Yrb2p is a nuclear protein that interacts with Prp20p, a yeast Rcc1 homologue.
A conserved family of Ran binding proteins (RBPs) has been defined by their ability to bind to the Ran GTPase and the presence of a common region of approximately 100 amino acids (the Ran binding domain). The yeast Saccharomyces cerevisiae genome predicts only three proteins with canonical Ran binding domains. Mutation of one of these, YRB1, results in defects in transport of macromolecules across the nuclear envelope (Schlenstedt, G., Wong, D. H., Koepp, D. M., and Silver, P. A. (1995) EMBO J. 14, 5367-5378). The second one, encoded by YRB2, is a 327-amino acid protein with a Ran binding domain at its C terminus and an internal cluster of FXFG and FG repeats conserved in nucleoporins. Yrb2p is located inside the nucleus, and this localization relies on the N terminus. Results of both genetic and biochemical analyses show interactions of Yrb2p with the Ran nucleotide exchanger Prp20p/Rcc1. Yrb2p binding to Gsp1p (yeast Ran) as well as to a novel 150-kDa GTP-binding protein is also detected. The Ran binding domain of Yrb2p is essential for function and for its association with Prp20p and the GTP-binding proteins. Taken together, we suggest that Yrb2p may play a role in the Ran GTPase cycle distinct from nuclear transport.
Taura
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Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School and the Dana Farber Cancer Institute, Boston, Massachusetts 02115, USA.
Schlenstedt
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Silver
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PA
D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins; D002467:Cell Nucleus / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D016366:Open Reading Frames; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D009687:Nuclear Proteins; C067050:SRM1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C113422:YRB2 protein, S cerevisiae