Figure 4. Characterizing PBP1b and RodZ... | Rockefeller University Press

Figure 4.

$Characterizing PBP1b and RodZ motion. (a–e) Analysis of GFP-PBP1b tracks (time step 25 ms) using ExTrack with two (a–c) or four states (d and e). (a) GFP-PBP1b track (130% expression level). Color bar: Probability of diffusion. (b) Diffusion lengths and fractions from two-state parameter fitting. (three replicates, each with >17,000 tracks of at least three positions, with average lifetimes from 6.3 to 7.5 positions). (c) State-duration histograms of PBP1b tracks of at least 21 positions (>600 tracks per replicate with average lifetimes from 28.5 to 32 positions), using global parameters from fitting a two-state model (a and Fig. S5). (d) Example PBP1b track (from 130% expression level) with associated state probabilities along time (first position on the left). (e) Fractions from four-state parameter fitting to the same datasets used in a. (f–h) Analysis of GFP-RodZ molecules (40 ms frame times). (f) RodZ tracks with overlapping binding sites. Color bar: Probability of diffusion. (g) Cartoon illustrating the rebinding of diffusive RodZ molecules to extended MreB-actin filaments in two dimensions. Blue solid line indicates distance between initial position and position after four diffusive steps for molecules rebinding (left) or continuing diffusion (right). (h) Histograms of distances between initial bound site and the site after four diffusive steps. Tracks rebind in closer vicinity to the initial binding site 33% more often than expected in case of random motion. Mann–Whitney U test: P value = 1.6e−6. See Materials and methods, Computational analysis... for details. Error bars and shaded regions: SDs between replicates.$

Characterizing PBP1b and RodZ motion. (a–e) Analysis of GFP-PBP1b tracks (time step 25 ms) using ExTrack with two (a–c) or four states (d and e). (a) GFP-PBP1b track (130% expression level). Color bar: Probability of diffusion. (b) Diffusion lengths and fractions from two-state parameter fitting. (three replicates, each with >17,000 tracks of at least three positions, with average lifetimes from 6.3 to 7.5 positions). (c) State-duration histograms of PBP1b tracks of at least 21 positions (>600 tracks per replicate with average lifetimes from 28.5 to 32 positions), using global parameters from fitting a two-state model (a and Fig. S5). (d) Example PBP1b track (from 130% expression level) with associated state probabilities along time (first position on the left). (e) Fractions from four-state parameter fitting to the same datasets used in a. (f–h) Analysis of GFP-RodZ molecules (40 ms frame times). (f) RodZ tracks with overlapping binding sites. Color bar: Probability of diffusion. (g) Cartoon illustrating the rebinding of diffusive RodZ molecules to extended MreB-actin filaments in two dimensions. Blue solid line indicates distance between initial position and position after four diffusive steps for molecules rebinding (left) or continuing diffusion (right). (h) Histograms of distances between initial bound site and the site after four diffusive steps. Tracks rebind in closer vicinity to the initial binding site 33% more often than expected in case of random motion. Mann–Whitney U test: P value = 1.6e−6. See Materials and methods, Computational analysis... for details. Error bars and shaded regions: SDs between replicates.

This Feature Is Available To Subscribers Only