Proteostasis is crucial for life and maintained by cellular chaperones and proteases. One major mitochondrial protease is the ClpXP complex, which is comprised of a catalytic ClpX subunit and a proteolytic ClpP subunit. Based on two separate observations, we hypothesized that ClpX may play a leading role in the cellular function of ClpXP. Therefore, we analyzed the effect of ClpX overexpression on a myoblast proteome by quantitative proteomics. ClpX overexpression results in the upregulation of markers of the mitochondrial proteostasis pathway, known as the "mitochondrial unfolded protein response" (UPRmt). Although this pathway is described in detail in Caenorhabditis elegans, it is not clear whether it is conserved in mammals. Therefore, we compared features of the classical nematode UPRmt with our mammalian ClpX-triggered UPRmt dataset. We show that they share the same retrograde mitochondria-to-nucleus signaling pathway that involves the key UPRmt transcription factor CHOP (also known as Ddit3, CEBPZ or GADD153). In conclusion, our data confirm the existence of a mammalian UPRmt that has great similarity to the C. elegans pathway. Furthermore, our results illustrate that ClpX overexpression is a good and simple model to study the underlying mechanisms of the UPRmt in mammalian cells.
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http://dx.doi.org/10.1016/j.bbamcr.2015.06.016 | DOI Listing |
Cell Mol Life Sci
December 2024
Center for Mitochondrial Research and Medicine, College of Medicine Chang Gung University, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.
Imbalances in gut microbiota and their metabolites have been implicated in osteoporotic disorders. Trimethylamine-n-oxide (TMAO), a metabolite of L-carnitine produced by gut microorganisms and flavin-containing monooxygenase-3, is known to accelerate tissue metabolism and remodeling; however, its role in bone loss remained unexplored. This study investigates the relationship between gut microbiota dysbiosis, TMAO production, and osteoporosis development.
View Article and Find Full Text PDFJ Pathol
January 2025
Department of Nutritional Sciences, University of Connecticut, Storrs, CT, USA.
Int J Biochem Cell Biol
January 2025
Department of Comparative Biomedical Sciences, University of Surrey, Guildford GU2 7AL, UK. Electronic address:
Biomolecules
October 2024
Institute of Parasitology, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.
The model organism and its relationship with the gut microbiome are gaining traction, especially for the study of neurodegenerative diseases such as Parkinson's Disease (PD). Gut microbes are known to be able to alter kynurenine metabolites in the host, directly influencing innate immunity in . While the mitochondrial unfolded protein response (UPR) was first characterized in in 2007, its relevance in host-microbiome interactions has only become apparent in recent years.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201.
The Mitochondrial Unfolded Protein Response (UPR), a mitochondria-originated stress response to altered mitochondrial proteostasis, plays important roles in various pathophysiological processes. In this study, we revealed that the endoplasmic reticulum (ER)-tethered stress sensor CREBH regulates UPR to maintain mitochondrial homeostasis and function in the liver. CREBH is enriched in and required for hepatic Mitochondria-Associated Membrane (MAM) expansion induced by energy demands.
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