Putative ATP-dependent protease. Required for the maturation of paraplegin (SPG7) after its cleavage by mitochondrial-processing peptidase (MPP), converting it into a proteolytically active mature form. Binds 1 zinc ion per subunit. Homooligomer (PubMed:17101804). Forms heterooligomers with SPG7 and AFG3L2 (PubMed:17101804, PubMed:19656850). Interacts with SPG7 and AFG3L2 (PubMed:19656850). In the N-terminal section; belongs to the AAA ATPase family. In the C-terminal section; belongs to the peptidase M41 family. The orthologous human gene is a pseudogene.