Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17931 (galectin-3)
 2,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cytoplasmic tubulovesicular and canalicular membranes of gastric parietal cells are intimately involved in hydrochloric acid secretion. To characterise the glycoproteins of these membranes, we examined a panel of lectins for reactivity with parietal cells in paraffin sections of rat, dog and pig stomach. The poly-N-acetyllactosamine-specific lectin from Lycopersicon esculentum (tomato) and from Solanum tuberosum (potato), and the galactose-specific lectin Ricinus communis agglutinin (RCA120), showed strong cytoplasmic binding of parietal cells of all three species, with a pattern indicative of an intracellular membrane network. Binding to parietal cells was confirmed by double-labelling studies with parietal cell auto-antibodies from patients with autoimmune gastritis. Mucous cells and mucin also bound these lectins strongly. Other gastric cell types did not stain with either tomato or potato lectin, but stained weakly with RCA120. Electron-microscopic examination of lectin binding sites using biotinylated tomato lectin or RCA120 and streptavidin-gold, revealed specific binding to the luminal face of parietal cell tubulovesicular and canalicular membranes as well as the contents of mucous cell secretory granules. Tomato lectin and RCA120 reacted by lectin blotting with a major species of apparent molecular weight 60-90 X 10(3) Mr from rat, dog and pig gastric membranes. A tubulovesicular membrane fraction, enriched 10-fold for K(+)-dependent phosphatase activity, was also enriched three-fold for tomato lectin binding as assessed by a solid-phase lectin assay. The 60-90K (K = 10(3) Mr) component, in 125I-labelled detergent extracts of dog tubulovesicular membranes, bound to an affinity support of tomato lectin-Sepharose and was specifically eluted with N,N',N'-triacetylchitotriose. Digestion with N-glycanase collapsed the 60-90K component into a sharp 35K band. We conclude that: (1) a 60-90K membrane glycoprotein localised on the luminal face of tubulovesicles and canaliculi of parietal cells interacts strongly with tomato lectin and RCA120; and (2) the glycoprotein is composed of a 35K core protein glycosylated with N-glycans probably containing poly-N-acetyllactosamine sequences with terminal galactosyl residues. The properties of this 60-90K glycoprotein are identical to a major parietal cell autoantigen recognised by sera of patients with autoimmune gastritis.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Poly-N-acetyllactosamine-specific tomato lectin interacts with gastric parietal cells. Identification of a tomato-lectin binding 60-90 X 10(3) Mr membrane glycoprotein of tubulovesicles. 216 41

A hundred years of lectin research has led to the development of lectinology as an independent field of study. Although lectinology is in part related to immunology, fundamental differences exist. Lectins are important tools in biochemistry, histochemistry and clinical diagnosis. The essential in vivo function of lectins is to combine glycoconjugates. The function of lectins in microorganisms and in animals is partially known, whereas the function of lectins in plants is mostly unclear. Of special interest, now as before, are the toxic lectins of the ricin type consisting of an A-chain (N-glycosidase) and a B-chain (D-galactose-specific lectin).
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PMID:[100 years of lectin research--a balance]. 218 42

IgE-binding protein (epsilon BP) is a protein which has affinity for IgE and was originally identified in rat basophilic leukemia (RBL) cells. Subsequently, it was found to be the rat homolog of CBP35, a murine beta-galactoside-specific lectin. This protein is also designated as L-34 and RL-29 and studied independently by several laboratories. More recently, CBP35 (epsilon BP) was found to be equivalent to Mac-2, a surface marker on activated macrophages. Using rat epsilon BP cDNA, we have succeeded in expressing recombinant epsilon BP in Escherichia coli. Milligram quantities of homogeneous epsilon BP could be obtained from bacterial lysate in a one-step affinity purification procedure utilizing lactosyl-Sepharose 4B and elution with a lactose gradient. The recombinant epsilon BP (r epsilon BP) binds mouse IgE and retains reactivity to anti-peptide antibodies specific for a sequence within rat epsilon BP. The purified r epsilon BP exhibits binding activity to various saccharides, with affinity for N-acetyllactosamine greater than thiodigalactoside greater than lactose much greater than D-galactose greater than L-arabinose, an order identical to that exhibited by native epsilon BP isolated from RBL cells. The recombinant lectin displayed hemagglutination activity when tested with rabbit erythrocytes. Although epsilon BP shares sequence homology to other lectins containing S-type (thiol-dependent) carbohydrate-recognition domains, r epsilon BP is resistant to air oxidation and does not require reducing agents for maintaining its activity. Furthermore, the single cysteine residue appears to be unexposed and can be alkylated only when the protein is denatured in 5.6 M guanidinium hydrochloride. The availability of a source for a large quantity of epsilon BP should facilitate the analysis of biological function(s) and structure-activity relationships of this lectin.
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PMID:Expression of biologically active recombinant rat IgE-binding protein in Escherichia coli. 224 84

