Promotes sorting of SMDT1/EMRE in mitochondria by ensuring its maturation. Interacts with the transit peptide region of SMDT1/EMRE precursor protein in the mitochondrial matrix, leading to protect it against protein degradation by YME1L1, thereby ensuring SMDT1/EMRE maturation by the mitochondrial processing peptidase (PMPCA and PMPCB). Interacts with AFG3L2. Interacts with SPG7. Interacts with SMDT1/EMRE (via the N-terminal transit peptide); interaction is direct and takes place before maturation of SMDT1/EMRE.