Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Concanavalin A (Con A), a tetravalent lectin, was shown to impair 8 chick embryo fibroblast (8 d CEF) spreading on a laminin (LM) substrate but not on a fibronectin substrate (FN), suggesting that cell surface Con A binding proteins could be involved in 8 d CEF spreading on a LM substrate. The interaction of Con A-binding proteins with Con A is dependent upon the carbohydrate moieties of the isolated glycoproteins; since they interact strongly with Con A-Sepharose and are eluted with 0.3 Mol/l alpha-methylmannopyranoside, the isolated Con A binding-proteins inhibit 8 d CEF adhesion to a Con A substrate to the same extent as alpha-methylmannopyranoside. Furthermore, the isolated Con A binding proteins specifically inhibit in a dose-dependent manner 8 d CEF spreading on LM but not on FN.
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PMID:Cell spreading on laminin substrate involves Con A-binding proteins. 239 33

Hybridoma generation, using specifically, maximally desialylated human blood group O erythrocytes (T RBC) as immunogen, and biochemical studies suggested the presence of immunogenic Tn epitopes. GalNAc alpha-O, on T RBC. We therefore investigated by immunochemical means whether or not Tn-specific epitopes immunoreactive with anti-Tn antibodies present in ordinary human sera occur on T RBC and on Thomsen-Friedenreich (T) antigen prepared from them. We did detect the Tn epitope with such antibodies, in addition to the T epitope, on isolated T antigen. T RBC absorbed specifically, under standard conditions, 25-60% of the heterogeneous anti-Tn antibody populations in ordinary human sera of appropriately adjusted titer score. The anti-Tn eluted from T RBC had scores ranging from 6.5 to 35% of those of the unabsorbed parent sera. The varying fine specificities of eluted anti-Tn were demonstrated by inhibition of Tn RBC agglutination with putative haptens and antigens. Tn-specific haptens and antigens were the most powerful inhibitors. Depending on the serum used to prepare the anti-Tn eluates, the antibodies could be divided into those that were inhibited well exclusively by GalNAc alpha-O derivatives and those that were also inhibited by Gal, notably by Gal alpha-O derivatives and more strongly by GalNAc and Me-alpha-GalNAc. In the two reciprocal hemagglutination inhibition systems used, Tn-specific haptens were considerably more active than the T-hapten Gal beta 1----3GalNAc alpha-O, and desialylated ovine submaxillary mucin (AS-OSM) had higher activity than T antigen. Inhibition of Tn RBC agglutination by haptens was uniformly more efficient than that of T RBC; this is, at least in part, due to the much higher negative charge of Tn as opposed to T RBC. In microprecipitin tests, Helix pomatia lectin was nearly as powerful a precipitin of T antigen as of AS-OSM. The importance of the terminal GalNAc alpha of T antigen for its precipitation with the Helix lectin was demonstrated by the very high and virtually exclusive inhibitory activity of Me-alpha-GalNAc and GalNAc. Our findings may contribute to comprehension of the significance of uncovered Tn in most carcinomas, and the role of anti-Tn as a "natural" anti-carcinoma antibody. They may also help illuminate the rare heterozygous, autosomal, apparently premalignant spot mutation that leads to Tn RBC in vivo.
Mol Immunol 1985 Nov
PMID:Tn epitopes, immunoreactive with ordinary anti-Tn antibodies, on normal, desialylated human erythrocytes and on Thomsen-Friedenreich antigen isolated therefrom. 241 12

