Acts as a component of the m-AAA protease complex which is an ATP-dependent metalloprotease mediating degradation of non-assembled mitochondrial inner membrane proteins (By similarity). The complex is necessary for the assembly of mitochondrial respiratory chain and ATPase complexes (By similarity). Functions both in post-translational assembly and in the turnover of mistranslated or misfolded polypeptides (PubMed:22700657, PubMed:25274306, PubMed:25773600). Plays a role in male tail tip morphogenesis (PubMed:21408209). Binds 1 zinc ion per subunit. RNAi-mediated knockdown disrupts tail tip morphogenesis resulting in retention of the pointed larval tail tip in adult males (also known as the Lep phenotype) (PubMed:21408209). RNAi-mediated knockdown induces nuclear and mitochondrial transcription of mitochondrial protective genes including chaperone hsp-60 as part of the mitochondrial unfolded protein response (PubMed:25773600, PubMed:25274306, PubMed:22700657). RNAi-mediated knockdown causes nuclear accumulation of transcription factor atfs-1 in intestinal cells (PubMed:22700657). RNAi-mediated knockdown results in mitochondria in intestinal cells which are abnormally elongated (PubMed:25274306). RNAi-mediated knockdown reduces oxygen consumption (PubMed:25773600). RNAi-mediated knockdown also induces the transcription of innate immunity-related genes such as lys-2, abf-2, clec-65 and clec-4 which results in resistance to P.aeruginosa-mediated infection (PubMed:25274306). RNAi-mediated knockdown abolishes transcription up-regulation in an atfs-1 (tm4919) mutant background (PubMed:22700657, PubMed:25274306, PubMed:25773600). Despite its gene name, this protein is an ortholog of human AFG3L2 and yeast AFG3 and not of human SPG7 and yeast YTA12 (C.elegans ortholog is actually ppgn-1). In the N-terminal section; belongs to the AAA ATPase family. In the C-terminal section; belongs to the peptidase M41 family.