The permeability of reconstituted nuclear pores provides direct evidence for the selective phase model.
Nuclear pore complexes (NPCs) maintain a permeability barrier between the nucleus and the cytoplasm through FG-repeat-containing nucleoporins (Nups). We previously proposed a "selective phase model" in which the FG repeats interact with one another to form a sieve-like barrier that can be locally disrupted by the binding of nuclear transport receptors (NTRs), but not by inert macromolecules, allowing selective passage of NTRs and associated cargo. Here, we provide direct evidence for this model in a physiological context. By using NPCs reconstituted from Xenopus laevis egg extracts, we show that Nup98 is essential for maintaining the permeability barrier. Specifically, the multivalent cohesion between FG repeats is required, including cohesive FG repeats close to the anchorage point to the NPC scaffold. Our data exclude alternative models that are based solely on an interaction between the FG repeats and NTRs and indicate that the barrier is formed by a sieve-like FG hydrogel.
Abteilung Zelluläre Logistik, Max-Planck-Institut für biophysikalische Chemie, Am Fassberg 11, D-37077 Göttingen, Germany.
Bastian B
BB
Hülsmann
Aksana A
AA
Labokha
Dirk
D
Görlich
D021581:Active Transport, Cell Nucleus; D000818:Animals; D008954:Models, Biological; D008969:Molecular Sequence Data; D022022:Nuclear Pore / Q000737:chemistry* / Q000378:metabolism*; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry / Q000378:metabolism*; D010539:Permeability; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism; D014981:Xenopus; D029867:Xenopus Proteins / Q000737:chemistry / Q000378:metabolism; D014982:Xenopus laevis / Q000378:metabolism*
D028861:Nuclear Pore Complex Proteins; C558728:Nup98 protein, Xenopus; D029867:Xenopus Proteins