Identification of phosphorylated oligosaccharides in cells of patients with a congenital disorders of glycosylation (CDG-I).

Protein N-glycosylation is initiated by the dolichol cycle in which the oligosaccharide precursor Glc(3)Man(9)GlcNAc(2)-PP-dolichol is assembled in the endoplasmic reticulum (ER). One critical step in the dolichol cycle concerns the availability of Dol-P at the cytosolic face of the ER membrane. In RFT1 cells, the lipid-linked oligosaccharide (LLO) intermediate Man(5)GlcNAc(2)-PP-Dol accumulates at the cytosolic face of the ER membrane.

The dual origin of Toxoplasma gondii N-glycans.

N-Linked glycosylation is the most frequent modification of secreted proteins in eukaryotic cells that plays a crucial role in protein folding and trafficking. Mature N-glycans are sequentially processed in the endoplasmic reticulum and Golgi apparatus through a pathway highly conserved in most eukaryotic organisms. Here, we demonstrate that the obligate intracellular protozoan parasite Toxoplasma gondii independently transfers endogenous truncated as well as host-derived N-glycans onto its own proteins.

Influence of intracellular nucleotide and nucleotide sugar contents on recombinant interferon-gamma glycosylation during batch and fed-batch cultures of CHO cells.

Both the macroheterogeneity of recombinant human IFN-gamma produced by CHO cells and intracellular levels of nucleotides and sugar nucleotides, have been characterized during batch and fed-batch cultures carried out in different media. Whereas PF-BDM medium was capable to maintain a high percentage of the doubly- glycosylated glycoforms all over the process, mono-glycosylated and non-glycosylated forms increased during the batch culture using SF-RPMI medium. Intracellular level of UTP was higher in PF-BDM all over the batch culture compared to the SF-RPMI process.

Protein ubiquitination is modulated by O-GlcNAc glycosylation.

During the past two decades, O-GlcNAc modification of cytosolic and nuclear proteins has been intensively studied. Nevertheless, the function of this post-translational modification remains unclear. It has been recently speculated that O-GlcNAc could act as a protective signal against proteasomal degradation, both by modifying target substrates and/or by inhibiting the proteasome itself.