Systematic mapping of mitochondrial calcium uniporter channel (MCUC)-mediated calcium signaling networks
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ABSTRACT:
SUBMITTER: Fabiana Perocchi
PROVIDER: S-SCDT-10_1038-S44318-024-00219-W | biostudies-other |
REPOSITORIES: biostudies-other
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Project description:The mitochondrial calcium uniporter channel (MCUC) mediates mitochondrial calcium entry, regulating energy metabolism and cell death. Although several MCUC components have been identified, the molecular basis of mitochondrial calcium signaling networks and their remodeling upon changes in uniporter activity have not been assessed. Here, we map the MCUC interactome under resting conditions and upon chronic loss or gain of mitochondrial calcium uptake. We identify 89 high-confidence interactors that link MCUC to several mitochondrial complexes and pathways, half of which are associated with human disease. As a proof-of-concept, we validate the mitochondrial intermembrane space protein EFHD1 as a binding partner of the MCUC subunits MCU, EMRE, and MCUB. We further show a MICU1-dependent inhibitory effect of EFHD1 on calcium uptake. Next, we systematically survey compensatory mechanisms and functional consequences of mitochondrial calcium dyshomeostasis by analyzing the MCU interactome upon EMRE, MCUB, MICU1, or MICU2 knockdown. While silencing EMRE reduces MCU interconnectivity, MCUB loss-of-function leads to a wider interaction network. Our study provides a comprehensive and high-confidence resource to gain insights into players and mechanisms regulating mitochondrial calcium signaling and their relevance in human diseases.
| S-EPMC11535509 | biostudies-literature
Project description:Mitochondria play an essential role in maintaining intraneuronal calcium homeostasis. Mitochondrial calcium uniporter (MCU) is a determined major brain mitochondrial calcium entry pathway. Activated MCU-mediated mitochondrial calcium overloading has been linked with brain mitochondrial pathology in disease conditions. Cyclophilin D (CypD)-mediated mitochondrial permeability transition (mPT) favors mitochondrial calcium efflux. The physiological function of CypD-mediated mPT has received increasing recognition. However, the regulatory role of CypD-mediated mPT in brain mitochondrial calcium dynamics in response to mitochondrial calcium accumulation via MCU has not been comprehensively studied. Here, by adopting purified brain mitochondria, we have determined an effect of CypD and CypD-mediated mPT against mitochondrial calcium overloading. In addition, blockade of CypD pharmaceutically or genetically blunts brain mitochondrial MCU's sensitivity to its inhibitor. Therefore, our findings suggest that CypD-mediated mPT is a mitochondrial compensatory response to MCU-mediated excess mitochondrial calcium accumulation. Moreover, CypD may potentially modulate MCU function in calcium-stressed mitochondria.
| S-EPMC7481651 | biostudies-literature
Project description: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.
| S-EPMC8260355 | biostudies-literature
Project description:Kidney is a vital organ responsible for homeostasis in the body. To retard kidney aging is of great importance for maintaining body health. Whereas the therapeutic strategies targeting against kidney aging are not elucidated. Recent studies show mitochondrial dysfunction is critical for renal tubular cell senescence and kidney aging, however, the underlying mechanisms of mitochondrial dysfunction in kidney aging have not been demonstrated. Herein, we found calcium overload, and the mitochondrial calcium uniporter (MCU) was induced in renal tubular cells and aged kidney. To activate MCU not only triggered mitochondrial calcium overload, but also induced reactive oxygen species (ROS) production and cellular senescence and age-related kidney fibrosis. Inversely, to block MCU or chelate calcium diminished ROS generation, restored mitochondrial homeostasis, and retarded cell senescence and protected against kidney aging. These results demonstrate MCU plays a key role in promote renal tubular cell senescence, which provides a new insight on the therapeutic strategy for fighting against kidney aging.
2024-10-02 | GSE262514 | GEO
Project description:T-cell receptor (TCR)-induced Ca2+ signals are essential for T-cell activation and function. In this context, mitochondria play an important role and take up Ca2+ to support elevated bioenergetic demands. However, the functional relevance of the mitochondrial-Ca2+-uniporter (MCU) complex in T-cells was not fully understood. Here, we demonstrate that TCR activation causes rapid mitochondrial Ca2+ (mCa2+) uptake in primary naive and effector human CD4+ T-cells. Compared to naive T-cells, effector T-cells display elevated mCa2+ and increased bioenergetic and metabolic output. Transcriptome and proteome analyses reveal molecular determinants involved in the TCR-induced functional reprogramming and identify signalling pathways and cellular functions regulated by MCU. Knockdown of MCUa (MCUaKD), diminishes mCa2+ uptake, mitochondrial respiration and ATP production, as well as T-cell migration and cytokine secretion. Moreover, MCUaKD in rat CD4+ T-cells suppresses autoimmune responses in an experimental autoimmune encephalomyelitis (EAE) multiple sclerosis model. In summary, we demonstrate that mCa2+ uptake through MCU is essential for proper T-cell function and has a crucial role in autoimmunity. T-cell specific MCU inhibition is thus a potential tool for targeting autoimmune disorders.
