RRC ID 3532
Author Paschinger K, Hackl M, Gutternigg M, Kretschmer-Lubich D, Stemmer U, Jantsch V, Lochnit G, Wilson IB.
Title A deletion in the golgi alpha-mannosidase II gene of Caenorhabditis elegans results in unexpected non-wild-type N-glycan structures.
Journal J. Biol. Chem.
Abstract The processing of N-linked oligosaccharides by alpha-mannosidases in the endoplasmic reticulum and Golgi is a process conserved in plants and animals. After the transfer of a GlcNAc residue to Asn-bound Man(5)GlcNAc(2) by N-acetylglucosaminyltransferase I, an alpha-mannosidase (EC removes one alpha1,3-linked and one alpha1,6-linked mannose residue. In this study, we have identified the relevant alpha-mannosidase II gene (aman-2; F58H1.1) from Caenorhabditis elegans and have detected its activity in both native and recombinant forms. For comparative studies, the two other cDNAs encoding class II mannosidases aman-1 (F55D10.1) and aman-3 (F48C1.1) were cloned; the corresponding enzymes are, respectively, a putative lysosomal alpha-mannosidase and a Co(II)-activated alpha-mannosidase. The analysis of the N-glycan structures of an aman-2 mutant strain demonstrates that the absence of alpha-mannosidase II activity results in a shift to structures not seen in wild-type worms (e.g. N-glycans with the composition Hex(5-7)HexNAc(2-3)Fuc(2)Me) and an accumulation of hybrid oligosaccharides. Paucimannosidic glycans are almost absent from aman-2 worms, indicative also of a general lack of alpha-mannosidase III activity. We hypothesize that there is a tremendous flexibility in the glycosylation pathway of C. elegans that does not impinge, under standard laboratory conditions, on the viability of worms with glycotypes very unlike the wild-type pattern.
Volume 281(38)
Pages 28265-77
Published 2006-9-22
DOI 10.1074/jbc.M602878200
PII M602878200
PMID 16864579
PMC PMC2848328
MeSH Animals Caenorhabditis elegans / enzymology* Glycosylation Golgi Apparatus / enzymology* Mutation Polysaccharides / biosynthesis Polysaccharides / chemistry* Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization alpha-Mannosidase / genetics alpha-Mannosidase / physiology*
IF 4.011
Times Cited 26
C.elegans tm1078