Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.53 (sialidase)
 2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Porcine interferon-gamma (SfPoIFN-gamma) was expressed with high efficiency in Spodoptera frugiperda (Sf9) cells by means of the baculovirus expression system. Up to 10(5) U/ml of antivirally active SfPoIFN-gamma could be tracked down in the culture medium at 64 h postinfection. Three proteins (17, 19, and 21 kDa), which under nondenaturing conditions primarily exist as mutual-dimeric combinations, were purified by immunoaffinity chromatography. Carbohydrate labeling and kinetic deglycosylation studies suggested that the 19- and 21-kDa proteins are N-glycosylated variants of a single 17-kDa protein carrying no N-linked sugars, in which one respectively two N-glycosylation sequons are occupied by glycans of 2 kDa. Both the quantitative recovery of SfPoIFN-gamma from a Con A column at 0.2 M methyl-alpha-mannopyranoside and the results of lectin blots, revealing strong affinity of the 19- and 21-kDa species for Galanthus nivalis agglutinin, support the presence of N-glycosidically linked high mannose-type chains in the carbohydrate moiety of SfPoIFN-gamma. Intriguingly, both 19- and 21-kDa glycoforms, but not their sialidase-treated derivatives, showed clear reactivity with the Sambucus nigra and Maackia amurensis agglutinins. These agglutinins specifically recognize sialic acid linked alpha(2-6) and alpha(2-3), respectively, to penultimate galactose residues. Their affinity for the larger glycoforms of PoIFN-gamma suggests that the biosynthetic pathways in Sf9 cells are able to modify oligomannose structures to complex or hybrid glycans.
Lymphokine Cytokine Res 1994 Aug
PMID:Glycoform heterogeneity of porcine interferon-gamma expressed in Sf9 cells. 799 24

Our previous studies have shown that the enzymatic activities of Neu-1, an endogenous sialidase encoded in the murine MHC, are involved in promoting IL-4 synthesis by naive CD4(+)T cells. Our present studies have characterized responsible sialoconjugate targets of Neu-1 and questioned possible biochemical mechanisms responsible for their regulatory influences on IL-4 gene expression. These studies determined that treatment of T cells with the naturally occurring ganglioside GM3 inhibited the production of IL-4 without affecting the production of IL-2. An analysis of IL-4-primed CD4(+)T cells further demonstrated that GM3 treatment specifically inhibited the restimulated production of IL-4, IL-5 and IL-13, without inhibiting the production of IL-2 and IFN-gamma. The inhibitory effects of GM3 could be overcome by treatment with thapsigargin or ionomycin, suggesting ganglioside regulation occurs upstream of activation-induced calcium mobilization. GM3 treatment attenuated the level of calcium influx following CD3epsilon crosslinking, and CD4(+)T cells from Neu-1-deficient B10.SM strain mice (neu-1(a)and IL-4-deficient) expressed reduced levels of intracellular calcium following activation. Our results indicate that activities by membrane gangliosides can influence the cytokine programs in CD4(+)T cells, possibly through the modulation of calcium responses induced by T cell activation.
Cytokine 2000 Jul
PMID:Ganglioside control over IL-4 priming and cytokine production in activated T cells. 1088 Feb 42