3D pathways of Imp β1 alone and Imp α/Imp β1 in complex with differently charged GFP cargo (−30 NLS-GFP), −7 NLS-GFP and +36 NLS-GFP).
(A) Imp β1 alone. Calculated electrostatic surface potentials of Imp β1 range from −15 kT/e (dark blue) to +15 kT/e (dark red), and neutral charge 0 is shown in green (I). Superimposed plots of localizations of single molecules located primarily within a rectangular area of 240×160 nm (II). N, the nucleoplasmic side of the NPC; C, the cytoplasmic side of the NPC. The locations in each 10×10 nm area were quantized and filtered with a Gaussian blur function to generate the 2D probability density map overlaid onto the NPC architecture (light blue). The highest density was 1.7×105 locations/µm2 and the lowest was 0 locations/µm2, shown in gray (III). A 3D probability density map (green cloud; brighter color indicates higher density) is shown in both side-view and a top-view orientations superimposed on the NPC architecture (blue). The length of pathway and the diameter at the central plane of NPC was measured and is labeled in nanometers. N, the nucleoplasmic side of the NPC. C, the cytoplasmic side of the NPC. (B–D) Nucleocytoplasmic transport pathways of −30NLS-GFP/Impα/Impβ1, −7NLS-GFP/Impα/Impβ1 and +36NLS-GFP/Impα/Impβ1.
