The Experts below are selected from a list of 21 Experts worldwide ranked by ideXlab platform
Jeremiah E. Silbert - One of the best experts on this subject based on the ideXlab platform.
-
Organization of glycosaminoglycan sulfation in the biosynthesis of Proteochondroitin Sulfate and proteodermatan Sulfate
Glycoconjugate Journal, 1996Co-Authors: Jeremiah E. SilbertAbstract:Although the intermediates for sulfation of Proteochondroitin and proteodermatan have been known for several decades, organizational aspects of this formation have not been clearly defined. Work in several laboratories, including our own, have indicated a pattern which strongly suggests that sulfation ordinarily takes place together with glycosaminoglycan polymerization in the same Golgi sites, and with close relationship to aspects of polymer elongation, polymer modification and polymer termination. the organization of sulfation together with polymerization may be a major factor controlling the location, type, and degree of sulfation, which in turn may direct specific functions of these proteoglycans.
-
relationship of sulfation to glycosaminoglycan polymerization in biosynthesis of Proteochondroitin Sulfate
Trends in Glycoscience and Glycotechnology, 1991Co-Authors: Jeremiah E. Silbert, 山田 修平, 菅原 一幸Abstract:プロテオコンドロイチンのグリコサミノグリカン部分の生合成の順序、グリコサミノグリカンの硫酸化、生合成中間体に関する相当量の情報が得られている。しかしながら、糖鎖の重合化 (polymerization) と硫酸化 (sulfetion) の二つの段階の関係は明白にはされていない。我々の研究室も含めいくつかの研究室での仕事は、硫酸化は重合化とともにゴルジ体の単一の部位で起こり、硫酸化、鎖の伸長及び終了の間には密接な相互関係があることを強く示唆している。これらの相互関係は、プロテオコンドロイチン硫酸の特異的な機能を決定しうる硫酸化の糖鎖上の位置と糖残基上の部位における多様性を制御している可能性がある。
-
subfractionation of chick embryo epiphyseal cartilage golgi localization of enzymes involved in the synthesis of the polysaccharide portion of Proteochondroitin Sulfate
Journal of Biological Chemistry, 1991Co-Authors: Geetha Sugumaran, Jeremiah E. SilbertAbstract:Membranes from chick embryo epiphyseal cartilage were fractionated by equilibrium sucrose density gradient centrifugation and assayed for galactosyl xylose transferase, chondroitin polymerization and sulfation as well as the marker enzymes glucose-6-phosphatase, NADH cytochrome c reductase, galactosyl ovalbumin transferase, and sialyltransferase. The order of distribution of chondroitin Sulfate synthesis from dense to light membranes correlated with the established sequence of events for its synthesis. The linkage region enzyme, viz. galactosyl xylose transferase, distributed with NADH cytochrome c reductase in an earlier and heavier cis compartment. Chondroitin polymerization and sulfation had a dual distribution similar to the galactosyl ovalbumin transferase and sialyltransferase in separate later and lighter medial and trans compartments, or in an extended medial or trans compartment. The galactosyl xylose transferase had a distribution distinctly different from that of the galactosyl ovalbumin transferase indicating that these distinct enzymes showed no cross-reactivity with their respective acceptor substrates. The dual distribution of chondroitin Sulfate synthesis was consistent with our previous demonstration of the two nascent Proteochondroitin populations produced by microsomal preparations from the same source. The results indicated separate subcellular locations for synthesis of the two forms.
Reinhard Schwartz-albiez - One of the best experts on this subject based on the ideXlab platform.
-
Modulated glycosylation of proteoglycans during differentiation of human B lymphocytes.
