoglobulin-like Receptor B1, Papain, Antigens, CD physiology, HLA Antigens metabolism, Histocompatibility Antigens Class I metabolism, Receptors, Immunologic physiology, beta 2-Microglobulin metabolism
- Abstract
For a proper development of the placenta, maternal NK cells should not attack the fetal extravillous cytotrophoblast cells. This inhibition of maternal NK cells is partially mediated via the nonclassical MHC class I molecule HLA-G. Recently, we demonstrated that HLA-G forms disulfide-linked high molecular complexes on the surface of transfected cells. In the present study, we demonstrate that HLA-G must associate with beta(2)m for its interaction with CD85J/leukocyte Ig-like receptor-1 (LIR-1). Although HLA-G free H chain complexes are expressed on the surface, they are not recognized and possibly interfere with CD85J/LIR-1 and HLA-G interaction. The formation of these complexes on the cell surface might represent a novel mechanism developed specifically by the HLA-G protein aimed to control the efficiency of the CD85J/LIR-1-mediated inhibition. We also show that endogenous HLA-G complexes are expressed on the cell surface. These findings provide novel insights into the delicate interaction between extravillous cytotrophoblast cells and NK cells in the decidua.
- Published
- 2005
- Full Text
- View/download PDF
39. Expression pattern of adaptor protein PAG: correlation between secondary lymphatic follicle and histogenetically related malignant lymphomas.
- Author
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Svec A, Velenská Z, and Horejsí V
- Subjects
- Adaptor Proteins, Signal Transducing, B-Lymphocytes pathology, CSK Tyrosine-Protein Kinase, Cell Differentiation, Cell Proliferation, Germinal Center pathology, Humans, Lymphoma, Follicular pathology, Lymphoma, Mantle-Cell metabolism, Lymphoma, Mantle-Cell pathology, Phosphotransferases metabolism, Protein-Tyrosine Kinases, Proto-Oncogene Proteins metabolism, src-Family Kinases, B-Lymphocytes metabolism, Biomarkers, Tumor biosynthesis, Gene Expression Regulation, Leukemic, Germinal Center metabolism, Lymphoma, Follicular metabolism, Membrane Proteins biosynthesis, Phosphoproteins biosynthesis
- Abstract
Transmembrane adaptor protein PAG, also known as Csk-binding protein (Cbp), which binds and activates the cytoplasmic tyrosine kinase Csk, the major negative regulator of Src-family kinases, was found to be expressed in germinal centers of lymphoid follicles as well as in follicular, but not mantle cell lymphomas. Expression of PAG may reflect its role in regulation of proliferation and differentiation of germinal center B-cells. From the routine histopathology point of view, PAG might be a new positive marker of follicular lymphoma and a negative marker of mantle cell lymphoma.
- Published
- 2005
- Full Text
- View/download PDF
40. Non-lineage antigens: section report.
- Author
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Horváth O, Drbel K, Angelisová P, Hilgert I, and Horejsí V
- Subjects
- Antibodies, Monoclonal immunology, Antibody Specificity, Cell Line, Humans, Lymphocyte Activation, Thymus Gland cytology, Thymus Gland immunology, Antigens, CD analysis, Lymphocytes immunology
- Abstract
Non-lineage section studied in total 90 mAb samples, including 23 submitted as known CD specificities. Thirty four samples submitted as unknown and potentially novel specificities recognized actually well known molecules (HLA class I, CD7, 11b, 14, 18, 44, 45, 45RB, 47, 59, 62L, 71, 82, 147). Seven samples reacted with newly defined CD molecules (CD281, 282, 284, 298, 315, 316, 321) and specificities of 12 samples remained unresolved.
- Published
- 2005
- Full Text
- View/download PDF
41. Lipid rafts and their roles in T-cell activation.
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Horejsí V
- Subjects
- Humans, Membrane Microdomains chemistry, Receptors, Antigen, T-Cell physiology, Signal Transduction physiology, Lymphocyte Activation physiology, Membrane Microdomains physiology, T-Lymphocytes physiology
- Abstract
Lipid rafts are defined as detergent-resistant membrane microdomains of specific lipid and protein composition. They are involved in many aspects of cell biology, including T-cell activation and immunoreceptor signaling. This review discusses current controversies around lipid rafts and summarizes recent developments in the area.