The functional and immunochemical characteristics of the human glomerular C3 receptor were investigated by adherence of sheep erythrocytes (Es) coated with defined C3 fragments and by using polyclonal and/or monoclonal antibodies directed against epitopes expressed on complement receptors CR1, CR2, and CR3. C3b-bearing Es (EsC3b) strongly adhered to glomeruli in frozen kidney sections in a reaction that was selectively inhibited by F(ab')2 anti-CR1 antibodies. There was no adherence of EsC3dg, EsC3d, and EsC3bi in the presence or absence of Ca++ and Mg++ under physiologic buffer conditions. The weak glomerular binding of EsC3bi, which was observed in half-isotonic buffer was selectively suppressed by anti-CR1 antibodies. By indirect immunofluorescence, anti-CR1 antibodies stained all podocytes in glomeruli, whereas no staining of kidney sections was seen with OKM1 and anti-Mol antibodies directed against the alpha-chain of CR3 and with anti-CR2 antibodies anti-B2 and BL13. Solubilization of membrane glycoproteins from freshly isolated glomeruli from three human kidneys, in the presence of 0.1% Nonidet P-40, yielded a material that bound to lentil lectin Sepharose and could accelerate the decay of preformed cell-bound amplification C3 convertase sites in a reaction that was inhibited by anti-CR1 antibodies. The material containing CR1 activity was labeled with 125I, immunoprecipitated with anti-CR1, and analyzed by SDS-PAGE and autoradiography. Anti-CR1 immunoprecipitated a form of CR1 of Mr 205,000 in solubilized glomeruli from three donors, and an additional form of Mr 160,000 in glomeruli from two of the donors. Immunoprecipitation of CR1 from surface-labeled erythrocytes from these individuals demonstrated them to be homozygous for the 205,000 Mr form of the receptor. Whether the 160,000 band represents in vitro or in vivo proteolytic cleavage of CR1, or cell specific-modulation of gene expression of glomerular CR1, remains unclear. Thus, CR1 is the only type of C3 receptor expressed in the human kidney. Glomerular CR1 shares the functional antigenic and biochemical properties of the C3b/C4b CR1 receptor of peripheral blood cells.
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PMID:Characterization of the human glomerular C3 receptor as the C3b/C4b complement type one (CR1) receptor. 241 13

A sialic acid binding lectin, AchatininH, was purified in single step from the hemolymph of the land snail, Achatina fulica, by the affinity chromatography on sheep submaxillary mucin coupled to Sepharose 4B. The yield of the lectin was found to be 3 mg from 100 ml of hemolymph. The homogeneity of the lectin was established by alkaline gel electrophoresis, immunodiffusion, immunoelectrophoresis and analytical isoelectrophoresis. The molecular weight of the native protein was 242,000, having identical subunits of Mr 15,000. The lectin agglutinated rabbit erythrocytes in the presence of Ca2+. The inhibition study clearly suggests that the binding site of the lectin recognizes sialic acid as the immunodominant sugar. This was further confirmed by the observation that there was a marked decrease of agglutinating activity of the lectin with neuraminidase treated rabbit erythrocytes and asialofetuin was unable to inhibit the activity of AchatininH. Among the inhibitors used the glycoconjugate containing alpha 2----6 linkages of N-acetylneuraminic acid with subterminal galactopyranose or 2-acetamido-2-deoxy-galactopyranose residue was found to be better inhibitor than that containing alpha 2----3 linkages of N-acetyl neuraminic acid. Besides that sialoglycoprotein containing both N and O type of glycosidic linkages plays an important role in binding with the lectin. Fetuin was found to be the best inhibitor.
Mol Cell Biochem 1986 Aug
PMID:A single step purification of a sialic acid binding lectin (AchatininH) from Achatina fulica snail. 243 Jan 70

The Ca2+ antagonist binding sites associated with the voltage dependent calcium channel in rabbit myocardium were found to distribute with the sarcolemmal Na+ + K+ ATPase and adenylate cyclase activities during subcellular fractionation on sucrose-density gradients. The equilibrium dissociation constants (KD) for the binding of [3H]nitrendipine and [3H]verapamil were 0.31 +/- 0.04 nM and 4.1 +/- 0.5 nM respectively, and displayed an average density of 0.55 +/- 0.05 pmol/mg and 0.4 +/- 0.03 pmol/mg protein respectively for the most enriched membrane fraction. The Ca2+ antagonist binding sites were solubilized from the membranes with the detergent 3-[(3-cholamidopropyl)dimethylammonio]propanesulfonate, and specific binding sites for [3H]PN200-110, [3H]verapamil and [3H]diltiazem were isolated on a wheat-germ lectin column. The binding sites for [3H]PN200-110 were enriched about 2,500 fold as compared with the original homogenate and displayed a density of 28.5 +/- 8 pmole/mg protein in the isolated fraction. Sodium dodecyl sulfate gel electrophoresis of the isolated drug binding proteins indicated enrichment of proteins of Mr 170,000, 140,000, 130,000, 100,000 and 53,000. The isolated receptor contained an intrinsic kinase activity that phosphorylated glycoproteins of Mr 170,000 and 53,000. Exogenously added cAMP-kinase stimulated phosphorylation of the 170,000, 100,000, 53,000 and 28,000 Mr glycoproteins in the receptor fraction. The results of this study indicate that the binding sites for [3H]nitrendipine, [3H]PN200-110, [3H]verapamil and [3H]diltiazem residue on glycoprotein(s) which are of sarcolemmal origin, and co-purify together on wheat germ lectin columns. The polypeptide composition of the Ca2+ antagonist binding sites from cardiac muscle appears to be very similar to that of the dihydropyridine receptor in skeletal muscle.
Mol Cell Biochem 1987 Aug
PMID:Subcellular distribution and isolation of the Ca2+ antagonist receptor associated with the voltage regulated Ca2+ channel from rabbit heart muscle. 244 72

