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Updated: Jul 15, 2025

Reconstitution of Msp1 Extraction Activity with Fully Purified Components
Published on: August 10, 2021
Early fate decision for mitochondrially encoded proteins by a molecular triage
Andreas Kohler1, Andreas Carlström2, Hendrik Nolte3
1Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden; Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria.
Abstract:
Folding of newly synthesized proteins poses challenges for a functional proteome. Dedicated protein quality control (PQC) systems either promote the folding of nascent polypeptides at ribosomes or, if this fails, ensure their degradation. Although well studied for cytosolic protein biogenesis, it is not understood how these processes work for mitochondrially encoded proteins, key subunits of the oxidative phosphorylation (OXPHOS) system. Here, we identify dedicated hubs in proximity to mitoribosomal tunnel exits coordinating mitochondrial protein biogenesis and quality control. Conserved prohibitin (PHB)/m-AAA protease supercomplexes and the availability of assembly chaperones determine the fate of newly synthesized proteins by molecular triaging. The localization of these competing activities in the vicinity of the mitoribosomal tunnel exit allows for a prompt decision on whether newly synthesized proteins are fed into OXPHOS assembly or are degraded.
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