Bacterial cell division protein FtsZ is stable against degradation by AAA family protease FtsH in Escherichia coli cells

Abstract

We have found that FtsH protease of Escherichia coli could degrade E. coli cell division protein FtsZ in an ATP- and Zn(2+)-dependent manner in vitro and that the degradation did not show specificity for the N-terminus or C-terminus of FtsZ, like in the case of degradation of its conventional substrate sigma(32) protein. In continuation of these observations, in the present study, we examined whether FtsH would affect the stability and turnover of FtsZ in vivo. We found that FtsZ levels were not elevated in E. coli AR754 (ftsH1 ts) cells at nonpermissive temperature as compared to the levels in an FtsH-active isogenic AR753 strain. Neither did FtsH degrade ectopically expressed FtsZ in AR754 strain nor did ectopic expression of FtsH reduced FtsZ levels in E. coli AR5090 ftsH null strain (ftsH::kan, sfhC21). Pulse chase experiments in AR754 and AR5090 strains showed that there were no compensatory changes in FtsZ turnover, in case FtsZ degradation had occurred. Even under cell division arrested conditions, wherein FtsZ was not required, FtsH protease did not degrade unutilized FtsZ. These experiments demonstrate that either FtsH protease may not have a role in regulating the levels of FtsZ in vivo under the conditions tested or that some cellular component(s) might be stabilising FtsZ against FtsH protease.

In vivo trapping of FtsH substrates by label‐free quantitative proteomics

“…Among the identified unstable proteins was the subunit GatY of the tagatose‐1,6‐bisphosphate aldolase, which was also trapped with ClpXP suggesting an involvement of both ClpXP and FtsH in GatY degradation . The cell division protein FtsZ found in our study and a previous FtsH‐trapping approach has been reported to be a substrate of ClpXP and not FtsH .…”

ZapE Is a Novel Cell Division Protein Interacting with FtsZ and Modulating the Z-Ring Dynamics

“…S3C to E), using fold recognition methods based on the extended AAA+ ATPase domain of the ATP-dependent metalloprotease FtsH (PDB identification number [ID] 2CE7). As FtsZ is a known FtsH substrate (11, 12), the structural similarity between ZapE and FtsH suggests that ZapE might interact directly with FtsZ.…”

“…FtsH is an ATP-dependent zinc metalloprotease targeting FtsZ in vitro (11), although this activity could not be confirmed in vivo (12). MinD belongs to the Min system involved in Z-ring positioning (20).…”

Structure and function of the bacterial AAA protease FtsH

“…Proteolysis of FtsZ in vitro is independent of terminal sequences and is modulated by the GTP-binding state [105,106]. Attempts to measure FtsZ degradation by FtsH in vivo were unsuccessful and FtsZ was found to be a substrate of ClpXP [107,108].…”