1
|
Colussi DM, Stathopulos PB. The mitochondrial calcium uniporter: Balancing tumourigenic and anti-tumourigenic responses. J Physiol 2024; 602:3315-3339. [PMID: 38857425 DOI: 10.1113/jp285515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Accepted: 05/20/2024] [Indexed: 06/12/2024] Open
Abstract
Increased malignancy and poor treatability associated with solid tumour cancers have commonly been attributed to mitochondrial calcium (Ca2+) dysregulation. The mitochondrial Ca2+ uniporter complex (mtCU) is the predominant mode of Ca2+ uptake into the mitochondrial matrix. The main components of mtCU are the pore-forming mitochondrial Ca2+ uniporter (MCU) subunit, MCU dominant-negative beta (MCUb) subunit, essential MCU regulator (EMRE) and the gatekeeping mitochondrial Ca2+ uptake 1 and 2 (MICU1 and MICU2) proteins. In this review, we describe mtCU-mediated mitochondrial Ca2+ dysregulation in solid tumour cancer types, finding enhanced mtCU activity observed in colorectal cancer, breast cancer, oral squamous cell carcinoma, pancreatic cancer, hepatocellular carcinoma and embryonal rhabdomyosarcoma. By contrast, decreased mtCU activity is associated with melanoma, whereas the nature of mtCU dysregulation remains unclear in glioblastoma. Furthermore, we show that numerous polymorphisms associated with cancer may alter phosphorylation sites on the pore forming MCU and MCUb subunits, which cluster at interfaces with EMRE. We highlight downstream/upstream biomolecular modulators of MCU and MCUb that alter mtCU-mediated mitochondrial Ca2+ uptake and may be used as biomarkers or to aid in the development of novel cancer therapeutics. Additionally, we provide an overview of the current small molecule inhibitors of mtCU that interact with the Asp residue of the critical Asp-Ile-Met-Glu motif or through other allosteric regulatory mechanisms to block Ca2+ permeation. Finally, we describe the relationship between MCU- and MCUb-mediating microRNAs and mitochondrial Ca2+ uptake that should be considered in the discovery of new treatment approaches for cancer.
Collapse
Affiliation(s)
- Danielle M Colussi
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| |
Collapse
|
2
|
Ghosh Dastidar R, Banerjee S, Lal PB, Ghosh Dastidar S. Multifaceted Roles of AFG3L2, a Mitochondrial ATPase in Relation to Neurological Disorders. Mol Neurobiol 2024; 61:3788-3808. [PMID: 38012514 PMCID: PMC11236935 DOI: 10.1007/s12035-023-03768-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 11/01/2023] [Indexed: 11/29/2023]
Abstract
AFG3L2 is a zinc metalloprotease and an ATPase localized in an inner mitochondrial membrane involved in mitochondrial quality control of several nuclear- and mitochondrial-encoded proteins. Mutations in AFG3L2 lead to diseases like slow progressive ataxia, which is a neurological disorder. This review delineates the cellular functions of AFG3L2 and its dysfunction that leads to major clinical outcomes, which include spinocerebellar ataxia type 28, spastic ataxia type 5, and optic atrophy type 12. It summarizes all relevant AFG3L2 mutations associated with the clinical outcomes to understand the detailed mechanisms attributable to its structure-related multifaceted roles in proteostasis and quality control. We face early diagnostic challenges of ataxia and optic neuropathy due to asymptomatic parents and variable clinical manifestations due to heterozygosity/homozygosity of AFG3L2 mutations. This review intends to promote AFG3L2 as a putative prognostic or diagnostic marker.
Collapse
Affiliation(s)
- Ranita Ghosh Dastidar
- Department of Biochemistry, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, Madhava Nagar, Manipal, 576104, Karnataka, India.
| | - Saradindu Banerjee
- Centre for Molecular Neurosciences, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, Madhava Nagar, Manipal, 576104, Karnataka, India
| | - Piyush Behari Lal
- Department of Microbiology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, Madhava Nagar, Manipal, 576104, Karnataka, India.
| | - Somasish Ghosh Dastidar
- Centre for Molecular Neurosciences, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, Madhava Nagar, Manipal, 576104, Karnataka, India.
| |
Collapse
|
3
|
Kaye SD, Goyani S, Tomar D. MICU1's calcium sensing beyond mitochondrial calcium uptake. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119714. [PMID: 38555977 PMCID: PMC11194792 DOI: 10.1016/j.bbamcr.2024.119714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/19/2024] [Accepted: 03/21/2024] [Indexed: 04/02/2024]
Abstract
The discovery of MICU1 as gatekeeper of mitochondrial calcium (mCa2+) entry has transformed our understanding of mCa2+ flux. Recent studies revealed an additional role of MICU1 as a Ca2+ sensor at MICOS (mitochondrial contact site and cristae organizing system). MICU1's presence at MICOS suggests its involvement in coordinating Ca2+ signaling and mitochondrial ultrastructure. Besides its role in Ca2+ regulation, MICU1 influences cellular signaling pathways including transcription, epigenetic regulation, metabolism, and cell death, thereby affecting human health. Here, we summarize recent findings on MICU1's canonical and noncanonical functions, and its relevance to human health and diseases.
Collapse
Affiliation(s)
- Sarah D Kaye
- Department of Internal Medicine, Section of Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Shanikumar Goyani
- Department of Internal Medicine, Section of Cardiovascular Medicine, Section of Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Dhanendra Tomar
- Department of Internal Medicine, Section of Cardiovascular Medicine, Section of Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
| |
Collapse
|
4
|
Bulthuis EP, Adjobo-Hermans MJW, de Potter B, Hoogstraten S, Wezendonk LHT, Tutakhel OAZ, Wintjes LT, van den Heuvel B, Willems PHGM, Kamsteeg EJ, Gozalbo MER, Sallevelt SCEH, Koudijs SM, Nicolai J, de Bie CI, Hoogendijk JE, Koopman WJH, Rodenburg RJ. SMDT1 variants impair EMRE-mediated mitochondrial calcium uptake in patients with muscle involvement. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166808. [PMID: 37454773 DOI: 10.1016/j.bbadis.2023.166808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/26/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Ionic calcium (Ca2+) is a key messenger in signal transduction and its mitochondrial uptake plays an important role in cell physiology. This uptake is mediated by the mitochondrial Ca2+ uniporter (MCU), which is regulated by EMRE (essential MCU regulator) encoded by the SMDT1 (single-pass membrane protein with aspartate rich tail 1) gene. This work presents the genetic, clinical and cellular characterization of two patients harbouring SMDT1 variants and presenting with muscle problems. Analysis of patient fibroblasts and complementation experiments demonstrated that these variants lead to absence of EMRE protein, induce MCU subcomplex formation and impair mitochondrial Ca2+ uptake. However, the activity of oxidative phosphorylation enzymes, mitochondrial morphology and membrane potential, as well as routine/ATP-linked respiration were not affected. We hypothesize that the muscle-related symptoms in the SMDT1 patients result from aberrant mitochondrial Ca2+ uptake.
Collapse
Affiliation(s)
- Elianne P Bulthuis
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6525 GA Nijmegen, the Netherlands
| | - Merel J W Adjobo-Hermans
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6525 GA Nijmegen, the Netherlands
| | - Bastiaan de Potter
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6525 GA Nijmegen, the Netherlands
| | - Saskia Hoogstraten
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6525 GA Nijmegen, the Netherlands; Human and Animal Physiology, Wageningen University & Research, 6700 AH Wageningen, the Netherlands
| | - Lisanne H T Wezendonk
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6525 GA Nijmegen, the Netherlands
| | - Omar A Z Tutakhel
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Centre, 6525 GA Nijmegen, the Netherlands
| | - Liesbeth T Wintjes
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Centre, 6525 GA Nijmegen, the Netherlands
| | - Bert van den Heuvel
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Centre, 6525 GA Nijmegen, the Netherlands
| | - Peter H G M Willems
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6525 GA Nijmegen, the Netherlands
| | - Erik-Jan Kamsteeg
- Department of Human Genetics, Radboud University Medical Centre, 6525 GA Nijmegen, the Netherlands
| | - M Estela Rubio Gozalbo
- Department of Pediatrics, Maastricht University Medical Centre, 6229 HX Maastricht, the Netherlands; Department of Clinical Genetics, Maastricht University Medical Centre, 6229 HX Maastricht, the Netherlands
| | - Suzanne C E H Sallevelt
- Department of Clinical Genetics, Maastricht University Medical Centre, 6229 HX Maastricht, the Netherlands
| | - Suzanne M Koudijs
- Department of Neurology, Maastricht University Medical Centre, 6229 HX Maastricht, the Netherlands
| | - Joost Nicolai
- Department of Neurology, Maastricht University Medical Centre, 6229 HX Maastricht, the Netherlands
| | - Charlotte I de Bie
- Department of Genetics, University Medical Centre Utrecht, 3508 AB Utrecht, the Netherlands
| | - Jessica E Hoogendijk
- Rudolf Magnus Institute of Neuroscience, University Medical Centre Utrecht, 3584 CG Utrecht, the Netherlands
| | - Werner J H Koopman
- Human and Animal Physiology, Wageningen University & Research, 6700 AH Wageningen, the Netherlands; Department of Pediatrics, Amalia Children's Hospital, Radboud Center for Mitochondrial Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500 HB Nijmegen, the Netherlands.
| | - Richard J Rodenburg
- Department of Pediatrics, Amalia Children's Hospital, Radboud Center for Mitochondrial Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500 HB Nijmegen, the Netherlands.
| |
Collapse
|
5
|
Abstract
Mitochondria are multifunctional organelles that play a central role in a wide range of life-sustaining tasks in eukaryotic cells, including adenosine triphosphate (ATP) production, calcium storage and coenzyme generation pathways such as iron-sulfur cluster biosynthesis. The wide range of mitochondrial functions is carried out by a diverse array of proteins comprising approximately 1500 proteins or polypeptides. Degradation of these proteins is mainly performed by four AAA+ proteases localized in mitochondria. These AAA+ proteases play a quality control role in degrading damaged or misfolded proteins and perform various other functions. This chapter describes previously identified roles for these AAA+ proteases that are localized in the mitochondria of animal cells.
Collapse
Affiliation(s)
- Yuichi Matsushima
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan.
| |
Collapse
|
6
|
Zhang S, Guo Y, Fidelito G, Robinson DR, Liang C, Lim R, Bichler Z, Guo R, Wu G, Xu H, Zhou QD, Singh BK, Yen P, Kappei D, Stroud DA, Ho L. LINC00116-encoded microprotein mitoregulin regulates fatty acid metabolism at the mitochondrial outer membrane. iScience 2023; 26:107558. [PMID: 37664623 PMCID: PMC10469944 DOI: 10.1016/j.isci.2023.107558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 07/04/2023] [Accepted: 08/02/2023] [Indexed: 09/05/2023] Open
Abstract
LINC00116 encodes a microprotein first identified as Mitoregulin (MTLN), where it was reported to localize to the inner membrane of mitochondria to regulate fatty acid oxidation and oxidative phosphorylation. These initial discoveries were followed by reports with differing findings about its molecular functions and submitochondrial localization. To clarify the apparent discrepancies, we constructed multiple orthogonal methods of determining the localization of MTLN, including split GFP-based reporters that enable efficient and reliable topology analyses for microproteins. These methods unequivocally demonstrate MTLN primarily localizes to the outer membrane of mitochondria, where it interacts with enzymes of fatty acid metabolism including CPT1B and CYB5B. Loss of MTLN causes the accumulation of very long-chain fatty acids (VLCFAs), especially docosahexaenoic acid (DHA). Intriguingly, loss of MTLN protects mice against western diet/fructose-induced insulin-resistance, suggests a protective effect of VLCFAs in this context. MTLN thus serves as an attractive target to control the catabolism of VLCFAs.
