title: GAP Activity, but Not Subcellular Targeting, Is Required for Arabidopsis RanGAP Cellular and Developmental Functions.
abstract: The Ran GTPase activating protein (RanGAP) is important to Ran signaling involved in nucleocytoplasmic transport, spindle organization, and postmitotic nuclear assembly. Unlike vertebrate and yeast RanGAP, plant RanGAP has an N-terminal WPP domain, required for nuclear envelope association and several mitotic locations of Arabidopsis thaliana RanGAP1. A double null mutant of the two Arabidopsis RanGAP homologs is gametophyte lethal. Here, we created a series of mutants with various reductions in RanGAP levels by combining a RanGAP1 null allele with different RanGAP2 alleles. As RanGAP level decreases, the severity of developmental phenotypes increases, but nuclear import is unaffected. To dissect whether the GAP activity and/or the subcellular localization of RanGAP are responsible for the observed phenotypes, this series of rangap mutants were transformed with RanGAP1 variants carrying point mutations abolishing the GAP activity and/or the WPP-dependent subcellular localization. The data show that plant development is differentially affected by RanGAP mutant allele combinations of increasing severity and requires the GAP activity of RanGAP, while the subcellular positioning of RanGAP is dispensable. In addition, our results indicate that nucleocytoplasmic trafficking can tolerate both partial depletion of RanGAP and delocalization of RanGAP from the nuclear envelope.
authors.affiliation: Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210.
authors.forename: Joanna
authors.initials: J
authors.lastname: Boruc
authors.affiliation: Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210 Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210.
authors.forename: Anna H N
authors.initials: AH
authors.lastname: Griffis
authors.affiliation: Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210.
authors.forename: Thushani
authors.initials: T
authors.lastname: Rodrigo-Peiris
authors.affiliation: Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210.
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210.
authors.forename: Bailey
authors.initials: B
authors.lastname: Tilford
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Daniël
authors.initials: D
authors.lastname: Van Damme
authors.affiliation: Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210 Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210 meier.56@osu.edu.
authors.forename: Iris
authors.initials: I
authors.lastname: Meier
mesh_terms: D000483:Alleles; D019943:Amino Acid Substitution; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D005838:Genotype; D009154:Mutation; D009685:Nuclear Envelope / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D056771:Ovule / Q000254:growth & development / Q000378:metabolism; D010641:Phenotype; D036226:Seedlings / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: C466201:AT3G63130 protein, Arabidopsis; D029681:Arabidopsis Proteins; D020690:GTPase-Activating Proteins; D009687:Nuclear Proteins