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)

We found and characterized a type D retrovirus produced in a human lymphoblastoid cell line of B-cell lineage. The amino acid sequence of the N-terminal region of the purified major structural protein (PVTRSQGQVSSNTTGRASPHPDTHTIPE) revealed no high homology with any of the known retroviral amino acid sequences. We have cloned cDNA and the proviral genome integrated in the retrovirus-producing cells, and determined the complete nucleotide sequence and gene structures of the genome. The provirus genome is 8785 bp long and has the structure of LTR-gag-prt-pol-eny-LTR. The nucleotide sequences of the long terminal repeat (LTR) region and a part of the pol gene were closely related to the available sequences of squirrel monkey retrovirus (SMRV), and we designated this virus SMRVHLB' abbreviated as SMRV-H. The primer (tRNA(Lys)1,2)-binding sequence of SMRV-H (TGGCGCCCAGGACGTGGGGCTCGA) has a GG insertion, which is different from that of SMRV. The transmembrane protein of the 3' terminal region of env gene contains an amino acid sequence of an immunosuppressive peptide (EVVLQNRRGLDLLTAEQGGICLALQERCCFYANKS), in which R is unique in SMRV-H. The core sequence of the glucocorticoid regulatory element is found upstream of the two 42-bp imperfect repeats in the LTR. Sequences partially homologous to those of the rat IgE-binding protein gene are in gag and pol genes.
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PMID:Molecular cloning, complete nucleotide sequence, and gene structure of the provirus genome of a retrovirus produced in a human lymphoblastoid cell line. 320 49

Antigen-retaining follicular dendritic cells (FDC) have been identified and studied in sections of lymph nodes and spleen, but studies of these cells in culture have been extremely limited. The purpose of this study was to establish techniques to release these fragile cells from mouse lymph nodes in a viable state and to identify these cells routinely in lymph node cell suspensions. FDC were obtained from passively or actively immunized popliteal lymph nodes of mice injected in the footpads with 125I-labeled human serum albumin (HSA) or horseradish peroxidase (HRP). Lymph nodes were removed 1 hr after the footpads had been injected with collagenase. After another hour of incubation in vitro with collagenase, protease, and deoxyribonuclease, FDC were released by gentle teasing and enriched by centrifugation on a low density bovine serum albumin (BSA) or Percoll gradient. Most FDC with the associated radiolabel floated at densities greater than 1.06 g/ml on BSA or Percoll gradients. Slides of the FDC-enriched fraction were prepared, using a cytobucket which allowed the cells to be affixed to glass slides by centrifugation in a less disruptive manner than by cytocentrifugation. FDC that were air-dried and fixed with 3% glutaraldehyde had a characteristic pink acidophilic cytoplasm after Wright's staining, and had a faintly basophilic euchromatic nucleus frequently with peripherally-clumped chromatin. In addition, these cells were large and irregularly shaped (up to 60 micron long). Fixation of FDC with 0.6% paraformaldehyde/ 0.9% glutaraldehyde on poly-L-lysine-coated slides resulted in a preservation of FDC which made possible visualization of long dendritic processes by Nomarski optics. Antigen presence on the cell surface was confirmed by autoradiography and, in the case of HRP, was also visualized enzymatically using diaminobenzidine. In contrast to resident peritoneal macrophages or some contaminating lymph node macrophages present on the same slides, FDC did not phagocytize opsonized sheep red blood cells (SRBC) or adhere to plastic surfaces although they did form rosettes with opsonized SRBC. Cell marker studies indicated FDC have a distinctive phenotype. They were positive for Ia, Fc receptor, and leukocyte common antigen, but negative for Thy-1, Ly-1, Ly-2, endogenous Ig, Mac-1, Mac-2, Mac-3, and F4/80, and negative to weakly positive for nonspecific esterase. Cultured FDC remained viable and retained radiolabeled antigen-antibody complexes on their surfaces and were significantly enriched for FDC.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Follicular dendritic cells in suspension: identification, enrichment, and initial characterization indicating immune complex trapping and lack of adherence and phagocytic activity. 396 23

Chemical modification studies have been carried out on the galactose-specific lectin (SGSL) purified from snake gourd (Trichosanthes anguina) seeds. Modification of the imidazole side chains of histidine residues with ethoxyformic anhydride resulted in a complete loss of activity of the lectin. A total of 9.5 (+/- 0.7) histidine residues were modified per dimer of M(r) 55,000 when the reaction was carried out for 2 hours. A partial protection was observed when the modification was done in the presence of 0.1 M galactose, indicating that histidine residues are directly involved in the sugar-binding activity of the lectin. Complete recovery of the lectin activity was observed when the modification was reversed by treatment with hydroxylamine. In immunodiffusion experiments, the histidine-modified lectin reacted with rabbit antiserum raised against the native SGSL forming a precipitin line, indicating that the loss of activity upon modification was not due to changes in the overall conformation of the lectin. Modification of the side chains of lysine, cysteine and tyrosine residues did not result in any change in the activity of SGSL.
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PMID:Identification of histidine residues in the sugar binding site of snake gourd (Trichosanthes anguina) seed lectin. 950 53

