Enzymes Involved in Generation and Degradation of the Free Oligosaccharides in the Cytosol of Caenorhabditis elegans

Abstract

Free oligosaccharides (FOS) in the cytosol of eukaryotic cells are mainly generated during endoplasmic reticulum-associated degradation (ERAD) of misfolded glycoproteins. We characterized the enzymes involved in generation and degradation of FOS in the nematode Caenorhabditis elegans. 1) Peptide: N-glycanase (PNGase) from Caenorhabditis elegans, which releases FOS from misfolded glycoproteins in the cytosol, was shown to be a unique bifunctional enzyme having both deglycosylation and protein disulfide reductase activities. 2) Endo-β-N-acetylglucosaminidase was proven to release a single GlcNAc residue at the reducing end of FOS in vivo. 3) Luminal class 1 α-mannosidases, probably Golgi α-mannosidase I, was involved in generation of M5A isoform of Man5GlcNAc1 that is specific to C. elegans.

The class I α1,2-mannosidases of Caenorhabditis elegans

“…As also proposed by others [36], such an analysis suggests that in the case of C. elegans two mannosidases are of the endoplasmic reticulum I type and two of the Golgi I type-this is in contrast to one endoplasmic reticulum type in many organisms such as Saccharomyces cerevisiae, Arabidopsis thaliana, Drosophila melanogaster and Homo sapiens and to three Golgi type I mannosidases encoded by the human genome; the model cerevisiae are analysed using the Multalin server [34]. Three major groups are apparent: the folding-associated mannosidases/mannosidase-like proteins, the Golgi type I mannosidases and the endoplasmic reticulum mannosidases plant and the model fly have each two Golgi class I enzymes.…”

Down regulation ofEngaseinCaenorhabditis elegansmay improve its stresses adaptivity

“…CeEngase deletion mutant was constructed by using conventional mutagenesis. In addition, fOSs and some basic biological indicators were examined under normal conditions [13, 14].…”