Fig. 3: CdpA, FtsZ1 and FtsZ2 show different localization interdependencies and strongly influence each other’s midcell structures.

All strains were grown in Hv-Cab medium with 0.2 mM Trp, and mid-log cultures were sampled for microscopy. a Phase-contrast and fluorescence composite images of CdpA-GFP in the absence of FtsZ1, FtsZ2, or both. Scale bars, 5 µm. The micrographs shown are representative of at least two independent experiments. b Left: localization of FtsZ1-mCherry in wild-type H26 and ΔcdpA backgrounds. The arrowhead indicates a poorly condensed FtsZ1-mCherry structure in ΔcdpA. Scale bars, 5 µm. The dot-plots show quantification of the degree of FtsZ1-mCherry localization versus individual localization thickness as a measurement of protein condensation along the long axis in the indicated backgrounds. The data points are coloured with a proximity heatmap. c localization of FtsZ2-GFP in H26 (scale bar, 5 µm) and ΔcdpA backgrounds (scale bars, 2 µm). The histograms show the number of FtsZ2-GFP rings detected versus cell length in the indicated backgrounds. Blue diagonals (“All”) represent 1 localization per 4 µm in length (i.e. approximately equivalent to all division sites detected at the normal frequency per cell length in wild-type cells), green (“−1”) indicates one fewer rings/cell length, yellow is two fewer, and red is 3 fewer. n_x=number of cells for the indicated number(x) of localizations examined over one biologically independent experiment. d Upper: localization of FtsZ1-mCherry and FtsZ2-GFP in H26 and ΔcdpA strains. Scale bars, 2 µm, Bottom: correlation coefficient between FtsZ1-mCherry and FtsZ2-GFP plotted as a frequency distribution. The majority (97%) of H26 cells had a correlation coefficient of ≥0.8, while only 32% of ΔcdpA cells had a correlation coefficient of ≥0.8. For b–d, n = number of cells examined in one independent experiment, and the data shown is representative of at least two independent experiments. Source data are provided as a Source Data file.