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J C Michalski

Publications and source records attributed to J C Michalski.

At least 37 records · Page 2Linked to original sources
PubMed1996

Interleukin 2 is a lectin that associates its receptor with the T-cell receptor complex.

To determine the nature of the mechanism by which the binding of interleukin-2 (IL-2) to its receptor (IL-2R beta) induces IL-2R beta phosphorylation by the tyrosine kinase p56lck associated with the T-cell receptor (TCR) complex, we investigated the possibility that this mechanism was due to the putative lectin activity of IL-2 ([Sherblom, Sathyamoorthy, Decker and Muchmore (1989) J. Immunol. 143, 939-944]. Here we demonstrate that IL-2 is a calcium-independent lectin specific for oligomannosidic N-glycans with five and six mannose residues. This lectin activity is preserved after binding of IL-2 to IL-2R beta. IL-2 behaves as a bifunctional molecule that associates IL-2R beta with specific glycoprotein ligands of the TCR complex including a glycosylated form of CD3.

Carbohydrate Sequence↗
PubMed1996

Oligomannosides or oligosaccharide-lipids as potential substrates for rat liver cytosolic alpha-D-mannosidase.

We have previously reported the substrate specificity of the cytosolic alpha-D-mannosidase purified from rat liver using Man9GlcNAc, i.e. Man alpha 1-2Man alpha 1-3(Man alpha 1-2Man alpha 1-6)Man alpha 1-6(Man alpha 1-2Man alpha 1-2Man alpha 1-3) Man beta 1-4G1cNAc, as substrate [Grard, Saint-Pol, Haeuw, Alonso, Wieruszeski, Strecker and Michalski (1994) Eur. J. Biochem. 223, 99-106]. Man9 G1cNAc is hydrolysed giving Man5GlcNAc, i.e. Man alpha 1-2 Man alpha 1-2Man alpha 1-3(Man alpha 1-6)Man beta 1-4GlcNAc, possessing the same structure as the oligosaccharide of the dolichol pathway formed in the cytosolic compartment during the biosynthesis of N-glycosylprotein glycans. We study here the activity of the purified cytosolic alpha-D-mannosidase towards the oligosaccharide-diphosphodolichol intermediates formed during the biosynthesis of N-glycans, and also towards soluble oligosaccharides released from the endoplasmic reticulum which are glucosylated or not and possessing at their reducing end either a single N-acetylglucosamine residue or a di-N-acetylchitobiose sequence. We demonstrate that (1) dolichol pyrophosphate oligosaccharide substrates are poorly hydrolysed by the cytosolic alpha-D-mannosidase; (2) oligosaccharides with a terminal reducing di-N-acetylchitobiose sequence are not hydrolysed at all; (3) soluble oligosaccharides bearing a single reducing N-acetylglucosamine are the real substrates for the enzyme. These results suggest a role for alpha-D-mannosidase in the catabolism of glycans released from the endoplasmic reticulum rather than in the regulation of the biosynthesis of asparagine-linked oligosaccharides.

Animals↗
PubMed1996

Purification by cobalamin-Sepharose affinity chromatography and intrinsic factor-binding activity of an extramembrane proteolytic product from pig ileal mucosa.

We have purified a cobalamin-binding protein obtained by papain digestion of pig intestine by cobalamin-AH-Sepharose affinity chromatography, with a purification factor of 17,300, a yield of 63% and a cobalamin-binding activity of 11,260 pmol/mg of protein. The protein contained 3.8% carbohydrate and was O- and N-glycosylated. Its molecular mass was 69 kDa on SDS/PAGE and its isoelectric point was 5.1. It had a binding activity for both [57Co]cobalamin and [57Co]cobalamin-intrinsic factor in native PAGE autoradiography and it inhibited the binding of intrinsic factor to the intact intestinal receptor with an IC50 of 49.31 nmol/l in a radioisotope assay. In conclusion, the purified protein shared a binding activity for both cobalamin and intrinsic factor-cobalamin complexes and could correspond to the extracellular domain of the ileal intrinsic factor receptor.

Animals↗
PubMed1996

Structure of the phosphopeptidomannans from flocculent and non-flocculent yeast Kluyveromyces lactis.

