Acts as a processive, ATP-dependent zinc metallopeptidase for both cytoplasmic and membrane proteins. Plays a role in the quality control of integral membrane proteins. In vitro partially degrades Spo0E, the phosphatase that acts on Spo0A-P. Recognition requires the last 14 residues of Spo0E (PubMed:19332814). Its stabile accumulation requires FlotA and Flot (PubMed:24222488). May degrade EzrA (Probable). Binds 1 zinc ion per subunit. Homohexamer (By similarity). Interacts with FloT at midcell (Probable) (PubMed:23651456, PubMed:26297017). Interacts with FloA at midcell (Probable). Another study shows only minor colocalization with FloA or FloT (PubMed:27362352). Accumulates in the midcell septum during vegetative cell division. At the septa colocalizes with FloA and FloT, which seem to stabilize it in the membrane (PubMed:10851010, PubMed:22882210). At the onset of sporulation appears at positions near the cell poles that may coincide with future division sites. Then, FtsH becomes concentrated at the sporulation septum and disappears from the distal pole (PubMed:10851010). Present in detergent-resistant membrane (DRM) fractions that may be equivalent to eukaryotic membrane rafts; these rafts include proteins involved in signaling, molecule trafficking and protein secretion (PubMed:22882210, PubMed:23651456). Necessary only for stage 0 of sporulation. Induced by osmotic shock (0.8 M NaCl) and by heat shock (52 degrees Celsius). Required for expression of the stage 0 sporulation gene Spo0A, as well as for a normal heat or osmotic stress response, cells lacking this gene grow as long filaments and tend to lyse upon entry into stationary phase. Secretion of some extracellular proteins is also reduced (PubMed:9076729). Loss of biofilm formation (PubMed:22882210). In the central section; belongs to the AAA ATPase family. In the C-terminal section; belongs to the peptidase M41 family.