Biochimica et biophysica acta, 1995Co-Authors: Susanna Engelmann, Olaf Ebeling, Reinhard Schwartz-albiezAbstract:Proteoglycans are mediators of cellular adhesion and regulate growth factor activities. Proteoglycans of B lymphocytes undergo structural changes during B cell ontogeny which may correspond to the specific requirements of the respective microenvironment of the maturing cell. We analyzed three human B cell lines representing pre-B cells (Nalm-6), activated B cells (Jok-1) and plasma cells (U266) for their cellular proteoglycans. Gel filtration of the 35S-labeled macromolecules of the three cell lines revealed an increase in size in the order Nalm-6 < Jok-1 < U266. In Jok-1 and U266 cells the major pool of proteoglycans consisted of Proteochondroitin Sulfates of 50 to 90 kDa. These proteolglycans carried a protein core of approx. 30 kDa to which 1 to 3 glycosaminoglycan chains in the range of 28 to 32 kDa were attached. In Nalm-6 cells only free chondroitin Sulfate chains of 23 kDa, but no intact proteoglycans, were detected. Chondroitin Sulfate chains were predominantly composed of chondroitin-4-Sulfate, those of Nalm-6 and U266 cells additionally contained 10-20% of unSulfated disaccharides. In U266 cells 30% of glycosaminoglycans consisted of heparan Sulfate either bound to pure proteoheparan Sulfate or to chondroitin Sulfate/heparan Sulfate hybrid-proteoglycans. Earlier, syndecan-1 was described as a hybrid proteoglycan containing heparan Sulfate/chondroitin Sulfate chains which is transcribed by murine B cells at early and late maturation stages. In order to see whether syndecan is transcribed by the human B cell lines used here, we measured expression of syndecan mRNA by the reverse transcriptase polymerase chain reaction. Similar to murine lymphocytes, syndecan-specific mRNA was detected in Nalm-6 and U266 cells, equivalent to early and late B cells, but not in lymphoblastoid Jok-1 cells. However, Nalm-6 cells do not produce proteoheparan Sulfate. In these cells, syndecan synthesis may be blocked at the translational level. Also, the proteoglycans of U266 are different from syndecan-1 in their composition of glycosaminoglycans and in size of protein cores. Together, these results indicate that the major pool of proteoglycans produced by human B cells consists of Proteochondroitin Sulfate and additionally in later stages of a smaller proportion of proteoheparan Sulfate which is not identical to syndecan-1. During distinct phases of B cell differentiation, modulations in the glycosaminoglycan moiety concerning size and sulfation of glycosaminoglycan chains were also found.
Reinhard Schwartzalbiez - One of the best experts on this subject based on the ideXlab platform.
-
characterization of cell surface expressed Proteochondroitin Sulfate of pre b nalm 6 cells and its possible role in laminin adhesion
Leukemia, 1996Co-Authors: L Blase, A Merling, S Engelmann, P Moller, Reinhard SchwartzalbiezAbstract:Cell surface-expressed proteoglycans mediate contacts to extracellular matrix (ECM). Human B lymphocytes produce a species of a Proteochondroitin Sulfate (CSPG) with an approximate molecular mass of 135-150 kDa. Using a monoclonal antibody (mAb) against B cell CSPG in flow cytometry we found that this CSPG is expressed on tumor cells of patients with CD19 + common acute lymphoblastic leukemia and on the corresponding cell lines Nalm-6, Reh and KM3. The CSPG Is also present on hairy cell leukemia JOK-1 cells and weakly on the myeloma line U266. Concomitant with CSPG expression, Nalm-6 cells express the integrins α5/β1 (CD49e/CD29) and α6/β1 (CD49f/CD29), adhesion receptors for fibronectin and laminin, in contrast to the other two cell lines tested. Expression patterns of these adhesion receptors and CSPG were paralleled by strong adhesion of Nalm-6 to fibronectin and laminin. Adhesion of Nalm-6 to fibronectin was inhibited by the α5-specific antibody SAM 1 by 80% whereas the α6-specific antibody GoH3 reduced binding to laminin only by 20%. A possible involvement of surface-expressed CSPG in adhesion to ECM components was investigated by 24h incubation of Nalm-6 cells with p-nltrophenyl-β-D-xyloside, an inhibitor of proteoglycan glycosylation. By this treatment, both adhesion of Nalm-6 to laminin and expression of CSPG were reduced by 40-50%. Furthermore, addition of chondroitin-6-Sulfate, a structural element of Nalm-6 CSPG, reduced adhesion of Nalm-6 to laminin by 60%. Chondroitin-4-Sulfate, heparin and heparan Sulfate did not effectively inhibit the adhesion process. These observations suggest that surface-expressed CSPG may be involved in binding of Nalm-6 cells to laminin and that the specific sulfation pattern of chondroitin-6-Sulfate may be essential in this regard.
