Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 58-kDa Golgi protein (gp58) was previously identified and found to be concentrated in cis Golgi cisternae in several cell types (Saraste, J., Palade, G.E., and Farquhar, M.G. (1987) J. Cell Biol. 105, 2021-2029). In this study the protein was partially purified from rat pancreas and mouse myeloma cells in order to characterize its oligosaccharides. It migrated on sodium dodecyl sulfate-polyacrylamide gels as a 57-58-kDa doublet under reducing conditions or as a single approximately 116-kDa band under nonreducing conditions. Pancreatic gp58 was susceptible to alpha-N-acetylgalactosaminidase digestion and it bound concanavalin A, Helix pomatia, Dolichos biflorus, soybean agglutinin, and Bauhinia purpurea lectins, but not Ricinus communis agglutinin or lectins from Griffonia simplicifolia-1, Arachis hypogaea, and Limulus polyphemus. It bound Ricinus communis agglutinin after galactosylation with GlcNAc galactosyltransferase. These data demonstrate that pancreatic p58 contains immature N-linked moieties with nonreducing terminal GlcNAc residues as well as the initiating GalNAc of O-linked glycoproteins. Myeloma gp58 was sensitive to endo-beta-N-acetylglucosaminidase H, and oligosaccharide analysis of its [3H]glucosamine-labeled glycopeptides indicated that it also contained immature N-linked glycans. Some of the latter consist of high mannose chains (high affinity for concanavalin A, endo-beta-N-acetylglucosaminidase H-sensitive), but the predominant (95%) species are neutral tri- or tetraantennary N-linked chains containing GlcNAc (no binding to concanavalin A). Glycopeptides from biosynthetically labeled myeloma cells did not contain detectable base labile oligosaccharides, indicating that unlike pancreatic p58, myeloma gp58 may not be an O-linked glycoprotein. Neither pancreatic nor myeloma gp58 contained terminally processed oligosaccharides, indicating that gp58 has not been modified by trans-Golgi glycosyltransferases. Thus, the oligosaccharide content of gp58 is consistent with the assumption that this protein is retained in the cis Golgi cisternae during biosynthesis instead of being transported across the Golgi stacks and targeted back to the cis Golgi from the trans side.
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PMID:A 58-kDa resident protein of the cis Golgi cisterna is not terminally glycosylated. 189 39

The carbohydrate structures and the enzymatic basis for glycosylation of IgG by bone marrow plasma cells were determined in 7 patients with monoclonal gammopathy of undetermined significance and 22 patients with IgG MM. Lectin-binding analysis showed that in all cases of monoclonal gammopathy of undetermined significance and normal controls the IgG heavy chains bound to Ricinus communis agglutinin more strongly than to concanavalin A. In contrast, the IgG in 11 of the 17 advanced cases of MM (stages II and III) studied reacted to concanavalin A more strongly. Structural analysis showed that the reduced R. communis agglutinin binding capacity of these MM IgGs was due to hypogalactosylation of IgG. The galactosyltransferase and N-acetylglucosaminyltransferase III activities of the bone marrow myeloma cells from 5 MM cases were found to have a low enzyme activity ratio of galactosyltransferase to N-acetylglucosaminyltransferase III which reflects the hypogalactosylation. This indicates that the difference in the carbohydrate moieties observed in myeloma proteins is due to variations in the activities of the two glycosyltransferases.
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PMID:Carbohydrate analysis of immunoglobulin G myeloma proteins by lectin and high performance liquid chromatography: role of glycosyltransferases in the structures. 238 41

A galactosyltransferase-rich subcellular fraction and wheat germ agglutinin(WGA)-binding microsomal proteins from rat myeloma cells have been used to immunize BALB/c mice. Fusion of the corresponding spleen cells with the Sp2/0 mouse myeloma has lead to the production of hybridomas secreting monoclonal antibodies directed against four proteins of the Golgi complex (GC) and other smooth membranes (SM). Subcellular fractionation of myeloma cells and rat liver, Triton X-114 partitioning, protease treatment and lectin binding studies have permitted us to identify--by immunoblotting--the molecular weight of the proteins involved, their topology and their mode of association with membranes. Morphological analysis has been performed by immunocytochemistry at the light and electron microscopic level. Judging by these criteria, the GCII antigen is a protein of 44 kDa which is loosely associated with the endodomain of Golgi cisternae. GCIII is a detergent-binding glycoprotein of 130 kDa whose epitope is on the endodomain of Golgi cisternae. SMI is a detergent-binding glycoprotein of 58 to 90 kDa found at several stations along the endocytic path: in coated pits, coated vesicles, endocytic vesicles, but not in lysosomes. The epitope recognized by the corresponding antibody faces the ectodomain. When this antibody is added to living cells in culture, it is rapidly internalized. SMII is a detergent-binding glycoprotein of 140 kDa. The epitope recognized is restricted to membranes of Golgi complex cisternae and multivesicular bodies. These reagents should be useful for dissection and perturbation of vesicular traffic.
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PMID:Monoclonal antibodies as markers of the endocytic and secretory pathways. 244 92