After extraction from whole cells, and purification by gel filtration, the chemical composition and molecular mass estimation of the cell-wall phosphopeptidomannan (PPM) showed no significant difference respectively between flocculent, weakly, very weakly and non-flocculent Kluyveromyces lactis yeast strains. However, when PPMs were tested as ligands of a lectin, extracted from the flocculent strain, the PPM isolated from the flocculent and weakly flocculent strain were recognized to a higher degree than those isolated from the non and very weakly flocculent strains. Acetolysis of PPM extracted from the four strains produced five oligosaccharide fractions corresponding to mono-, di-, tri-, penta-and hexa-saccharides. The flocculent strain was characterised by a high content of di-and penta-saccharides. The 1H NMR analysis of the oligosaccharides demonstrated that the flocculent strain contained equivalent levels of the two mannobioses: Man(alpha 1-->2)Man and Man(alpha 1-->3)Man and of the two mannotrioses Man(alpha 1-->2)Man(alpha 1-->2)Man and Man(alpha 1-->3)Man(alpha 1-->2)Man. In contrast, the non-flocculent and the very weakly flocculent strains contained a single type of mannobiose Man(alpha 1-->2)Man and one type of mannotriose Man(alpha 1-->2)Man(alpha 1-->2)Man.

Acetylglucosamine↗
PubMed1996

Lectin activities of cytokines and growth factors: function and implications for pathology.

The discovery that certain cytokines have carbohydrate-binding (lectin) properties opens new concepts in the understanding of their mechanism of action. The carbohydrate-recognition domain, which is localized opposite to the receptor-binding domain, makes these molecules bi-functional. The expression of the biological activity of the cytokine relies on its carbohydrate-binding activity which allows the association of the cytokine receptor with molecular complexes comprising the specific kinase involved in receptor phosphorylation and in specific signal transduction. It is expected that blood accumulation of free or membrane-bound glucan ligands of cytokines may dramatically perturb their endogenous function inducing specific immunodeficiencies.

Acquired Immunodeficiency Syndrome↗
PubMed1995

First evidence of human meconium glycoasparagines.

During a systematic study of carbohydrate material present in human meconium, in addition to the previously described mucins, glycolipids and free oligosaccharides, we have now characterized a significant quantity of free glycoasparagines. These glycoasparagines have been isolated from human meconium by a combination of ion-exchange, concanavalin A (ConA)-affinity and high-performance liquid (HPLC) chromatographies. Their structures have been established by 400 MHz 1H-NMR spectroscopy. These compounds are related to N-acetyllactosaminic type structures and are based on the common core: [formula: see text] These glycoasparagines are probably derived from both protease and partial exoglycosidase hydrolysis of fetal gastrointestinal N-glycosyl proteins. Their structures are discussed in the context of the known catabolic pathways of N-glycans.

Amino Acids↗
PubMed1995

Catabolism of glycan moieties of lipid intermediates leads to a single Man5GlcNAc oligosaccharide isomer: a study with permeabilized CHO cells.

This paper presents kinetic and structural analyses of oligosaccharide material released during glycosylation in permeabilized Chinese hamster ovary cells incubated with sugar nucleotides. Permeabilized cells released 30 times more oligosaccharide material than metabolically labelled cells, normalized to the amount of labelled glycoprotein acceptor, making this an amenable system for study. Fifteen to forty per cent of the oligosaccharide material released by permeabilized cells was oligosaccharide-phosphate, depending on the nature and amount of the oligosaccharide-lipids synthesized. The oligosaccharide-phosphates released were recovered in the cytosol, and were exclusively Man2Glc-NAc2P and Man5GlcNAc2P, released from oligosaccharide-lipids thought to be facing the cytosol. In contrast, the structures found as neutral oligosaccharide material were similar to those attached to newly synthesized glycoproteins, indicating that the oligosaccharides were subjected to the same processing enzymes whether or not they were protein bound. Importantly, the kinetics of the transfer to protein and the release of free neutral oligosaccharide were parallel, suggesting that the same enzyme was responsible for both processes. Structural analyses demonstrated that the same Man5GlcNAc2 structure was transferred to protein and released as free oligosaccharide. Neutral oligosaccharides were found in both the cytosol and the pellet; however, oligosaccharides with one GlcNAc residue at the reducing end (OS-Gn1) were found exclusively in the supernate. The major neutral oligosaccharide produced after 2 h of metabolic labelling was Man5GlcNAc and it was found in the cytosol.

