Poster abstracts
Poster number 29 submitted by Anna H. N. Griffis
Dissecting the requirement of Arabidopsis RanGAP1 subcellular targeting and GAP activity for its cellular and developmental functions
Anna H. N. Griffis (Molecular, Cellular, and Developmental Biology and the Center for RNA Biology, The Ohio State University), Joanna Boruc (Department of Plant Systems Biology and Department of Plant Biotechnology and Bioinformatics, VIB, Ghent, Belgium), Tushani Rodrigo-Peiris (Department of Molecular Genetics, The Ohio State University), Xiao Zhou, Bailey Tilford (Department of Molecular Genetics, The Ohio State University), Daniel Van Damme (Department of Plant Systems Biology and Department of Plant Biotechnology and Bioinformatics, VIB, Ghent, Belgium), Iris Meier (Department of Molecular Genetics and Center for RNA Biology, The Ohio State University)
Abstract:
The Ran GTPase activating protein (RanGAP) is important to Ran signaling involved in nucleocytoplasmic transport, spindle organization and post-mitotic 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 RanGAP1. A double null mutant of the two Arabidopsis RanGAP homologs is gametophyte lethal. Here, we have 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, 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 requires the GAP activity of RanGAP and is susceptible to reductions in RanGAP protein level, 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 form the nuclear envelope.
Keywords: RanGAP, Arabidopsis, Mitosis