Metabolic adaptations in response to changes in energy supply and demand are essential for survival. The mitochondrial calcium uniporter plays a key role in coordinating metabolic homeostasis by regulating TCA cycle activation, mitochondrial fatty acid oxidation and cellular calcium signaling. However, a comprehensive analysis of uniporter-regulated mitochondrial metabolic pathways has remained unexplored. Here, we investigate metabolic consequences of uniporter loss- and gain-of-function using uniporter knock out cells and the liver cancer fibrolamellar carcinoma (FLC), which we demonstrate to have elevated mitochondrial calcium levels. Our results reveal that branched chain amino acid (BCAA) catabolism and the urea cycle are uniporter-regulated metabolic pathways. Reduced uniproter function increases expression of BCAA catabolism genes, and the urea cycle enzyme ornithine transcarbamylase (OTC). In contrast, high uniporter activity in FLC suppresses their expression. This suppression happens via the transcription factor KLF15, a master regulator of liver metabolism, suggesting that calcium signaling plays a central role in FLC-associated metabolic changes, including hyperammonemia. Consistent with this, activation of BCAA catabolism in FLC cells impairs their growth. Collectively, our study identifies an important role for mitochondrial calcium signaling in metabolic adaptation through transcriptional regulation of metabolism and elucidates its importance for BCAA and ammonia metabolism in FLC.
[doi:10.25345/C5WM1457F]
[dataset license: CC0 1.0 Universal (CC0 1.0)]
Keywords: MCU ; DatasetType:Proteomics
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Yasemin Sancak, University of Washington, United States |
Submitting User: | shaoen |
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Owner | Reanalyses | |
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