a Schematic of ADEP-dependent degradation of FtsZ. ADEP (orange) activates bacterial ClpP peptidase (blue) for untimely protein degradation, and nucleotide-free, monomeric FtsZ (dark green) represents a preferred protein substrate for ADEP-ClpP18,20. As a consequence, the cytoplasmic FtsZ pool is depleted (indicated by the shift from dark to light green), whereas GTP-bound FtsZ (GTP in yellow) is stabilized against proteolytic attack at antibiotic concentrations close to the MIC. FtsZ ring assembly relies on the dynamic exchange of FtsZ subunits between the FtsZ ring and the cytoplasmic FtsZ pool (indicated by dark blue arrow). In the presence of ADEP, the depletion of the FtsZ pool ultimately results in an inhibition of FtsZ ring formation and cell division, finally leading to bacterial cell death. However, it remained unresolved, whether only early or also later stages of the FtsZ ring/divisome are affected by ADEP treatment. b In vitro FtsZ polymerization and FtsZ degradation by ADEP-activated ClpP. Light transmission analysis of GTP-dependent FtsZ polymerization in vitro followed by incubation with a ClpP reaction mixture in the absence or presence of ADEP and/or GTP (−GTP/−ADEP, in gray; +GTP/−ADEP, in blue; +GTP/+ADEP, in orange). Here, polymerized FtsZ is not affected by incubation with ADEP-ClpP. The graphs show mean values of two independent experiments, bottom and top values of indicator bars show the individual data points of each respective replicate. Source data underlying the graphs is presented in Supplementary Table 1. As an independent control, we determined FtsZ protein amounts of samples that were incubated with or without GTP for 120 min in the absence or presence of ADEP. DMSO was used in untreated control reactions. Representative SDS-PAGE images of triplicates are depicted. Source data of the full, uncropped gel image is presented in Supplementary Fig. 4.