title: Drosophila GTPase nucleostemin 2 changes cellular distribution during larval development and the GTP-binding motif is essential to nucleoplasmic localization.
abstract: Nucleostemin (NS), a nucleolar guanosine triphosphate (GTP)-binding protein, plays significant roles in cell cycle progression and ribosomal biogenesis. Drosophila Nucleostemin 2 (NS2), a member of the Drosophila NS family, regulates early eye development and is essential to cell survival in vivo, but the underlying mechanisms have yet to be clarified. Biochemical analysis using the recombinant NS2 protein indicated that NS2 has GTPase activity. Immunohistochemistry revealed that NS2 changes in subcellular locus from the nucleolus to the nucleoplasm during larval development, and that a mutation in the ATP/GTP-binding site motif A (p-loop) prevents nuclear localization of NS2 and results in cytoplasmic distribution. Furthermore, downregulation of NS2 altered the rRNA proportions between the nucleus and the cytoplasm. These results suggest that NS2 at least requires GTP to import into the nucleoplasm.
authors.affiliation: Molecular Entomology Laboratory, RIKEN Advanced Science Institute, Wako, Saitama, Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Matsuo
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nagamine
authors.forename: Shogo
authors.initials: S
authors.lastname: Matsumoto
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Tsuneizumi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002466:Cell Nucleolus / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000201:enzymology / Q000235:genetics*; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D006160:Guanosine Triphosphate / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007814:Larva / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D008969:Molecular Sequence Data; D009024:Morphogenesis / Q000235:genetics*; D009154:Mutation; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D012335:RNA, Ribosomal / Q000032:analysis / Q000096:biosynthesis
chemical_list: D029721:Drosophila Proteins; D012335:RNA, Ribosomal; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; C569284:NS2 protein, Drosophila