Lipoarabinomannans (LAMs) from mycobacteria were investigated concerning their effect on human neutrophils. Two types of LAM, the mannose-capped ManLAM from the virulent Mycobacterium tuberculosis H37Rv and the mannose-lacking AraLAM from a rapidly growing mycobacterial strain were used. Neither AraLAM nor ManLAM induced any significant direct activation of the NADPH-oxidase. Both LAMs, however, primed the neutrophils so that subsequent stimulation with the peptide chemoattractants fMet-Leu-Phe (fMLF), Trp-Lys-Tyr-Met-Val-DMet (WKYMVm) and the mammalian lactose-binding lectin galectin-3 resulted in a markedly enhanced oxidative response. The LAM-induced priming was accompanied by an increased exposure of complement receptors 1 and 3 as well as the formyl peptide receptor on the neutrophil surface, suggesting that the enhanced oxidative response could be due to upregulation of receptors on the cell surface as a result of granule mobilisation. Since LAM-primed neutrophils released 65% of the cell content of gelatinase but showed no increased release of vitamin B(12)-binding protein, mobilisation of the gelatinase granules rather than the specific granules is concluded to be responsible for the priming effects. This is in agreement with the subcellular localisation of receptors for fMLF, WKYMVm, as well as galectin-3, which are stored in the secretory vesicles and gelatinase granules. The priming effect appeared very similar to that of Escherichia coli lipopolysaccharide, and since no differences in activity could be detected between AraLAM and ManLAM, we hypothesize that the lipid anchor of the LAM is responsible for the priming effects.
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PMID:Priming of human neutrophils by mycobacterial lipoarabinomannans: role of granule mobilisation. 1170 90

In search of specific and highly selective sugar clusters for cell receptors, such as membrane lectins, various disaccharides were coupled to small peptide cores through an amide bond. In a first step, the reducing disaccharides, i.e. lactose and three different dimannoses, were converted into glycosyl-pyroglutamyl-beta-alanine derivatives. The free carboxylic group of these conjugates was then coupled to the alpha and epsilon amino groups of the core peptide (Lys( n )-Ala-Cys-NH2) with n =1 to 5, with complete substitution leading to homogeneous glycoclusters. The thiol group of the cysteine residue was used to tag the glycosylated oligolysines upon reaction with fluorescein iodoacetamide. The affinity of these glycoclusters towards two plant lectins was assessed by surface plasmon resonance. The selectivity of their cell uptake was investigated by flow cytometry using two types of cells: a human hepatoma cell line (HepG2 cells) expressing the plasma membrane galactose-specific lectin, and monocyte-derived dendritic cells expressing the plasma membrane mannose-specific lectin. The glycoclusters containing four or five disaccharides were shown to bind plant lectins and cell surface membrane lectins with a narrow selectivity and with a high affinity.
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PMID:Oligolysine-based saccharide clusters: synthesis and specificity. 1211 48

Helicobacter pylori (H. pylori) infection leads to gastroduodenal inflammation, peptic ulceration and gastric carcinoma. H. pylori may induce disease-specific gene expression in gastric epithelial cells. cDNA microarray for 352 cancer-related genes was used to identify the genes altered by H. pylori (cagA positive) in gastric epithelial AGS cells. Expressions of the genes identified on the microarray and other genes closely associated with these genes were determined by reverse transcriptase-polymerase chain reaction (RT-PCR). Western blot analysis and cell adhesion assay were performed to confirm the protein levels of the genes and the role of the genes on cell adhesion in H. pylori-infected AGS cells. As a result, the expression of four genes (galectin 1, aldolase A, integrin alpha5, LIM domain only 7 (LMO7)) were up-regulated by H. pylori in AGS cells, determined by cDNA microarray. RT-PCR analysis showed that the genes up-regulated by H. pylori were the genes regulating cell-cell adhesion and cell-extracellular matrix interaction, such as galectin-1 and galectin-3, integrin alpha5, and LIM domain only 7 (LMO7), and cancer-related glycolytic enzyme aldolase A and C. Cell adhesion to extracellular matrix proteins such as poly-L-lysine and fibronectin was mediated by H. pylori-induced expression of integrin alpha5. RT-PCR and Western blot analysis showed that E-cadherin, regulating cell adhesion and contact cell inhibition, was decreased by H. pylori in AGS cells. In conclusion, the increased expression of cell adhesion molecules and decrease in E-cadherin expression by H. pylori might contribute to cell adhesion, invasion and possibly cell proliferation in gastric epithelial cells.
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PMID:Cell adhesion-related gene expression by Helicobacter pylori in gastric epithelial AGS cells. 1275 65

A galactose-specific lectin has earlier been isolated from the seeds of Dolichos lablab in our laboratory by conventional protein purification methods. We now established conditions to bind the lectin on Sepharose-galactose gel in the presence of 1.5 M ammonium sulfate in Tris-buffered saline, pH 7.4. It can be specifically eluted with 0.3 M galactose. The purified lectin is a glycoprotein, binds to Con A, agglutinates erythrocytes, and has an apparent native molecular weight of 120 +/- 5 kDa. In SDS-PAGE under reducing conditions, it dissociates into two subunits of molecular mass (Mr) 31 and 29 kDa. Among a number of sugars tested for inhibitory activity of the lectin, galactose was found to be a potent inhibitor. Rabbit polyclonal antibody to the purified lectin specifically reacted with the lectin subunits in Western blot analysis and additionally, an antibody raised to the isolated 31 kDa subunit show reactivity with both the subunits. Amino terminal sequences of both the subunits are identical. The purified lectin is stable up to 40 degrees C with a pH optimum of 7.4. The lectin has a high content of acidic amino acids and lacks sulfur-containing amino acids. Chemical modification of the lectin with group-specific reagents indicates the possible role of histidine, lysine, and tyrosine residues in lectin activity.
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PMID:Affinity purification, physicochemical and immunological characterization of a galactose-specific lectin from the seeds of Dolichos lablab (Indian lablab beans). 1612 71

A database search using peptide mass fingerprints obtained by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry leads to protein identification with incomplete sequence coverage, because certain peptides are preferentially desorbed/ionized and some are not detected at all. We show that certain tryptic peptides mainly with C-terminal arginine not detected before derivatization become detectable upon dansylation. Others, mainly with C-terminal lysine, are suppressed. An increase in protein sequence coverage and protein identification score by combined data from underivatized and dansylated peptides in database search is demonstrated using human amnion proteins (human serum albumin precursor, calmodulin, collagen alpha 2(VI) chain precursor, galectin-3) separated by two-dimensional gel electrophoresis as well as femtomole amounts of BSA in solution.
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PMID:Dansylation of tryptic peptides for increased sequence coverage in protein identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometric peptide mass fingerprinting. 1620 24

High blood pressure (HBP) is an important risk factor for cardiac, renal, and vascular dysfunction. Excess inflammation is the major pathogenic mechanism for HBP-induced target organ damage (TOD). N-acetyl-Ser-Asp-Lys-Pro (Ac-SDKP), a tetrapeptide specifically degraded by angiotensin converting enzyme (ACE), reduces inflammation, fibrosis, and TOD induced by HBP. Our hypothesis is that Ac-SDKP exerts its anti-inflammatory effects by inhibiting: 1) differentiation of bone marrow stem cells (BMSC) to macrophages, 2) activation and migration of macrophages, and 3) release of the proinflammatory cytokine TNF-alpha by activated macrophages. BMSC were freshly isolated and cultured in macrophage growth medium. Differentiation of murine BMSC to macrophages was analyzed by flow cytometry using F4/80 as a marker of macrophage maturation. Macrophage migration was measured in a modified Boyden chamber. TNF-alpha release by activated macrophages in culture was measured by ELISA. Myocardial macrophage activation in mice with ANG II-induced hypertension was studied by Western blotting of Mac-2 (galectin-3) protein. Interstitial collagen deposition was measured by picrosirius red staining. We found that Ac-SDKP (10 nM) reduced differentiation of cultured BMSC to mature macrophages by 24.5% [F4/80 positivity: 14.09 +/- 1.06 mean fluorescent intensity for vehicle and 10.63 +/- 0.35 for Ac-SDKP; P < 0.05]. Ac-SDKP also decreased galectin-3 and macrophage colony-stimulating factor-dependent macrophage migration. In addition, Ac-SDKP decreased secretion of TNF-alpha by macrophages stimulated with bacterial LPS. In mice with ANG II-induced hypertension, Ac-SDKP reduced expression of galectin-3, a protein produced by infiltrating macrophages in the myocardium, and interstitial collagen deposition. In conclusion, this study demonstrates that part of the anti-inflammatory effect of Ac-SDKP is due to its direct effect on BMSC and macrophage, inhibiting their differentiation, activation, and cytokine release. These effects explain some of the anti-inflammatory and antifibrotic properties of Ac-SDKP in hypertension.
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PMID:Novel anti-inflammatory mechanisms of N-Acetyl-Ser-Asp-Lys-Pro in hypertension-induced target organ damage. 1817 15

Mitogaligin, a protein encoded by galig, an internal cytotoxic gene of the galectin-3 locus, is mostly a mitochondrial protein. Mitochondrial targeting is due to an already identified mitochondrial localization signal. Interaction of mitogaligin with mitochondria leads to cytochrome c cytosolic leakage and ultimately to cell death. We have previously pointed out that mitogaligin can also be directed to the nucleus when the mitochondrial addressing signal is inactivated, indicating a possible dual intracellular localization of the protein. When expressed in the nucleus, mitogaligin exhibits also apoptotic properties leading to cell death. In this report, we show that nuclear addressing of mitogaligin depends on a sequence differing from classical signals containing basic, lysine or proline-tyrosine rich residues. The signal consists of a long sequence of amino acids residues based on a series of a short repetitive degenerated sequence.
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PMID:The mitogaligin protein is addressed to the nucleus via a non-classical localization signal. 2005 10


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