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Updated: Dec 11, 2025

Author Spotlight: Unveiling Mitochondrial Contact Sites and Architectural Insights
Published on: June 16, 2023
Solid-phase inclusion as a mechanism for regulating unfolded proteins in the mitochondrial matrix
Linhao Ruan1,2, Joshua T McNamara1,2, Xi Zhang1
1Center for Cell Dynamics and Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Abstract:
Proteostasis declines with age, characterized by the accumulation of unfolded or damaged proteins. Recent studies suggest that proteins constituting pathological inclusions in neurodegenerative diseases also enter and accumulate in mitochondria. How unfolded proteins are managed within mitochondria remains unclear. Here, we found that excessive unfolded proteins in the mitochondrial matrix of yeast cells are consolidated into solid-phase inclusions, which we term deposits of unfolded mitochondrial proteins (DUMP). Formation of DUMP occurs in mitochondria near endoplasmic reticulum-mitochondria contact sites and is regulated by mitochondrial proteins controlling the production of cytidine 5'-diphosphate-diacylglycerol. DUMP formation is age dependent but accelerated by exogenous unfolded proteins. Many enzymes of the tricarboxylic acid cycle were enriched in DUMP. During yeast cell division, DUMP formation is necessary for asymmetric inheritance of damaged mitochondrial proteins between mother and daughter cells. We provide evidence that DUMP-like structures may be induced by excessive unfolded proteins in human cells.
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