- Published
- 2005
- Full Text
- View/download PDF
42. Grb2 and the non-T cell activation linker NTAL constitute a Ca(2+)-regulating signal circuit in B lymphocytes.
- Author
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Stork B, Engelke M, Frey J, Horejsí V, Hamm-Baarke A, Schraven B, Kurosaki T, and Wienands J
- Subjects
- Animals, Base Sequence, Carrier Proteins physiology, Cells, Cultured, Chickens, GRB2 Adaptor Protein, Membrane Microdomains metabolism, Molecular Sequence Data, Phospholipase C gamma, Phosphoproteins physiology, Signal Transduction, Type C Phospholipases physiology, Adaptor Proteins, Signal Transducing physiology, B-Lymphocytes metabolism, Calcium metabolism
- Abstract
Activation of the B cell antigen receptor triggers phosphorylation of cytoplasmic and transmembrane adaptor proteins such as SLP-65 and NTAL, respectively. Specific phosphoacceptor sites in SLP-65 serve as docking sites for Ca(2+)-mobilizing enzymes Btk and PLC-gamma2. Phosphorylated NTAL recruits the Grb2 linker, but downstream signaling cascades are unclear. We now show that receptor-induced tyrosine phosphorylation of NTAL and concomitant Grb2 complex formation critically modulate the Ca(2+) response without affecting SLP-65 and PLC-gamma2 phosphorylation. Grb2 turned out to play a negative regulatory role, which appears to be eliminated upon binding to NTAL. This allows for a sustained release of intracellular Ca(2+) and is mandatory for subsequent entry of Ca(2+) from extracellular sources. Thus, elevation of Ca(2+) is regulated by at least two signaling modules, the B cell-specific Ca(2+) initiation complex comprising SLP-65, Btk, and PLC-gamma2 and the more ubiquitously expressed NTAL/Grb2 complex, which acts as an amplifier by switching off inhibitory elements.
- Published
- 2004
- Full Text
- View/download PDF
43. Negative regulation of mast cell signaling and function by the adaptor LAB/NTAL.
- Author
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Volná P, Lebduska P, Dráberová L, Símová S, Heneberg P, Boubelík M, Bugajev V, Malissen B, Wilson BS, Horejsí V, Malissen M, and Dráber P
- Subjects
- Adaptor Proteins, Signal Transducing physiology, Animals, Calcium metabolism, Cell Degranulation, Membrane Proteins physiology, Mice, Phosphatidylinositol 3-Kinases physiology, Phospholipase C gamma, Phosphoproteins physiology, Phosphorylation, Receptors, IgE physiology, Type C Phospholipases metabolism, Tyrosine metabolism, Adaptor Proteins, Vesicular Transport physiology, Mast Cells physiology, Proteins physiology, Signal Transduction
- Abstract
Engagement of the Fcepsilon receptor I (FcepsilonRI) on mast cells and basophils initiates signaling pathways leading to degranulation. Early activation events include tyrosine phosphorylation of two transmembrane adaptor proteins, linker for activation of T cells (LAT) and non-T cell activation linker (NTAL; also called LAB; a product of Wbscr5 gene). Previous studies showed that the secretory response was partially inhibited in bone marrow-derived mast cells (BMMCs) from LAT-deficient mice. To clarify the role of NTAL in mast cell degranulation, we compared FcepsilonRI-mediated signaling events in BMMCs from NTAL-deficient and wild-type mice. Although NTAL is structurally similar to LAT, antigen-mediated degranulation responses were unexpectedly increased in NTAL-deficient mast cells. The earliest event affected was enhanced tyrosine phosphorylation of LAT in antigen-activated cells. This was accompanied by enhanced tyrosine phosphorylation and enzymatic activity of phospholipase C gamma1 and phospholipase C gamma2, resulting in elevated levels of inositol 1,4,5-trisphosphate and free intracellular Ca2+. NTAL-deficient BMMCs also exhibited an enhanced activity of phosphatidylinositol 3-OH kinase and Src homology 2 domain-containing protein tyrosine phosphatase-2. Although both LAT and NTAL are considered to be localized in membrane rafts, immunogold electron microscopy on isolated membrane sheets demonstrated their independent clustering. The combined data show that NTAL is functionally and topographically different from LAT.