Human chorionic gonadotropin (hCG) beta-subunit core fragment (beta-fragment) is present in the urine of pregnant individuals as well as those with trophoblast disease and certain other cancers at concentrations 0.8 (early pregnancy) to 7 (second trimester pregnancy)-fold greater than that of hCG. The core fragment may be directly secreted by trophoblast tissue into the circulation or possibly originates from peripheral degradation of circulating hormone by the kidney. We examined the former hypothesis. We examined 24-h organ cultures of trophoblast tissue from first, second, and third trimester pregnancy. The media from this tissue contained hCG, free beta-subunit, and beta-fragment. The amount of beta-fragment present exceeded that of hCG, as was observed in second and third trimester pregnancy urine. The beta-fragment immunoreactive material produced by trophoblast tissue was compared to a standard preparation of urinary beta-fragment. The material in medium was identical to the standard beta-fragment in its elution pattern from a gel filtration column, from a reverse-phase HPLC column, from an ion-exchange gel, and from an immobilized lectin affinity column, and also by electrophoresis and immunoblotting with fragment-reactive monoclonal antibodies. We conclude that beta-fragment can also originate directly from trophoblast tissue, and could be the principal hCG beta-immunoreactive molecule secreted.
Mol Endocrinol 1988 Sep
PMID:Origin and occurrence of human chorionic gonadotropin beta-subunit core fragment. 245 7

An immunodominant species-specific surface glycoprotein antigen was purified from procyclic culture forms of Trypanosoma brucei rhodesiense using lectin affinity chromatography and a monoclonal antibody immunoadsorbent. The purified molecule appears on a 10% polyacrylamide gel as a wide, dark silver staining band having an apparent molecular mass of between 30 and 40 kDa, identical to that revealed by immunoblotting using anti-procyclic lysates. The molecule, which we have named procyclin, was shown by immunofluorescence and immunoelectron microscopy to be exposed on the surface of procyclic trypanosomes. Gas-phase protein microsequencing and micro-amino acid analysis revealed an unusual acidic polypeptide with an amino-terminal amino acid sequence which matched portions of previously published sequences predicted from two different cDNAs obtained using mRNA from procyclic trypanosomes. The procyclin molecules contained a large glutamic acid-proline repeat and the form we isolated was highly water soluble. Ten different monoclonal antibodies were used in ELISA with synthetic peptides to localize parasite surface epitopes to various portions of procyclin. The results showed that surface epitopes were spread throughout most of the procyclin molecule, including the glutamic acid-proline repeat portion. Procyclin is distributed over the surface of both culture form and tsetse fly midgut form procyclic trypanosomes, is developmentally regulated and is immunologically species-specific.
Mol Biochem Parasitol 1988 Dec
PMID:Procyclin: an unusual immunodominant glycoprotein surface antigen from the procyclic stage of African trypanosomes. 246 63

