• gene knockout;
  • glycoblotting;
  • glycoprotein N-glycans;
  • glycosphingolipids;
  • glycotyping analysis;
  • GM3 synthase
Thumbnail image of graphical abstract

The cover picture shows that gene knockout of the enzymes responsible for glycosphingolipid (GSL) synthesis significantly influences the biosynthesis of glycoprotein N-glycans. On p. 73 ff., S.-I. Nishimura et al. describe how they have established a general and comprehensive glycomics protocol of cellular GLSs and N-glycans of glycoproteins. To test the feasibility of a glycoblotting-based protocol, whole glycans released both from GLSs and glycoproteins were profiled concurrently by using the GM3 synthase-deficient mouse embryonic fibroblast GM3(−/−). GM3(−/−) cells did not synthesize GM3 or any downstream product of GM3 synthase. Instead, expression levels of o-series gangliosides involving GM1b and GD1-α were increased dramatically whereas a-/b-series gangliosides were predominantly detected in wild-type cells. It was also discovered that glycoprotein N-glycan profiles of GM3(−/−) cells are significantly different from those of WT cells, though GM3 synthase is responsible only for GSL synthesis and is not associated with glycoprotein N-glycan biosynthesis.