Data Supplement for Journal of Biological Chemistry: Volume 276

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Quicktime Movie files:

QuickTime Video 1: Movie illustrating one model for import across the NPC. Normally, the narrow diameter of the channel, and the Brownian motion of the flanking, closely spaced, filamentous "FG" nucleoporins (red, green, light blue), likely make diffusion of a cytoplasmic macromolecule (pink) across the NPC entropically unfavorable. However, if this macromolecule carries an NLS, it can be bound as cargo by a karyopherin (dark blue). The karyopherin can also reversibly bind the "FG" nucleoporins, and the energy associated with this binding can overcome the entropic exclusion of the NPC. As most of these FG nucleoporins are equally distributed on both sides of the NE (green), transport factor-cargo complexes could then readily exchange between nucleoporins on both sides of the NE. Nuclear high affinity binding sites (light blue) likely contribute to determining the directionality of transport by trapping the transport factor-cargo complex the extreme nuclear face of the NPC until Ran-GTP (gray) binds the karyopherin, dissociates the transport factor-cargo complex, and releases the cargo into the nucleoplasm, where (now unable to bind the NPC) it remains.

QuickTime Video 1

QuickTime Video 2: Movie of a three-dimensional diagram illustrating the major structural features of the nuclear pore complex.

QuickTime Video 2