Dataset Information

Glycopeptide specificity of the secretory protein folding sensor UDP-glucose glycoprotein:glucosyltransferase.

ABSTRACT: Secretory and membrane N-linked glycoproteins undergo folding and oligomeric assembly in the endoplasmic reticulum with the aid of a folding mechanism known as the calnexin cycle. UDP-glucose glycoprotein:glucosyltransferase (UGGT) is the sensor component of the calnexin cycle, which recognizes these glycoproteins when they are incompletely folded, and transfers a glucose residue from UDP-glucose to N-linked Man9-GlcNAc2 glycans. To determine how UGGT recognizes incompletely folded glycoproteins, we used purified enzyme to glucosylate a set of Man9-GlcNAc2 glycopeptide substrates in vitro, and determined quantitatively the glucose incorporation into each glycan by mass spectrometry. A ranked order of glycopeptide specificity was found that provides the criteria for the recognition of substrates by UGGT. The preference for amino-acid residues close to N-linked glycans provides criteria for the recognition of glycopeptide substrates by UGGT.

SUBMITTER: Taylor SC

PROVIDER: S-EPMC1319153 | biostudies-literature | 2003 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Glycopeptide specificity of the secretory protein folding sensor UDP-glucose glycoprotein:glucosyltransferase.

Taylor Sean C SC Thibault Pierre P Tessier Daniel C DC Bergeron John J M JJ Thomas David Y DY

EMBO reports 20030401 4

Secretory and membrane N-linked glycoproteins undergo folding and oligomeric assembly in the endoplasmic reticulum with the aid of a folding mechanism known as the calnexin cycle. UDP-glucose glycoprotein:glucosyltransferase (UGGT) is the sensor component of the calnexin cycle, which recognizes these glycoproteins when they are incompletely folded, and transfers a glucose residue from UDP-glucose to N-linked Man9-GlcNAc2 glycans. To determine how UGGT recognizes incompletely folded glycoproteins ...[more]

PMID: 12671684

Similar Datasets

Project description:The UDP-Glc:glycoprotein glucosyltransferase (UGGT) is the sensor of glycoprotein conformations in the glycoprotein folding quality control as it exclusively glucosylates glycoproteins not displaying their native conformations. Monoglucosylated glycoproteins thus formed may interact with the lectin-chaperones calnexin (CNX) and calreticulin (CRT). This interaction prevents premature exit of folding intermediates to the Golgi and enhances folding efficiency. Bioinformatic analysis showed that in C. elegans there are two open reading frames (F48E3.3 and F26H9.8 to be referred as uggt-1 and uggt-2, respectively) coding for UGGT homologues. Expression of both genes in Schizosaccharomyces pombe mutants devoid of UGGT activity showed that uggt-1 codes for an active UGGT protein (CeUGGT-1). On the other hand, uggt-2 coded for a protein (CeUGGT-2) apparently not displaying a canonical UGGT activity. This protein was essential for viability, although cnx/crt null worms were viable. We constructed transgenic worms carrying the uggt-1 promoter linked to the green fluorescent protein (GFP) coding sequence and found that CeUGGT-1 is expressed in cells of the nervous system. uggt-1 is upregulated under ER stress through the ire-1 arm of the unfolded protein response (UPR). Real-time PCR analysis showed that both uggt-1 and uggt-2 genes are expressed during the entire C. elegans life cycle. RNAi-mediated depletion of CeUGGT-1 but not of CeUGGT-2 resulted in a reduced lifespan and that of CeUGGT-1 and CeUGGT-2 in a developmental delay. We found that both CeUGGT1 and CeUGGT2 play a protective role under ER stress conditions, since 10 µg/ml tunicamycin arrested development at the L2/L3 stage of both uggt-1(RNAi) and uggt-2(RNAi) but not of control worms. Furthermore, we found that the role of CeUGGT-2 but not CeUGGT-1 is significant in relieving low ER stress levels in the absence of the ire-1 unfolding protein response signaling pathway. Our results indicate that both C. elegans UGGT homologues have distinct biological functions.

Dataset Information

Glycopeptide specificity of the secretory protein folding sensor UDP-glucose glycoprotein:glucosyltransferase.

Publications

Glycopeptide specificity of the secretory protein folding sensor UDP-glucose glycoprotein:glucosyltransferase.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets