MIRO1 Is Required for Dynamic Increases in Mitochondria-ER Contact Sites and Mitochondrial ATP During the Cell Cycle
Mitochondria-ER contact sites (MERCS) are vital for mitochondrial dynamics, lipid exchange, Ca<sup>2+</sup> homeostasis, and energy metabolism. We examined whether mitochondrial metabolism changes during the cell cycle depend on MERCS dynamics and are regulated by the outer mitochondrial...
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MDPI AG
2025-03-01
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| author | Benney T. Endoni Olha M. Koval Chantal Allamargot Tara Kortlever Lan Qian Riley J. Sadoski Denise Juhr Isabella M. Grumbach |
| author_facet | Benney T. Endoni Olha M. Koval Chantal Allamargot Tara Kortlever Lan Qian Riley J. Sadoski Denise Juhr Isabella M. Grumbach |
| author_sort | Benney T. Endoni |
| collection | DOAJ |
| description | Mitochondria-ER contact sites (MERCS) are vital for mitochondrial dynamics, lipid exchange, Ca<sup>2+</sup> homeostasis, and energy metabolism. We examined whether mitochondrial metabolism changes during the cell cycle depend on MERCS dynamics and are regulated by the outer mitochondrial protein mitochondrial rho GTPase 1 (MIRO1). Wound healing was assessed in mice with fibroblast-specific deletion of MIRO1. Wild-type and MIRO1<sup>-/-</sup> fibroblasts and vascular smooth muscle cells were evaluated for proliferation, cell cycle progression, number of MERCS, distance, and protein composition throughout the cell cycle. Restoration of MIRO1 mutants was used to test the role of MIRO1 domains; Ca<sup>2+</sup> transients and mitochondrial metabolism were evaluated using biochemical, immunodetection, and fluorescence techniques. MERCS increased in number during G1/S compared with during G0, which was accompanied by a notable rise in protein–protein interactions involving VDAC1 and IP3R as well as GRP75 and MIRO1 by proximity-ligation assays. Split-GFP ER/mitochondrial contacts of 40 nm also increased. Mitochondrial Ca<sup>2+</sup> concentration ([Ca<sup>2+</sup>]), membrane potential, and ATP levels correlated with the formation of MERCS during the cell cycle. MIRO1 deficiency blocked G1/S progression and the cell-cycle-dependent formation of MERCS and altered ER Ca<sup>2+</sup> release and mitochondrial Ca<sup>2+</sup> uptake. MIRO1 mutants lacking the Ca<sup>2+</sup>-sensitive EF hands or the transmembrane domain did not rescue cell proliferation or the formation of MERCS. MIRO1 controls an increase in the number of MERCS during cell cycle progression and increases mitochondrial [Ca<sup>2+</sup>], driving metabolic activity and proliferation through its EF hands. |
| format | Article |
| id | doaj-art-246995cec91741048bbcf96b0328045a |
| institution | DOAJ |
| issn | 2073-4409 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Cells |
| spelling | doaj-art-246995cec91741048bbcf96b0328045a2025-08-20T03:08:45ZengMDPI AGCells2073-44092025-03-0114748210.3390/cells14070482MIRO1 Is Required for Dynamic Increases in Mitochondria-ER Contact Sites and Mitochondrial ATP During the Cell CycleBenney T. Endoni0Olha M. Koval1Chantal Allamargot2Tara Kortlever3Lan Qian4Riley J. Sadoski5Denise Juhr6Isabella M. Grumbach7Abboud Cardiovascular Research Center, Division of Cardiovascular Medicine, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USAAbboud Cardiovascular Research Center, Division of Cardiovascular Medicine, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USACentral Microscopy Research Facility, University of Iowa, Iowa City, IA 52242, USAAbboud Cardiovascular Research Center, Division of Cardiovascular Medicine, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USAAbboud Cardiovascular Research Center, Division of Cardiovascular Medicine, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USAAbboud Cardiovascular Research Center, Division of Cardiovascular Medicine, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USAAbboud Cardiovascular Research Center, Division of Cardiovascular Medicine, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USAAbboud Cardiovascular Research Center, Division of Cardiovascular Medicine, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USAMitochondria-ER contact sites (MERCS) are vital for mitochondrial dynamics, lipid exchange, Ca<sup>2+</sup> homeostasis, and energy metabolism. We examined whether mitochondrial metabolism changes during the cell cycle depend on MERCS dynamics and are regulated by the outer mitochondrial protein mitochondrial rho GTPase 1 (MIRO1). Wound healing was assessed in mice with fibroblast-specific deletion of MIRO1. Wild-type and MIRO1<sup>-/-</sup> fibroblasts and vascular smooth muscle cells were evaluated for proliferation, cell cycle progression, number of MERCS, distance, and protein composition throughout the cell cycle. Restoration of MIRO1 mutants was used to test the role of MIRO1 domains; Ca<sup>2+</sup> transients and mitochondrial metabolism were evaluated using biochemical, immunodetection, and fluorescence techniques. MERCS increased in number during G1/S compared with during G0, which was accompanied by a notable rise in protein–protein interactions involving VDAC1 and IP3R as well as GRP75 and MIRO1 by proximity-ligation assays. Split-GFP ER/mitochondrial contacts of 40 nm also increased. Mitochondrial Ca<sup>2+</sup> concentration ([Ca<sup>2+</sup>]), membrane potential, and ATP levels correlated with the formation of MERCS during the cell cycle. MIRO1 deficiency blocked G1/S progression and the cell-cycle-dependent formation of MERCS and altered ER Ca<sup>2+</sup> release and mitochondrial Ca<sup>2+</sup> uptake. MIRO1 mutants lacking the Ca<sup>2+</sup>-sensitive EF hands or the transmembrane domain did not rescue cell proliferation or the formation of MERCS. MIRO1 controls an increase in the number of MERCS during cell cycle progression and increases mitochondrial [Ca<sup>2+</sup>], driving metabolic activity and proliferation through its EF hands.https://www.mdpi.com/2073-4409/14/7/482mitochondriaERMERCSMAMMIRO1cell cycle |
| spellingShingle | Benney T. Endoni Olha M. Koval Chantal Allamargot Tara Kortlever Lan Qian Riley J. Sadoski Denise Juhr Isabella M. Grumbach MIRO1 Is Required for Dynamic Increases in Mitochondria-ER Contact Sites and Mitochondrial ATP During the Cell Cycle Cells mitochondria ER MERCS MAM MIRO1 cell cycle |
| title | MIRO1 Is Required for Dynamic Increases in Mitochondria-ER Contact Sites and Mitochondrial ATP During the Cell Cycle |
| title_full | MIRO1 Is Required for Dynamic Increases in Mitochondria-ER Contact Sites and Mitochondrial ATP During the Cell Cycle |
| title_fullStr | MIRO1 Is Required for Dynamic Increases in Mitochondria-ER Contact Sites and Mitochondrial ATP During the Cell Cycle |
| title_full_unstemmed | MIRO1 Is Required for Dynamic Increases in Mitochondria-ER Contact Sites and Mitochondrial ATP During the Cell Cycle |
| title_short | MIRO1 Is Required for Dynamic Increases in Mitochondria-ER Contact Sites and Mitochondrial ATP During the Cell Cycle |
| title_sort | miro1 is required for dynamic increases in mitochondria er contact sites and mitochondrial atp during the cell cycle |
| topic | mitochondria ER MERCS MAM MIRO1 cell cycle |
| url | https://www.mdpi.com/2073-4409/14/7/482 |
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