The level of beta 1-4 galactosyltransferase activity was examined in a number of spontaneously, chemically, or virally transformed murine tumor cell lines. Increased levels of enzyme activity were observed for the murine myeloma cell line K181 and in vivo MOPC 104E. The Maloney Sarcoma Virus (MSV) transformed T-cell lymphoma, YC-8, also demonstrated elevated levels of enzyme activity when compared to a second independently MSV transformed T stem-cell lymphoma, LSTRA. Cell surface immunofluorescence was also detected in YC-8 with a monoclonal antibody for galactosyltransferase. The introduction of galactosyltransferase specific substrates, both in vivo and in vitro, led to the retardation of growth in the cell lines K181, MOPC 104E, and YC-8, but not in the cell line LSTRA; this suggests the selective growth control of transformed cells demonstrating elevated levels of galactosyltransferase.
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PMID:In vitro and in vivo growth control of transformed lymphoid cells expressing plasma membrane galactosyltransferase. 251 Jan 14

The rat myeloma cells chosen for study (IR202) are highly specialized toward the synthesis and secretion of immunoglobulin M (IgM). In [35S]methionine pulse-chase protocols the half-time for secretion of newly synthesized [35S]Ig at 37 degrees C is approximately 2 1/2 h. No degradation of [35S]Ig was detected in such experiments. Pulse-chase experiments with [3H]galactose show that addition of this terminal sugar occurs only approximately 2 min before discharge. The intracellular pool of Ig bearing mature oligosaccharides is therefore very small. Incubation at 20 degrees C stops secretion of the [35S]- and [3H]Ig. We describe a subcellular fractionation protocol for these cells which results in the recovery of a total microsomal fraction by gel filtration. This fraction includes approximately 1/4 of the galactosyltransferase and uridine diphosphatase (UDPase) of the homogenate. By employing two cytological Golgi markers (an "overosmicatable material" and UDPase), galactosyltransferase activity and [35S]methionine and [3H]galactose pulse-chase protocols with the chase at 15 degrees C we document the partial resolution of Golgi subcompartments in isopycnic sucrose gradients used to subfractionate the total microsomal fraction. Electron microscopic and enzymologic examination of the fractions resolved by these gradients confirm that rough microsomes are well separated from Golgi membranes and that the fractions most highly enriched in galactosyltransferase activity have a protein-based specific activity approximately 10 times that of the total microsomal fraction. These studies, therefore, form the basis for an analysis of the composition of the membranes of the Golgi Complex and document the location of proximal Golgi elements, as defined by cytological criteria, in isopycnic gradients.
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PMID:Biochemical, kinetic and cytochemical approaches resolve Golgi subcompartments of IgM-secreting rat myeloma cells. 274 93

We have previously reported that human B cell differentiation is accompanied by sequential changes in glycosphingolipid expression. Pre-B cells contain lacto-series type II chain-based glycolipids and GM3 ganglioside; mature/activated B cells do not synthesize lacto-series compounds but express GM3 and globo-series glycolipids (Gb3 and Gb4); terminally differentiated B cells, in addition to these compounds, also contain GM2 ganglioside. At the cell surface, Gb3, Gb4 and GM2 constitute stage-specific antigens. To elucidate the biosynthetic mechanism leading to these modifications we have compared activities of the glycosyltransferases involved in the core structure assembly and the first elongation steps of neo-lacto, ganglio- and globo-series glycolipids. These glycosyltransferase activities have been measured in B cell lines and normal B lymphocytes at various stages of differentiation. We first determined the optimal requirements of the four glycosyltransferases which synthesize Lc3, GM3, Gb4 and GM2 glycolipids in B lymphocytes and then tested these enzymes and the Gb3 synthetase in the selected B cells. The following results were obtained: beta 1-->3 N-Acetylglucosaminyltransferase (Lc3 synthetase) has a high activity in pro- and pre-B cells whereas it is undetectable in more differentiated cells; alpha 2-->3 sialytransferase (GM3 synthetase) is activated from the pre-B cell stage to the terminally differentiated myeloma cells; alpha 1-->4 galactosyltransferase (Gb3 synthetase) is only detected in cells representing the late stages of B cell differentiation; beta 1-->3 N-Acetylgalactosaminyltransferase (Gb4 synthetase) is only found in some lymphoblastoid cell lines, representative of activated B cells whereas the beta 1-->4 N-Acetylgalactosaminyltransferase (GM2 synthetase) has a high activity in these lymphoblastoid cell lines and in terminally differentiated myeloma cells. These results suggest that the sequential shifts in the three major glycosphingolipid series observed during B cell differentiation are mostly due to sequential activations of the corresponding glycosyltransferases.
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PMID:Sequential changes in glycolipid expression during human B cell differentiation: enzymatic bases. 781 47

