Caenorhabditis Elegans N-Glycan Core Beta-Galactoside Confers Sensitivity Towards Nematotoxic Fungal Galectin Cgl2.
Butschi, A., Titz, A., Walti, M.A., Olieric, V., Paschinger, K., Nobauer, K., Guo, X., Seeberger, P.H., Wilson, I.B.H., Aebi, M., Hengartner, M.O., Kunzler, M.(2010) PLoS Pathog 6: E717
- PubMed: 20062796 
- DOI: https://doi.org/10.1371/journal.ppat.1000717
- Primary Citation of Related Structures:  
2WKK - PubMed Abstract: 
The physiological role of fungal galectins has remained elusive. Here, we show that feeding of a mushroom galectin, Coprinopsis cinerea CGL2, to Caenorhabditis elegans inhibited development and reproduction and ultimately resulted in killing of this nematode. The lack of toxicity of a carbohydrate-binding defective CGL2 variant and the resistance of a C. elegans mutant defective in GDP-fucose biosynthesis suggested that CGL2-mediated nematotoxicity depends on the interaction between the galectin and a fucose-containing glycoconjugate. A screen for CGL2-resistant worm mutants identified this glycoconjugate as a Galbeta1,4Fucalpha1,6 modification of C. elegans N-glycan cores. Analysis of N-glycan structures in wild type and CGL2-resistant nematodes confirmed this finding and allowed the identification of a novel putative glycosyltransferase required for the biosynthesis of this glycoepitope. The X-ray crystal structure of a complex between CGL2 and the Galbeta1,4Fucalpha1,6GlcNAc trisaccharide at 1.5 A resolution revealed the biophysical basis for this interaction. Our results suggest that fungal galectins play a role in the defense of fungi against predators by binding to specific glycoconjugates of these organisms.
Organizational Affiliation: 
Institute of Molecular Biology, University of Zürich, Zürich, Switzerland.