Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Saccharomyces cerevisiae alg12delta mutant accumulates oligosaccharide lipid with a Man(7)GlcNAc(2) oligosaccharide. To determine the N-glycan structures present on S. cerevisiae glycoproteins in the alg12delta strain, we made attempts to purify external invertase, a highly glycosylated secreted protein. These efforts revealed that, in the alg12delta background, external invertase was mildly hypoglycosylated and rapidly destroyed proteolytically. Although secreted alg9delta invertase was more severely hypoglycosylated than the alg12delta form, it was paradoxically stable during purification. The loss of periplasmic invertase was prevented by addition of pepstatin A to the cell cultures, suggesting that aspartyl proteases were active. We found that during overexpression of invertase in alg12delta yeast, sufficient protease A was mistargeted to the periplasmic space, where it hydrolyzed the invertase. Even though alg9delta invertase is underglycosylated in comparison to the alg12delta form, it is more stable because in this genetic background much less protease A is secreted compared to alg12delta cells. These observations may be relevant to studies using other extracellular proteins (e.g., mating factors, alpha-glucosidase) as probes when characterizing glycosylation defects in yeast.
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PMID:Hypoglycosylation in the alg12delta yeast mutant destabilizes protease A and causes proteolytic loss of external invertase. 1246 Sep 38

N-glycosylation in nearly all eukaryotes proceeds in the endoplasmic reticulum (ER) by transfer of the precursor Glc(3)Man(9)GlcNAc(2) from dolichyl pyrophosphate (PP-Dol) to consensus Asn residues in nascent proteins. The Saccharomyces cerevisiae alg (asparagine-linked glycosylation) mutants fail to synthesize oligosaccharide lipid properly, and the alg12 mutant accumulates a Man(7)GlcNAc(2)-PP-Dol intermediate. We show that the Man(7)GlcNAc(2) released from alg12Delta-secreted invertase is Manalpha1,2Manalpha1,2Manalpha1,3(Manalpha1,2Manalpha1,3Manalpha1,6)-Manbeta1,4-GlcNAcbeta1-4GlcNAcalpha/beta, confirming that the Man(7)GlcNAc(2) is the product of the middle-arm terminal alpha1,2-mannoslytransferase encoded by the ALG9 gene. Although the ER glucose addition and trimming events are similar in alg12Delta and wild-type cells, the central-arm alpha1,2-linked Man residue normally removed in the ER by Mns1p persists in the alg12Delta background. This confirms in vivo earlier in vitro experiments showing that the upper-arm Manalpha1,2Manalpha1,6-disaccharide moiety, missing in alg12Delta Man(7)GlcNAc(2), is recognized and required by Mns1p for optimum mannosidase activity. The presence of this Man influences downstream glycan processing by reducing the efficiency of Ochlp, the cis-Golgi alpha1,6-mannosyltransferase responsible for initiating outer-chain mannan synthesis, leading to hypoglycosylation of external invertase and vacuolar protease A.
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PMID:The Saccharomyces cerevisiae alg12delta mutant reveals a role for the middle-arm alpha1,2Man- and upper-arm alpha1,2Manalpha1,6Man- residues of Glc3Man9GlcNAc2-PP-Dol in regulating glycoprotein glycan processing in the endoplasmic reticulum and Golgi apparatus. 1246 Sep 43

The occurrence of intermixing, especially that resulting from genetically modified (GM) species, is increasingly becoming a problem in the delicate chain of feed and food quality control. Thus, a strategy is needed for precisely quantifying the presence of intermixing. An analytical assay based on real-time PCR has been developed; it can ascertain the extent of unexpected intermixing of GM soybean with maize meal. Three soybean-maize mix levels, with soybean intermix percentages of, respectively, 0.1, 0.5, and 1%, were prepared to simulate samples containing traces of soybean. As calibrator standards, ad hoc multiple-target pGEM-T plasmids containing soybean and maize reference genes in a 1:1 ratio were constructed. Four different maize endogenous genes, alcohol dehydrogenase 1 (adh1), high-mobility group protein a (hmga), invertase 1 (ivr1), and zein (zein), were assessed, each combined with the soybean endogenous lectin 1 (lect1) gene. Plasmids containing adh1-lect1 and zein-lect1 genes were found to be the most reliable calibration systems for this analysis, providing precise and accurate quantification results. Measuring the percentage of GM soybean intermixing makes it possible to calculate the actual transgenic component of the total sample.
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PMID:Development of a real-time PCR method based on duplo target plasmids for determining an unexpected genetically modified soybean intermix with feed components. 1730 Jan 50

S. cerevisiae mutants lacking VPS4 missort several vacuolar proteins to the extracellular space, including carboxypeptidase (CPY), vacuolar protease A (PrA), and vacuolar protease B (PrB). In addition, certain soluble secretory proteins, such as invertase and acid phosphatase, are missorted from the pre-vacuolar compartment (PVC) to the general secretory pathway prior to exocytosis. Although little is known about sorting of proteins via the PVC in Candida albicans, we have previously demonstrated that the C. albicans vps4Delta null mutant missorts PrA and CPY extracellularly, but fails to secrete the aspartyl proteases Sap2p and Sap4-6p. To further define the role of C. albicans VPS4 in the trafficking of pre-vacuolar proteins, we have used 2 dimensional gel electrophoresis (2-DE) and mass spectrometry techniques to study soluble proteins in the supernatants of planktonic cultures obtained from the C. albicans vps4Delta mutant compared to control strain DAY185. Results indicated that lack of VPS4 results in a decrease of canonically secreted proteins whilst having a limited effect on non-canonically secreted extracellular proteins. Four canonically secreted proteins (Cht3p, Pra1p, Mp65p and Sun41p) were identified as reduced in the supernatants from the mutant strain. We also indentified two other major consequences of lack of VPS4, likely associated with secretion defects: altered branching and biofilm formation.
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PMID:A proteomic analysis of secretory proteins of a pre-vacuolar mutant of Candida albicans. 1981 58