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Updated: May 13, 2025

Measurement of Protein Import Capacity of Skeletal Muscle Mitochondria
Published on: January 7, 2022
Quality control of un-imported mitochondrial proteins at a glance
Megan Balzarini1, John Kim1, Hilla Weidberg1
1Life Sciences Institute, Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
Abstract:
Mitochondria are metabolic hubs that are essential for cellular homeostasis. Most mitochondrial proteins are translated in the cytosol and imported into the organelle. However, import machineries can become overwhelmed or disrupted by physiological demands, mitochondrial damage or diseases, such as metabolic and neurodegenerative disorders. Impaired import affects mitochondrial function and causes un-imported pre-proteins to accumulate not only in the cytosol but also in other compartments, including the endoplasmic reticulum and nucleus. Quality control pathways have evolved to mitigate the accumulation of these mistargeted proteins and prevent proteotoxicity. In this Cell Science at a Glance article and the accompanying poster, we summarize the fate of un-imported mitochondrial proteins and the compartment-specific quality control pathways that regulate them.
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