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排序方式: 共有329条查询结果,搜索用时 218 毫秒
1.
Cells of the human promyelocytic HL60 line were induced to differentiate into granulocyte-like cells with dimethylsulphoxide (DMSO) or macrophage-like cells with 12-0-tetradecanoylphorbol-13-acetate (TPA). The synthesis of Cathepsin B by these cells was studied by immunoperoxidase staining and assay of cell lysates using the fluorimetric substrate benzoyloxycarbonyl-phenylanalyl-arginine-4-methyl-7-coumarylamide. Only 2–5% of the uninduced HL60 cells and DMSO-induced cells were immunohistochemically positive for Cathepsin B, compared with over 80% of the TPA-induced cells. Cathepsin B activity was lowest in the lysates of uninduced HL60s. DMSO-induced cells contained 1.5–2-fold the enzyme activity of HL60s and TPA-induced cell lysates demonstrated 5–14-fold the activity of uninduced HL60s. Induction of Cathepsin B synthesis was therefore associated with differentiation of the promyelocytes into cells of the monocyte/macrophage type, but not granulocyte-like cells. Cathepsin B was located immunohistochemically in human palatine tonsils. The enzyme was only demonstrated within macrophages in these tissues. Cathepsin B may therefore be a useful immunohistochemical marker for malignant and nonmalignant cells of the monocyte/macrophage lineage. 相似文献
2.
Kristina Mrkoci Sørge Kelm Paul R. Crocker Roland Schauer Eric G. Berger 《Glycoconjugate journal》1996,13(4):567-573
Previously, 1,3-galactosyltransferase-deficient (Tn+) and normal (TF+) T-lymphocyte clones have been established from a patient suffering from Tn-syndrome [Thurnheret al. (1992)Eur J Immunol
22: 1835–42], Tn+ T lymphocytes express only Tn antigen (GalNAc1-O-R) while other O-glycan structures such as sialosyl-Tn (Neu5Ac2,6GalNAc1-O-R) or TF (Gal1-3GalNAc1-O-R) antigens are absent from these cells as shown by flow cytometry using specific mABs for TF and sialosyl-Tn antigen, respectively. Normal T lymphocytes express the TF antigen and derivatives thereof. The surface glycans of Tn+ and TF+ cells were then analysed by flow cytometry using the following sialic acid-binding lectins:Amaranthus caudatus (ACA),Maackia amurensis (MAA),Limax flavus (LFA),Sambucus nigra (SNA) andTriticum vulgare (WGA). Equal and weak binding of MAA and SNA to both TF+ and Tn+ cells was found. WGA, LFA and ACA bound more strongly to TF+ cells than to Tn+ cells. Binding of ACA to TF+ cells was enhanced after sialidase treatment. To investigate the possible biological consequences of hyposialylation, binding of three sialic acid-dependent adhesion molecules to Tn+ and TF+ cells was estimated using radiolabelled Fc-chimeras of sialoadhesin (Sn), myelin-associated glycoprotein (MAG) and CD22. Equal and strong binding of human CD22 to both TF+ and Tn+ cells was found. Whereas binding of Sn and MAG to TF+ cells was strong (100%), binding to Tn+ cells amounted only to 33% (Sn) and 19% (MAG). These results indicate that thein vivo interactions of T lymphocytes in the Tn syndrome with CD22 are not likely to be affected, whereas adhesion mediated by Sn or MAG could be strongly reduced. 相似文献
3.
