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Query: UNIPROT:P17931 (galectin-3)
 2,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A D-galactose-specific lectin I was extracted from the sponge Geodia cydonium and purified by affinity chromatography. The molecular weight of lectin I as determined by high-pressure liquid gel chromatography, was found to be 36500 +/- 1300. Disc gel electrophoresis in the presence and in the absence of sodium dodecyl sulfate showed that lectin I is a trimer composed of three different subunits (Mr: 13800, 13000 and 12200); two of the three subunits are linked by one disulfide bond. Isoelectric focusing gave a pI of 5.6 for the native molecule and a pI of 4.4 and of 7.4 for the subunits. The three subunits carry carbohydrate side chains, composed of D-galactose (94%) and of arabinose (5%). Based on experiments with lectins, the terminal D-galactose residues are bound by beta 1 leads to 6 and/or beta 1 leads to 4 glycosidic linkages. The Geodia lectin I contains, besides two carbohydrate recognition sites, at least one receptor site for a second lectin I molecule.
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PMID:Characterization of the trimeric, self-recognizing Geodia cydonium lectin I. 685 38

The Mac-2 protein is a lectin specific for galactose-containing glycoconjugates. Present in some normal cells, it was also associated with the metastatic potential of some carcinoma cells. We studied Mac-2 expression in three human melanoma cell lines and in five variants and clones from one of them. By using the M3/38 rat monoclonal antibody, Mac-2 was demonstrated on cell surface by flow cytometry as well as in the cytoplasm and in the nucleus by confocal microscopy. The expression of Mac-2 was not correlated with that of terminal unsialylated Gal beta 1-3 GalNac structures on metastatic melanoma cell lines. However, the presence of extracellular Mac-2 containing vesicles was observed in cell lines with metastatic potency. Western blot analysis of cell lysates, in reducing or non-reducing conditions, revealed two bands of 34-36 and 93-98 kDa apparent M(r), also found in HL60 and P388.D1 cell lines used as positive controls.
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PMID:Expression of the galactose binding protein Mac-2 by human melanoma cell-lines. 801 32

The carbohydrate binding specificity of recombinant carbohydrate-binding protein 35 (rCBP35) has been investigated by quantitative precipitation using a series of glycoproteins and carbohydrate-protein conjugates and by inhibition of precipitation using well defined carbohydrate haptens. Synthetic glycoconjugates and glycoproteins containing terminal nonreducing galactosyl units in beta-linkage were capable of forming a precipitate with rCBP35. If the glycoprotein or glycoconjugate contained terminal Neu5Ac, or galactose in alpha-linkage, precipitate formation was not observed. We also found that murine laminin, which contains polylactosamine structures, reacted more strongly than did bovine fetuin. Using carbohydrate-bovine serum albumin (BSA) glycoconjugates, we found that the tetrasaccharide Gal beta 1, 4GlcNAc beta 1, 3Gal beta 1,4-GlcNAc-BSA reacted more strongly than the disaccharide Gal beta 1, 4GlcNAc-BSA conjugate, suggesting that the binding site accommodates carbohydrate ligands greater in size than a disaccharide. Equilibrium dialysis experiments using [3H]lactose showed that rCBP35 binds 1 mol (n = 0.84) of lactose/30,000 g atoms of protein, with an affinity constant of 2.07 x 10(4) M-1. The binding site on the polypeptide appears to contain four subsites that recognize the sequence Gal beta 1,4GlcNAc beta 1, Gal beta 1,X-. All disaccharides tested that contain a nonreducing beta-galactosyl unit behaved as inhibitors of precipitation at approximately the same concentration, suggesting that the reducing position of the tetrasaccharide does not play an important role in the specific binding to the fourth subsite. The reducing sugar may serve to hold the saccharide in a tunnel like binding pocket since methyl-beta-D-galactoside itself is an extremely poor inhibitor.
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PMID:Carbohydrate-binding protein 35. II. Analysis of the interaction of the recombinant polypeptide with saccharides. 832 71

Malignant transformation is accompanied by changes in cell-matrix interactions. Upon transfection with EJ-ras oncogene, transformed fibroblasts acquired a migratory phenotype towards laminin-1. The increase in integrin expression was responsible for the migratory activity of transformed fibroblasts. In addtion alpha 6 beta 1 integrins, both galectin-3 and an unidentified laminin-binding polypeptide had their expression pattern altered upon transformation. Here, we review these two classes of laminin-binding proteins and their possible roles in cell-laminin interactions.
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PMID:Laminin-binding proteins in EJ-ras-transformed fibroblasts. 918 Oct 57