Assay of the activity of beta-1,4-galactosyltransferase (beta-1,4-GT) revealed that in addition to serum, milk, colostrum, amniotic and cerebrospinal fluids and malignant effusions, this enzyme is present also in tears and saliva. Molecular-sieve chromatography of human colostral whey and serum and subsequent assay of beta-1,4-GT activity have shown that beta-1,4-GT was present as a free enzyme (55 kDa) and associated with components of larger molar mass. The elution pattern did not change when the chromatography was carried out in a buffer devoid of, or enriched with, Mn2+, a cofactor of beta-1,4-GT activity. However, the activity associated with the large molar mass components was absent when the chromatography was carried out in the presence of a chelating agent (EDTA). Analyses of the eluted material by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE), and by immunodiffusion indicated that the major colostral component in beta-1,4-GT activity-containing fractions was secretory IgA (S-IgA); in addition, the beta-1,4-GT activity was detected in fractions that contained lactoferrin and alpha-lactalbumin. Interactions of beta-1,4-GT with S-IgA and lactoferrin in colostrum were also demonstrated by the detection of radioactivity in precipitin lines obtained by immunoelectrophoresis and autoradiography of the colostral whey after it had been incubated with UDP-[3H]-galactose. Furthermore, radioactively labeled S-IgA and alpha-chain were detected when colostral whey incubated with UDP-[3H]-galactose was analyzed by SDS-PAGE under non-reducing and reducing conditions, respectively. In serum, the beta-1,4-GT-binding components identified in fractions after molecular-sieve chromatography were IgG, IgA, IgM and transferrin. The binding of beta-1,4-GT to immunoglobulins (Ig) was also demonstrated by assaying the beta-1,4-GT activity associated with Sepharose-4B-immobilized Ig of various isotypes and molecular forms, which were incubated with colostral beta-1,4-GT in the presence of Mn2+. Beta-1,4-GT measured by enzyme activity was bound to these Ig in order: polymeric IgA2 > monomeric IgA1 = polymeric IgA1 = secretory IgA = pentameric IgM > IgG. Immobilized component chains, namely alpha, mu and J chains, bound beta-1,4-GT more effectively than native Ig. Incubation of the IgA1 myeloma protein with crude human colostral galactosyltransferase in the presence of UDP[3H]-galactose and Mn2+ resulted in galactosylation of both N- and O-linked carbohydrate side chains.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Interactions of galactosyltransferase with serum and secretory immunoglobulins and their component chains. 843 6

IgM are glycoproteins secreted by plasma cells as (mu2L2)5+J or (mu2L2)6 polymers. In most species, mu- and J-chains bear five and one N -glycans, respectively. Here we compare the terminal glycosylation patterns of 4-hydroxy-3-nitrophenylacetyl (NP)-specific IgM secreted by transfectants of the J558L mouse myeloma deficient in the alpha2,6 sialyltransferase [alpha2,6ST(N)] or by a hybridoma expressing this enzyme (B1.8 cells). The absence of alpha2,6-sialylation results in an increased addition of alpha1, 3-galactosyl residues to mu- and J-chain N-glycans. Since alpha1, 3-galactosyltransferase (alpha1,3Gal-T) is similarly expressed in the two cell lines, these results indicate that a competition reaction occurs in vivo between alpha2,6ST(N) and alpha1,3Gal-T. In the alpha2,6ST(N) deficient transfectants, mu-chains lacking the C-subterminal Cys575 residue, which are secreted mainly in the form of mu2L2 monomers, are more efficiently capped by alpha1, 3-galactosyl residues, confirming that polymerization significantly reduces the accessibility of mu-chain glycans to the Golgi processing enzymes involved in the biogenesis of antennary sugars. Functional assays indicate that IgM sialylation affects antigen-binding and complement-dependent hemolysis of haptenated red blood cells.
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PMID:Differential expression of Galalpha1,3Gal epitope in polymeric and monomeric IgM secreted by mouse myeloma cells deficient in alpha2, 6-sialyltransferase. 963 16