SMM and FRAP analyses provide a consistent model of the intranuclear mobility of the GR.

<p>(A) A two-population fit of SMM analysis for dexamethasone-bound YFP-GR identifies two fractions of approximately equal size. (B) Both fractions show a linear increase in mean squared displacement (MSD) over time, but with a 40-fold difference in MSD. Diffusion coefficients (D_fast and D_slow) are calculated from a linear fit of the experimental data (dashed lines; D = slope/4). The D_fast of 1.31 µm²/s fits to diffusing molecules, while the D_slow of only 0.03 µm²/s best fits to the slow movement of chromatin and the molecules bound to it. (C) A 3-population Monte Carlo simulation of the FRAP curve for dexamethasone-bound YFP-GR shows that half of the nuclear population is diffusing, while the remainder is subdivided into two bound fractions that differ in their immobilization times. The fraction size of the diffusing fraction is similar in size as that obtained from SMM analysis. (D) Both bound fractions are only transiently immobilized, with a 3-fold difference in duration. (A and B) Data represented as best fit ± SEM (of 3 separate PICS analyses). (C and D) Data represented as average of top 10% best fits ± SEM.