title: RNA1 encodes a GTPase-activating protein specific for Gsp1p, the Ran/TC4 homologue of Saccharomyces cerevisiae.
abstract: Ran/TC4 is a ras-related GTP-binding protein predominantly located in the nucleus. Ran/TC4 is essential for nuclear transport and is involved in mitotic control. In Saccharomyces cerevisiae a gene highly homologous to Ran/TC4 has been identified and named GSP1. Like all ras-related GTP-binding proteins, Gsp1p undergoes cycles of GTP hydrolysis and GDP/GTP exchange. The switching between the two different nucleotide bound states regulates the function of these GTP-binding proteins. Here we identify the product of the yeast RNA1 gene as the GTPase-activating protein (GAP) of Gsp1p. RNA1 belongs to a group of genes which are conserved in a variety of different organisms. We have expressed and purified recombinant Gsp1p and Rna1p from Escherichia coli. The GTPase activity of Gsp1p is stimulated 10(7)-fold by Rna1p. In addition, we find that the previously identified human RanGAP1 and rna1p from Schizosaccharomyces pombe are also able to induce GTPase activity of Gsp1p. The GTP hydrolysis of Ran is induced by RanGAP1 and rna1p but not by Rna1p. Implications for the suggested functions of Ran/TC4/Gsp1p in nuclear transport and mitotic control are discussed.
authors.affiliation: Max-Planck Institut für Molekulare Physiologie, Abteilung Strukturelle Biologie, Dortmund, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Becker
authors.forename: F
authors.initials: F
authors.lastname: Melchior
authors.forename: V
authors.initials: V
authors.lastname: Gerke
authors.forename: F R
authors.initials: FR
authors.lastname: Bischoff
authors.forename: H
authors.initials: H
authors.lastname: Ponstingl
authors.forename: A
authors.initials: A
authors.lastname: Wittinghofer
mesh_terms: D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D020690:GTPase-Activating Proteins; D005800:Genes, Fungal; D020662:Guanine Nucleotide Exchange Factors; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D012323:RNA Processing, Post-Transcriptional; D012331:RNA, Fungal / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins; D013045:Species Specificity; D020931:ran GTP-Binding Protein; D020703:ras GTPase-Activating Proteins
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C080324:GSP1 protein, S cerevisiae; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D009687:Nuclear Proteins; D011506:Proteins; C092317:RANGAP1 protein, human; C062521:RCC1 protein, human; D012331:RNA, Fungal; D012333:RNA, Messenger; C060997:RNA1 protein, S cerevisiae; D011993:Recombinant Fusion Proteins; C067050:SRM1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D020703:ras GTPase-Activating Proteins; C499298:rna1 protein, S pombe; D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins; D020559:Monomeric GTP-Binding Proteins; D020931:ran GTP-Binding Protein