Steady-state nuclear localization of exportin-t involves RanGTP binding and two distinct nuclear pore complex interaction domains.
Vertebrate tRNA export receptor exportin-t (Xpo-t) binds to RanGTP and mature tRNAs cooperatively to form a nuclear export complex. Xpo-t shuttles bidirectionally through nuclear pore complexes (NPCs) but is mainly nuclear at steady state. The steady-state distribution of Xpo-t is shown to depend on its interaction with RanGTP. Two distinct ... Xpo-t NPC interaction domains that bind differentially to peripherally localized nucleoporins in vitro are identified. The N terminus binds to both Nup153 and RanBP2/Nup358 in a RanGTP-dependent manner, while the C terminus binds to CAN/Nup214 independently of Ran. We propose that these interactions increase the concentration of tRNA export complexes and of empty Xpo-t in the vicinity of NPCs and thus increase the efficiency of the Xpo-t transport cycle.
Mesh Terms:
Active Transport, Cell Nucleus, Animals, Carrier Proteins, Hela Cells, Humans, Microinjections, Models, Biological, Nuclear Pore, Nuclear Proteins, Nucleocytoplasmic Transport Proteins, Oocytes, Protein Binding, Protein Structure, Tertiary, RNA, Transfer, Xenopus laevis, ran GTP-Binding Protein
Active Transport, Cell Nucleus, Animals, Carrier Proteins, Hela Cells, Humans, Microinjections, Models, Biological, Nuclear Pore, Nuclear Proteins, Nucleocytoplasmic Transport Proteins, Oocytes, Protein Binding, Protein Structure, Tertiary, RNA, Transfer, Xenopus laevis, ran GTP-Binding Protein
Mol. Cell. Biol.
Date: Aug. 01, 2002
PubMed ID: 12138183
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