Janina Becker

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The recently discovered small ubiquitin-related modifier SUMO-1 belongs to the growing family of ubiquitin-related proteins involved in postranslational protein modification. Unlike ubiquitin, SUMO-1 does not appear to target proteins for degradation but seems to be involved in the modulation of protein-protein interactions. Independent studies demonstrate(More)
The gene encoding the regulator of chromosome condensation (RCC1) was cloned by virtue of its ability to complement the temperature-sensitive phenotype of the hamster cell line tsBN2, which undergoes premature chromosome condensation or arrest in the G1 phase of the cell cycle at non-permissive temperatures. RCC1 homologues have been identified in many(More)
SUMOylation is an essential modification that regulates hundreds of proteins in eukaryotic cells. Owing to its dynamic nature and low steady-state levels, endogenous SUMOylation is challenging to detect. Here, we present a method that allows efficient enrichment and identification of endogenous targets of SUMO1 and the nearly identical SUMO2 and 3 (SUMO(More)
rna1p is the Schizosaccharomyces pombe ortholog of the mammalian GTPase-activating protein (GAP) of Ran. Both proteins are essential for nuclear transport. Here, we report the crystal structure of rna1p at 2.66 A resolution. It contains 11 leucine-rich repeats that adopt the nonglobular shape of a crescent, bearing no resemblance to RhoGAP or RasGAP. The(More)
Recently, the retinitis pigmentosa 3 (RP3) gene has been cloned and named retinitis pigmentosa GTPase regulator (RPGR). The amino-terminal half of RPGR is homologous to regulator of chromosome condensation (RCC1), the nucleotide exchange factor for the small GTP-binding protein Ran. In a yeast two-hybrid screen we identified the delta subunit of rod cyclic(More)
Recently, we have shown that the delta subunit of the cGMP phosphodiesterase (PDE delta) interacts with the retinitis pigmentosa guanine regulator (RPGR). Here, using the two-hybrid system, we identify a member of the Arf-like protein family of Ras-related GTP-binding proteins, Arl3, that interacts with PDE delta. The interaction was verified by(More)
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(More)
Ypt1p of Saccharomyces cerevisiae is a ras-related GTP-binding protein that fulfils an essential function in intracellular protein transport between the endoplasmic reticulum (ER) and the Golgi complex. Ypt proteins from yeasts and mammals that share an identical sequence in the region analogous to the ras effector domain are functionally interchangeable.(More)
Receptor-mediated nucleocytoplasmic transport is dependent on the GTPase Ran and Ran-binding protein 1 (RanBP1). The acidic C terminus of Ran is required for high affinity interaction between Ran and RanBP1. We found that a novel Ran mutant with four of its five acidic C-terminal amino acids modified to alanine (RanC4A) has an approximately 20-fold reduced(More)
The small GTP binding protein Ran is an essential component of the nuclear protein import machinery whose GTPase cycle is regulated by the nuclear guanosine nucleotide exchange factor RCC1 and by the cytosolic GTPase activating protein RanGAP. In the yeasts Schizosaccharomyces pombe and Saccharomyces cerevisiae the RanGAP activity is encoded by the RNA1(More)