Animals↗
PubMed1994

Soluble forms of alpha-D-mannosidases from rat liver. Separation and characterization of two enzymic forms with different substrate specificities.

We have previously reported the substrate specificity of the rat liver cytosolic alpha-D-mannosidase [Haeuw, J. F., Strecker, G., Wieruszeski, J. M., Montreuil, J. & Michalski, J.-C. (1991) Eur. J. Biochem. 202, 1257-1268]. Here, we report the characterization and the purification of this alpha-D-mannosidase and the presence of two soluble forms of alpha-D-mannosidases from rat liver. The cytosolic alpha-D-mannosidase was purified nearly 660-fold with 2.66% recovery to a state approaching homogeneity using: (a) (NH4)2SO4 precipitation; (b) concanavalin-A-Sepharose chromatography; (c) affinity chromatography on a cobalt-chelating Sepharose column; (d) ion-exchange (DEAE-trisacryl M) column chromatography; (e) molecular-size chromatography (Sephacryl S 200). The enzyme was eluted from the final column at an apparent molecular mass of 113 kDa. SDS/PAGE analysis yielded a major protein band at 108 kDa. Moreover, the purification allowed to distinguish two mannosidase activities with different kinetic properties. The first cytosolic activity retained on the cobalt-chelating column was optimally active at neutral pH, was activated by Co2+, was strongly inhibited by swainsonine (Ki = 3.7 microM) but not by deoxymannojirimycin and was active with p-nitrophenyl alpha-D-mannoside (Km = 0.072 mM). Man9GlcNAc was hydrolysed by the purified enzyme down to a Man5GlcNAc structure, i.e. Man(alpha 1-2)Man(alpha 1-2)Man(alpha 1-3)[Man(alpha 1-6)]Man(beta 1-4) GlcNA c, which represents the Man5 oligosaccharide chain of the dolichol pathway formed in the cytosolic compartment during the biosynthesis of N-glycosylprotein glycans. The second activity not retained on the cobalt-chelating column was optimally active at neutral pH, was inhibited by swainsonine (Ki = 28.4 microM) but not by deoxymannojirimycin and was active with p-nitrophenyl alpha-D-mannoside (Km = 0.633 mM). Man9GlcNAc was broken by this enzymic activity down to Man8GlcNAc and Man7GlcNAc structures. Similitaries with endoplasmic reticulum alpha-D-mannosidase exist and this enzyme could be the cytosolic form of the endoplasmic reticulum alpha-D-mannosidase.

Animals↗
PubMed1994

Expression of beta 1-6-branched N-linked oligosaccharides is associated with activation in human T4 and T8 cell populations.

Activation of human T lymphocytes by phorbol 12-myristate 13-acetate and leukoagglutinin from Phaseolus vulgaris (L-PHA) results in important changes in N-glycosylation. The most important event is the increase, in both T4 and T8 cells (especially the latter), of L-PHA+ structures characterized by beta 1-6-branching of complex-type oligosaccharides. Moreover, the existence of a CD4-mediated increase of these beta 1-6-branched structures on positively selected T4 cells, as compared with the negatively selected ones, suggests that the presence of these structures, not detectable on T8 resting cells, could be related to stimulation events triggered by both selection methods. This beta 1-6-branching on N-glycans, strongly associated with a metastatic phenotype in human and rodent tumors, is exhibited by numerous glycoproteins on stimulated cells, as shown by blot analysis.

Antigens, CD↗
PubMed1994

The core-specific lysosomal alpha(1-6)-mannosidase activity depends on aspartamidohydrolase activity.

