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MCUR1 is an essential component of mitochondrial Ca2+ uptake that regulates cellular metabolism

A Corrigendum to this article was published on 30 June 2015

A Corrigendum to this article was published on 24 December 2012

This article has been updated

Abstract

Ca2+ flux across the mitochondrial inner membrane regulates bioenergetics, cytoplasmic Ca2+ signals and activation of cell death pathways1,2,3,4,5,6,7,8,9,10,11. Mitochondrial Ca2+ uptake occurs at regions of close apposition with intracellular Ca2+ release sites12,13,14, driven by the inner membrane voltage generated by oxidative phosphorylation and mediated by a Ca2+ selective ion channel (MiCa; ref. 15) called the uniporter16,17,18 whose complete molecular identity remains unknown. Mitochondrial calcium uniporter (MCU) was recently identified as the likely ion-conducting pore19,20. In addition, MICU1 was identified as a mitochondrial regulator of uniporter-mediated Ca2+ uptake in HeLa cells21,22. Here we identified CCDC90A, hereafter referred to as MCUR1 (mitochondrial calcium uniporter regulator 1), an integral membrane protein required for MCU-dependent mitochondrial Ca2+ uptake. MCUR1 binds to MCU and regulates ruthenium-red-sensitive MCU-dependent Ca2+ uptake. MCUR1 knockdown does not alter MCU localization, but abrogates Ca2+ uptake by energized mitochondria in intact and permeabilized cells. Ablation of MCUR1 disrupts oxidative phosphorylation, lowers cellular ATP and activates AMP kinase-dependent pro-survival autophagy. Thus, MCUR1 is a critical component of a mitochondrial uniporter channel complex required for mitochondrial Ca2+ uptake and maintenance of normal cellular bioenergetics.

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Figure 1: RNAi screen identifies MCUR1 as a regulator of mitochondrial Ca2+ uptake.
Figure 2: MCUR1 is required for Ru360-sensitive mitochondrial Ca2+ uptake but is independent of the mitochondrial Ca2+ efflux pathway.
Figure 3: Mitochondrial inner membrane localization and topology of MCUR1 and its interaction with MCU.
Figure 4: MCUR1 is essential for MCU-dependent mitochondrial Ca2+ uptake.
Figure 5: MCUR1 is required for the maintenance of cellular bioenergetics.

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  • 10 June 2015

    In the version of this Letter originally published, a key funding source was omitted from the Acknowledgements. César Cárdenas's credit should have read 'C.C. was supported by the Fondo Nacional de Desarrollo Cientifico y Tecnologico (FONDECYT) grant #1120443 and an award from the American Heart Association'.

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Acknowledgements

This work was supported by the National Institutes of Health grants R01 HL086699, HL086699-01A2S1 and 1S10RR027327-01 to M.M., and GM56328 to J.K.F. C.C. was supported by the Fondo Nacional de Desarrollo Cientifico y Tecnologico (FONDECYT) grant #1120443 and an award from the American Heart Association.

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K.M., M.M. and J.K.F. designed the project. K.M., C.C., P.D., H.C.C., K.M.I., P.M., J.Y., M.M., T.G., G.C. and R.M. performed the experimental work. K.M., C.C., P.D, H.C.C., K.M.I. and M.M. analysed the results. G.H. and G.C. designed the mitopericam experiments and interpreted the results. J.E.K. and B.K. performed mtDNA analysis. J.M. contributed reagents. K.M. M.M. and J.K.F. wrote the manuscript. All authors discussed the results and commented onthe manuscript.

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Correspondence to J. Kevin Foskett or Muniswamy Madesh.

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Mallilankaraman, K., Cárdenas, C., Doonan, P. et al. MCUR1 is an essential component of mitochondrial Ca2+ uptake that regulates cellular metabolism. Nat Cell Biol 14, 1336–1343 (2012). https://doi.org/10.1038/ncb2622

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