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The Ran GTPase plays critical roles in both providing energy for and determining the directionality of nucleocytoplasmic transport. The mechanism that couples the RanGTP gradient to nuclear protein export will determine the rate of and limits to accumulation of export cargoes in the cytoplasm, but is presently unknown. We reasoned that plausible coupling mechanisms could be distinguished by comparing the rates of reverse motion of export cargoes through the nuclear pore complex (NPC) with the predictions of a mathematical model. Measurement of reverse export rates in Xenopus oocytes revealed that nuclear export signals can facilitate RanGTP-dependent cargo movement into the nucleus against the RanGTP gradient at rates comparable to export rates. Although export cargoes with high affinity for their receptor are exported faster than those with low affinity, their reverse transport is also greater. The ratio of the rates of reverse and forward export of a cargo is proportional to its rate of diffusion through the NPC, i.e., to the ability of the cargo to penetrate the NPC permeability barrier. The data substantiate a diffusional mechanism of coupling and suggest the existence of a high concentration of RanGTP-receptor complexes within the NPC that decreases sharply at the cytoplasmic boundary of the NPC permeability barrier.
Allen,
Proteomic analysis of nucleoporin interacting proteins.
2001, Pubmed
Allen,
Proteomic analysis of nucleoporin interacting proteins.
2001,
Pubmed
Askjaer,
RanGTP-regulated interactions of CRM1 with nucleoporins and a shuttling DEAD-box helicase.
1999,
Pubmed
,
Xenbase
Astumian,
Thermodynamics and kinetics of a Brownian motor.
1997,
Pubmed
Astumian,
Fluctuation driven transport and models of molecular motors and pumps.
1998,
Pubmed
Ben-Efraim,
Gradient of increasing affinity of importin beta for nucleoporins along the pathway of nuclear import.
2001,
Pubmed
Bischoff,
Catalysis of guanine nucleotide exchange of Ran by RCC1 and stimulation of hydrolysis of Ran-bound GTP by Ran-GAP1.
1995,
Pubmed
Englmeier,
RanBP3 influences interactions between CRM1 and its nuclear protein export substrates.
2001,
Pubmed
Englmeier,
Receptor-mediated substrate translocation through the nuclear pore complex without nucleotide triphosphate hydrolysis.
1999,
Pubmed
Ferrell,
How regulated protein translocation can produce switch-like responses.
1998,
Pubmed
Fornerod,
CRM1 is an export receptor for leucine-rich nuclear export signals.
1997,
Pubmed
,
Xenbase
Fornerod,
The human homologue of yeast CRM1 is in a dynamic subcomplex with CAN/Nup214 and a novel nuclear pore component Nup88.
1997,
Pubmed
Fukuda,
CRM1 is responsible for intracellular transport mediated by the nuclear export signal.
1997,
Pubmed
,
Xenbase
Gilchrist,
Accelerating the rate of disassembly of karyopherin.cargo complexes.
2002,
Pubmed
Gnaiger,
High phosphorylation efficiency and depression of uncoupled respiration in mitochondria under hypoxia.
2000,
Pubmed
Görlich,
Transport between the cell nucleus and the cytoplasm.
1999,
Pubmed
Hervagault,
Predictions of thermodynamic efficiency in a pumped biochemical reaction.
1989,
Pubmed
Ishii,
Chromatin boundaries in budding yeast: the nuclear pore connection.
2002,
Pubmed
Izaurralde,
The asymmetric distribution of the constituents of the Ran system is essential for transport into and out of the nucleus.
1997,
Pubmed
Kaffman,
Regulation of nuclear localization: a key to a door.
1999,
Pubmed
Kalab,
Visualization of a Ran-GTP gradient in interphase and mitotic Xenopus egg extracts.
2002,
Pubmed
,
Xenbase
Kawasaki-Nishi,
Yeast V-ATPase complexes containing different isoforms of the 100-kDa a-subunit differ in coupling efficiency and in vivo dissociation.
2001,
Pubmed
Kehlenbach,
A role for RanBP1 in the release of CRM1 from the nuclear pore complex in a terminal step of nuclear export.
1999,
Pubmed
Koepp,
A GTPase controlling nuclear trafficking: running the right way or walking RANdomly?
1996,
Pubmed
Krupka,
Limits on the tightness of coupling in active transport.
1999,
Pubmed
Kuersten,
Steady-state nuclear localization of exportin-t involves RanGTP binding and two distinct nuclear pore complex interaction domains.
2002,
Pubmed
,
Xenbase
Lindsay,
Ran-binding protein 3 is a cofactor for Crm1-mediated nuclear protein export.
2001,
Pubmed
Mattaj,
Nucleocytoplasmic transport: the soluble phase.
1998,
Pubmed
Nachury,
The direction of transport through the nuclear pore can be inverted.
1999,
Pubmed
Peskin,
Cellular motions and thermal fluctuations: the Brownian ratchet.
1993,
Pubmed
Rexach,
Protein import into nuclei: association and dissociation reactions involving transport substrate, transport factors, and nucleoporins.
1995,
Pubmed
Ribbeck,
NTF2 mediates nuclear import of Ran.
1998,
Pubmed
Ribbeck,
Kinetic analysis of translocation through nuclear pore complexes.
2001,
Pubmed
Ribbeck,
The permeability barrier of nuclear pore complexes appears to operate via hydrophobic exclusion.
2002,
Pubmed
Rout,
The yeast nuclear pore complex: composition, architecture, and transport mechanism.
2000,
Pubmed
Rubinow,
The facilitated diffusion of oxygen by hemoglobin and myoglobin.
1977,
Pubmed
Schell,
Dependence of thermodynamic efficiency of proton pumps on frequency of oscillatory concentration of ATP.
1987,
Pubmed
SCHOLANDER,
Oxygen transport through hemoglobin solutions.
1960,
Pubmed
Shah,
Major binding sites for the nuclear import receptor are the internal nucleoporin Nup153 and the adjacent nuclear filament protein Tpr.
1998,
Pubmed
,
Xenbase
Smith,
Nuclear import of Ran is mediated by the transport factor NTF2.
,
Pubmed
Stade,
Exportin 1 (Crm1p) is an essential nuclear export factor.
1997,
Pubmed
Sumbilla,
The slippage of the Ca2+ pump and its control by anions and curcumin in skeletal and cardiac sarcoplasmic reticulum.
2002,
Pubmed
Walther,
The nucleoporin Nup153 is required for nuclear pore basket formation, nuclear pore complex anchoring and import of a subset of nuclear proteins.
2001,
Pubmed
,
Xenbase