The substrate specificity of the core-specific rat liver lysosomal alpha(1-6)-mannosidase was investigated using mannosylated oligosaccharides and glycoasparagines. Hydrolysis of Man(alpha 1-6) linkage hydrolysis was demonstrated to follow the action of endoglycosidases, namely aspartyl-N-acetyl-beta-D-glucosaminidase and endo-N-acetyl-beta-D-glucosaminidase. The results are discussed with respect to the nature of the carbohydrate materials stored in the tissues and excreted in the urine from patients suffering from aspartylglucosaminuria and fucosidosis.

Acetylation↗
PubMed1993

Primary structure of human milk octa-, dodeca- and tridecasaccharides determined by a combination of 1H-NMR spectroscopy and fast-atom-bombardment mass spectrometry. Evidence for a new core structure, the para-lacto-N-octaose.

Two octasaccharides, two dodecasaccharides and a tridecasaccharide have been isolated from human milk by a combination of paper chromatography, high-performance liquid chromatography and high-performance anion-exchange chromatography. Their structural analysis investigated by 400-MHz 1H- and 13C-NMR spectroscopy and by mass spectrometry led to the following structures. [formula: see text] The two octasaccharides have been previously characterized in human milk; the complete assignment of the 1H and 13C spectra is reported here. One of the dodecasaccharides is a tetrafucosyl derivative with a new core: typeI-(beta 1-3)-typeII-(beta 1-3)-typeII-(beta 1-3)-Gal((beta 1-4)Glc, where typeI = Gal(beta 1-3)GlcNAc and typeII = Gal(beta 1-4)GlcNAc. These oligosaccharides display simultaneously Lewis(b) and Lewis(x) determinants or Lewis(a), Lewis(b) and Lewis(x) determinants.

Carbohydrate Conformation↗
PubMed1992

Complete 1H- and 13C-resonance assignments for D-mannooligosaccharides of the beta-D-(1-->2)-linked series released from the phosphopeptidomannan of Candida albicans VW.32 (serotype A).

D-Mannooligosaccharides (dp 1 to > 17) were released by mild acid hydrolysis from the phosphopeptidomannan of a Candida albicans strain of A serotype (VW.32). Among these, mannooligosaccharides ranging from bi- to hepta-ose, which were obtained in appreciable amounts, were structurally investigated and found to belong to the beta-D-(1-->2)-linked series. The occurrence of such compounds has already been reported in other Candida albicans strains. The complete 1H- and 13C-resonance assignments for manno-tri- to manno-hepta-ose are reported and general rules applicable for the 1NMR spectrum analysis of linear mannooligosaccharide of the general structure, beta-D-Man p-(1-->2)-[beta-D-Man p-(1-->2)]n-beta-D-Man p are proposed.

Acids↗
PubMed1992

1H-and 13C-n.m.r. spectroscopy of 2-oxo-3-deoxy-D-glycero-D- galactononulosonic acid-containing oligosaccharide-alditols bearing Lewis X, Lewis Y and A-Lewis Y determinants isolated from the jelly coat of Pleurodeles waltl eggs.

Three acidic oligosaccharide-alditols carrying Lewis X, Lewis Y and A-Lewis Y determinants were isolated from the jelly coat of Pleurodeles waltl eggs. These compounds possess the following structures. Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3[2-oxo-3-deoxy-D- glycero-D-galactononulosonic acid (KDN)alpha 2-6] GalNAc-ol; Fuc alpha 1-2Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3(KDN alpha 2-6) GalNAc-ol and Fuc alpha 1-2(GalNAc alpha 1-3)Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3(KDN alpha 2-6)GalNAc-ol. The complete 1H-n.m.r.-spectrum assignment for the three compounds and the 13C-n.m.r. analysis of the A-Lewis Y determinant-containing heptasaccharide are reported.

Animals↗
PubMed1992

Primary structure of neutral and acidic oligosaccharide-alditols derived from the jelly coat of the Mexican axolotl. Occurrence of oligosaccharides with fucosyl(alpha 1-3)fucosyl(alpha 1-4)-3-deoxy-D-glycero-D-galacto-nonulosonic acid and galactosyl(alpha 1-4)[fucosyl(alpha 1-2)]galactosyl(beta 1-4)-N-acetylglucosamine sequences.