- Published
- 2004
- Full Text
- View/download PDF
44. Transmembrane adaptor proteins: organizers of immunoreceptor signalling.
- Author
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Horejsí V, Zhang W, and Schraven B
- Subjects
- Animals, Carrier Proteins metabolism, Humans, Membrane Proteins metabolism, Phosphoproteins metabolism, Proteins metabolism, Signal Transduction physiology, Adaptor Proteins, Signal Transducing, Adaptor Proteins, Vesicular Transport immunology, Membrane Proteins immunology, Receptors, Immunologic immunology, Signal Transduction immunology
- Published
- 2004
- Full Text
- View/download PDF
45. Amino acids at the N- and C-termini of human glutamate carboxypeptidase II are required for enzymatic activity and proper folding.
- Author
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Barinka C, Mlcochová P, Sácha P, Hilgert I, Majer P, Slusher BS, Horejsí V, and Konvalinka J
- Subjects
- Amino Acids chemistry, Animals, Antigens, Surface chemistry, Base Sequence, Blotting, Western, Catalysis, DNA Primers, Electrophoresis, Polyacrylamide Gel, Glutamate Carboxypeptidase II chemistry, Humans, Amino Acids metabolism, Antigens, Surface metabolism, Glutamate Carboxypeptidase II metabolism, Protein Folding
- Abstract
Human glutamate carboxypeptidase II (GCPII) is a co-catalytic metallopeptidase and its putative catalytic domain is homologous to the aminopeptidases from Vibrio proteolyticus and Streptomyces griseus. In humans, the enzyme is expressed predominantly in the nervous system and the prostate. The prostate form, termed prostate-specific membrane antigen, is overexpressed in prostate cancer and is used as a diagnostic marker of the disease. Inhibition of the form of GCPII expressed in the central nervous system has been shown to protect against ischemic injury in experimental animal models. Human GCPII consists of 750 amino acids, and six individual domains were predicted to constitute the protein structure. Here, we report the analysis of the contribution of these putative domains to the structure/function of recombinant human GCPII. We cloned 13 mutants of human GCPII that are truncated or extended at one or both the N- and C-termini of the GCPII sequence. The clones were used to generate stably transfected Drosophila Schneider's cells, and the expression and carboxypeptidase activities of the individual protein products were determined. The extreme C-terminal region of human GCPII was found to be critical for the hydrolytic activity of the enzyme. The deletion of as few as 15 amino acids from the C-terminus was shown to completely abolish the enzymatic activity of GCPII. Furthermore, the GCPII carboxypeptidase activity was abrogated upon removal of more than 60 amino acid residues from the N-terminus of the protein. Overall, these results clearly show that amino acid segments at the N- and C-termini of the ectodomain of GCPII are essential for its carboxypeptidase activity and/or proper folding.
- Published
- 2004
- Full Text
- View/download PDF
46. Transmembrane adaptor proteins in membrane microdomains: important regulators of immunoreceptor signaling.
- Author
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Horejsí V
- Subjects
- Adaptor Proteins, Signal Transducing immunology, Animals, Humans, Intercellular Signaling Peptides and Proteins, Membrane Proteins immunology, Mice, Phosphoproteins immunology, Rats, Adaptor Proteins, Vesicular Transport immunology, Membrane Microdomains immunology, Receptors, Immunologic immunology, Signal Transduction immunology
- Abstract
Membrane microdomains enriched in glycosphingolipids, cholesterol, glycosylphosphatidylinositol-anchored proteins and Src-family kinases (lipid rafts, GEMs) appear to play many important roles, especially in immunoreceptor signaling. Most transmembrane proteins are excluded from these specialized areas of membranes, notable exceptions being several palmitoylated proteins such as the T cell coreceptors CD4 and CD8, and several recently described transmembrane adaptor proteins, LAT, non-T cell activation linker (NTAL)/linker for activation of B cells (LAB), phosphoprotein associated with GEMs (PAG)/Csk-binding protein (Cbp) and LIME. All these molecules possess a very short N-terminal extracellular peptide (4-17 amino acids), transmembrane segment followed by a palmitoylation motif (CxxC) and cytoplasmic domain containing up to 10 tyrosine residues potentially phosphorylated by the Src- or Syk-family kinases. Tyrosine-phosphorylated transmembrane adaptors bind (directly via SH2 domains or indirectly) other signaling molecules such as several cytoplasmic adaptors and enzymes. LAT is indispensable for TCR signaling (and participates also at signal transduction initiated by some other receptors), NTAL/LAB appears to play a LAT-like role in signaling initiated by BCR and some Fc-receptors; PAG/Cbp cooperates with Csk, the cytoplasmic tyrosine kinase negatively regulating Src-family kinases. Additional transmembrane adaptors exist (TRIM, SIT, LAX) that are however not palmitoylated and therefore excluded from the lipid rafts; structurally and functionally, the zeta-chain family proteins tightly associated with immunoreceptors and activating NK-receptors may be also considered as transmembrane adaptors.