Collapse
Affiliation(s)
- Shan Zhang
- Department of Biochemistry, Department of Cardiology of The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Cardiovascular and Metabolic Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Yabo Guo
- Department of Biochemistry, Department of Cardiology of The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Gio Fidelito
- Cardiovascular and Metabolic Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - David R.L. Robinson
- Department of Biochemistry and Pharmacology, The Bio21 Molecular Science & Biotechnology Institute, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Chao Liang
- Cardiovascular and Metabolic Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Radiance Lim
- Cardiovascular and Metabolic Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Zoë Bichler
- Behavioral Neuroscience Laboratory, National Neuroscience Institute, Singapore 308433, Singapore
| | - Ruiyang Guo
- Department of Biochemistry, Department of Cardiology of The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Gaoqi Wu
- Institute of Immunology, Department of Surgical Oncology of The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - He Xu
- Institute of Immunology, Department of Surgical Oncology of The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Quan D. Zhou
- Institute of Immunology, Department of Surgical Oncology of The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Brijesh K. Singh
- Cardiovascular and Metabolic Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Paul Yen
- Cardiovascular and Metabolic Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Dennis Kappei
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
- NUS Center for Cancer Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
| | - David A. Stroud
- Department of Biochemistry and Pharmacology, The Bio21 Molecular Science & Biotechnology Institute, University of Melbourne, Melbourne, VIC 3010, Australia
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3010, Australia
- Victorian Clinical Genetics Services, Murdoch Children’s Research Institute, Melbourne, VIC 3010, Australia
| | - Lena Ho
- Cardiovascular and Metabolic Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| |
Collapse
|
7
|
Chapoy Villanueva H, Sung JH, Stevens JA, Zhang MJ, Nelson PM, Denduluri LS, Feng F, O'Connell TD, Townsend D, Liu JC. Distinct effects of cardiac mitochondrial calcium uniporter inactivation via EMRE deletion in the short and long term. J Mol Cell Cardiol 2023; 181:33-45. [PMID: 37230379 PMCID: PMC10524693 DOI: 10.1016/j.yjmcc.2023.05.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 05/13/2023] [Accepted: 05/18/2023] [Indexed: 05/27/2023]
Abstract
Transport of Ca2+ into mitochondria is thought to stimulate the production of ATP, a critical process in the heart's fight or flight response, but excess Ca2+ can trigger cell death. The mitochondrial Ca2+ uniporter complex is the primary route of Ca2+ transport into mitochondria, in which the channel-forming protein MCU and the regulatory protein EMRE are essential for activity. In previous studies, chronic Mcu or Emre deletion differed from acute cardiac Mcu deletion in response to adrenergic stimulation and ischemia/reperfusion (I/R) injury, despite equivalent inactivation of rapid mitochondrial Ca2+ uptake. To explore this discrepancy between chronic and acute loss of uniporter activity, we compared short-term and long-term Emre deletion using a novel conditional cardiac-specific, tamoxifen-inducible mouse model. After short-term Emre deletion (3 weeks post-tamoxifen) in adult mice, cardiac mitochondria were unable to take up Ca2+, had lower basal mitochondrial Ca2+ levels, and displayed attenuated Ca2+-induced ATP production and mPTP opening. Moreover, short-term EMRE loss blunted cardiac response to adrenergic stimulation and improved maintenance of cardiac function in an ex vivo I/R model. We then tested whether the long-term absence of EMRE (3 months post-tamoxifen) in adulthood would lead to distinct outcomes. After long-term Emre deletion, mitochondrial Ca2+ handling and function, as well as cardiac response to adrenergic stimulation, were similarly impaired as in short-term deletion. Interestingly, however, protection from I/R injury was lost in the long-term. These data suggest that several months without uniporter function are insufficient to restore bioenergetic response but are sufficient to restore susceptibility to I/R.
Collapse
Affiliation(s)
- Hector Chapoy Villanueva
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Jae Hwi Sung
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Jackie A Stevens
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Michael J Zhang
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA; Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Peyton M Nelson
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Lalitha S Denduluri
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Feng Feng
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Timothy D O'Connell
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - DeWayne Townsend
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Julia C Liu
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
| |
Collapse
|
8
|
Novorolsky RJ, Kasheke GDS, Hakim A, Foldvari M, Dorighello GG, Sekler I, Vuligonda V, Sanders ME, Renden RB, Wilson JJ, Robertson GS. Preserving and enhancing mitochondrial function after stroke to protect and repair the neurovascular unit: novel opportunities for nanoparticle-based drug delivery. Front Cell Neurosci 2023; 17:1226630. [PMID: 37484823 PMCID: PMC10360135 DOI: 10.3389/fncel.2023.1226630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 06/22/2023] [Indexed: 07/25/2023] Open
Abstract
The neurovascular unit (NVU) is composed of vascular cells, glia, and neurons that form the basic component of the blood brain barrier. This intricate structure rapidly adjusts cerebral blood flow to match the metabolic needs of brain activity. However, the NVU is exquisitely sensitive to damage and displays limited repair after a stroke. To effectively treat stroke, it is therefore considered crucial to both protect and repair the NVU. Mitochondrial calcium (Ca2+) uptake supports NVU function by buffering Ca2+ and stimulating energy production. However, excessive mitochondrial Ca2+ uptake causes toxic mitochondrial Ca2+ overloading that triggers numerous cell death pathways which destroy the NVU. Mitochondrial damage is one of the earliest pathological events in stroke. Drugs that preserve mitochondrial integrity and function should therefore confer profound NVU protection by blocking the initiation of numerous injury events. We have shown that mitochondrial Ca2+ uptake and efflux in the brain are mediated by the mitochondrial Ca2+ uniporter complex (MCUcx) and sodium/Ca2+/lithium exchanger (NCLX), respectively. Moreover, our recent pharmacological studies have demonstrated that MCUcx inhibition and NCLX activation suppress ischemic and excitotoxic neuronal cell death by blocking mitochondrial Ca2+ overloading. These findings suggest that combining MCUcx inhibition with NCLX activation should markedly protect the NVU. In terms of promoting NVU repair, nuclear hormone receptor activation is a promising approach. Retinoid X receptor (RXR) and thyroid hormone receptor (TR) agonists activate complementary transcriptional programs that stimulate mitochondrial biogenesis, suppress inflammation, and enhance the production of new vascular cells, glia, and neurons. RXR and TR agonism should thus further improve the clinical benefits of MCUcx inhibition and NCLX activation by increasing NVU repair. However, drugs that either inhibit the MCUcx, or stimulate the NCLX, or activate the RXR or TR, suffer from adverse effects caused by undesired actions on healthy tissues. To overcome this problem, we describe the use of nanoparticle drug formulations that preferentially target metabolically compromised and damaged NVUs after an ischemic or hemorrhagic stroke. These nanoparticle-based approaches have the potential to improve clinical safety and efficacy by maximizing drug delivery to diseased NVUs and minimizing drug exposure in healthy brain and peripheral tissues.
Collapse
Affiliation(s)
- Robyn J. Novorolsky
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Gracious D. S. Kasheke
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Antoine Hakim
- School of Pharmacy, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| | - Marianna Foldvari
- School of Pharmacy, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| | - Gabriel G. Dorighello
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben Gurion University, Beersheva, Israel
| | | | | | - Robert B. Renden
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, United States
| | - Justin J. Wilson
- Department of Chemistry and Chemical Biology, College of Arts and Sciences, Cornell University, Ithaca, NY, United States
| | - George S. Robertson
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Department of Psychiatry, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| |
Collapse
|
9
|
Tu YC, Chao FY, Tsai MF. Mechanisms of dual modulatory effects of spermine on the mitochondrial calcium uniporter complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.06.543936. [PMID: 37333420 PMCID: PMC10274775 DOI: 10.1101/2023.06.06.543936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
The mitochondrial Ca 2 + uniporter mediates the crucial cellular process of mitochondrial Ca 2 + uptake, which regulates cell bioenergetics, intracellular Ca 2 + signaling, and cell death initiation. The uniporter contains the pore-forming MCU subunit, an EMRE protein that binds to MCU, and the regulatory MICU1 subunit, which can dimerize with MICU1 or MICU2 and under resting cellular [Ca 2 + ] occludes the MCU pore. It has been known for decades that spermine, which is ubiquitously present in animal cells, can enhance mitochondrial Ca 2 + uptake, but the underlying mechanisms remain unclear. Here, we show that spermine exerts dual modulatory effects on the uniporter. In physiological concentrations of spermine, it enhances uniporter activity by breaking the physical interactions between MCU and the MICU1-containing dimers to allow the uniporter to constitutively take up Ca 2 + even in low [Ca 2 + ] conditions. This potentiation effect does not require MICU2 or the EF-hand motifs in MICU1. When [spermine] rises to millimolar levels, it inhibits the uniporter by targeting the pore region in a MICU-independent manner. The MICU1-dependent spermine potentiation mechanism proposed here, along with our previous finding that cardiac mitochondria have very low MICU1, can explain the puzzling observation in the literature that mitochondria in the heart show no response to spermine.
Collapse
Affiliation(s)
- Yung-Chi Tu
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Fan-Yi Chao
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Ming-Feng Tsai
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| |
Collapse
|
10
|
Moon DO. Calcium's Role in Orchestrating Cancer Apoptosis: Mitochondrial-Centric Perspective. Int J Mol Sci 2023; 24:ijms24108982. [PMID: 37240331 DOI: 10.3390/ijms24108982] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 05/28/2023] Open
Abstract
Calcium is an essential intracellular messenger that plays a vital role in controlling a broad range of cellular processes, including apoptosis. This review offers an in-depth analysis of calcium's multifaceted role in apoptosis regulation, focusing on the associated signaling pathways and molecular mechanisms. We will explore calcium's impact on apoptosis through its effects on different cellular compartments, such as the mitochondria and endoplasmic reticulum (ER), and discuss the connection between calcium homeostasis and ER stress. Additionally, we will highlight the interplay between calcium and various proteins, including calpains, calmodulin, and Bcl-2 family members, and the role of calcium in regulating caspase activation and pro-apoptotic factor release. By investigating the complex relationship between calcium and apoptosis, this review aims to deepen our comprehension of the fundamental processes, and pinpointing possible treatment options for illnesses associated with imbalanced cell death is crucial.
Collapse
Affiliation(s)
- Dong-Oh Moon
- Department of Biology Education, Daegu University, 201, Daegudae-ro, Gyeongsan-si 38453, Gyeongsangbuk-do, Republic of Korea
| |
Collapse
|
11
|
Szabo I, Szewczyk A. Mitochondrial Ion Channels. Annu Rev Biophys 2023; 52:229-254. [PMID: 37159294 DOI: 10.1146/annurev-biophys-092622-094853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Mitochondria are involved in multiple cellular tasks, such as ATP synthesis, metabolism, metabolite and ion transport, regulation of apoptosis, inflammation, signaling, and inheritance of mitochondrial DNA. The majority of the correct functioning of mitochondria is based on the large electrochemical proton gradient, whose component, the inner mitochondrial membrane potential, is strictly controlled by ion transport through mitochondrial membranes. Consequently, mitochondrial function is critically dependent on ion homeostasis, the disturbance of which leads to abnormal cell functions. Therefore, the discovery of mitochondrial ion channels influencing ion permeability through the membrane has defined a new dimension of the function of ion channels in different cell types, mainly linked to the important tasks that mitochondrial ion channels perform in cell life and death. This review summarizes studies on animal mitochondrial ion channels with special focus on their biophysical properties, molecular identity, and regulation. Additionally, the potential of mitochondrial ion channels as therapeutic targets for several diseases is briefly discussed.
Collapse
Affiliation(s)
- Ildiko Szabo
- Department of Biology, University of Padova, Italy;
| | - Adam Szewczyk
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland;
| |
Collapse
|
12
|
MacEwen MJ, Sancak Y. Beyond the matrix: structural and physiological advancements in mitochondrial calcium signaling. Biochem Soc Trans 2023; 51:665-673. [PMID: 36960768 PMCID: PMC10212541 DOI: 10.1042/bst20220317] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/25/2023]
Abstract
Mitochondrial calcium (Ca2+) signaling has long been known to regulate diverse cellular functions, ranging from ATP production via oxidative phosphorylation, to cytoplasmic Ca2+ signaling to apoptosis. Central to mitochondrial Ca2+ signaling is the mitochondrial Ca2+ uniporter complex (MCUC) which enables Ca2+ flux from the cytosol into the mitochondrial matrix. Several pivotal discoveries over the past 15 years have clarified the identity of the proteins comprising MCUC. Here, we provide an overview of the literature on mitochondrial Ca2+ biology and highlight recent findings on the high-resolution structure, dynamic regulation, and new functions of MCUC, with an emphasis on publications from the last five years. We discuss the importance of these findings for human health and the therapeutic potential of targeting mitochondrial Ca2+ signaling.
