Fig. 4.

Statistical analyses of purinosome motions based on both their localization and MSD in HPRT-deficient fibroblasts. (A) Relative proportion of trajectories that displayed directed motion. Of those purinosomes colocalized with microtubules but not mitochondria (−Mito, +Tub), 85% had directed motion, whereas 16% of dual-colocalized purinosomes (+Mito, +Tub) had directed motion. Those purinosomes not colocalized with either (−Mito, −Tub), and did not have any directed motion. n = 50 representative trajectories for dual-colocalized and microtubule-colocalized purinosomes; n = 28 representative trajectories for nonlocalized purinosomes. The percentage of purinosomes in their respective group [(±) mito or tub] is also shown. (B) Distribution of the distance a purinosome traveled between two consecutive frames in a trajectory. For those that were on the microtubule only, the median distance that a purinosome traveled between two consecutive frames in a directed motion was 344 nm. n = 30 cells, 135 purinosomes, 4,135 total frames. (C) A frequency plot of the time that a purinosome displayed directed motion. The median value is 20 s. Data are presented as accumulated count, n = 100 representative trajectories.