Abstract:Galactoseβ1-4fucose (Galβ1-4Fuc), a unique disaccharide unit found only on the N-glycans of Protostomia, has been intensively studied, particularly in Nematoda. Galβ1-4Fuc attached to the 6-OH of the innermost GlcNAc of N-glycans has been identified as an endogenous target recognized by Caenorhabditis elegans galectin LEC-6 and might function as an endogenous ligand for other galectins as well. Interactions between galectins and N-glycans might be subject to fine-tuning through modifications of the penultimate… Show more
“…This result indicates that fucose moieties are α(1–6)-linked to core GlcNAc (reducing termini) and are capped by hexoses. As galactosylated fucose moieties are reported to be constituents of CCMs in N -glycans of protostomes ( 20 ), we suspected that the hexoses attached to core fucose were galactose. To confirm this, these structures were subjected to β(1–4)-galactosidase (from Aspergillus oryzae ) treatment.…”
Cell surface–associated glycans mediate many cellular processes, including adhesion, migration, signaling, and extracellular matrix organization. The galactosylation of core fucose (GalFuc epitope) in paucimannose and complex-type N-glycans is characteristic of protostome organisms, including flatworms (planarians). Although uninvestigated, the structures of these glycans may play a role in planarian regeneration. Whole-organism MALDI-MS analysis of N-linked oligosaccharides from the planarian Schmidtea mediterranea revealed the presence of multiple isomeric high-mannose and paucimannose structures with unusual mono-, di-, and polygalactosylated (n = 3–5) core fucose structures; the latter structures have not been reported in other systems. Di- and trigalactosylated core fucoses were the most dominant glycomers. N-Glycans showed extensive, yet selective, methylation patterns, ranging from non-methylated to polymethylated glycoforms. Although the majority of glycoforms were polymethylated, a small fraction also consisted of non-methylated glycans. Remarkably, monogalactosylated core fucose remained unmethylated, whereas its polygalactosylated forms were methylated, indicating structurally selective methylation. Using database searches, we identified two potential homologs of the Galβ1–4Fuc–synthesizing enzyme from nematodes (GALT-1) that were expressed in the prepharyngeal, pharyngeal, and mesenchymal regions in S. mediterranea. The presence of two GALT-1 homologs suggests different requirements for mono- and polygalactosylation of core fucose for the formation of multiple isomers. Furthermore, we observed variations in core fucose glycosylation patterns in different planarian strains, suggesting evolutionary adaptation in fucose glycosylation. The various core chitobiose modifications and methylations create >60 different glycoforms in S. mediterranea. These results contribute greatly to our understanding of N-glycan biosynthesis and suggest the presence of a GlcNAc-independent biosynthetic pathway in S. mediterranea.
“…This result indicates that fucose moieties are α(1–6)-linked to core GlcNAc (reducing termini) and are capped by hexoses. As galactosylated fucose moieties are reported to be constituents of CCMs in N -glycans of protostomes ( 20 ), we suspected that the hexoses attached to core fucose were galactose. To confirm this, these structures were subjected to β(1–4)-galactosidase (from Aspergillus oryzae ) treatment.…”
Cell surface–associated glycans mediate many cellular processes, including adhesion, migration, signaling, and extracellular matrix organization. The galactosylation of core fucose (GalFuc epitope) in paucimannose and complex-type N-glycans is characteristic of protostome organisms, including flatworms (planarians). Although uninvestigated, the structures of these glycans may play a role in planarian regeneration. Whole-organism MALDI-MS analysis of N-linked oligosaccharides from the planarian Schmidtea mediterranea revealed the presence of multiple isomeric high-mannose and paucimannose structures with unusual mono-, di-, and polygalactosylated (n = 3–5) core fucose structures; the latter structures have not been reported in other systems. Di- and trigalactosylated core fucoses were the most dominant glycomers. N-Glycans showed extensive, yet selective, methylation patterns, ranging from non-methylated to polymethylated glycoforms. Although the majority of glycoforms were polymethylated, a small fraction also consisted of non-methylated glycans. Remarkably, monogalactosylated core fucose remained unmethylated, whereas its polygalactosylated forms were methylated, indicating structurally selective methylation. Using database searches, we identified two potential homologs of the Galβ1–4Fuc–synthesizing enzyme from nematodes (GALT-1) that were expressed in the prepharyngeal, pharyngeal, and mesenchymal regions in S. mediterranea. The presence of two GALT-1 homologs suggests different requirements for mono- and polygalactosylation of core fucose for the formation of multiple isomers. Furthermore, we observed variations in core fucose glycosylation patterns in different planarian strains, suggesting evolutionary adaptation in fucose glycosylation. The various core chitobiose modifications and methylations create >60 different glycoforms in S. mediterranea. These results contribute greatly to our understanding of N-glycan biosynthesis and suggest the presence of a GlcNAc-independent biosynthetic pathway in S. mediterranea.
“…This theory merits further investigation and we are planning to test this hypothesis. Since the GalFuc epitope is widely distributed in Phylum Nematoda (Takeuchi et al 2016), targeting it with Gal-2 and/or Gal-2-Toxin conjugate as described by Tateno et al (2017) might be suitable in the diagnosis and treatment of NTDs such as lymphatic filariasis and soil-borne helminthiases.…”
“…A similar chain has been found in N ‐glycans from the marine snail Volvarina rubella (Eckmair et al, 2016). The occurrence and significance of galactosylated core fucose in N ‐glycans of nematodes has been reviewed by Takeuchi, Arata, & Kasai (2016). …”
Section: Studies On Specific Carbohydrate Typesmentioning
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
