Disease relevance of YRB2

• Yeast cells mutated in YRB2, which encodes a nuclear protein with similarity to other Ran-binding proteins, fail to export nuclear export signal (NES)-containing proteins including HIV Rev out of the nucleus [1].

High impact information on YRB2

• Unlike Xpo1p/Crm1p/exportin, an NES receptor, Yrb2p does not shuttle between the nucleus and the cytoplasm but instead remains inside the nucleus [1].
• However, unlike Yrb1p, Yrb2p did not inhibit the nucleotide-releasing activity of Prp20p [2].
• Using GSP1, encoding the yeast Ran, as bait, we isolated YRB2 [2].
• While overproduction of Yrb1p inhibited the growth of a mutant possessing a PRP20 mutation (srm1-1) and suppressed the rna1-1 mutation, overproduction of Yrb2p showed no effect on the growth of these mutants [2].
• A point mutation in a potential leucine-rich nuclear export signal (NES) enhances the nuclear localization of the protein, and delta-yrb2 cells exhibit an apparent Clb2p nuclear export defect [3].

Associations of YRB2 with chemical compounds

• The export of SRP from the nucleus required the transport receptor Xpo1p/Crm1p and Yrb2p, both components of the pathway that exports leucine-rich nuclear export signal (NES)-containing proteins from the nucleus [4].

Physical interactions of YRB2

• Consistent with such a tight functional interaction, Xpo1p/Crm1p directly bound to Yrb2p, but not Yrb1p, and Deltayrb2 cells were found to have a defect in nuclear export signal (NES)-dependent nuclear protein export [5].
• Gtr1p bound the Ran-binding domain of Yrb2p [6].
• Yrb2p is a nuclear protein that interacts with Prp20p, a yeast Rcc1 homologue [7].
• Yrb2p binding to Gsp1p (yeast Ran) as well as to a novel 150-kDa GTP-binding protein is also detected [7].

Other interactions of YRB2

• Disruption of the YRB2 gene retards nuclear protein export, causing a profound mitotic delay, and can be rescued by overexpression of XPO1/CRM1 [5].

References