Collapse
Affiliation(s)
| | - Yasemin Sancak
- Department of Pharmacology, University of Washington, Seattle, WA 98195, U.S.A
| |
Collapse
|
13
|
Garbincius JF, Luongo TS, Lambert JP, Mangold AS, Murray EK, Hildebrand AN, Jadiya P, Elrod JW. MCU gain- and loss-of-function models define the duality of mitochondrial calcium uptake in heart failure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.17.537222. [PMID: 37131819 PMCID: PMC10153142 DOI: 10.1101/2023.04.17.537222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Background Mitochondrial calcium (mCa2+) uptake through the mitochondrial calcium uniporter channel (mtCU) stimulates metabolism to meet acute increases in cardiac energy demand. However, excessive mCa2+ uptake during stress, as in ischemia-reperfusion, initiates permeability transition and cell death. Despite these often-reported acute physiological and pathological effects, a major unresolved controversy is whether mtCU-dependent mCa2+ uptake and long-term elevation of cardiomyocyte mCa2+ contributes to the heart's adaptation during sustained increases in workload. Objective We tested the hypothesis that mtCU-dependent mCa2+ uptake contributes to cardiac adaptation and ventricular remodeling during sustained catecholaminergic stress. Methods Mice with tamoxifen-inducible, cardiomyocyte-specific gain (αMHC-MCM × flox-stop-MCU; MCU-Tg) or loss (αMHC-MCM × Mcufl/fl; Mcu-cKO) of mtCU function received 2-wk catecholamine infusion. Results Cardiac contractility increased after 2d of isoproterenol in control, but not Mcu-cKO mice. Contractility declined and cardiac hypertrophy increased after 1-2-wk of isoproterenol in MCU-Tg mice. MCU-Tg cardiomyocytes displayed increased sensitivity to Ca2+- and isoproterenol-induced necrosis. However, loss of the mitochondrial permeability transition pore (mPTP) regulator cyclophilin D failed to attenuate contractile dysfunction and hypertrophic remodeling, and increased isoproterenol-induced cardiomyocyte death in MCU-Tg mice. Conclusions mtCU mCa2+ uptake is required for early contractile responses to adrenergic signaling, even those occurring over several days. Under sustained adrenergic load excessive MCU-dependent mCa2+ uptake drives cardiomyocyte dropout, perhaps independent of classical mitochondrial permeability transition pore opening, and compromises contractile function. These findings suggest divergent consequences for acute versus sustained mCa2+ loading, and support distinct functional roles for the mPTP in settings of acute mCa2+ overload versus persistent mCa2+ stress.
Collapse
Affiliation(s)
- Joanne F. Garbincius
- Cardiovascular Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Timothy S. Luongo
- Cardiovascular Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Jonathan P. Lambert
- Cardiovascular Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Adam S. Mangold
- Cardiovascular Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Emma K. Murray
- Cardiovascular Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Alycia N. Hildebrand
- Cardiovascular Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Pooja Jadiya
- Cardiovascular Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - John W. Elrod
- Cardiovascular Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| |
Collapse
|
14
|
Tsai CW, Liu TY, Chao FY, Tu YC, Rodriguez MX, Van Keuren AM, Ma Z, Bankston J, Tsai MF. Evidence supporting the MICU1 occlusion mechanism and against the potentiation model in the mitochondrial calcium uniporter complex. Proc Natl Acad Sci U S A 2023; 120:e2217665120. [PMID: 37036971 PMCID: PMC10120041 DOI: 10.1073/pnas.2217665120] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 03/03/2023] [Indexed: 04/12/2023] Open
Abstract
The mitochondrial calcium uniporter is a Ca2+ channel that imports cytoplasmic Ca2+ into the mitochondrial matrix to regulate cell bioenergetics, intracellular Ca2+ signaling, and apoptosis. The uniporter contains the pore-forming MCU subunit, an auxiliary EMRE protein, and the regulatory MICU1/MICU2 subunits. Structural and biochemical studies have suggested that MICU1 gates MCU by blocking/unblocking the pore. However, mitoplast patch-clamp experiments argue that MICU1 does not block, but instead potentiates MCU via allosteric mechanisms. Here, we address this direct clash of the proposed MICU1 function. Supporting the MICU1-occlusion mechanism, patch-clamp demonstrates that purified MICU1 strongly suppresses MCU Ca2+ currents, and this inhibition is abolished by mutating the MCU-interacting K126 residue. Moreover, a membrane-depolarization assay shows that MICU1 prevents MCU-mediated Na+ flux into intact mitochondria under Ca2+-free conditions. Examining the observations underlying the potentiation model, we found that MICU1 occlusion was not detected in mitoplasts not because MICU1 cannot block, but because MICU1 dissociates from the uniporter complex. Furthermore, MICU1 depletion reduces uniporter transport not because MICU1 can potentiate MCU, but because EMRE is down-regulated. These results firmly establish the molecular mechanisms underlying the physiologically crucial process of uniporter regulation by MICU1.
Collapse
Affiliation(s)
- Chen-Wei Tsai
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Tsung-Yun Liu
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Fan-Yi Chao
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Yung-Chi Tu
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Madison X. Rodriguez
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Anna M. Van Keuren
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Zhiwei Ma
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO65211
| | - John Bankston
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Ming-Feng Tsai
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| |
Collapse
|
15
|
Walters GC, Usachev YM. Mitochondrial calcium cycling in neuronal function and neurodegeneration. Front Cell Dev Biol 2023; 11:1094356. [PMID: 36760367 PMCID: PMC9902777 DOI: 10.3389/fcell.2023.1094356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/12/2023] [Indexed: 01/26/2023] Open
Abstract
Mitochondria are essential for proper cellular function through their critical roles in ATP synthesis, reactive oxygen species production, calcium (Ca2+) buffering, and apoptotic signaling. In neurons, Ca2+ buffering is particularly important as it helps to shape Ca2+ signals and to regulate numerous Ca2+-dependent functions including neuronal excitability, synaptic transmission, gene expression, and neuronal toxicity. Over the past decade, identification of the mitochondrial Ca2+ uniporter (MCU) and other molecular components of mitochondrial Ca2+ transport has provided insight into the roles that mitochondrial Ca2+ regulation plays in neuronal function in health and disease. In this review, we discuss the many roles of mitochondrial Ca2+ uptake and release mechanisms in normal neuronal function and highlight new insights into the Ca2+-dependent mechanisms that drive mitochondrial dysfunction in neurologic diseases including epilepsy, Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. We also consider how targeting Ca2+ uptake and release mechanisms could facilitate the development of novel therapeutic strategies for neurological diseases.
Collapse
Affiliation(s)
- Grant C. Walters
- Department of Neuroscience and Pharmacology, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
| | - Yuriy M. Usachev
- Department of Neuroscience and Pharmacology, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
| |
Collapse
|
16
|
Colussi DM, Stathopulos PB. From passage to inhibition: Uncovering the structural and physiological inhibitory mechanisms of MCUb in mitochondrial calcium regulation. FASEB J 2023; 37:e22678. [PMID: 36538269 PMCID: PMC10107711 DOI: 10.1096/fj.202201080r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/14/2022] [Accepted: 11/21/2022] [Indexed: 12/24/2022]
Abstract
Mitochondrial calcium (Ca2+ ) regulation is critically implicated in the regulation of bioenergetics and cell fate. Ca2+ , a universal signaling ion, passively diffuses into the mitochondrial intermembrane space (IMS) through voltage-dependent anion channels (VDAC), where uptake into the matrix is tightly regulated across the inner mitochondrial membrane (IMM) by the mitochondrial Ca2+ uniporter complex (mtCU). In recent years, immense progress has been made in identifying and characterizing distinct structural and physiological mechanisms of mtCU component function. One of the main regulatory components of the Ca2+ selective mtCU channel is the mitochondrial Ca2+ uniporter dominant-negative beta subunit (MCUb). The structural mechanisms underlying the inhibitory effect(s) exerted by MCUb are poorly understood, despite high homology to the main mitochondrial Ca2+ uniporter (MCU) channel-forming subunits. In this review, we provide an overview of the structural differences between MCUb and MCU, believed to contribute to the inhibition of mitochondrial Ca2+ uptake. We highlight the possible structural rationale for the absent interaction between MCUb and the mitochondrial Ca2+ uptake 1 (MICU1) gatekeeping subunit and a potential widening of the pore upon integration of MCUb into the channel. We discuss physiological and pathophysiological information known about MCUb, underscoring implications in cardiac function and arrhythmia as a basis for future therapeutic discovery. Finally, we discuss potential post-translational modifications on MCUb as another layer of important regulation.
Collapse
Affiliation(s)
- Danielle M Colussi
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
17
|
Delgado BD, Long SB. Mechanisms of ion selectivity and throughput in the mitochondrial calcium uniporter. SCIENCE ADVANCES 2022; 8:eade1516. [PMID: 36525497 PMCID: PMC9757755 DOI: 10.1126/sciadv.ade1516] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
The mitochondrial calcium uniporter, which regulates aerobic metabolism by catalyzing mitochondrial Ca2+ influx, is arguably the most selective ion channel known. The mechanisms for this exquisite Ca2+ selectivity have not been defined. Here, using a reconstituted system, we study the electrical properties of the channel's minimal Ca2+-conducting complex, MCU-EMRE, from Tribolium castaneum to probe ion selectivity mechanisms. The wild-type TcMCU-EMRE complex recapitulates hallmark electrophysiological properties of endogenous Uniporter channels. Through interrogation of pore-lining mutants, we find that a ring of glutamate residues, the "E-locus," serves as the channel's selectivity filter. Unexpectedly, a nearby "D-locus" at the mouth of the pore has diminutive influence on selectivity. Anomalous mole fraction effects indicate that multiple Ca2+ ions are accommodated within the E-locus. By facilitating ion-ion interactions, the E-locus engenders both exquisite Ca2+ selectivity and high ion throughput. Direct comparison with structural information yields the basis for selective Ca2+ conduction by the channel.
Collapse
Affiliation(s)
- Bryce D. Delgado
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
- Graduate Program in Biochemistry and Structural Biology, Cell and Developmental Biology, and Molecular Biology, Weill Cornell Medicine Graduate School of Medical Sciences, New York, NY 10065, USA
| | - Stephen B. Long
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| |
Collapse
|
18
|
Yoo J. Structural basis of Ca 2+ uptake by mitochondrial calcium uniporter in mitochondria: a brief review. BMB Rep 2022; 55:528-534. [PMID: 36195565 PMCID: PMC9712701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Indexed: 12/14/2022] Open
Abstract
Mitochondria are cellular organelles that perform various functions within cells. They are responsible for ATP production, cell-signal regulation, autophagy, and cell apoptosis. Because the mitochondrial proteins that perform these functions need Ca2+ ions for their activity, mitochondria have ion channels to selectively uptake Ca2+ ions from the cytoplasm. The ion channel known to play the most important role in the Ca2+ uptake in mitochondria is the mitochondrial calcium uniporter (MCU) holo-complex located in the inner mitochondrial membrane (IMM). This ion channel complex exists in the form of a complex consisting of the pore-forming protein through which the Ca2+ ions are transported into the mitochondrial matrix, and the auxiliary protein involved in regulating the activity of the Ca2+ uptake by the MCU holo-complex. Studies of this MCU holocomplex have long been conducted, but we didn't know in detail how mitochondria uptake Ca2+ ions through this ion channel complex or how the activity of this ion channel complex is regulated. Recently, the protein structure of the MCU holo-complex was identified, enabling the mechanism of Ca2+ uptake and its regulation by the MCU holo-complex to be confirmed. In this review, I will introduce the mechanism of action of the MCU holo-complex at the molecular level based on the Cryo-EM structure of the MCU holo-complex to help understand how mitochondria uptake the necessary Ca2+ ions through the MCU holo-complex and how these Ca2+ uptake mechanisms are regulated. [BMB Reports 2022; 55(11): 528-534].
Collapse
Affiliation(s)
- Jiho Yoo
- College of Pharmacy, Chung-Ang University, Seoul 06974, Korea,Corresponding author. Tel: +82-2-820-5673; E-mail:
| |
Collapse
|
19
|
Yoo J. Structural basis of Ca 2+ uptake by mitochondrial calcium uniporter in mitochondria: a brief review. BMB Rep 2022; 55:528-534. [PMID: 36195565 PMCID: PMC9712701 DOI: 10.5483/bmbrep.2022.55.11.134] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 09/16/2022] [Accepted: 09/30/2022] [Indexed: 03/17/2024] Open
Abstract
Mitochondria are cellular organelles that perform various functions within cells. They are responsible for ATP production, cell-signal regulation, autophagy, and cell apoptosis. Because the mitochondrial proteins that perform these functions need Ca2+ ions for their activity, mitochondria have ion channels to selectively uptake Ca2+ ions from the cytoplasm. The ion channel known to play the most important role in the Ca2+ uptake in mitochondria is the mitochondrial calcium uniporter (MCU) holo-complex located in the inner mitochondrial membrane (IMM). This ion channel complex exists in the form of a complex consisting of the pore-forming protein through which the Ca2+ ions are transported into the mitochondrial matrix, and the auxiliary protein involved in regulating the activity of the Ca2+ uptake by the MCU holo-complex. Studies of this MCU holocomplex have long been conducted, but we didn't know in detail how mitochondria uptake Ca2+ ions through this ion channel complex or how the activity of this ion channel complex is regulated. Recently, the protein structure of the MCU holo-complex was identified, enabling the mechanism of Ca2+ uptake and its regulation by the MCU holo-complex to be confirmed. In this review, I will introduce the mechanism of action of the MCU holo-complex at the molecular level based on the Cryo-EM structure of the MCU holo-complex to help understand how mitochondria uptake the necessary Ca2+ ions through the MCU holo-complex and how these Ca2+ uptake mechanisms are regulated. [BMB Reports 2022; 55(11): 528-534].