- Published
- 2004
- Full Text
- View/download PDF
47. LIME: a new membrane Raft-associated adaptor protein involved in CD4 and CD8 coreceptor signaling.
- Author
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Brdicková N, Brdicka T, Angelisová P, Horváth O, Spicka J, Hilgert I, Paces J, Simeoni L, Kliche S, Merten C, Schraven B, and Horejsí V
- Subjects
- Adaptor Proteins, Vesicular Transport genetics, Adaptor Proteins, Vesicular Transport metabolism, Amino Acid Sequence, CSK Tyrosine-Protein Kinase, DNA, Complementary, Databases, Protein, Humans, Lymphocyte Specific Protein Tyrosine Kinase p56(lck) metabolism, Molecular Sequence Data, Phosphorylation, Protein-Tyrosine Kinases metabolism, src-Family Kinases, Adaptor Proteins, Vesicular Transport immunology, CD4 Antigens immunology, CD8 Antigens immunology, Membrane Microdomains immunology
- Abstract
Lymphocyte membrane rafts contain molecules critical for immunoreceptor signaling. Here, we report identification of a new raft-associated adaptor protein LIME (Lck-interacting molecule) expressed predominantly in T lymphocytes. LIME becomes tyrosine phosphorylated after cross-linking of the CD4 or CD8 coreceptors. Phospho-LIME associates with the Src family kinase Lck and its negative regulator, Csk. Ectopic expression of LIME in Jurkat T cells results in an increase of Csk in lipid rafts, increased phosphorylation of Lck and higher Ca2+ response to CD3 stimulation. Thus, LIME appears to be involved in regulation of T cell activation by coreceptors.
- Published
- 2003
- Full Text
- View/download PDF
48. Special organization of the HLA-G protein on the cell surface.
- Author
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Gonen-Gross T, Gazit R, Achdout H, Hanna J, Mizrahi S, Markel G, Horejsí V, and Mandelboim O
- Subjects
- Animals, Antigens, CD genetics, Antigens, CD immunology, COS Cells, Cell Line, Transformed, Cell Line, Tumor, Chlorocebus aethiops, HLA Antigens genetics, HLA-G Antigens, Histocompatibility Antigens Class I genetics, Humans, Leukocyte Immunoglobulin-like Receptor B1, Macromolecular Substances, Microscopy, Confocal, Receptors, Immunologic genetics, Receptors, Immunologic immunology, Recombinant Fusion Proteins metabolism, Solubility, Transfection, Antigens, CD metabolism, Cell Membrane immunology, HLA Antigens metabolism, Histocompatibility Antigens Class I metabolism, Receptors, Immunologic metabolism
- Abstract
The human leukocyte antigen G (HLA-G) molecule possesses unique properties such as low polymorphism and restricted distribution mainly to the extravillous cytotrophoblast (EVT) cells. The EVT cells vigorously penetrate into the maternal decidual tissues and are found in contact with maternal lymphocytes, mainly with natural killer (NK) cells. The HLA-G molecule inhibits the effector function of maternal NK cells via interaction with the KIR2DL4 and the ILT-2 inhibitory NK receptors. Previously, we have demonstrated that complexes of the HLA-G protein are expressed on the cell surface. We reported that these complexes are formed due to the presence of two unique cysteine residues located at positions 42 and 147. Finally, we demonstrated that efficient binding and function of ILT-2 is dependent on the presence of HLA-G complexes on the cell surface. Here we expand the significance of these observations by revealing that complexes of HLA-G are present on the cell surface using different assays and cell lines and further demonstrate that complexes of HLA-G might be present in a soluble form after interaction with ILT-2. Therefore, the HLA-G molecule has developed a special mechanism to increase the avidity of NK receptors to the HLA-G molecule, which provides better protection for the fetus from maternal NK rejection.