Six major neutral and acidic oligosaccharide-alditols were prepared from the jelly coat of Mexican axolotl eggs. These compounds were demonstrated to contain 3-deoxy-D-glycero-D-galacto-nonulosonic acid (dNloA) and L-fucose (Fuc). The structures of the six major oligosaccharides were established as follows: [sequence: see text]

Ambystoma↗
PubMed1992

Comparative study of asparagine-linked glycans of plasma T-kininogen in normal rats and during acute inflammation.

Rat T-kininogen has been separated into two molecular variants by affinity chromatography on concanavalin A (ConA): a ConA-reactive (ConA+) and a ConA-non-reactive (ConA-) fraction, from which carbohydrate chains were quantitatively released by hydrazinolysis. On the basis of high-resolution 400 MHz 1H-n.m.r. spectroscopy of the re-N-acetylated hydrazinolysates, the carbohydrate structures of the two ConA molecular variants of rat T-kininogen were established. The ConA-non-reactive species contains a single type of carbohydrate chain with the following structure: [formula: see text] The ConA-reactive fraction contains the same structure and the following additional one: [formula: see text] The relative abundance of the two molecular forms is profoundly affected during inflammation (ratio ConA+/ConA-: 44% in normal and 95% in inflamed T-kininogen), but no structural modification of the carbohydrate chains was observed.

Animals↗
PubMed1992

Primary structure of four human milk octa-, nona-, and undeca-saccharides established by 1H- and 13C-nuclear magnetic resonance spectroscopy.

The structures of two octasaccharides, one nonasaccharide, and one undecasaccharide, isolated from human milk, have been investigated by 1H- and 13C-nuclear magnetic resonance spectroscopy. The structures of these oligosaccharides are: beta-D-Galp-(1----4)-[alpha-L-Fucp- (1----3)]-beta-D-GlcpNAc-(1----3)-beta-D-Galp-(1----4)-[alpha-L-Fucp+ ++- (1----3)]-beta-D-GlcpNAc-(1----3)-beta-D-Galp-(1----4)-D-Glc; beta-D-GALp-(1----3)-[alpha-L-Fucp-(1----4)]-beta-D-GlcpNAc-(1---- 3)-beta-D - Galp-(1----4)-[alpha-L-Fucp-(1----3)]-beta-D-GlcpNAc-(1----3)-beta -D-Galp- (1----4)-D-Glc; beta-D-Galp-(1----4)-[alpha-L-Fucp-(1----3)]-beta-D-GlcpNAc-(1---- 6)-(alpha - L-Fucp-(1----2)-beta-D-Gal-(1----3)-[alpha-L-Fucp-(1----4)]- beta-D-GlcpNAc- (1----3))-beta-D-Galp-(1----4)-D-Glc; and alpha-L-Fucp-(1----2)-beta-D-Galp-(1----3)-beta-D-GlcpNAc-(1----3) -beta-D- Galp-(1----4)-[alpha-L-Fucp-(1----3)]-beta-D-GlcpNAc-(1----6)-[alp ha-L- Fucp-(1----2)-beta-D-Galp-(1----3)-beta-D-GlcpNAc-(1----3)]-beta-D -Galp- (1----4)-D-Glc. The two octasaccharides have been previously isolated from human milk as a mixture, and in a pure form from new-born feces, but the n.m.r. data were not provided. These two octasaccharides display the di-Lewis X and the composite Lewis A-Lewis X antigenic determinant, previously described as neo-antigens of adenocarcinoma cell lines.

Carbohydrate Sequence↗
PubMed1992

Characterization of Le(x), Le(y) and A Le(y) antigen determinants in KDN-containing O-linked glycan chains from Pleurodeles waltlii jelly coat eggs.

Novel acidic oligosaccharides were isolated in large amounts by reductive alkaline treatment of the jelly coat of Pleurodeles waltlii (Michah) eggs. The oligosaccharides were found to contain the newly described KDN as acidic monosaccharide and possess either the Le(x), Le(y) and A Le(y) antigenic determinants. Occurrence of Le(x) and Le(y) determinants previously recognized as tumor-associated antigen (TAA) demonstrates that mucins of lower animals may represent a rich and easily available source for preparing TAA. Moreover, it reinforces the hypothesis according to which TAA are evolution markers.

Animals↗