Collapse
Affiliation(s)
- Jiho Yoo
- College of Pharmacy, Chung-Ang University, Seoul 06974, Korea
| |
Collapse
|
20
|
Ruberti C, Feitosa-Araujo E, Xu Z, Wagner S, Grenzi M, Darwish E, Lichtenauer S, Fuchs P, Parmagnani AS, Balcerowicz D, Schoenaers S, de la Torre C, Mekkaoui K, Nunes-Nesi A, Wirtz M, Vissenberg K, Van Aken O, Hause B, Costa A, Schwarzländer M. MCU proteins dominate in vivo mitochondrial Ca2+ uptake in Arabidopsis roots. THE PLANT CELL 2022; 34:4428-4452. [PMID: 35938694 PMCID: PMC9614509 DOI: 10.1093/plcell/koac242] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 07/31/2022] [Indexed: 06/15/2023]
Abstract
Ca2+ signaling is central to plant development and acclimation. While Ca2+-responsive proteins have been investigated intensely in plants, only a few Ca2+-permeable channels have been identified, and our understanding of how intracellular Ca2+ fluxes is facilitated remains limited. Arabidopsis thaliana homologs of the mammalian channel-forming mitochondrial calcium uniporter (MCU) protein showed Ca2+ transport activity in vitro. Yet, the evolutionary complexity of MCU proteins, as well as reports about alternative systems and unperturbed mitochondrial Ca2+ uptake in knockout lines of MCU genes, leave critical questions about the in vivo functions of the MCU protein family in plants unanswered. Here, we demonstrate that MCU proteins mediate mitochondrial Ca2+ transport in planta and that this mechanism is the major route for fast Ca2+ uptake. Guided by the subcellular localization, expression, and conservation of MCU proteins, we generated an mcu triple knockout line. Using Ca2+ imaging in living root tips and the stimulation of Ca2+ transients of different amplitudes, we demonstrated that mitochondrial Ca2+ uptake became limiting in the triple mutant. The drastic cell physiological phenotype of impaired subcellular Ca2+ transport coincided with deregulated jasmonic acid-related signaling and thigmomorphogenesis. Our findings establish MCUs as a major mitochondrial Ca2+ entry route in planta and link mitochondrial Ca2+ transport with phytohormone signaling.
Collapse
Affiliation(s)
| | - Elias Feitosa-Araujo
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, D-48143, Germany
| | - Zhaolong Xu
- Department of Biosciences, University of Milano, Milan, I-20133, Italy
- Jiangsu Provincial Key Laboratory of Agrobiology, Institute of Germplasm Resources and Biotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu 210014, China
| | | | - Matteo Grenzi
- Department of Biosciences, University of Milano, Milan, I-20133, Italy
| | - Essam Darwish
- Department of Biology, Lund University, Lund, 22362, Sweden
- Agricultural Botany Department, Faculty of Agriculture, Plant Physiology Section, Cairo University, Giza, 12613, Egypt
| | - Sophie Lichtenauer
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, D-48143, Germany
| | | | | | - Daria Balcerowicz
- Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, B-2020, Belgium
| | - Sébastjen Schoenaers
- Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, B-2020, Belgium
| | - Carolina de la Torre
- NGS Core Facility, Medical Faculty Mannheim, University of Heidelberg, Mannheim, D-68167, Germany
| | - Khansa Mekkaoui
- Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry (IPB), Halle (Saale), D-06120, Germany
| | - Adriano Nunes-Nesi
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, 36570-900, Brazil
| | - Markus Wirtz
- Centre for Organismal Studies (COS) Heidelberg, University of Heidelberg, Heidelberg, D-69120, Germany
| | - Kris Vissenberg
- Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, B-2020, Belgium
- Department of Agriculture, Plant Biochemistry and Biotechnology Lab, Hellenic Mediterranean University, Heraklion, 71410, Greece
| | | | - Bettina Hause
- Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry (IPB), Halle (Saale), D-06120, Germany
| | - Alex Costa
- Authors for correspondence: (A.C); (M.S.)
| | | |
Collapse
|
21
|
Tsai CW, Rodriguez MX, Van Keuren AM, Phillips CB, Shushunov HM, Lee JE, Garcia AM, Ambardekar AV, Cleveland JC, Reisz JA, Proenza C, Chatfield KC, Tsai MF. Mechanisms and significance of tissue-specific MICU regulation of the mitochondrial calcium uniporter complex. Mol Cell 2022; 82:3661-3676.e8. [PMID: 36206740 PMCID: PMC9557913 DOI: 10.1016/j.molcel.2022.09.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 05/16/2022] [Accepted: 09/07/2022] [Indexed: 12/29/2022]
Abstract
Mitochondrial Ca2+ uptake, mediated by the mitochondrial Ca2+ uniporter, regulates oxidative phosphorylation, apoptosis, and intracellular Ca2+ signaling. Previous studies suggest that non-neuronal uniporters are exclusively regulated by a MICU1-MICU2 heterodimer. Here, we show that skeletal-muscle and kidney uniporters also complex with a MICU1-MICU1 homodimer and that human/mouse cardiac uniporters are largely devoid of MICUs. Cells employ protein-importation machineries to fine-tune the relative abundance of MICU1 homo- and heterodimers and utilize a conserved MICU intersubunit disulfide to protect properly assembled dimers from proteolysis by YME1L1. Using the MICU1 homodimer or removing MICU1 allows mitochondria to more readily take up Ca2+ so that cells can produce more ATP in response to intracellular Ca2+ transients. However, the trade-off is elevated ROS, impaired basal metabolism, and higher susceptibility to death. These results provide mechanistic insights into how tissues can manipulate mitochondrial Ca2+ uptake properties to support their unique physiological functions.
Collapse
Affiliation(s)
- Chen-Wei Tsai
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Madison X Rodriguez
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Anna M Van Keuren
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Charles B Phillips
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Hannah M Shushunov
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Jessica E Lee
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Anastacia M Garcia
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Amrut V Ambardekar
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Joseph C Cleveland
- Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Julie A Reisz
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Catherine Proenza
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Kathryn C Chatfield
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ming-Feng Tsai
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
| |
Collapse
|
22
|
Raja AA, Dandare A, Khan MJ, Khan MJ. Free Fatty Acid Overload Targets Mitochondria: Gene Expression Analysis of Palmitic Acid-Treated Endothelial Cells. Genes (Basel) 2022; 13:genes13101704. [PMID: 36292589 PMCID: PMC9601498 DOI: 10.3390/genes13101704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 08/30/2022] [Accepted: 09/20/2022] [Indexed: 11/16/2022] Open
Abstract
Lipotoxicity is known to cause cellular dysfunction and death in non-adipose tissue. A major cause of lipotoxicity is the accumulation of saturated free fatty acids (FFA). Palmitic acid (PA) is the most common saturated fatty acid found in the human body. Endothelial cells form the blood vessels and are the first non-adipose cells to encounter FFA in the bloodstream. FFA overload has a direct impact on metabolism, which is evident through the changes occurring in mitochondria. To study these changes, the PA-treated human coronary artery endothelial cell (HCAEC) dataset was obtained from the Gene Expression Omnibus (GEO), and it was analyzed to obtain differentially expressed genes (DEGs) from the nucleus and mitochondria. Functional and pathway enrichment analyses were performed on DEGs. Results showed that nuclear and mitochondrial DEGs were implicated in several processes, e.g., reactive oxygen species (ROS) production, mitochondrial fusion and fission, Ca2+ sequestering, membrane transport, the electron transport chain and the process of apoptosis. To better understand the role of FFA in endothelial cell damage, these DEGs can lead to future experiments based on these findings.
Collapse
Affiliation(s)
- Afraz Ahmad Raja
- Functional Genomics Laboratory, Department of Biosciences, COMSATS University Islamabad, Islamabad 45550, Pakistan
| | - Abdullahi Dandare
- Functional Genomics Laboratory, Department of Biosciences, COMSATS University Islamabad, Islamabad 45550, Pakistan
- Department of Biochemistry, Usmanu Danfodiyo University, Sokoto P.M.B. 2346, Nigeria
| | - Muhammad Jawad Khan
- Functional Genomics Laboratory, Department of Biosciences, COMSATS University Islamabad, Islamabad 45550, Pakistan
- Correspondence: ; Tel.: +92-5190496140
| | - Muhammad Jadoon Khan
- Functional Genomics Laboratory, Department of Biosciences, COMSATS University Islamabad, Islamabad 45550, Pakistan
| |
Collapse
|
23
|
Xue K, Wu D, Wang Y, Zhao Y, Shen H, Yao J, Huang X, Li X, Zhou Z, Wang Z, Qiu Y. The mitochondrial calcium uniporter engages UCP1 to form a thermoporter that promotes thermogenesis. Cell Metab 2022; 34:1325-1341.e6. [PMID: 35977541 DOI: 10.1016/j.cmet.2022.07.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 03/03/2022] [Accepted: 07/25/2022] [Indexed: 01/08/2023]
Abstract
Uncoupling protein 1 (UCP1)-mediated adaptive thermogenesis protects mammals against hypothermia and metabolic dysregulation. Whether and how mitochondrial calcium regulates this process remains unclear. Here, we show that mitochondrial calcium uniporter (MCU) recruits UCP1 through essential MCU regulator (EMRE) to form an MCU-EMRE-UCP1 complex upon adrenergic stimulation. This complex formation increases mitochondrial calcium uptake to accelerate the tricarboxylic acid cycle and supply more protons that promote uncoupled respiration, functioning as a thermogenic uniporter. Mitochondrial calcium uptake 1 (MICU1) negatively regulates thermogenesis probably through inhibiting thermogenic uniporter formation. Accordingly, the deletion of Mcu or Emre in brown adipocytes markedly impairs thermogenesis and exacerbates obesity and metabolic dysfunction. Remarkably, the enhanced assembly of the thermogenic uniporter via Micu1 knockout or expressing linked EMRE-UCP1 results in opposite phenotypes. Thus, we have uncovered a "thermoporter" that provides a driving force for the UCP1 operation in thermogenesis, which could be leveraged to combat obesity and associated metabolic disorders.
Collapse
Affiliation(s)
- Kaili Xue
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Dongmei Wu
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Yushuang Wang
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Yiheng Zhao
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Hongyu Shen
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Jingfei Yao
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Xun Huang
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Xinmeng Li
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Zhao Zhou
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Zihao Wang
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Yifu Qiu
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China.
| |
Collapse
|
24
|
Roberts-Craig FT, Worthington LP, O’Hara SP, Erickson JR, Heather AK, Ashley Z. CaMKII Splice Variants in Vascular Smooth Muscle Cells: The Next Step or Redundancy? Int J Mol Sci 2022; 23:ijms23147916. [PMID: 35887264 PMCID: PMC9318135 DOI: 10.3390/ijms23147916] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 02/05/2023] Open
Abstract
Vascular smooth muscle cells (VSMCs) help to maintain the normal physiological contractility of arterial vessels to control blood pressure; they can also contribute to vascular disease such as atherosclerosis. Ca2+/calmodulin-dependent kinase II (CaMKII), a multifunctional enzyme with four isoforms and multiple alternative splice variants, contributes to numerous functions within VSMCs. The role of these isoforms has been widely studied across numerous tissue types; however, their functions are still largely unknown within the vasculature. Even more understudied is the role of the different splice variants of each isoform in such signaling pathways. This review evaluates the role of the different CaMKII splice variants in vascular pathological and physiological mechanisms, aiming to show the need for more research to highlight both the deleterious and protective functions of the various splice variants.
Collapse
Affiliation(s)
- Finn T. Roberts-Craig
- Department of Medicine, University of Otago, Dunedin 9016, New Zealand;
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (L.P.W.); (S.P.O.); (J.R.E.); (A.K.H.)
| | - Luke P. Worthington
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (L.P.W.); (S.P.O.); (J.R.E.); (A.K.H.)
