title: Sorting nexin homologues are targets of phosphatidylinositol 3-phosphate in sporulation of Schizosaccharomyces pombe.
abstract: Schizosaccharomyces pombe defective in phosphatidylinositol (PtdIns) 3-kinase shows various defects in forespore membrane formation, including onset, growth orientation, and closure. Downstream factors of PtdIns 3-kinase in this system were explored. Among various phox homology (PX) domain-containing proteins, Vps5p and Vps17p, homologues of sorting nexins, were found to be required for efficient sporulation. Cells defective in these proteins showed a disordered growth orientation of the forespore membrane, as is the case with Deltapik3 cells. Vps5p and Vps17p with mutations in the PX domains failed to suppress the defects of their relevant disruptants. Vps5p and Vps17p migrated toward the the forespore membrane in a pik3+-dependent manner, suggesting that these proteins may interact with PtdIns(3)P. Electron-microscopic analysis revealed that the forespore membrane fails to engulf the nucleus in some of these cells, accumulating vesicle-like bodies similar to those seen in Deltaspo3 cells. These results suggest that Vps5p and Vps17p are the targets of PtdIns(3)P in vesicle transport required for onset of the forespore membrane formation.
authors.affiliation: Laboratory of Biological Chemistry, Graduate School of Agricultural and Life Science, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Koga
authors.forename: Masayuki
authors.initials: M
authors.lastname: Onishi
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Aiko
authors.initials: A
authors.lastname: Hirata
authors.forename: Taro
authors.initials: T
authors.lastname: Nakamura
authors.forename: Chikashi
authors.initials: C
authors.lastname: Shimoda
authors.forename: Tomoko
authors.initials: T
authors.lastname: Iwaki
authors.forename: Kaoru
authors.initials: K
authors.lastname: Takegawa
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Fukui
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001692:Biological Transport; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D002452:Cell Count; D002462:Cell Membrane / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D017124:Conserved Sequence; D004171:Diploidy; D005456:Fluorescent Dyes; D005973:Glutamine / Q000378:metabolism; D007211:Indoles; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D012568:Schizosaccharomyces / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D013172:Spores, Fungal / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D013696:Temperature; D013997:Time Factors; D014617:Vacuoles / Q000378:metabolism / Q000648:ultrastructure; D033921:Vesicular Transport Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D005456:Fluorescent Dyes; D005973:Glutamine; D007211:Indoles; D019869:Phosphatidylinositol 3-Kinases; D018129:Phosphatidylinositol Phosphates; D033921:Vesicular Transport Proteins; C055525:phosphatidylinositol 3-phosphate; C007293:DAPI