Paraplegin–AFG3L2 m-AAA protease complex (m-AAA protease)

The Paraplegin–AFG3L2 m-AAA protease complex is a critical hetero-oligomeric enzyme assembly located within the inner mitochondrial membrane, composed of subunits encoded by the SPG7 and AFG3L2 genes (UniProt Q9UQ90, Q9Y4W6). It functions as an ATP-dependent metalloprotease and molecular chaperone, playing a central role in mitochondrial protein quality control by degrading misfolded proteins and processing specific substrates such as the ribosomal protein MRPL32 (Nolden et al., 2005). This processing is essential for the assembly of mitochondrial ribosomes and subsequent protein synthesis. Mutations in the SPG7 subunit are the primary cause of Hereditary Spastic Paraplegia type 7, while mutations in AFG3L2 lead to Spinocerebellar Ataxia type 28 and Spastic Ataxia type 5 (Di Bella et al., 2010). These neurodegenerative conditions result from the accumulation of damaged proteins and impaired respiratory chain assembly, leading to progressive axonal loss. While there are currently no FDA-approved drugs that directly target this complex, it is a significant focus for therapeutic research, including gene therapy and small-molecule modulators aimed at restoring mitochondrial proteostasis (Pareek et al., 2018). Understanding the structural dynamics of this complex is vital for developing interventions for mitochondrial-related neurodegeneration (Puchades et al., 2020).

Other names

SPG7-AFG3L2 complexMitochondrial m-AAA proteaseMatrix-AAA protease complexm-AAA protease complex

Restoration or stabilization of mitochondrial protease activity to maintain proteostasis