Kinetic analysis of translocation through nuclear pore complexes.
The mechanism of facilitated translocation through nuclear pore complexes (NPCs) is only poorly understood. Here, we present a kinetic analysis of the process using various model substrates. We find that the translocation capacity of NPCs is unexpectedly high, with a single NPC allowing a mass flow of nearly 100 MDa/s and rates in the order of 10(3) translocation events per second. Our data further indicate that high affinity interactions between the translocation substrate and NPC components are dispensable for translocation. We propose a 'selective phase model' that could explain how NPCs function as a permeability barrier for inert molecules and yet become selectively permeable for nuclear transport receptors and receptor-cargo complexes.
ZMBH, INF 282, 69120 Heidelberg, Germany.
K
K
Ribbeck
D
D
Görlich
D021581:Active Transport, Cell Nucleus; D002352:Carrier Proteins / Q000378:metabolism*; D004058:Diffusion; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D028884:Karyopherins; D008164:Luminescent Proteins / Q000378:metabolism*; D008962:Models, Theoretical; D022022:Nuclear Pore / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*
D002352:Carrier Proteins; D028884:Karyopherins; D008164:Luminescent Proteins; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D049452:Green Fluorescent Proteins