- HeartOtago, University of Otago, Dunedin 9016, New Zealand
| | - Samuel P. O’Hara
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (L.P.W.); (S.P.O.); (J.R.E.); (A.K.H.)
- HeartOtago, University of Otago, Dunedin 9016, New Zealand
| | - Jeffrey R. Erickson
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (L.P.W.); (S.P.O.); (J.R.E.); (A.K.H.)
- HeartOtago, University of Otago, Dunedin 9016, New Zealand
| | - Alison K. Heather
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (L.P.W.); (S.P.O.); (J.R.E.); (A.K.H.)
- HeartOtago, University of Otago, Dunedin 9016, New Zealand
| | - Zoe Ashley
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (L.P.W.); (S.P.O.); (J.R.E.); (A.K.H.)
- HeartOtago, University of Otago, Dunedin 9016, New Zealand
- Correspondence: ; Tel.: +64-3-479-7646
| |
Collapse
|
25
|
Allen JG, Tessem JS. Ca 2+ Sensors Assemble: Function of the MCU Complex in the Pancreatic Beta Cell. Cells 2022; 11:cells11131993. [PMID: 35805078 PMCID: PMC9265474 DOI: 10.3390/cells11131993] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 12/05/2022] Open
Abstract
The Mitochondrial Calcium Uniporter Complex (MCU Complex) is essential for β-cell function due to its role in sustaining insulin secretion. The MCU complex regulates mitochondrial Ca2+ influx, which is necessary for increased ATP production following cellular glucose uptake, keeps the cell membrane K+ channels closed following initial insulin release, and ultimately results in sustained insulin granule exocytosis. Dysfunction in Ca2+ regulation results in an inability to sustain insulin secretion. This review defines the functions, structure, and mutations associated with the MCU complex members mitochondrial calcium uniporter protein (MCU), essential MCU regulator (EMRE), mitochondrial calcium uptake 1 (MICU1), mitochondrial calcium uptake 2 (MICU2), and mitochondrial calcium uptake 3 (MICU3) in the pancreatic β-cell. This review provides a framework for further evaluation of the MCU complex in β-cell function and insulin secretion.
Collapse
|
26
|
Singh R, Bartok A, Paillard M, Tyburski A, Elliott M, Hajnóczky G. Uncontrolled mitochondrial calcium uptake underlies the pathogenesis of neurodegeneration in MICU1-deficient mice and patients. SCIENCE ADVANCES 2022; 8:eabj4716. [PMID: 35302860 PMCID: PMC8932652 DOI: 10.1126/sciadv.abj4716] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 01/26/2022] [Indexed: 06/01/2023]
Abstract
Dysregulation of mitochondrial Ca2+ homeostasis has been linked to neurodegenerative diseases. Mitochondrial Ca2+ uptake is mediated via the calcium uniporter complex that is primarily regulated by MICU1, a Ca2+-sensing gatekeeper. Recently, human patients with MICU1 loss-of-function mutations were diagnosed with neuromuscular and cognitive impairments. While studies in patient-derived cells revealed altered mitochondrial calcium signaling, the neuronal pathogenesis was difficult to study. To fill this void, we created a neuron-specific MICU1-KO mouse model. These animals show progressive, abnormal motor and cognitive phenotypes likely caused by the degeneration of motor neurons in the spinal cord and the cortex. We found increased susceptibility to mitochondrial Ca2+ overload-induced excitotoxic insults and cell death in MICU1-KO neurons and MICU1-deficient patient-derived cells, which can be blunted by inhibiting the mitochondrial permeability transition pore. Thus, our study identifies altered neuronal mitochondrial Ca2+ homeostasis as causative in the clinical symptoms of MICU1-deficient patients and highlights potential therapeutic targets.
Collapse
Affiliation(s)
- Raghavendra Singh
- MitoCare Center, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Adam Bartok
- MitoCare Center, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
- Departent of Biochemistry, Semmelweis University, Budapest, Hungary
| | - Melanie Paillard
- MitoCare Center, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Ashley Tyburski
- Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, PA, USA
| | - Melanie Elliott
- Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, PA, USA
| | - György Hajnóczky
- MitoCare Center, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| |
Collapse
|
27
|
Lai HT, Canoy RJ, Campanella M, Vassetzky Y, Brenner C. Ca2+ Transportome and the Interorganelle Communication in Hepatocellular Carcinoma. Cells 2022; 11:cells11050815. [PMID: 35269437 PMCID: PMC8909868 DOI: 10.3390/cells11050815] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 12/24/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is a type of liver cancer with a poor prognosis for survival given the complications it bears on the patient. Though damages to the liver are acknowledged prodromic factors, the precise molecular aetiology remains ill-defined. However, many genes coding for proteins involved in calcium (Ca2+) homeostasis emerge as either mutated or deregulated. Ca2+ is a versatile signalling messenger that regulates functions that prime and drive oncogenesis, favouring metabolic reprogramming and gene expression. Ca2+ is present in cell compartments, between which it is trafficked through a network of transporters and exchangers, known as the Ca2+ transportome. The latter regulates and controls Ca2+ dynamics and tonicity. In HCC, the deregulation of the Ca2+ transportome contributes to tumorigenesis, the formation of metastasizing cells, and evasion of cell death. In this review, we reflect on these aspects by summarizing the current knowledge of the Ca2+ transportome and overviewing its composition in the plasma membrane, endoplasmic reticulum, and the mitochondria.
Collapse
Affiliation(s)
- Hong-Toan Lai
- CNRS, Institut Gustave Roussy, Aspects Métaboliques et Systémiques de l’Oncogénèse pour de Nouvelles Approches Thérapeutiques, Université Paris-Saclay, 94805 Villejuif, France; (H.-T.L.); (R.J.C.); (M.C.); (Y.V.)
| | - Reynand Jay Canoy
- CNRS, Institut Gustave Roussy, Aspects Métaboliques et Systémiques de l’Oncogénèse pour de Nouvelles Approches Thérapeutiques, Université Paris-Saclay, 94805 Villejuif, France; (H.-T.L.); (R.J.C.); (M.C.); (Y.V.)
- Institute of Human Genetics, National Institutes of Health, University of the Philippines, Manila 1000, Philippines
| | - Michelangelo Campanella
- CNRS, Institut Gustave Roussy, Aspects Métaboliques et Systémiques de l’Oncogénèse pour de Nouvelles Approches Thérapeutiques, Université Paris-Saclay, 94805 Villejuif, France; (H.-T.L.); (R.J.C.); (M.C.); (Y.V.)
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, London NW1 0TU, UK
- Consortium for Mitochondrial Research, University College London, London WC1 0TU, UK
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Yegor Vassetzky
- CNRS, Institut Gustave Roussy, Aspects Métaboliques et Systémiques de l’Oncogénèse pour de Nouvelles Approches Thérapeutiques, Université Paris-Saclay, 94805 Villejuif, France; (H.-T.L.); (R.J.C.); (M.C.); (Y.V.)
| | - Catherine Brenner
- CNRS, Institut Gustave Roussy, Aspects Métaboliques et Systémiques de l’Oncogénèse pour de Nouvelles Approches Thérapeutiques, Université Paris-Saclay, 94805 Villejuif, France; (H.-T.L.); (R.J.C.); (M.C.); (Y.V.)
- Correspondence:
| |
Collapse
|
28
|
Watanabe A, Maeda K, Nara A, Hashida M, Ozono M, Nakao A, Yamada A, Shinohara Y, Yamamoto T. Quantitative analysis of mitochondrial calcium uniporter (MCU) and essential MCU regulator (EMRE) in mitochondria from mouse tissues and HeLa cells. FEBS Open Bio 2022; 12:811-826. [PMID: 35060355 PMCID: PMC8972046 DOI: 10.1002/2211-5463.13371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 11/27/2021] [Accepted: 01/19/2022] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial calcium homeostasis plays critical roles in cell survival and aerobic metabolism in eukaryotes. The calcium uniporter is a highly selective calcium ion channel consisting of several subunits. Mitochondrial calcium uniporter (MCU) and essential MCU regulator (EMRE) are core subunits of the calcium uniporter required for calcium uptake activity in the mitochondria. Recent 3D structure analysis of the MCU‐EMRE complex reconstituted in nanodiscs revealed that the human MCU exists as a tetramer forming a channel pore, with EMRE bound to each MCU at a 1 : 1 ratio. However, the stoichiometry of MCU and EMRE in the mitochondria has not yet been investigated. We here quantitatively examined the protein levels of MCU and EMRE in the mitochondria from mouse tissues by using characterized antibodies and standard proteins. Unexpectedly, the number of EMRE molecules was lower than that of MCU; moreover, the ratios between MCU and EMRE were significantly different among tissues. Statistical calculations based on our findings suggest that a MCU tetramer binding to 4 EMREs may exist, but at low levels in the mitochondrial inner membrane. In brain mitochondria, the majority of MCU tetramers bind to 2 EMREs; in mitochondria in liver, kidney, and heart, MCU tetramers bind to 1 EMRE; and in kidney and heart, almost half of MCU tetramers bound to no EMRE. We propose here a novel stoichiometric model of the MCU‐EMRE complex in mitochondria.
Collapse
Affiliation(s)
- Akira Watanabe
- Division of Molecular Target and Gene Therapy Products National Institute of Health Sciences 3‐25‐26, Tonomachi, Kawasaki‐ku, Kawasaki‐shi Kanagawa 210‐9501 Japan
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
- Faculty of Pharmaceutical Sciences Tokushima University Shomachi‐1 Tokushima 770‐8505 Japan
| | - Kousuke Maeda
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
- Faculty of Pharmaceutical Sciences Tokushima University Shomachi‐1 Tokushima 770‐8505 Japan
| | - Atsushi Nara
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
- Faculty of Pharmaceutical Sciences Tokushima University Shomachi‐1 Tokushima 770‐8505 Japan
| | - Mei Hashida
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
- Faculty of Pharmaceutical Sciences Tokushima University Shomachi‐1 Tokushima 770‐8505 Japan
| | - Mizune Ozono
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
- Faculty of Pharmaceutical Sciences Tokushima University Shomachi‐1 Tokushima 770‐8505 Japan
| | - Ayaka Nakao
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
- Faculty of Pharmaceutical Sciences Tokushima University Shomachi‐1 Tokushima 770‐8505 Japan
| | - Akiko Yamada
- School of Dentistry Nihon University 1‐8‐13, Kanda‐Surugadai, Chiyoda‐ku Tokyo 101‐8310 Japan
| | - Yasuo Shinohara
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
- Faculty of Pharmaceutical Sciences Tokushima University Shomachi‐1 Tokushima 770‐8505 Japan
| | - Takenori Yamamoto
- Division of Molecular Target and Gene Therapy Products National Institute of Health Sciences 3‐25‐26, Tonomachi, Kawasaki‐ku, Kawasaki‐shi Kanagawa 210‐9501 Japan
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
| |
Collapse
|
29
|
Quantitative assays to measure the transport activity of the mitochondrial calcium uniporter in cell lines or Xenopus oocytes. STAR Protoc 2021; 2:100979. [PMID: 34877549 PMCID: PMC8633362 DOI: 10.1016/j.xpro.2021.100979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mitochondrial calcium uniporter, which mediates mitochondrial Ca2+ uptake, regulates key cellular functions, including intracellular Ca2+ signaling, cell-fate determination, and mitochondrial bioenergetics. Here, we describe two complementary strategies to quantify the uniporter's transport activity. First, we detail a mitochondrial Ca2+ radionuclide uptake assay in cultured cell lines. Second, we describe electrophysiological recordings of the uniporter expressed in Xenopus oocytes. These approaches enable a detailed kinetic analysis of the uniporter to link its molecular properties to physiological functions. For complete details on the use and execution of this protocol, please refer to Tsai and Tsai (2018) and Phillips et al. (2019).