This interpretive review attempts to dovetail advanced work by different groups of investigators on blood group and carcinoma (CA) glycoconjugates that have terminal, immunoreactive Tn epitopes (GalNAc alpha-O-Ser/Thr), and on the interaction of those structures with complementary antibodies and lectins. Fenlon et al. (1987) and Leathem and Brooks (1987) found a positive correlation between primary breast CA aggressiveness and its affinity for Helix pomatia (HPA) lectin. This phenomenon was used successfully to accurately predict, in studies on 305 breast CA patients, early or late CA recurrence and patient survival time. The innate specificity of the large HPA combining groove (aside from its avid reactivity with appropriately spaced GalNAc alpha-O-) remains obscure, despite careful investigation for more than a decade (Baker et al., 1983). Leathem and Brooks presumed that HPA recognizes a hitherto "undefined biological marker" that indicates a breast CA's aggressiveness. Our own work has shown that the chemically fully defined Tn epitope, as measured with human polyclonal and murine monoclonal anti-Tn antibodies, occurs in immunoreactive form in approximately 90% of all breast and lung adenoCAs studied. Tn is occluded and non-reactive in healthy and non-CA-diseased tissues. We found that CA-associated Tn is an adhesion molecule in attachment to healthy cells; an increase in its density on breast CA cell membranes parallels greater aggressiveness of breast tumors in both humans and mice (the only species studied). Thus, Tn may be all or a major part of the postulated "as yet undefined biological marker" associated with high breast CA aggressiveness. Besides being helpful in the elucidation of some aspects of breast CA pathogenesis, these findings on primary breast CA have clinical implications in that they should facilitate stratification of breast CA patients for adjuvant treatment.
Mol Immunol 1989 Jan
PMID:Tn epitope (N-acetyl-D-galactosamine alpha-O-serine/threonine) density in primary breast carcinoma: a functional predictor of aggressiveness. 246 92

During the cellular differentiation of the cultured smooth muscle cells, BC3H1, the Kd and the number of binding sites for [3H]-pyrilamine were decreased transiently from 276 nM to 46.5 nM and from 13.3 x 10(6)/cell to 2 x 10(6) cell, respectively. Concanavalin A (Con-A), wheat germ agglutinin, and lentil lectin inhibited [3H]pyrilamine binding to differentiated BC3H1 cells but not to undifferentiated cells. The [3H]pyrilamine binding activity of digitonin-solubilized membranes from differentiated cells was successively recovered from Con-A agarose affinity chromatography but not from undifferentiated cell membranes. The glycosylation inhibitors tunicamycin and swainsonine inhibited the expression of high affinity pyrilamine binding sites during BC3H1 cell differentiation. The molecular weight of high affinity [3H]pyrilamine binding sites on differentiated cells were approximately 68,000 as analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis, which after treatment with N-glycanase was shifted to 40,000, a molecular weight similar to that of low affinity [3H]pyrilamine binding sites on undifferentiated cells. These data suggest that one element contributing to H1-receptor heterogeneity is receptor-N-glycosylation.
Mol Pharmacol 1989 Mar
PMID:Receptor glycosylation regulates the affinity of histamine H1 receptors during smooth muscle cell differentiation. 249 28

[3H]Thymidine incorporation by adult rat thymocytes, in the presence of phytohaemagglutinin (PHA), was stimulated by bovine inhibin (ED50 0.7 nM), and inhibited by bovine activin (ID50 0.4 nM) and porcine transforming growth factor-beta (TGF-beta) (ID50 4 pM); inhibin opposed the actions of activin and TGF-beta. Bovine 35 kDa follicle stimulating hormone (FSH) suppressing protein (FSP) had no effect on either unstimulated or PHA-stimulated thymocytes. Inhibin also stimulated thymocytes in the presence of a submaximal dose of concanavalin A (ConA), and in the absence of either lectin. Thymocytes which had been maximally stimulated by ConA were inhibited by TGF-beta (ID50 0.02 nM), but not affected by inhibin and activin. Both activin and TGF-beta stimulated [3H]thymidine uptake by 3T3 fibroblasts, but inhibin and FSP had no effect, alone or on activin-stimulated 3T3 fibroblasts. The results indicate that inhibin and activin have opposing, cell type-specific effects on the proliferation of T-lymphocytes, while activin also stimulates fibroblast proliferation in vitro.
Mol Cell Endocrinol 1989 Jan
PMID:Inhibin and activin regulate [3H]thymidine uptake by rat thymocytes and 3T3 cells in vitro. 250 Nov 19


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