The murine Mac-2 protein is a galactose- and IgE-binding lectin secreted by inflammatory macrophages. We describe here the cloning and characterization of a cDNA representing the human homolog of Mac-2 (hMac-2). The amino acid sequence derived from the hMac-2 cDNA indicates that the protein is evolutionarily highly conserved, with 85% of its amino acid residues being similar to those in the murine homolog. This conservation is especially marked in the carboxyl-terminal lectin domain. The amino-terminal half of the protein is less conserved but still contains the repetitive proline-glycine-rich motif seen in the mouse protein. hMac-2 synthesized in vitro is recognized by the M3/38 monoclonal antibody to Mac-2 and binds to the desialylated glycoprotein asialofetuin and to laminin, a major component of basement membranes. These findings are discussed in the context of the potential functions of hMac-2.
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PMID:Molecular cloning of a human macrophage lectin specific for galactose. 240 11

We report the complete primary and secondary structures of a metastasis-associated Mr 34,000 galactoside-binding lectin. The polypeptide sequence (264 amino acids) was derived from the nucleotide sequence of three overlapping complementary DNA clones isolated from lambda gt11 and lambda gt10 phage libraries of UV-induced murine fibrosarcomas. Striking features of the polypeptide sequence are two distinct regions of beta-sheet and globular structures at the amino and carboxy terminals, respectively. Homology search suggests that the polypeptide is a chimeric gene product formed by fusion of the 5'-end of an Mr approximately 14,000 galactoside-binding lectin with an internal domain of the collagen alpha gene. Enzymatic treatment with collagenase confirmed the presence of a collagen-like structure in the polypeptide. Unexpectedly, the entire sequence is greater than 85% homologous to a rat low affinity IgE-binding protein.
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PMID:Identification of the metastasis-associated, galactoside-binding lectin as a chimeric gene product with homology to an IgE-binding protein. 252 69

A cDNA encoding the Mac-2 antigen, a surface marker highly expressed by thioglycollate-elicited macrophages, has been cloned by immunoscreening of a lambda gt11-P388D1 expression library. The nucleotide sequence of the cDNA is identical to that of carbohydrate-binding protein 35, a galactose-specific lectin found in fibroblasts and highly homologous to a rat IgE-binding protein from basophilic leukemia cells. The in vitro synthesized Mac-2 protein displayed the expected carbohydrate- and IgE-binding properties. By pulse-chase analysis and subcellular fractionation studies, the Mac-2 protein was found in the cytosol but was also seen to accumulate in the extracellular medium. The latter finding was surprising in view of the fact that the cDNA did not encode a signal peptide or transmembrane domain. An alternatively spliced cDNA with the potential to encode a NH2 terminally extended Mac-2 protein with a stretch of hydrophobic amino acids at its NH2 terminus was also found, but it is not clear whether it is the source of the extracellular Mac-2. Possible functions for the Mac-2 protein based on its lectin- and IgE-binding properties are discussed.
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PMID:The Mac-2 antigen is a galactose-specific lectin that binds IgE. 258 31

