Fig. 4: Membrane diffusion and protein binding dynamics contribute to co-treadmilling of FtsA and FtsZ.
From: In vitro reconstitution of Escherichia coli divisome activation
a, b Representative micrographs of Alexa488-FtsZ (grey) and Cy5-FtsA WT-His6 (green) (a) or Alexa488-FtsZ (grey) and Cy5-FtsA R286W-His6 (cyan) (b) at increasing Tris-NTA lipid densities. Scale bars are 2 µm. c Colocalization of FtsZ with WT-His6 (green) or R286W-His6 (cyan) quantified by PCC. d Dynamic colocalization of FtsZ with WT-His6 (green) or R286W-His6 (cyan) quantified by PCCdiff. The experiments to measure PCC and PCCdiff were repeated three times for each Tris-NTA lipid density. e, f Representative micrographs of acceptor bleaching recovery and donor intensity increase of FtsA WT-His6 (e) and FtsA R286W-His6 (f). Scale bars are 5 µm. Right: Kymographs depicting the bleaching recovery, as well as the FRET signal for FtsA WT-His6 (green) or R286W-His6 (cyan). Scale bars are 4 µm and 40 s, respectively. g While self-interaction of His-tagged FtsAs increases with increasing protein density, there was no FRET for His-SUMO detected. FRET signal for FtsA WT-His6 is higher compared to FtsA R286W-His6 and FtsZ has no effect on the self-interaction. h While the mobility of His-SUMO remains unchanged, the diffusion coefficient of His-tagged FtsAs decreases with increasing protein density. The experiments in g and h were replicated twice for Tris-NTA densities < 0.6% and three times for Tris-NTA densities > 0.6%. Dots in all plots represent independent experiments, thick lines indicate the mean and error bars depict the standard deviation. Source data are provided as a Source Data file.