- Published
- 2003
- Full Text
- View/download PDF
49. A novel monoclonal reagent recognizing native and denatured Vbeta5.3-related chains of human T cell receptor.
- Author
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Pavlistová D, Drbal K, Hilgert I, and Horejsí V
- Subjects
- Animals, Cell Line, Cells, Cultured, Chromatography, Affinity, Humans, Mice, Protein Denaturation, Receptors, Antigen, T-Cell, alpha-beta chemistry, Receptors, Antigen, T-Cell, alpha-beta immunology, Antibodies, Monoclonal immunology, Receptors, Antigen, T-Cell chemistry, Receptors, Antigen, T-Cell immunology
- Abstract
Monoclonal antibodies to specific families of TCR variable domains serve as highly useful immunochemical tools for basic research in T-cell biology and diagnosis of autoimmune diseases. Monoclonal antibody MEM-262 characterized in this communication recognizes beta chains of the TCR expressed by HPB-ALL cell line (carrying Vbeta5.3) and a small subset of peripheral blood T cells. This subset is larger than that recognized by a previously described Vbeta5.3-specific mAb. MEM-262 potently stimulates selective expansion of the T-cell subset, efficiently immunoisolates native TCR complexes as well as free beta chains and uniquely recognizes denatured TCRbeta chains under the conditions of Western blotting.
- Published
- 2003
- Full Text
- View/download PDF
50. Complexes of HLA-G protein on the cell surface are important for leukocyte Ig-like receptor-1 function.
- Author
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Gonen-Gross T, Achdout H, Gazit R, Hanna J, Mizrahi S, Markel G, Goldman-Wohl D, Yagel S, Horejsí V, Levy O, Baniyash M, and Mandelboim O
- Subjects
- Amino Acid Sequence, Animals, Antigens, CD metabolism, Binding, Competitive genetics, Binding, Competitive immunology, Cell Line, Transformed, Cysteine genetics, Cysteine physiology, Cytotoxicity, Immunologic genetics, Decidua cytology, Decidua immunology, Down-Regulation genetics, Down-Regulation immunology, Female, HLA Antigens biosynthesis, HLA Antigens genetics, HLA Antigens metabolism, HLA-G Antigens, Histocompatibility Antigens Class I biosynthesis, Histocompatibility Antigens Class I genetics, Histocompatibility Antigens Class I metabolism, Humans, Leukocyte Immunoglobulin-like Receptor B1, Macromolecular Substances, Membrane Glycoproteins biosynthesis, Membrane Glycoproteins genetics, Membrane Glycoproteins metabolism, Molecular Sequence Data, Mutagenesis, Site-Directed, Protein Binding genetics, Protein Binding immunology, Rats, Receptors, Immunologic antagonists & inhibitors, Receptors, Immunologic metabolism, Transfection, Tumor Cells, Cultured, Antigens, CD physiology, HLA Antigens physiology, Histocompatibility Antigens Class I physiology, Membrane Glycoproteins physiology, Receptors, Immunologic physiology
- Abstract
The nonclassical class I MHC molecule HLA-G is selectively expressed on extravillous cytotrophoblast cells at the maternal-fetal interface during pregnancy. HLA-G can inhibit the killing mediated by NK cells via interaction with the inhibitory NK cell receptor, leukocyte Ig-like receptor-1 (LIR-1). Comparison of the sequence of the HLA-G molecule to other class I MHC proteins revealed two unique cysteine residues located in positions 42 and 147. Mutating these cysteine residues resulted in a dramatic decrease in LIR-1 Ig binding. Accordingly, the mutated HLA-G transfectants were less effective in the inhibition of NK killing and RBL/LIR-1 induced serotonin release. Immunoprecipitation experiments demonstrated the involvement of the cysteine residues in the formation of HLA-G protein oligomers on the cell surface. The cysteine residue located at position 42 is shown to be critical for the expression of such complexes. These oligomers, unique among the class I MHC proteins, probably bind to LIR-1 with increased avidity, resulting in an enhanced inhibitory function of LIR-1 and an impaired killing function of NK cells.
- Published
- 2003
- Full Text
- View/download PDF
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