In this report, we have analyzed the adhesive interactions of a breast carcinoma cell line, BT-549, and its galectin-3-transfected subclone 11-9-1-4 with laminin, collagen IV and fibronectin. We determined that 11-9-1-4 cells adhered much more rapidly (within 1 h of plating) to laminin- and collagen IV-coated wells than the galectin-3 null expressing BT-549 cells. However, after 24 h, both cell lines fully adhered to laminin and collagen IV. Both cell lines also achieved maximum adhesion to fibronectin within 30 min. Not only did 11-9-1-4 express galectin-3 in the usual punctate pattern on its cell surface, it demonstrated a higher surface expression of alpha 6 beta 1 integrin compared to BT-549. The 11-9-1-4 cells were able to invade through matrigel-coated polycarbonate filters at approximately 3 times the rate of BT-549 parental cells. Our data suggest that galectin-3 is essential for adhesion to laminin and collagen IV but not fibronectin by breast carcinoma cells. In addition, galectin-3 expression may modulate the surface expression of some of the integrins specific for laminin and collagen IV adhesion and invasion of basement membrane by breast carcinoma cells.
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PMID:Adhesion of human breast carcinoma to extracellular matrix proteins is modulated by galectin-3. 956 Oct 29

The control of cellular adhesion to extracellular matrix proteins is poorly understood. In the present analyses, we set out to test the hypothesis that high galectin-3 concentration on the cell surface downregulates cellular adhesion to the extracellular matrix proteins. Various tumor cell lines were briefly incubated without or with galectin-3 and then allowed to adhere to wells coated with laminin-1, collagen IV and fibronectin. Our data demonstrated that the cells which were incubated with galectin-3 prior to plating had significantly reduced adhesion to extracellular matrix proteins. This inhibition involved the carbohydrate recognition domain of the lectin because adhesion was achieved in the presence of galectin-3 and lactose but not galectin-3 and sucrose. Furthermore we demonstrated that galectin-3 associates with alpha 1 beta 1 integrin in a lactose dependent manner.
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PMID:Regulation of cellular adhesion to extracellular matrix proteins by galectin-3. 961 90

Although Gal beta 1-4GlcNAc (LacNAc) moieties are the most common constituents of N-linked glycans on vertebrate proteins, GalNAc beta 1-4GlcNAc (LacdiNAc, LDN)-containing glycans are widespread in invertebrates, such as helminths. We postulated that LDN might be a molecular pattern for recognition of helminth parasites by the immune system. Using LDN-based affinity chromatography and mass spectrometry, we have identified galectin-3 as the major LDN-binding protein in macrophages. By contrast, LDN binding was not observed with galectin-1. Surface plasmon resonance (SPR) analysis and a solid phase binding assay demonstrated that galectin-3 binds directly to neoglycoconjugates carrying LDN glycans. In addition, galectin-3 bound to Schistosoma mansoni soluble egg Ags and a mAb against the LDN glycan inhibited this binding, suggesting that LDN glycans within S. mansoni soluble egg Ags contribute to galectin-3 binding. Immunocytochemistry demonstrated high levels of galectin-3 in liver granulomas of S. mansoni-infected hamsters, and a colocalization of galectin-3 and LDN glycans was observed on the parasite eggshells. Finally, we demonstrate that galectin-3 can mediate recognition and phagocytosis of LDN-coated particles by macrophages. These findings provide evidence that LDN-glycans constitute a parasite pattern for galectin-3-mediated immune recognition.
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PMID:LacdiNAc-glycans constitute a parasite pattern for galectin-3-mediated immune recognition. 1526 23

Luteolysis is characterized by a reduction in progesterone (P4) production and tissue degeneration in the corpus luteum (CL). One of major events during luteolysis is luteal cell death. Galectin-3, a ubiquitously expressed protein involved in many cellular processes, serves as an antiapoptotic and/or proapoptotic factor in various cell types. Although galectin-3 is detected in the bovine CL, its role remains unclear. The expression of galectin-3 in the bovine CL was higher at the regressed stage than at the other luteal stages. Galectin-3 was localized on luteal steroidogenic cells (LSCs). When cultured LSCs were exposed to prostaglandin F2alpha (PGF) for 48 h, the expression and secretion of galectin-3 increased. When the cultured LSCs were treated with galectin-3 for 24 h, cleaved caspase-3 expression was increased, and the cell viability was decreased, whereas P4 production did not change. Beta 1 integrin, a target protein of galectin-3, was expressed in bovine CL and possessed glycans, which galectin-3 binds. Furthermore, galectin-3 bound to glycans of luteal beta 1 integrin. The decreased cell viability of cultured LSCs by galectin-3 was suppressed by beta 1 integrin antibody. The overall findings suggest that the secreted galectin-3 stimulated by PGF plays a role in structural luteolysis by binding to beta 1 integrin.
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PMID:Galectin-3 contributes to luteolysis by binding to Beta 1 integrin in the bovine corpus luteum. 2485 2