TY - JOUR TI - Mitochondrial protein import clogging as a mechanism of disease AU - Coyne, Liam P AU - Wang, Xiaowen AU - Song, Jiyao AU - de Jong, Ebbing AU - Schneider, Karin AU - Massa, Paul T AU - Middleton, Frank A AU - Becker, Thomas AU - Chen, Xin Jie A2 - Wiseman, R Luke A2 - Kornmann, Benoît A2 - Weidberg, Hilla VL - 12 PY - 2023 DA - 2023/05/02 SP - e84330 C1 - eLife 2023;12:e84330 DO - 10.7554/eLife.84330 UR - https://doi.org/10.7554/eLife.84330 AB - Mitochondrial biogenesis requires the import of >1,000 mitochondrial preproteins from the cytosol. Most studies on mitochondrial protein import are focused on the core import machinery. Whether and how the biophysical properties of substrate preproteins affect overall import efficiency is underexplored. Here, we show that protein traffic into mitochondria can be disrupted by amino acid substitutions in a single substrate preprotein. Pathogenic missense mutations in ADP/ATP translocase 1 (ANT1), and its yeast homolog ADP/ATP carrier 2 (Aac2), cause the protein to accumulate along the protein import pathway, thereby obstructing general protein translocation into mitochondria. This impairs mitochondrial respiration, cytosolic proteostasis, and cell viability independent of ANT1’s nucleotide transport activity. The mutations act synergistically, as double mutant Aac2/ANT1 causes severe clogging primarily at the translocase of the outer membrane (TOM) complex. This confers extreme toxicity in yeast. In mice, expression of a super-clogger ANT1 variant led to neurodegeneration and an age-dependent dominant myopathy that phenocopy ANT1-induced human disease, suggesting clogging as a mechanism of disease. More broadly, this work implies the existence of uncharacterized amino acid requirements for mitochondrial carrier proteins to avoid clogging and subsequent disease. KW - mitochondria KW - protein import KW - clogging KW - Ant1 KW - disease KW - mPOS JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -