Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.52 (PNGase F)
 1,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Swainsonine, a known inhibitor of the alpha-mannosidase II involved in processing of asparagine-linked glycoproteins, causes accumulation of hybrid-type oligosaccharide-containing glycoproteins in mammalian cells. Swainsonine augments lymphokine-activated, killer-cell induction at suboptimal doses of interleukin-2; the amount needed to increase LAK activity is 100-1000 fold higher than required to completely inhibit mannosidase II. Human mononuclear lymphocytes, when treated with these relatively high (58 microM) concentrations of swainsonine showed a 3-4 fold increase in D-[3H]mannose incorporation into the glycan as compared to glycans of untreated cells. Analysis indicated accumulation of high-mannose type, free oligosaccharides in the soluble fractions of the cell. Chromatographic analysis of glycan obtained by D-[2-3H]mannose labeling of human mononuclear lymphocytes showed synthesis of a new oligosaccharide, at 58 microM of swainsonine, that contained 36% of the total radioactivity incorporated into the glycan (oligosaccharide pool). This oligosaccharide fraction was resistant to hydrolysis by endoglycosidase H, endoglycosidase F, O and N-glycanase, but was susceptible to cleavage by Jack bean alpha-mannosidase and was bound > 90% to concanavalin A-Sepharose. A similar chromatographic elution profile was obtained from glycans labeled with D-[2-3H]mannose from mouse B16F10 melanoma and baby hamster kidney cells subsequent to swainsonine treatment. Methylation analysis of free oligosaccharides obtained from MNL revealed the presence of a pentamannose. These results indicate the accumulation of a free high-mannose oligosaccharide rather than expected hybrid-type structure on treatment of cells with relatively high concentrations of swainsonine.
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PMID:Accumulation of pentamannose oligosaccharides in human mononuclear leukocytes by action of swainsonine, an inhibitor of glycoprotein processing. 825 42

In this study, we show that NKRP1A is expressed and functions on a subset of immature human thymocytes. We took advantage of the monoclonal antibody (mAb) 191B8 that was obtained by immunizing mice with cultured human thymocytes characterized by an immature surface phenotype [CD2- CD3- CD4- CD8- stem cell factor receptor (SCFR)+] and expressing cytoplasmic CD3 epsilon chain. The 191B8 antibody homogeneously reacted with the immunizing population but not with most unfractionated thymocytes. It stained a minor population of resting immature thymocytes co-expressing CD34, SCFR, or both. Following culture of the CD34+ or CD34- fractions of CD2- CD3- CD4- CD8- purified immature thymocytes with recombinant interleukin-2 (rIL-2), the 191B8-defined antigen was expressed on virtually all cells even when 191B8+ cells were removed from the starting population. On the other hand, no 191B8+ cells were detected in fresh or cultured thymocytes expressing a more mature phenotype. Biochemical analysis of 191B8 mAb-reactive molecules revealed, under non-reducing conditions, two bands displaying apparent molecular masses of 80 and 44 kDa and a single band of 44 kDa under reducing conditions. Digestion with proteases indicated that the 80-kDa form represented a homodimeric form of two 44-kDa molecules, while deglycosylation with N-glycanase suggested the existence of four N-glycosylation sites. Transfection of COS7 or NIH3T3 cells with hNKRP1A cDNA showed that the 191B8 mAb recognized NKRP1A as shown by both immunofluorescence analysis and immunoprecipitation experiments. Functional studies showed that the 191B8/NKRP1A molecule mediated strong inhibition of the cytolytic activity of cultured CD2- CD3- immature thymocytes against a panel of tumor target cells. More importantly, 191B8 mAb induced proliferation of CD2- CD3- fresh thymocytes which was not increased by rIL-2. Thus, we propose that NKRP1A molecules, which are expressed in highly immature thymocytes, may play a regulatory role in their growth and function.
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PMID:Expression of human NKRP1A by CD34+ immature thymocytes: NKRP1A-mediated regulation of proliferation and cytolytic activity. 864 3

Interleukin-2 and interleukin-6 can stimulate the growth and proliferation of T lymphocytes and the differentiation of activated B lymphocytes respectively, and in turn enhance cellular and humoral immune responses. In this work, an expression clone using Pichia pastoris, a methylotrophic yeast strain, has been developed in order to produce large amounts of the functional recombinant fusion protein pIL-6-IL-2, which contains the mature porcine interleukin-6 peptide and the mature porcine interleukin-2 peptide. Two components of the fusion protein were connected by means of a flexible linker (Gly-Gly-Gly-Gly-Ser-Glu-Phe-Gly-Ser-Gly-Gly). In response to 1% methanol induction, the recombinant strain GS115\9K-IL6-IL2 secreted an exogenous protein, with a molecular weight of approximately 40 kD, into the culture medium. This was confirmed to be pIL-6-IL-2 by means of SDS-PAGE and Western Blot analysis. The protein was visible on the 2nd day following methanol induction, and peaked on the 4th day. By this time, the level had reached 50 mg\L as determined using the method of Bradford. After treatment with PNGase F and analysis of the concentration of sugar, the fusion protein pIL-6-IL-2 was further confirmed to be mainly a glycoprotein with an approximately 2 kDa sugar decoration. In addition, the IL-6 and IL-2 biological activities of the fusion protein, determined by cell proliferation assays using the IL6-dependent cell line B9 and the IL2-dependent cell line CTLL-2, reached 1 x 10(5) U\mg and 8 x 10(5) U\mg, respectively. This report is the first description of fused porcine cytokines expressed in P. pastoris, which might be an interesting adjuvant product for veterinary vaccines.
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PMID:Expression of an interleukin-6 - interleukin-2 fusion protein (pIL-6-IL-2) in P. pastoris. 1554 49