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 cytoplasmic proteins inside the nucleus.

A complex network of molecular chaperones and proteolytic machinery safeguards the proteins which comprise the proteome, from the time they are synthesized on ribosomes to their destruction via proteolysis. Impaired protein quality control results in the accumulation of aberrant proteins, which may undergo unwanted spurious interactions with other proteins, thereby interfering with a broad range of cellular functions. To protect the cellular environment, such proteins are degraded or sequestered into inclusions in different subcellular compartments.