Passive and facilitated transport in nuclear pore complexes is largely uncoupled.
Nuclear pore complexes provide the sole gateway for the exchange of material between nucleus and cytoplasm of interphase eukaryotic cells. They support two modes of transport: passive diffusion of ions, metabolites, and intermediate-sized macromolecules and facilitated, receptor-mediated translocation of proteins, RNA, and ribonucleoprotein complexes. It is generally assumed that both modes of transport occur through a single diffusion channel located within the central pore of the nuclear pore complex. To test this hypothesis, we studied the mutual effects between transporting molecules utilizing either the same or different modes of translocation. We find that the two modes of transport do not interfere with each other, but molecules utilizing a particular mode of transport do hinder motion of others utilizing the same pathway. We therefore conclude that the two modes of transport are largely segregated.
Naim
Bracha
B
Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
Brumfeld
Vlad
V
Kapon
Ruti
R
Kiss
Vladimir
V
Nevo
Reinat
R
Reich
Ziv
Z
D021581:Active Transport, Cell Nucleus; D002467:Cell Nucleus / Q000378:metabolism*; D003911:Dextrans / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D028884:Karyopherins / Q000378:metabolism; D008845:Microinjections; D019913:Nuclear Localization Signals / Q000502:physiology; D022022:Nuclear Pore / Q000378:metabolism*; D028861:Nuclear Pore Complex Proteins / Q000378:metabolism*
D003911:Dextrans; D005456:Fluorescent Dyes; D028884:Karyopherins; D019913:Nuclear Localization Signals; D028861:Nuclear Pore Complex Proteins; D049452:Green Fluorescent Proteins; D005982:Glutathione Transferase