Taxonomic group: fungi / Ascomycota
(Phylum: Ascomycota)
NCBI PubMed ID: 20388730Publication DOI: 10.1242/jcs.059139Journal NLM ID: 0052457Publisher: Cambridge: Company of Biologists
Correspondence: takegawa
agr.kyushu-u.ac.jp
Institutions: Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan, Department of Chemistry, Faculty of Sciences, Kyushu University, Fukuoka, Japan, Department of Life Sciences, Faculty of Agriculture, Kagawa University, Miki-cho, Japan, National Institute for Agro-Environmental Sciences, Kannondai, Japan, Department of Biology, Graduate School of Science, Osaka City University, Osaka, Japan
In Saccharomyces cerevisiae, three classes of sphingolipids contain myo-inositol--inositol phosphorylceramide (IPC), mannosylinositol phosphorylceramide (MIPC) and mannosyldiinositol phosphorylceramide [M(IP)(2)C]. No fission yeast equivalent of Ipt1p, the inositolphosphotransferase that synthesizes M(IP)(2)C from MIPC, has been found in the Schizosaccharomyces pombe genome. Analysis of the sphingolipid composition of wild-type cells confirmed that MIPC is the terminal and most abundant complex sphingolipid in S. pombe. Three proteins (Sur1p, Csg2p and Csh1p) have been shown to be involved in the synthesis of MIPC from IPC in S. cerevisiae. The S. pombe genome has three genes (SPAC2F3.01, SPCC4F11.04c and SPAC17G8.11c) that are homologues of SUR1, termed imt1(+), imt2(+) and imt3(+), respectively. To determine whether these genes function in MIPC synthesis in S. pombe, single and multiple gene disruptants were constructed. Single imt disruptants were found to be viable. MIPC was not detected and IPC levels were increased in the triple disruptant, indicating that the three SUR1 homologues are involved in the synthesis of MIPC. GFP-tagged Imt1p, Imt2p and Imt3p localized to Golgi apparatus membranes. The MIPC-deficient mutant exhibited pleiotropic phenotypes, including defects in cellular and vacuolar morphology, and in localization of ergosterols. MIPC seemed to be required for endocytosis of a plasma-membrane-localized amino acid transporter, because sorting of the transporter from the plasma membrane to the vacuole was severely impaired in the MIPC-deficient mutant grown under nitrogen-limiting conditions. These results suggest that MIPC has multiple functions not only in the maintenance of cell and vacuole morphology but also in vesicular trafficking in fission yeast.
Mannosyltransferase, sphingolipid, Schizosaccharomyces pombe, inositol phosphorylceramide, lipid rafts
Structure type: monomer
Location inside paper: fig.2, MIPC
Compound class: mannosylinositol phosphorylceramide
Contained glycoepitopes: IEDB_130701,IEDB_144983,IEDB_144993,IEDB_152206,IEDB_983930,SB_44,SB_67,SB_72
Methods: TLC, biological assays, radiolabeling, extraction
Related record ID(s): 43436
NCBI Taxonomy refs (TaxIDs): 1247190,
4896
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There is only one chemically distinct structure:
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