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Taxonomic group: fungi / Ascomycota (Phylum: Ascomycota)

NCBI PubMed ID: 2146492
Journal NLM ID: 8109087
Publisher: American Society for Microbiology
Institutions: Center for Cancer Research, Massachusetts Institute of Technology, Cambridge 02139

Glycosyl phosphatidylinositol (GPI) anchoring, N glycosylation, and O mannosylation of protein occur in the rough endoplasmic reticulum and involve transfer of precursor structures that contain mannose. Direct genetic evidence is presented that dolichol phosphate mannose (Dol-P-Man) synthase, which transfers mannose from GDPMan to the polyisoprenoid dolichol phosphate, is required in vivo for all three biosynthetic pathways leading to these covalent modifications of protein in yeast cells. Temperature-sensitive yeast mutants were isolated after in vitro mutagenesis of the yeast DPM1 gene. At the nonpermissive temperature of 37 degrees C, the dpm1 mutants were blocked in [2-3H]myo-inositol incorporation into protein and accumulated a lipid that could be radiolabeled with both [2-3H]myo-inositol and [2-3H]glucosamine and met existing criteria for an intermediate in GPI anchor biosynthesis. The likeliest explanation for these results is that Dol-P-Man donates the mannose residues needed for completion of the GPI anchor precursor lipid before it can be transferred to protein. Dol-P-Man synthase is also required in vivo for N glycosylation of protein, because (i) dpm1 cells were unable to make the full-length precursor Dol-PP-GlcNAc2Man9Glc3 and instead accumulated the intermediate Dol-PP-GlcNAc2Man5 in their pool of lipid-linked precursor oligosaccharides and (ii) truncated, endoglycosidase H-resistant oligosaccharides were transferred to the N-glycosylated protein invertase after a shift to 37 degrees C. Dol-P-Man synthase is also required in vivo for O mannosylation of protein, because chitinase, normally a 150-kDa O-mannosylated protein, showed a molecular size of 60 kDa, the size predicted for the unglycosylated protein, after shift of the dpm1 mutant to the nonpermissive temperature.

Structure type: oligomer
Location inside paper: fig. 1
Trivial name: Glc3Man9GlcNAc2
Compound class: N-glycan, high-mannose
Contained glycoepitopes: IEDB_130701,IEDB_135813,IEDB_136104,IEDB_137340,IEDB_137485,IEDB_140116,IEDB_141793,IEDB_141807,IEDB_141828,IEDB_141829,IEDB_141830,IEDB_141831,IEDB_142488,IEDB_143632,IEDB_144983,IEDB_144998,IEDB_146664,IEDB_149158,IEDB_151079,IEDB_151531,IEDB_152206,IEDB_153220,IEDB_164174,IEDB_232584,IEDB_233377,IEDB_429156,IEDB_857734,IEDB_983930,IEDB_983931,SB_136,SB_191,SB_192,SB_196,SB_197,SB_198,SB_44,SB_53,SB_67,SB_72,SB_73,SB_77

Related record ID(s): 143795
NCBI Taxonomy refs (TaxIDs): 4932
Reference(s) to other database(s): CCSD:37071, CBank-STR:21304
Show glycosyltransferases

There is only one chemically distinct structure:

CC(=O)N[C@@H]1[C@@H](O)[C@H](O[C@@H]2O[C@H](CO)[C@@H](O[C@@H]3O[C@H](CO[C@H]4O[C@H](CO[C@H]5O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]5O[C@H]5O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]5O)[C@@H](O)[C@H](O[C@H]5O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]5O[C@H]5O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]5O)[C@@H]4O)[C@@H](O)[C@H](O[C@H]4O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]4O[C@H]4O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]4O[C@H]4O[C@H](CO)[C@@H](O)[C@H](O[C@H]5O[C@H](CO)[C@@H](O)[C@H](O[C@H]6O[C@H](CO)[C@@H](O)[C@H](O)[C@H]6O[C@H]6O[C@H](CO)[C@@H](O)[C@H](O)[C@H]6O)[C@H]5O)[C@@H]4O)[C@@H]3O)[C@H](O)[C@H]2NC(C)=O)[C@@H](CO)O[C@H]1NC(=O)CC(N)C(=O)O

SVG MW SMILES 3D mol Ionize