Collapse
|
30
|
He J, Rössner N, Hoang MTT, Alejandro S, Peiter E. Transport, functions, and interaction of calcium and manganese in plant organellar compartments. PLANT PHYSIOLOGY 2021; 187:1940-1972. [PMID: 35235665 PMCID: PMC8890496 DOI: 10.1093/plphys/kiab122] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/02/2021] [Indexed: 05/05/2023]
Abstract
Calcium (Ca2+) and manganese (Mn2+) are essential elements for plants and have similar ionic radii and binding coordination. They are assigned specific functions within organelles, but share many transport mechanisms to cross organellar membranes. Despite their points of interaction, those elements are usually investigated and reviewed separately. This review takes them out of this isolation. It highlights our current mechanistic understanding and points to open questions of their functions, their transport, and their interplay in the endoplasmic reticulum (ER), vesicular compartments (Golgi apparatus, trans-Golgi network, pre-vacuolar compartment), vacuoles, chloroplasts, mitochondria, and peroxisomes. Complex processes demanding these cations, such as Mn2+-dependent glycosylation or systemic Ca2+ signaling, are covered in some detail if they have not been reviewed recently or if recent findings add to current models. The function of Ca2+ as signaling agent released from organelles into the cytosol and within the organelles themselves is a recurrent theme of this review, again keeping the interference by Mn2+ in mind. The involvement of organellar channels [e.g. glutamate receptor-likes (GLR), cyclic nucleotide-gated channels (CNGC), mitochondrial conductivity units (MCU), and two-pore channel1 (TPC1)], transporters (e.g. natural resistance-associated macrophage proteins (NRAMP), Ca2+ exchangers (CAX), metal tolerance proteins (MTP), and bivalent cation transporters (BICAT)], and pumps [autoinhibited Ca2+-ATPases (ACA) and ER Ca2+-ATPases (ECA)] in the import and export of organellar Ca2+ and Mn2+ is scrutinized, whereby current controversial issues are pointed out. Mechanisms in animals and yeast are taken into account where they may provide a blueprint for processes in plants, in particular, with respect to tunable molecular mechanisms of Ca2+ versus Mn2+ selectivity.
Collapse
Affiliation(s)
- Jie He
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Nico Rössner
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Minh T T Hoang
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Santiago Alejandro
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Edgar Peiter
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
- Author for communication:
| |
Collapse
|
31
|
Dong Z, Yao X. Insight of the role of mitochondrial calcium homeostasis in hepatic insulin resistance. Mitochondrion 2021; 62:128-138. [PMID: 34856389 DOI: 10.1016/j.mito.2021.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 11/16/2021] [Accepted: 11/24/2021] [Indexed: 12/06/2022]
Abstract
Due to the rapid rise in the prevalence of chronic metabolic disease, more and more clinicians and basic medical researchers focus their eyesight on insulin resistance (IR), an early and central event of metabolic diseases. The occurrence and development of IR are primarily caused by excessive energy intake and reduced energy consumption. Liver is the central organ that controls glucose homeostasis, playing a considerable role in systemic IR. Decreased capacity of oxidative metabolism and mitochondrial dysfunction are being blamed as the direct reason for the development of IR. Mitochondrial Ca2+ plays a fundamental role in maintaining proper mitochondrial function and redox stability. The maintaining of mitochondrial Ca2+ homeostasis requires the cooperation of ion channels in the inner and outer membrane of mitochondria, such as mitochondrial calcium uniporter complex (MCUC) and voltage-dependent anion channels (VDACs). In addition, the crosstalk between the endoplasmic reticulum (ER), lysosome and plasma membrane with mitochondria is also significant for mitochondrial calcium homeostasis, which is responsible for an efficient network of cellular Ca2+ signaling. Here, we review the recent progression in the research about the regulation factors for mitochondrial Ca2+ and how the dysregulation of mitochondrial Ca2+ homeostasis is involved in the pathogenesis of hepatic IR, providing a new perspective for further exploring the role of ion in the onset and development of IR.
Collapse
Affiliation(s)
- Zhanchen Dong
- Department of Occupational and Environmental Health, Dalian Medical University, 9 W Lushun South Road, Dalian 116044, PR China
| | - Xiaofeng Yao
- Department of Occupational and Environmental Health, Dalian Medical University, 9 W Lushun South Road, Dalian 116044, PR China.
| |
Collapse
|
32
|
Abstract
The uptake of calcium into and extrusion of calcium from the mitochondrial matrix is a fundamental biological process that has critical effects on cellular metabolism, signaling, and survival. Disruption of mitochondrial calcium (mCa2+) cycling is implicated in numerous acquired diseases such as heart failure, stroke, neurodegeneration, diabetes, and cancer, and is genetically linked to several inherited neuromuscular disorders. Understanding the mechanisms responsible for mCa2+ exchange therefore holds great promise for the treatment of these diseases. The past decade has seen the genetic identification of many of the key proteins that mediate mitochondrial calcium uptake and efflux. Here, we present an overview of the phenomenon of mCa2+ transport, and a comprehensive examination of the molecular machinery that mediates calcium flux across the inner mitochondrial membrane: the mitochondrial uniporter complex (consisting of MCU, EMRE, MICU1, MICU2, MICU3, MCUB, and MCUR1), NCLX, LETM1, the mitochondrial ryanodine receptor, and the mitochondrial permeability transition pore. We then consider the physiological implications of mCa2+ flux and evaluate how alterations in mCa2+ homeostasis contribute to human disease. This review concludes by highlighting opportunities and challenges for therapeutic intervention in pathologies characterized by aberrant mCa2+ handling and by summarizing critical unanswered questions regarding the biology of mCa2+ flux.
Collapse
Affiliation(s)
- Joanne F Garbincius
- Center for Translational Medicine, Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | | |
Collapse
|
33
|
Li Z, Song X, Yin S, Yan J, Lv P, Shan H, Cui K, Liu H, Liu Q. Single-Cell RNA-Seq Revealed the Gene Expression Pattern during the In Vitro Maturation of Donkey Oocytes. Genes (Basel) 2021; 12:genes12101640. [PMID: 34681034 PMCID: PMC8535270 DOI: 10.3390/genes12101640] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/13/2021] [Accepted: 10/16/2021] [Indexed: 12/15/2022] Open
Abstract
Donkeys are an important domesticated animal, providing labor, meat, milk, and medicinal materials for humans. However, the donkey population is continuously declining and even at risk of extinction. The application of modern animal production technology, such as oocyte in vitro maturation, is a promising method to improve the donkey population. In this study, we explore the gene expression patterns of donkey germinal vesicle (GV) and in vitro matured metaphase II (MII) oocytes using single cell RNA-seq of the candidate genes along with the regulatory mechanisms that affect donkey oocyte maturation. We identified a total of 24,164 oocyte genes of which 9073 were significant differentially expressed in the GV and MII oocytes. Further Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that these genes were associated with the meiotic cell cycle, mitochondrion activity, and N-glycan biosynthesis, which might be the key genes and regulatory mechanisms affecting the maturation of donkey oocytes. Our study provides considerable understanding regarding the maturation of donkey oocytes and serves as a theoretical basis for improving the development of donkey oocytes, which could ultimately benefit the expansion of the donkey population and conservation of biodiversity and genetic resources.
Collapse
Affiliation(s)
- Zhipeng Li
- Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Univesity, Nanning 530005, China; (X.S.); (J.Y.); (H.S.); (K.C.); (Q.L.)
- Correspondence: (Z.L.); (H.L.); Tel.: +86-185-0136-1752 (Z.L.); +86-132-0370-1212 (H.L.)
| | - Xinhui Song
- Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Univesity, Nanning 530005, China; (X.S.); (J.Y.); (H.S.); (K.C.); (Q.L.)
| | - Shan Yin
- Henan Chuangyuan Biotechnology Co. Ltd.; Zhengzhou 451100, China; (S.Y.); (P.L.)
| | - Jiageng Yan
- Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Univesity, Nanning 530005, China; (X.S.); (J.Y.); (H.S.); (K.C.); (Q.L.)
| | - Peiru Lv
- Henan Chuangyuan Biotechnology Co. Ltd.; Zhengzhou 451100, China; (S.Y.); (P.L.)
| | - Huiquan Shan
- Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Univesity, Nanning 530005, China; (X.S.); (J.Y.); (H.S.); (K.C.); (Q.L.)
| | - Kuiqing Cui
- Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Univesity, Nanning 530005, China; (X.S.); (J.Y.); (H.S.); (K.C.); (Q.L.)
| | - Hongbo Liu
- Henan Chuangyuan Biotechnology Co. Ltd.; Zhengzhou 451100, China; (S.Y.); (P.L.)
- Correspondence: (Z.L.); (H.L.); Tel.: +86-185-0136-1752 (Z.L.); +86-132-0370-1212 (H.L.)
| | - Qingyou Liu
- Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Univesity, Nanning 530005, China; (X.S.); (J.Y.); (H.S.); (K.C.); (Q.L.)
| |
Collapse
|
34
|
Structural characterization of the mitochondrial Ca 2+ uniporter provides insights into Ca 2+ uptake and regulation. iScience 2021; 24:102895. [PMID: 34401674 PMCID: PMC8353469 DOI: 10.1016/j.isci.2021.102895] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The mitochondrial uniporter is a Ca2+-selective ion-conducting channel in the inner mitochondrial membrane that is involved in various cellular processes. The components of this uniporter, including the pore-forming membrane subunit MCU and the modulatory subunits MCUb, EMRE, MICU1, and MICU2, have been identified in recent years. Previously, extensive studies revealed various aspects of uniporter activities and proposed multiple regulatory models of mitochondrial Ca2+ uptake. Recently, the individual auxiliary components of the uniporter and its holocomplex have been structurally characterized, providing the first insight into the component structures and their spatial relationship within the context of the uniporter. Here, we review recent uniporter structural studies in an attempt to establish an architectural framework, elucidating the mechanism that governs mitochondrial Ca2+ uptake and regulation, and to address some apparent controversies. This information could facilitate further characterization of mitochondrial Ca2+ permeation and a better understanding of uniporter-related disease conditions. The uniporter contains multiple subunits regulating various cellular processes Significant structural progresses have been made for the holo-complex of uniporter The holo-complex structures have inspired to propose several regulatory models
Collapse
|
35
|
|
36
|
Mitostasis, Calcium and Free Radicals in Health, Aging and Neurodegeneration. Biomolecules 2021; 11:biom11071012. [PMID: 34356637 PMCID: PMC8301949 DOI: 10.3390/biom11071012] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 07/06/2021] [Accepted: 07/07/2021] [Indexed: 12/18/2022] Open
Abstract
Mitochondria play key roles in ATP supply, calcium homeostasis, redox balance control and apoptosis, which in neurons are fundamental for neurotransmission and to allow synaptic plasticity. Their functional integrity is maintained by mitostasis, a process that involves mitochondrial transport, anchoring, fusion and fission processes regulated by different signaling pathways but mainly by the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). PGC-1α also favors Ca2+ homeostasis, reduces oxidative stress, modulates inflammatory processes and mobilizes mitochondria to where they are needed. To achieve their functions, mitochondria are tightly connected to the endoplasmic reticulum (ER) through specialized structures of the ER termed mitochondria-associated membranes (MAMs), which facilitate the communication between these two organelles mainly to aim Ca2+ buffering. Alterations in mitochondrial activity enhance reactive oxygen species (ROS) production, disturbing the physiological metabolism and causing cell damage. Furthermore, cytosolic Ca2+ overload results in an increase in mitochondrial Ca2+, resulting in mitochondrial dysfunction and the induction of mitochondrial permeability transition pore (mPTP) opening, leading to mitochondrial swelling and cell death through apoptosis as demonstrated in several neuropathologies. In summary, mitochondrial homeostasis is critical to maintain neuronal function; in fact, their regulation aims to improve neuronal viability and to protect against aging and neurodegenerative diseases.
Collapse
|
37
|
Wang Y, Li X, Zhao F. MCU-Dependent mROS Generation Regulates Cell Metabolism and Cell Death Modulated by the AMPK/PGC-1α/SIRT3 Signaling Pathway. Front Med (Lausanne) 2021; 8:674986. [PMID: 34307407 PMCID: PMC8299052 DOI: 10.3389/fmed.2021.674986] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 06/14/2021] [Indexed: 11/13/2022] Open
Abstract
The mitochondrial calcium uniporter is an intensively investigated calcium channel, and its molecular components, structural features, and encoded genes have long been explored. Further studies have shown that the mitochondrial calcium unidirectional transporter (MCU) is a macromolecular complex related to intracellular and extracellular calcium regulation. Based on the current understanding, the MCU is crucial for maintaining cytosolic Ca2+ (cCa2+) homeostasis by modulating mitochondrial Ca2+ (mCa2+) uptake. The elevation of MCU-induced calcium levels is confirmed to be the main cause of mitochondrial reactive oxygen species (mROS) generation, which leads to disordered cellular metabolic patterns and cell death. In particular, in an I/R injury model, cancer cells, and adipocytes, MCU expression is maintained at high levels. As is well accepted, the AMPK/PGC-1α/SIRT3 pathway is believed to have an affinity for mROS formation and energy consumption. Therefore, we identified a link between MCU-related mROS formation and the AMPK/PGC-1α/SIRT3 signaling pathway in controlling cell metabolism and cell death, which may provide a new possibility of targeting the MCU to reverse relevant diseases.
