Overexpression of AtNTF2a in plants disrupts nuclear import in a Ran-binding-dependent manner. A, GFP fluorescence of an R-GFP fusion protein expressed in N. benthamiana leaf epidermis cells; B, corresponding transmitted light image; C, GFP fluorescence of R-GFP coexpressed with AtNTF2a; D, corresponding transmitted light image; E, GFP fluorescence of R-GFP coexpressed with AtNTF2aE38K; and F, corresponding transmitted light image. Size bars = 10 μm.