title: Evolutionary diversity of social amoebae N-glycomes may support interspecific autonomy.
abstract: Multiple species of cellular slime mold (CSM) amoebae share overlapping subterranean environments near the soil surface. Despite similar life-styles, individual species form independent starvation-induced fruiting bodies whose spores can renew the life cycle. N-glycans associated with the cell surface glycocalyx have been predicted to contribute to interspecific avoidance, resistance to pathogens, and prey preference. N-glycans from five CSM species that diverged 300-600 million years ago and whose genomes have been sequenced were fractionated into neutral and acidic pools and profiled by MALDI-TOF-MS. Glycan structure models were refined using linkage specific antibodies, exoglycosidase digestions, MALDI-MS/MS, and chromatographic studies. Amoebae of the type species Dictyostelium discoideum express modestly trimmed high mannose N-glycans variably modified with core α3-linked Fuc and peripherally decorated with 0-2 residues each of β-GlcNAc, Fuc, methylphosphate and/or sulfate, as reported previously. Comparative analyses of D. purpureum, D. fasciculatum, Polysphondylium pallidum, and Actyostelium subglobosum revealed that each displays a distinctive spectrum of high-mannose species with quantitative variations in the extent of these modifications, and qualitative differences including retention of Glc, mannose methylation, and absence of a peripheral GlcNAc, fucosylation, or sulfation. Starvation-induced development modifies the pattern in all species but, except for universally observed increased mannose-trimming, the N-glycans do not converge to a common profile. Correlations with glycogene repertoires will enable future reverse genetic studies to eliminate N-glycomic differences to test their functions in interspecific relations and pathogen evasion.
authors.affiliation: Department of Biochemistry & Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, 975 NE 10th St., BRC-415, OUHSC, Oklahoma City, OK, 73104, USA, christa.feasley@thermofisher.com.
authors.forename: Christa L
authors.initials: CL
authors.lastname: Feasley
authors.forename: Hanke
authors.initials: H
authors.lastname: van der Wel
authors.forename: Christopher M
authors.initials: CM
authors.lastname: West
mesh_terms: D000656:Amoeba / Q000378:metabolism*; D000838:Anions; D019143:Evolution, Molecular; D005643:Fucose / Q000378:metabolism; D005944:Glucosamine / Q000378:metabolism; D054794:Glycomics; D006023:Glycoproteins / Q000378:metabolism; D008358:Mannose / Q000378:metabolism; D008745:Methylation; D010755:Organophosphates; D010802:Phylogeny; D011134:Polysaccharides / Q000378:metabolism*; D013431:Sulfates / Q000378:metabolism
chemical_list: D000838:Anions; D006023:Glycoproteins; D010755:Organophosphates; D011134:Polysaccharides; D013431:Sulfates; D005643:Fucose; C027265:methylphosphate; D005944:Glucosamine; D008358:Mannose