Geetha Sugumaran - One of the best experts on this subject based on the ideXlab platform.
-
subfractionation of chick embryo epiphyseal cartilage golgi localization of enzymes involved in the synthesis of the polysaccharide portion of Proteochondroitin Sulfate
Journal of Biological Chemistry, 1991Co-Authors: Geetha Sugumaran, Jeremiah E. SilbertAbstract:Membranes from chick embryo epiphyseal cartilage were fractionated by equilibrium sucrose density gradient centrifugation and assayed for galactosyl xylose transferase, chondroitin polymerization and sulfation as well as the marker enzymes glucose-6-phosphatase, NADH cytochrome c reductase, galactosyl ovalbumin transferase, and sialyltransferase. The order of distribution of chondroitin Sulfate synthesis from dense to light membranes correlated with the established sequence of events for its synthesis. The linkage region enzyme, viz. galactosyl xylose transferase, distributed with NADH cytochrome c reductase in an earlier and heavier cis compartment. Chondroitin polymerization and sulfation had a dual distribution similar to the galactosyl ovalbumin transferase and sialyltransferase in separate later and lighter medial and trans compartments, or in an extended medial or trans compartment. The galactosyl xylose transferase had a distribution distinctly different from that of the galactosyl ovalbumin transferase indicating that these distinct enzymes showed no cross-reactivity with their respective acceptor substrates. The dual distribution of chondroitin Sulfate synthesis was consistent with our previous demonstration of the two nascent Proteochondroitin populations produced by microsomal preparations from the same source. The results indicated separate subcellular locations for synthesis of the two forms.
Theodore R Oegema - One of the best experts on this subject based on the ideXlab platform.
-
mercuric salt catalyzed removal of unsaturated glucuronic acid from chondroitinase treated Proteochondroitin Sulfate
Archives of Biochemistry and Biophysics, 1997Co-Authors: Lata Sundaram, Laurel B Deloria, Theodore R OegemaAbstract:Abstract Aggrecan (PG) was isolated from Swarm rat chondrosarcoma and the chondroitin 4-Sulfate removed with chondroitinase ABC (ABC) or ACII (AC), leaving a 4-deoxy-β- d -gluc-4-enuronosyl (ΔGlcA) residue on the nonreducing terminus of the attached chondroitin Sulfate chains. Mercuric acetate (as low as 5 m m ) removed the ΔGlcA from the PG-ABC within 10 min at 25°C at pH 5.0, and the rate was pH independent between pH 3.0 and 5.0. The reaction was readily monitored by following the loss of reactivity to the monoclonal antibodies specific for 4-Sulfated and nonSulfated unsaturated disaccharides in ELISA. After mercury treatment, there was a loss of carbazole-positive material and a decrease in the size of the linkage region oligosaccharides consistent with ΔGlcA being removed. Aside from the loss of ΔGlcA, neutral sugar composition and sialic acid content remained unchanged. After electrophoresis in a 4% polyacrylamide gel, Hg-treated PG-ABC and PG-AC migrated as single major bands, but with reduced mobilities, which is consistent with a loss of charge. There was a loss of reactivity to specific monoclonal antibodies. Treated aggrecan did not bind hyaluronic acid. This loss was not completely prevented by being present in a complex with link protein and hyaluronic acid. However, link protein could partially restore the hyaluronic acid interaction, so the effect of mercuric acetate on biological function will have to be assessed on an individual basis. Treatment with mercuric acetate is an effective, rapid, reproducible way of removing ΔGlcA from both chondroitinase ABC and ACII-digested proteoglycan.
