Identification of proteins that interact with mammalian peptide:N-glycanase and implicate this hydrolase in the proteasome-dependent pathway for protein degradation.

Peptide:N-glycanase (PNGase) cleaves oligosaccharide chains from glycopeptides and glycoproteins. Recently the deduced amino acid sequence of a cytoplasmic PNGase has been identified in various eukaryotes ranging from yeast to mammals, suggesting that deglycosylation may play a central role in some catabolic process. Several lines of evidence indicate that the cytoplasmic ...
enzyme is involved in the quality control system for newly synthesized glycoproteins. Two-hybrid library screening by using mouse PNGase as the target yielded several PNGase-interacting proteins that previously had been implicated in proteasome-dependent protein degradation: mHR23B, ubiquitin, a regulatory subunit of the 19S proteasome, as well as a protein containing an ubiquitin regulatory motif (UBX) and an ubiquitin-associated motif (UBA). These findings by using the two-hybrid system were further confirmed either by in vitro binding assays or size fractionation assays. These results suggest that PNGase may be required for efficient proteasome-mediated degradation of misfolded glycoproteins in mammalian cells.
Mesh Terms:
3T3 Cells, Amidohydrolases, Animals, COS Cells, Cercopithecus aethiops, Cloning, Molecular, Cysteine Endopeptidases, Cytoplasm, Escherichia coli, Gene Library, Mammals, Mice, Multienzyme Complexes, Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase, Proteasome Endopeptidase Complex, Proteins, Recombinant Fusion Proteins, Recombinant Proteins, Saccharomyces cerevisiae, Substrate Specificity, Transfection, Ubiquitin
Proc. Natl. Acad. Sci. U.S.A.
Date: Sep. 25, 2001
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