Fluorescence recovery of 2xEGFP within the nucleus in cells overexpressing Kapβ1-iRFP. Top: The time elapsed per frame is 1 s. Kapβ1-iRFP fluorescence is visualized in the last panel. Lightning indicates the nuclear photobleaching event at t = 0. Scale bar, 10 µm. Bottom: τ (left) and permeability (right) of 2xEGFP do not change significantly following Kapβ1-iRFP overexpression. Statistical analysis was performed using a nonparametric (Mann-Whitney) two-tailed test. Error bars denote minimum and maximum measured values.