Collapse
Affiliation(s)
- Yuxin Wang
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiang Li
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Fengchao Zhao
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| |
Collapse
|
38
|
Paß T, Wiesner RJ, Pla-Martín D. Selective Neuron Vulnerability in Common and Rare Diseases-Mitochondria in the Focus. Front Mol Biosci 2021; 8:676187. [PMID: 34295920 PMCID: PMC8290884 DOI: 10.3389/fmolb.2021.676187] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 06/08/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial dysfunction is a central feature of neurodegeneration within the central and peripheral nervous system, highlighting a strong dependence on proper mitochondrial function of neurons with especially high energy consumptions. The fitness of mitochondria critically depends on preservation of distinct processes, including the maintenance of their own genome, mitochondrial dynamics, quality control, and Ca2+ handling. These processes appear to be differently affected in common neurodegenerative diseases, such as Alzheimer’s and Parkinson’s disease, as well as in rare neurological disorders, including Huntington’s disease, Amyotrophic Lateral Sclerosis and peripheral neuropathies. Strikingly, particular neuron populations of different morphology and function perish in these diseases, suggesting that cell-type specific factors contribute to the vulnerability to distinct mitochondrial defects. Here we review the disruption of mitochondrial processes in common as well as in rare neurological disorders and its impact on selective neurodegeneration. Understanding discrepancies and commonalities regarding mitochondrial dysfunction as well as individual neuronal demands will help to design new targets and to make use of already established treatments in order to improve treatment of these diseases.
Collapse
Affiliation(s)
- Thomas Paß
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Rudolf J Wiesner
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - David Pla-Martín
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, University of Cologne, Cologne, Germany
| |
Collapse
|
39
|
Le Vasseur M, Friedman J, Jost M, Xu J, Yamada J, Kampmann M, Horlbeck MA, Salemi MR, Phinney BS, Weissman JS, Nunnari J. Genome-wide CRISPRi screening identifies OCIAD1 as a prohibitin client and regulatory determinant of mitochondrial Complex III assembly in human cells. eLife 2021; 10:67624. [PMID: 34034859 PMCID: PMC8154037 DOI: 10.7554/elife.67624] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/10/2021] [Indexed: 01/01/2023] Open
Abstract
Dysfunction of the mitochondrial electron transport chain (mETC) is a major cause of human mitochondrial diseases. To identify determinants of mETC function, we screened a genome-wide human CRISPRi library under oxidative metabolic conditions with selective inhibition of mitochondrial Complex III and identified ovarian carcinoma immunoreactive antigen (OCIA) domain-containing protein 1 (OCIAD1) as a Complex III assembly factor. We find that OCIAD1 is an inner mitochondrial membrane protein that forms a complex with supramolecular prohibitin assemblies. Our data indicate that OCIAD1 is required for maintenance of normal steady-state levels of Complex III and the proteolytic processing of the catalytic subunit cytochrome c1 (CYC1). In OCIAD1 depleted mitochondria, unprocessed CYC1 is hemylated and incorporated into Complex III. We propose that OCIAD1 acts as an adaptor within prohibitin assemblies to stabilize and/or chaperone CYC1 and to facilitate its proteolytic processing by the IMMP2L protease.
Collapse
Affiliation(s)
- Maxence Le Vasseur
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, Davis, United States
| | - Jonathan Friedman
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, Davis, United States.,Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Marco Jost
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, United States.,Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, United States.,Department of Microbiology and Immunology, University of California at San Francisco, San Francisco, United States
| | - Jiawei Xu
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, Davis, United States
| | - Justin Yamada
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, Davis, United States
| | - Martin Kampmann
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, United States.,Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, United States.,Institute for Neurodegenerative Diseases and Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, United States.,Chan-Zuckerberg Biohub, San Francisco, United States
| | - Max A Horlbeck
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, United States.,Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, United States
| | - Michelle R Salemi
- Proteomics Core Facility, University of California, Davis, Davis, United States
| | - Brett S Phinney
- Proteomics Core Facility, University of California, Davis, Davis, United States
| | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, United States.,Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, United States.,Whitehead Institute, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Jodi Nunnari
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, Davis, United States
| |
Collapse
|
40
|
Pallafacchina G, Zanin S, Rizzuto R. From the Identification to the Dissection of the Physiological Role of the Mitochondrial Calcium Uniporter: An Ongoing Story. Biomolecules 2021; 11:biom11060786. [PMID: 34071006 PMCID: PMC8224590 DOI: 10.3390/biom11060786] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 05/14/2021] [Accepted: 05/20/2021] [Indexed: 12/16/2022] Open
Abstract
The notion of mitochondria being involved in the decoding and shaping of intracellular Ca2+ signals has been circulating since the end of the 19th century. Despite that, the molecular identity of the channel that mediates Ca2+ ion transport into mitochondria remained elusive for several years. Only in the last decade, the genes and pathways responsible for the mitochondrial uptake of Ca2+ began to be cloned and characterized. The gene coding for the pore-forming unit of the mitochondrial channel was discovered exactly 10 years ago, and its product was called mitochondrial Ca2+ uniporter or MCU. Before that, only one of its regulators, the mitochondria Ca2+ uptake regulator 1, MICU1, has been described in 2010. However, in the following years, the scientific interest in mitochondrial Ca2+ signaling regulation and physiological role has increased. This shortly led to the identification of many of its components, to the description of their 3D structure, and the characterization of the uniporter contribution to tissue physiology and pathology. In this review, we will summarize the most relevant achievements in the history of mitochondrial Ca2+ studies, presenting a chronological overview of the most relevant and landmarking discoveries. Finally, we will explore the impact of mitochondrial Ca2+ signaling in the context of muscle physiology, highlighting the recent advances in understanding the role of the MCU complex in the control of muscle trophism and metabolism.
Collapse
Affiliation(s)
- Giorgia Pallafacchina
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
- Neuroscience Institute, Italian National Research Council (CNR), 35131 Padua, Italy
- Correspondence: (G.P.); (R.R.); Tel.: +39-049-827-6029 (G.P.); +39-049-827-3001 (R.R.)
| | - Sofia Zanin
- Department of Immunology, Infectiology and Haematology, Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, 75015 Paris, France;
| | - Rosario Rizzuto
- Neuroscience Institute, Italian National Research Council (CNR), 35131 Padua, Italy
- Correspondence: (G.P.); (R.R.); Tel.: +39-049-827-6029 (G.P.); +39-049-827-3001 (R.R.)
| |
Collapse
|
41
|
Arines FM, Hamlin AJ, Yang X, Liu YYJ, Li M. A selective transmembrane recognition mechanism by a membrane-anchored ubiquitin ligase adaptor. J Cell Biol 2021; 220:211632. [PMID: 33351099 PMCID: PMC7759299 DOI: 10.1083/jcb.202001116] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 09/10/2020] [Accepted: 10/30/2020] [Indexed: 12/30/2022] Open
Abstract
While it is well-known that E3 ubiquitin ligases can selectively ubiquitinate membrane proteins in response to specific environmental cues, the underlying mechanisms for the selectivity are poorly understood. In particular, the role of transmembrane regions, if any, in target recognition remains an open question. Here, we describe how Ssh4, a yeast E3 ligase adaptor, recognizes the PQ-loop lysine transporter Ypq1 only after lysine starvation. We show evidence of an interaction between two transmembrane helices of Ypq1 (TM5 and TM7) and the single transmembrane helix of Ssh4. This interaction is regulated by the conserved PQ motif. Strikingly, recent structural studies of the PQ-loop family have suggested that TM5 and TM7 undergo major conformational changes during substrate transport, implying that transport-associated conformational changes may determine the selectivity. These findings thus provide critical information concerning the regulatory mechanism through which transmembrane domains can be specifically recognized in response to changing environmental conditions.
Collapse
Affiliation(s)
- Felichi Mae Arines
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Aaron Jeremy Hamlin
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Xi Yang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Yun-Yu Jennifer Liu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Ming Li
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| |
Collapse
|
42
|
Popovic R, Celardo I, Yu Y, Costa AC, Loh SHY, Martins LM. Combined Transcriptomic and Proteomic Analysis of Perk Toxicity Pathways. Int J Mol Sci 2021; 22:4598. [PMID: 33925631 PMCID: PMC8124185 DOI: 10.3390/ijms22094598] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/19/2021] [Accepted: 04/23/2021] [Indexed: 12/17/2022] Open
Abstract
In Drosophila, endoplasmic reticulum (ER) stress activates the protein kinase R-like endoplasmic reticulum kinase (dPerk). dPerk can also be activated by defective mitochondria in fly models of Parkinson's disease caused by mutations in pink1 or parkin. The Perk branch of the unfolded protein response (UPR) has emerged as a major toxic process in neurodegenerative disorders causing a chronic reduction in vital proteins and neuronal death. In this study, we combined microarray analysis and quantitative proteomics analysis in adult flies overexpressing dPerk to investigate the relationship between the transcriptional and translational response to dPerk activation. We identified tribbles and Heat shock protein 22 as two novel Drosophila activating transcription factor 4 (dAtf4) regulated transcripts. Using a combined bioinformatics tool kit, we demonstrated that the activation of dPerk leads to translational repression of mitochondrial proteins associated with glutathione and nucleotide metabolism, calcium signalling and iron-sulphur cluster biosynthesis. Further efforts to enhance these translationally repressed dPerk targets might offer protection against Perk toxicity.
Collapse
Affiliation(s)
| | | | | | | | | | - L. Miguel Martins
- MRC Toxicology Unit, University of Cambridge, Gleeson Building, Tennis Court Road, Cambridge CB2 1QR, UK; (R.P.); (I.C.); (Y.Y.); (A.C.C.); (S.H.Y.L.)
| |
Collapse
|
43
|
Alevriadou BR, Patel A, Noble M, Ghosh S, Gohil VM, Stathopulos PB, Madesh M. Molecular nature and physiological role of the mitochondrial calcium uniporter channel. Am J Physiol Cell Physiol 2021; 320:C465-C482. [PMID: 33296287 PMCID: PMC8260355 DOI: 10.1152/ajpcell.00502.2020] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/23/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023]
Abstract
Calcium (Ca2+) signaling is critical for cell function and cell survival. Mitochondria play a major role in regulating the intracellular Ca2+ concentration ([Ca2+]i). Mitochondrial Ca2+ uptake is an important determinant of cell fate and governs respiration, mitophagy/autophagy, and the mitochondrial pathway of apoptosis. Mitochondrial Ca2+ uptake occurs via the mitochondrial Ca2+ uniporter (MCU) complex. This review summarizes the present knowledge on the function of MCU complex, regulation of MCU channel, and the role of MCU in Ca2+ homeostasis and human disease pathogenesis. The channel core consists of four MCU subunits and essential MCU regulators (EMRE). Regulatory proteins that interact with them include mitochondrial Ca2+ uptake 1/2 (MICU1/2), MCU dominant-negative β-subunit (MCUb), MCU regulator 1 (MCUR1), and solute carrier 25A23 (SLC25A23). In addition to these proteins, cardiolipin, a mitochondrial membrane-specific phospholipid, has been shown to interact with the channel core. The dynamic interplay between the core and regulatory proteins modulates MCU channel activity after sensing local changes in [Ca2+]i, reactive oxygen species, and other environmental factors. Here, we highlight the structural details of the human MCU heteromeric assemblies and their known roles in regulating mitochondrial Ca2+ homeostasis. MCU dysfunction has been shown to alter mitochondrial Ca2+ dynamics, in turn eliciting cell apoptosis. Changes in mitochondrial Ca2+ uptake have been implicated in pathological conditions affecting multiple organs, including the heart, skeletal muscle, and brain. However, our structural and functional knowledge of this vital protein complex remains incomplete, and understanding the precise role for MCU-mediated mitochondrial Ca2+ signaling in disease requires further research efforts.