A galactose-specific lectin, recently described by our laboratory, is immunologically demonstrable on the surface of neoplastic cells derived from patients with Hodgkin's disease. This Hodgkin's lectin is shown to be functionally and antigenically related to the galactose-N-acetylgalactosamine-specific lectin of the hepatocyte (HBP). Poly- and monoclonal antibodies against either the cytoplasmic tail or the cell-surface binding site of HBP recognize the Hodgkin's lectin as a 55 Kd protein. Expression of the 55 Kd antigen appears to be restricted to Hodgkin's disease involved tissues and cells of the monocyte/macrophage lineage. The putative identification of the Hodgkin's lectin as an ectosialyltransferase unique to Hodgkin's cells is supported by inhibition of enzymatic activity by anti-HBP antibodies. Cultured Hodgkin's cells, in analogy to purified HBP, agglutinate T-lymphocytes mediated by the Hodgkin's lectin. This cell-to-cell interaction results in the incorporation of sialic acid into lymphocyte surface asialoglycans as well as in the stimulation of lymphocyte proliferation. The function of the Hodgkin's lectin as lymphocyte agglutinant in vitro suggests its role as an immunomodulator contributing to the immunodeficiencies associated with Hodgkin's disease.
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PMID:A marker and putative pathoantigen of Hodgkin's cells. 269 Feb 34

A full-length cDNA for a 14K-type human lung beta-galactoside-binding lectin was cloned. The cDNA includes a 405 bp open reading frame coding 135 amino acids including the initiator methionine, and having a single internal EcoRI site and a polyadenylation signal. The deduced amino-acid sequence agreed completely with the sequence of a human placenta lectin determined by direct amino-acid sequence analysis (Hirabayashi, J. and Kasai, K. (1988) J. Biochem. 104, 1-4). It showed extensive sequence similarity with other vertebrate 14K-type lectins and a 35K-type lectin (carbohydrate-binding protein 35) of mouse 3T3 cell. Search of a Genbank sequence data base revealed significant sequence similarity between the beta-galactoside-binding lectins and the carboxyl-terminal half of an IgE-binding protein, the cDNA of which has been cloned from rat basophilic leukemia cells. Thus, 14K-type lectin, 35K-type lectin and IgE-binding protein appeared to form a superfamily of proteins. Almost all invariant residues are located in the central region of the 14K-type lectins, so this region may constitute an essential part of the lectins, such as the sugar-binding domain.
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PMID:Cloning and nucleotide sequence of a full-length cDNA for human 14 kDa beta-galactoside-binding lectin. 271 64

In previous studies, we observed proliferation-dependent expression and nuclear localization of the lectin, designated carbohydrate-binding protein 35 (CBP35), in 3T3 fibroblasts at the polypeptide level by Western blot and immunofluorescence analysis. In the present study, we have compared the expression of the CBP35 gene in quiescent and proliferative 3T3 cells at the levels of (a) accumulated mRNA by Northern blotting and (b) nuclear transcription by run-off assays. When serum-starved, quiescent cultures of 3T3 cells were stimulated by the addition of serum, there was an increase in the nuclear transcription of the CBP35 gene and in the accumulation of its mRNA early (1-3 h) in the activation process, well before the first wave of DNA synthesis. These increases were not dependent on de novo protein synthesis inasmuch as they occurred even in the presence of cycloheximide. There was also an elevated transcription rate and mRNA level in transformed cells when compared to their normal counterparts. Finally, the expression of CBP35 was compared between sparse, proliferating cultures of 3T3 cells and density-inhibited confluent monolayers of the same cells. Although the rate of transcription of the CBP35 gene was approximately the same in the two cultures, there was a higher level of CBP35 mRNA in the dense cells. Thus, it appears that post-transcriptional mechanisms may be involved in the accumulation of mRNA.
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PMID:Carbohydrate-binding protein 35. Levels of transcription and mRNA accumulation in quiescent and proliferating cells. 279 53

1. A D-galactose-specific lectin was isolated from crude extracts of the marine sponge Cinachyrella alloclada by affinity chromatography on Sepharose 4B. 2. The lectin agglutinated human erythrocytes irrespective of their ABO group antigens. 3. Hemagglutination inhibition tests indicated that the lectin binds D-galactose or carbohydrates having a terminal nonreducing D-galactosyl group. 4. C. alloclada lectin was mitogenic for human peripheral blood lymphocytes when AB serum was omitted during the first 24 h of culture. 5. Human serum apparently contains substances which bind or inactivate this lectin.
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PMID:Isolation and functional characterization of a mitogenic lectin from the marine sponge Cinachyrella alloclada. 280 72


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