Sialoadhesin, a macrophage sialic acid binding receptor for haemopoietic cells with 17 immunoglobulin-like domains. 总被引:15,自引:0,他引:15 下载免费PDF全文
P R Crocker S Mucklow V Bouckson A McWilliam A C Willis S Gordon G Milon S Kelm P Bradfield 《The EMBO journal》1994,13(19):4490-4503
Sialoadhesin is a macrophage-restricted adhesion molecule of 185 kDa that mediates sialic acid-dependent binding to cells. It is expressed strongly by macrophages in lymphoid and haemopoietic tissues where it is likely to mediate cell-cell interactions. Here we report the molecular cloning of murine sialoadhesin and show that it is a new member of the immunoglobulin (Ig) superfamily with 17 Ig-like domains. COS cells transfected with a cDNA encoding full-length sialoadhesin bound mouse bone marrow cells in a sialic acid-dependent manner. Alternatively spliced cDNAs, predicting soluble forms of sialoadhesin containing the first three or 16 Ig-like domains of sialoadhesin, were expressed in COS cells and the respective proteins purified. When immobilized on plastic, the 16-domain form bound cells in a sialic acid-dependent manner, suggesting that sialoadhesin can function in both secreted and membrane-bound forms. The most similar proteins in the database were CD22, myelin-associated glycoprotein, Schwann cell myelin protein and CD33. Like sialoadhesin, CD22 mediates sialic acid-dependent cell adhesion. The sequence similarity of sialoadhesin to CD22 and related members of the Ig superfamily indicates the existence of a novel family of sialic acid binding proteins involved in cell-cell interactions. 相似文献
4.
5.
M Platz A S Admasu S Kwiatkowski P J Crocker N Imai D S Watt 《Bioconjugate chemistry》1991,2(5):337-341
The photolysis of 3-(4-tolyl)-3-(trifluoromethyl)diazirine in the presence of benzene, methanol, carbon tetrachloride, cyclohexane, triethylsilane, or diethylamine led to photoproducts consistent with the intermediacy of a singlet carbene. In the case of diethylamine, the photoinsertion into the N-H bond of diethylamine produced the expected adduct, 1-(diethylamino)-2,2,2-trifluoro-1-(4-tolyl)ethane. However, the base-catalyzed elimination of hydrogen fluoride from this adduct afforded an enamine, alpha-(diethylamino)-beta,beta-difluoro-4-methylstyrene, and the subsequent hydrolysis of this enamine furnished diethylamine and 2,2-difluoro-1-(4-tolyl)ethanone. This elimination and hydrolysis sequence effectively reversed the photoinsertion process. A similar photoinsertion and hydrolysis process using 3-(4-n-octylphenyl)-3-(trifluoromethyl)diazirine also produced 2,2-difluoro-1-(4-n-octylphenyl)ethanone in modest yield. These results suggest that the photoinsertion products from 3-aryl-3-(trifluoromethyl)-diazirines in biological systems may suffer similar fates limiting, in part, their utility in obtaining primary sequence data. 相似文献
6.
7.
Willis Cory M. Sutter Pearl Rouillard Megan Crocker Stephen J. 《Neurochemical research》2020,45(3):694-707
Neurochemical Research - The aging brain is associated with significant pathophysiological changes reflected in changes in astrocyte function. In this study, we hypothesized that the response of... 相似文献
8.
Michael L. Patnode Chu-Wen Cheng Chi-Chi Chou Mark S. Singer Matilda S. Elin Kenji Uchimura Paul R. Crocker Kay-Hooi Khoo Steven D. Rosen 《The Journal of biological chemistry》2013,288(37):26533-26545
Eosinophil accumulation is a characteristic feature of the immune response to parasitic worms and allergens. The cell surface carbohydrate-binding receptor Siglec-F is highly expressed on eosinophils and negatively regulates their accumulation during inflammation. Although endogenous ligands for Siglec-F have yet to be biochemically defined, binding studies using glycan arrays have implicated galactose 6-O-sulfate (Gal6S) as a partial recognition determinant for this receptor. Only two sulfotransferases are known to generate Gal6S, namely keratan sulfate galactose 6-O-sulfotransferase (KSGal6ST) and chondroitin 6-O-sulfotransferase 1 (C6ST-1). Here we use mice deficient in both KSGal6ST and C6ST-1 to determine whether these sulfotransferases are required for the generation of endogenous Siglec-F ligands. First, we characterize ligand expression on leukocyte populations and find that ligands are predominantly expressed on cell types also expressing Siglec-F, namely eosinophils, neutrophils, and alveolar macrophages. We also detect Siglec-F ligand activity in bronchoalveolar lavage fluid fractions containing polymeric secreted mucins, including MUC5B. Consistent with these observations, ligands in the lung increase dramatically during infection with the parasitic nematode, Nippostrongylus brasiliensis, which is known to induce eosinophil accumulation and mucus production. Surprisingly, Gal6S is undetectable in sialylated glycans from eosinophils and BAL fluid analyzed by mass spectrometry. Furthermore, none of the ligands we describe are diminished in mice lacking KSGal6ST and C6ST-1, indicating that neither of the known galactose 6-O-sulfotransferases is required for ligand synthesis. These results establish that ligands for Siglec-F are present on several cell types that are relevant during allergic lung inflammation and argue against the widely held view that Gal6S is critical for glycan recognition by this receptor. 相似文献
9.
Stephen K. Tavoni Cory D. Champagne Dorian S. Houser Daniel E. Crocker 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2013,183(4):537-546
Elephant seals maintain rates of endogenous glucose production (EGP) typical of post-absorptive mammals despite enduring prolonged periods of food deprivation concurrent with low rates of glucose oxidation. These high rates of EGP suggest extensive glucose recycling during fasting. We investigated lactate metabolism in fasting elephant seals to assess its role in glucose recycling. Whole-animal glucose and lactate fluxes were measured as the rates of appearance of glucose and lactate (Ra gluc and Ra lac, respectively) using a primed constant infusion of [U-14C] lactate and [6-3H] glucose, and we calculated the minimum contribution of lactate to gluconeogenesis (GNG lac). Ra lac was high compared to resting values in other species (3.21 ± 0.71 mmol min?1* kg?1), did not change between 14 ± 1 and 31 ± 8 days of fasting and varied directly with Ra glu. The minimum GNG lac was 44.6 ± 6.0 % of EGP, varied directly with plasma lactate levels, and did not change over the fast. Ra lac and Ra glu both varied directly with plasma insulin concentrations. These data suggest that lactate is the predominant gluconeogenic precursor in fasting elephant seals and that high rates of glucose recycling through Cori cycle activity contribute to the maintenance of EGP during fasting. High levels of Cori cycle activity and EGP may be important components of metabolic adaptations that maintain glucose production while avoiding ketosis during extended fasting or are related to sustained metabolic alterations associated with extended breath-holds in elephant seals. 相似文献
10.
Orr SJ Morgan NM Buick RJ Boyd CR Elliott J Burrows JF Jefferies CA Crocker PR Johnston JA 《The Journal of biological chemistry》2007,282(6):3418-3422
CD33-related Siglecs (sialic acid-binding immunoglobulin-like lectins) 5-11 are inhibitory receptors that contain a membrane proximal ITIM (immunoreceptor tyrosine-based inhibitory motif) (I/V/L/)XYXX(L/V), which can recruit SHP-1/2. However, little is known about the regulation of these receptors. SOCS3 (suppressor of cytokine signaling 3) is up-regulated during inflammation and competes with SHP-1/2 for binding to ITIM-like motifs on various cytokine receptors resulting in inhibition of signaling. We show that SOCS3 binds the phosphorylated ITIM of Siglec 7 and targets it for proteasomal-mediated degradation, suggesting that Siglec 7 is a novel SOCS target. Following ligation, the ECS E3 ligase is recruited by SOCS3 to target Siglec 7 for proteasomal degradation, and SOCS3 expression is decreased concomitantly. In addition, we found that SOCS3 expression blocks Siglec 7-mediated inhibition of cytokine-induced proliferation. This is the first time that a SOCS target has been reported to degrade simultaneously with the SOCS protein and that inhibitory receptors have been shown to be degraded in this way. This may be a mechanism by which the inflammatory response is potentiated during infection. 相似文献