Mitochondrial complexome reveals quality-control pathways of protein import.

Mitochondria have crucial roles in cellular energetics, metabolism, signalling and quality control. They contain around 1,000 different proteins that often assemble into complexes and supercomplexes such as respiratory complexes and preprotein translocases. The composition of the mitochondrial proteome has been characterized; however, the organization of mitochondrial proteins into stable and dynamic assemblies is poorly understood for major parts of the proteome.

Quality control of protein import into mitochondria.

Mitochondria import about 1000 proteins that are produced as precursors on cytosolic ribosomes. Defects in mitochondrial protein import result in the accumulation of non-imported precursor proteins and proteotoxic stress. The cell is equipped with different quality control mechanisms to monitor protein transport into mitochondria.