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Nucleoporin 2 Ran-binding domain Yeast protein Nup2 transiently associates with Nuclear pore complexes (NPCs) and when artificially tethered to DNA, can prevent the spread of transcriptional activation or repression between flanking genes, a function termed boundary activity (BA). Nup2 and the Ran guanylyl-nucleotide exchange factor, Prp20, interact at specific chromatin regions and enable the NPC to play an active role in chromatin organization. Nup60p, the nup responsible for anchoring Nup2 and the Mlp proteins to the NPC is required for Nup2-dependent BA. Nup2 contains an N-terminal Nup50 family domain and a C-terminal RanBD. Ran is a Ras-like nuclear small GTPase, which regulates receptor-mediated transport between the nucleus and the cytoplasm. RanGTP hydrolysis is stimulated by RanGAP together with the Ran-binding domain containing acessory proteins RanBP1 and RanBP2. These accessory proteins stabilize the active GTP-bound form of Ran. RabBD shares structural similarity to the PH domain, but lacks detectable sequence similarity.
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