Treatment with a low dose (0.5 microgram/ml) of tunicamycin (an inhibitor of N-linked glycosylation) blocked the cell cycle progression of both normal Balb/c 3T3 cells (A31) and their SV40-transformed derivatives (SVA31) specifically in early G1 (0-3 h after mitosis). Upon release after an 8-h treatment the A31 cells returned to the cell cycle via a 9-h recovery phase, indicating that they were...

Formation of the dolichol oligosaccharide precursor is essential for the production of asparagine- (N-) linked oligosaccharides (N-glycans) in eukaryotic cells. The first step in precursor biosynthesis requires the enzyme UDP-GlcNAc: dolichol phosphate N-acetylglucosamine-1-phosphate transferase (GPT). Without GPT activity, subsequent steps necessary in constructing the oligosaccharide precurso...

Human hepatic lipase (HL) is a glycoprotein with four N-linked oligosaccharide side chains. The importance of glycosylation for the secretion of catalytically active HL was studied in HepG2 cells by using inhibitors of intracellular trafficking, N-glycosylation and oligosaccharide processing. Secretion of HL was inhibited by carbonyl cyanide m-chlorophenylhydrazone (CCCP), monensin, brefeldin A...

We have investigated the role of the carbohydrate moiety in the biological activity of fibronectin in vitro by using tunicamycin to inhibit the glycosylation of this glycoprotein. Tunicamycin is a glucosamine-containing antibiotic that specifically inhibits glycosylation of protein asparaginyl residues mediated by dolichol pyrophosphate. Fibronectin synthesized in the presence of 0.5 microgram ...

We have analyzed the role of N-linked glycosylation in functional cell surface expression of the D1 and D5 dopamine receptor subtypes. Treatment of transfected HEK 293 cells with tunicamycin, an inhibitor of N-linked oligosaccharide addition, was found to prevent localization of D5 receptors in the plasma membrane. In contrast, tunicamycin treatment had no effect on the plasma membrane localiza...

Matched pairs of malignant and non-malignant hybrid cells were compared in their response to glucose deprivation and to tunicamycin. Glucose deprivation induced an increase in the maximum velocity in the malignant cells, but not in the non-malignant cells. The Michaelis constant of hexose uptake was largely unchanged by glucose deprivation except in the case of one melanoma derivative, PG19 G-,...

The transcription factor CHOP/GADD153 is induced during the unfolded protein response (UPR) and is associated to the induction of ER stress-related apoptosis. However, how the transition between the pro-survival and the pro-apoptotic role of ER stress is being orchestrated remains poorly understood. Here we show that tunicamycin, an antibiotic promoting ER stress, suppresses the expression of p...

I-cell cultured fibroblasts secrete excessive amounts of N-acetyl-fl-D-hexosaminidase and a -L-fucosidase into the culture media as compared with normal fibroblasts. Addition of tunicamycin or cycloheximide at doses that inhibit the incorporation of [3Hlmannose (60-80%) and [14C]leucine (40-50%) into trichloroacetic acid-precipitable material decreased the secretion of these I-cell hydrolases t...

Cytotoxic T cell (CTL)-specific activation antigens, termed CT determinants, have been detected by monoclonal antibodies (mAb) that inhibit CTL function. At the cell surface, the CT antigens are associated with the T200 glycoproteins and two other proteins of Mr 140,000 and 85,000 and are present on a secreted protein, gp155. Periodate treatment followed by binding analysis and immunoprecipitat...

The mosquito-active protein crystals produced by Bacillus thuringiensis subsp. israelensis contain covalently attached aminosugars which are critical for their larvicidal activity. The 50% lethal concentrations toward Aedes aegypti larvae were increased up to 10-fold by mild periodate treatment, up to 40-fold by forming the protein crystals in the presence of tunicamycin, and up to 7-fold by th...