Collapse
Affiliation(s)
- B Rita Alevriadou
- Department of Biomedical Engineering, Jacobs School of Medicine and Biomedical Sciences and School of Engineering and Applied Sciences, University at Buffalo-State University of New York, Buffalo, New York
| | - Akshar Patel
- Department of Biomedical Engineering, Jacobs School of Medicine and Biomedical Sciences and School of Engineering and Applied Sciences, University at Buffalo-State University of New York, Buffalo, New York
| | - Megan Noble
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Sagnika Ghosh
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Vishal M Gohil
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Muniswamy Madesh
- Department of Medicine/Cardiology Division, Center for Precision Medicine, University of Texas Health San Antonio, San Antonio, Texas
| |
Collapse
|
44
|
Mitochondrial Calcium Signaling in Pancreatic β-Cell. Int J Mol Sci 2021; 22:ijms22052515. [PMID: 33802289 PMCID: PMC7959128 DOI: 10.3390/ijms22052515] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/22/2021] [Accepted: 02/26/2021] [Indexed: 12/13/2022] Open
Abstract
Accumulation of calcium in energized mitochondria of pancreatic β-cells is emerging as a crucial process for pancreatic β-cell function. β-cell mitochondria sense and shape calcium signals, linking the metabolism of glucose and other secretagogues to the generation of signals that promote insulin secretion during nutrient stimulation. Here, we describe the role of mitochondrial calcium signaling in pancreatic β-cell function. We report the latest pharmacological and genetic findings, including the first mitochondrial calcium-targeted intervention strategies developed to modulate pancreatic β-cell function and their potential relevance in the context of diabetes.
Collapse
|
45
|
Tanwar J, Singh JB, Motiani RK. Molecular machinery regulating mitochondrial calcium levels: The nuts and bolts of mitochondrial calcium dynamics. Mitochondrion 2021; 57:9-22. [PMID: 33316420 PMCID: PMC7610953 DOI: 10.1016/j.mito.2020.12.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 11/18/2020] [Accepted: 12/03/2020] [Indexed: 02/06/2023]
Abstract
Mitochondria play vital role in regulating the cellular energetics and metabolism. Further, it is a signaling hub for cell survival and apoptotic pathways. One of the key determinants that calibrate both cellular energetics and survival functions is mitochondrial calcium (Ca2+) dynamics. Mitochondrial Ca2+ regulates three Ca2+-sensitive dehydrogenase enzymes involved in tricarboxylic acid cycle (TCA) cycle thereby directly controlling ATP synthesis. On the other hand, excessive Ca2+ concentration within the mitochondrial matrix elevates mitochondrial reactive oxygen species (mROS) levels and causes mitochondrial membrane depolarization. This leads to opening of the mitochondrial permeability transition pore (mPTP) and release of cytochrome c into cytosol eventually triggering apoptosis. Therefore, it is critical for cell to maintain mitochondrial Ca2+ concentration. Since cells can neither synthesize nor metabolize Ca2+, it is the dynamic interplay of Ca2+ handling proteins involved in mitochondrial Ca2+ influx and efflux that take the center stage. In this review we would discuss the key molecular machinery regulating mitochondrial Ca2+ concentration. We would focus on the channel complex involved in bringing Ca2+ into mitochondrial matrix i.e. Mitochondrial Ca2+ Uniporter (MCU) and its key regulators Mitochondrial Ca2+ Uptake proteins (MICU1, 2 and 3), MCU regulatory subunit b (MCUb), Essential MCU Regulator (EMRE) and Mitochondrial Ca2+ Uniporter Regulator 1 (MCUR1). Further, we would deliberate on major mitochondrial Ca2+ efflux proteins i.e. Mitochondrial Na+/Ca2+/Li+ exchanger (NCLX) and Leucine zipper EF hand-containing transmembrane1 (Letm1). Moreover, we would highlight the physiological functions of these proteins and discuss their relevance in human pathophysiology. Finally, we would highlight key outstanding questions in the field.
Collapse
Affiliation(s)
- Jyoti Tanwar
- CSIR-Institute of Genomics and Integrative Biology (IGIB), New Delhi 10025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Jaya Bharti Singh
- Laboratory of Calciomics and Systemic Pathophysiology (LCSP), Regional Centre for Biotechnology (RCB), Faridabad, Delhi-NCR, India
| | - Rajender K Motiani
- Laboratory of Calciomics and Systemic Pathophysiology (LCSP), Regional Centre for Biotechnology (RCB), Faridabad, Delhi-NCR, India.
| |
Collapse
|
46
|
Márta K, Hasan P, Rodríguez-Prados M, Paillard M, Hajnóczky G. Pharmacological inhibition of the mitochondrial Ca 2+ uniporter: Relevance for pathophysiology and human therapy. J Mol Cell Cardiol 2021; 151:135-144. [PMID: 33035551 PMCID: PMC7880870 DOI: 10.1016/j.yjmcc.2020.09.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 09/26/2020] [Accepted: 09/28/2020] [Indexed: 12/20/2022]
Abstract
Mitochondrial Ca2+ uptake has long been considered crucial for meeting the fluctuating energy demands of cells in the heart and other tissues. Increases in mitochondrial matrix [Ca2+] drive mitochondrial ATP production via stimulation of Ca2+-sensitive dehydrogenases. Mitochondria-targeted sensors have revealed mitochondrial matrix [Ca2+] rises that closely follow the cytoplasmic [Ca2+] signals in many paradigms. Mitochondrial Ca2+ uptake is mediated by the Ca2+ uniporter (mtCU). Pharmacological manipulation of the mtCU is potentially key to understanding its physiological significance, but no specific, cell-permeable inhibitors were identified. In the past decade, as the molecular identity of the mtCU was brought to light, efforts have focused on genetic targeting. However, in the cells/animals that are able to survive impaired mtCU function, robust compensatory changes were found in the mtCU as well as other mechanisms. Thus, the discovery, through chemical library screens on normal and mtCU-deficient cells, of new small-molecule inhibitors with improved cell permeability and specificity might offer a better chance to test the relevance of mitochondrial Ca2+ uptake. Success with the development of small molecule mtCU inhibitors is also expected to have clinical impact, considering the growing evidence for the role of mitochondrial Ca2+ uptake in a variety of diseases, including heart attack, stroke and various neurodegenerative disorders. Here, we review the progress in pharmacological targeting of mtCU and illustrate the challenges in this field using data obtained with MCU-i11, a new small molecule inhibitor.
Collapse
Affiliation(s)
- Katalin Márta
- MitoCare Center, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Prottoy Hasan
- MitoCare Center, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Macarena Rodríguez-Prados
- MitoCare Center, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Melanie Paillard
- MitoCare Center, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA; Univ-Lyon, CarMeN Laboratory, INSERM, INRA, Université Claude Bernard Lyon-1, INSA-Lyon, HCL, 69500 Bron, France
| | - György Hajnóczky
- MitoCare Center, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| |
Collapse
|
47
|
Boyman L, Greiser M, Lederer WJ. Calcium influx through the mitochondrial calcium uniporter holocomplex, MCU cx. J Mol Cell Cardiol 2021; 151:145-154. [PMID: 33147447 PMCID: PMC7880866 DOI: 10.1016/j.yjmcc.2020.10.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 10/20/2020] [Accepted: 10/28/2020] [Indexed: 12/11/2022]
Abstract
Ca2+ flux into the mitochondrial matrix through the MCU holocomplex (MCUcx) has recently been measured quantitatively and with milliseconds resolution for the first time under physiological conditions in both heart and skeletal muscle. Additionally, the dynamic levels of Ca2+ in the mitochondrial matrix ([Ca2+]m) of cardiomyocytes were measured as it was controlled by the balance between influx of Ca2+ into the mitochondrial matrix through MCUcx and efflux through the mitochondrial Na+ / Ca2+ exchanger (NCLX). Under these conditions [Ca2+]m was shown to regulate ATP production by the mitochondria at only a few critical sites. Additional functions attributed to [Ca2+]m continue to be reported in the literature. Here we review the new findings attributed to MCUcx function and provide a framework for understanding and investigating mitochondrial Ca2+ influx features, many of which remain controversial. The properties and functions of the MCUcx subunits that constitute the holocomplex are challenging to tease apart. Such distinct subunits include EMRE, MCUR1, MICUx (i.e. MICU1, MICU2, MICU3), and the pore-forming subunits (MCUpore). Currently, the specific set of functions of each subunit remains non-quantitative and controversial. The more contentious issues are discussed in the context of the newly measured native MCUcx Ca2+ flux from heart and skeletal muscle. These MCUcx Ca2+ flux measurements have been shown to be a highly-regulated, tissue-specific with femto-Siemens Ca2+ conductances and with distinct extramitochondrial Ca2+ ([Ca2+]i) dependencies. These data from cardiac and skeletal muscle mitochondria have been examined quantitatively for their threshold [Ca2+]i levels and for hypothesized gatekeeping function and are discussed in the context of model cell (e.g. HeLa, MEF, HEK293, COS7 cells) measurements. Our new findings on MCUcx dependent matrix [Ca2+]m signaling provide a quantitative basis for on-going and new investigations of the roles of MCUcx in cardiac function ranging from metabolic fuel selection, capillary blood-flow control and the pathological activation of the mitochondrial permeability transition pore (mPTP). Additionally, this review presents the use of advanced new methods that can be readily adapted by any investigator to enable them to carry out quantitative Ca2+ measurements in mitochondria while controlling the inner mitochondrial membrane potential, ΔΨm.
Collapse
Affiliation(s)
- Liron Boyman
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA; The Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Maura Greiser
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA; The Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - W Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA; The Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
48
|
Mechanisms of EMRE-Dependent MCU Opening in the Mitochondrial Calcium Uniporter Complex. Cell Rep 2020; 33:108486. [PMID: 33296646 PMCID: PMC7764451 DOI: 10.1016/j.celrep.2020.108486] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 10/09/2020] [Accepted: 11/13/2020] [Indexed: 12/02/2022] Open
Abstract
The mitochondrial calcium uniporter is a multi-subunit Ca2+-activated Ca2+ channel, made up of the pore-forming MCU protein, a metazoan-specific EMRE subunit, and MICU1/MICU2, which mediate Ca2+ activation. It has been established that metazoan MCU requires EMRE binding to conduct Ca2+, but how EMRE promotes MCU opening remains unclear. Here, we demonstrate that EMRE controls MCU activity via its transmembrane helix, while using an N-terminal PKP motif to strengthen binding with MCU. Opening of MCU requires hydrophobic interactions mediated by MCU residues near the pore’s luminal end. Enhancing these interactions by single mutation allows human MCU to transport Ca2+ without EMRE. We further show that EMRE may facilitate MCU opening by stabilizing the open state in a conserved MCU gating mechanism, present also in non-metazoan MCU homologs. These results provide insights into the evolution of the uniporter machinery and elucidate the mechanism underlying the physiologically crucial EMRE-dependent MCU activation process. The mitochondrial calcium uniporter is a multi-subunit ion channel that imports cytoplasmic Ca2+ into mitochondria to regulate cell energy production and death. In this work, Van Keuren et al. report a key activation mechanism of the uniporter, mediated by an auxiliary EMRE subunit in the channel complex.
Collapse
|
49
|
Feno S, Rizzuto R, Raffaello A, Vecellio Reane D. The molecular complexity of the Mitochondrial Calcium Uniporter. Cell Calcium 2020; 93:102322. [PMID: 33264708 DOI: 10.1016/j.ceca.2020.102322] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/19/2020] [Accepted: 11/19/2020] [Indexed: 12/20/2022]
Abstract
The role of mitochondria in regulating cellular Ca2+ homeostasis is crucial for the understanding of different cellular functions in physiological and pathological conditions. Nevertheless, the study of this aspect was severely limited by the lack of the molecular identity of the proteins responsible for mitochondrial Ca2+ uptake. In 2011, the discovery of the gene encoding for the Mitochondrial Calcium Uniporter (MCU), the selective channel responsible for mitochondrial Ca2+ uptake, gave rise to an explosion of studies aimed to characterize the composition, the regulation of the channel and its pathophysiological roles. Here, we summarize the recent discoveries on the molecular structure and composition of the MCU complex by providing new insights into the mechanisms that regulate MCU channel activity.
Collapse
Affiliation(s)
- Simona Feno
- Department of Biomedical Science, University of Padua, via G. Colombo 3, 35100 Padua, Italy
| | - Rosario Rizzuto
- Department of Biomedical Science, University of Padua, via G. Colombo 3, 35100 Padua, Italy
| | - Anna Raffaello
- Department of Biomedical Science, University of Padua, via G. Colombo 3, 35100 Padua, Italy; Myology Center, University of Padua, via G. Colombo 3, 35100 Padova, Italy.
| | - Denis Vecellio Reane
- Department of Biomedical Science, University of Padua, via G. Colombo 3, 35100 Padua, Italy.
| |
Collapse
|
50
|
Abstract
New cryo-electron microscopy structures of the mitochondrial Ca2+ uniporter ion channel complex in various conformations reveal channel gating regulation by Ca2+-dependent unblock of the channel pore by MICU1.
Collapse
Affiliation(s)
- J Kevin Foskett
- Departments of Physiology and Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States.
| |
Collapse
|