| S-EPMC11772621 | biostudies-literature
Project description:T-cell receptor-induced Ca2+ signals are essential for proper T-cell activation and function. In this context, mitochondria play an important role and take up Ca2+ to support elevated bioenergetic demands. The protein machinery that regulates mitochondrial Ca2+ (mCa2+) uptake; the mitochondrial calcium uniporter (MCU) complex, could be thus implicated in T-cell immunity. However, the exact role of MCU in T-cells is not understood. Here, we show that upon activation of naïve T-cells, the MCU complex undergoes a compositional rearrangement that causes elevated mCa2+ uptake and increased bioenergetic output. Transcriptome and proteome analyses reveal molecular determinants involved in mitochondrial functional reprograming and identify signaling pathways controlled by MCU. MCUa knockdown diminishes mCa2+ uptake, mitochondrial respiration and ATP production as well as T-cell invasion and cytokine secretion. In vivo, downregulation of MCUa in rat CD4+ T-cells suppresses autoimmune responses in a multiple sclerosis model of inflammatory experimental autoimmune encephalomyelitis. In summary, Ca2+ uptake through MCU is essential for proper T-cell function and is involved in autoimmunity. T-cell specific MCU inhibition is a potential tool for treating autoimmune disorders.
2024-10-23 | GSE253049 | GEO
Project description:BackgroundThe mitochondrial calcium uniporter (mtCU) is an ≈700-kD multisubunit channel residing in the inner mitochondrial membrane required for mitochondrial Ca2+ (mCa2+) uptake. Here, we detail the contribution of MCUB, a paralog of the pore-forming subunit MCU, in mtCU regulation and function and for the first time investigate the relevance of MCUB to cardiac physiology.MethodsWe created a stable MCUB knockout cell line (MCUB-/-) using CRISPR-Cas9n technology and generated a cardiac-specific, tamoxifen-inducible MCUB mutant mouse (CAG-CAT-MCUB x MCM; MCUB-Tg) for in vivo assessment of cardiac physiology and response to ischemia/reperfusion injury. Live-cell imaging and high-resolution spectrofluorometery were used to determine intracellular Ca2+ exchange and size-exclusion chromatography; blue native page and immunoprecipitation studies were used to determine the molecular function and impact of MCUB on the high-molecular-weight mtCU complex.ResultsUsing genetic gain- and loss-of-function approaches, we show that MCUB expression displaces MCU from the functional mtCU complex and thereby decreases the association of mitochondrial calcium uptake 1 and 2 (MICU1/2) to alter channel gating. These molecular changes decrease MICU1/2-dependent cooperative activation of the mtCU, thereby decreasing mCa2+ uptake. Furthermore, we show that MCUB incorporation into the mtCU is a stress-responsive mechanism to limit mCa2+ overload during cardiac injury. Indeed, overexpression of MCUB is sufficient to decrease infarct size after ischemia/reperfusion injury. However, MCUB incorporation into the mtCU does come at a cost; acute decreases in mCa2+ uptake impair mitochondrial energetics and contractile function.ConclusionsWe detail a new regulatory mechanism to modulate mtCU function and mCa2+ uptake. Our results suggest that MCUB-dependent changes in mtCU stoichiometry are a prominent regulatory mechanism to modulate mCa2+ uptake and cellular physiology.
| S-EPMC6996560 | biostudies-literature
Project description:Background: Calcium uptake research has a long history. However, the mitochondrial calcium uniporter (MCU) protein was first discovered in 2011. As investigations of mitochondrial calcium uniporter represent a new research hotspot, a comprehensive and objective perspective of the field is lacking. Hence, this bibliometric analysis aimed to provide the current study status and trends related to mitochondrial calcium uniporter research in the past decade. Methods: Articles were acquired from the Web of Science Core Collection database. We quantified and visualized information regarding annual publications, journals, cocited journals, countries/regions, institutions, authors, and cocited authors by using CiteSpace 5.8. R3 and VOSviewer. In addition, we analysed the citation and keyword bursts related to mitochondrial calcium uniporter studies. Results: From 2011 to 2022, 1,030 articles were published by 5,050 authors from 1,145 affiliations and 62 countries or regions. The country with the most published articles was the United States. The institution with the most published articles was the University of Padua. Rosario Rizzuto published the most articles and was also the most cocited author. Cell Calcium published the largest number of articles, whereas Journal of Biological Chemistry had the most cocitations. The top 5 keywords related to pathological processes were oxidative stress, cell death, permeability transition, apoptosis, and metabolism. MICU1, calcium, ryanodine receptor, ATP synthase and cyclophilin D were the top 5 keywords related to molecules. Conclusion: mitochondrial calcium uniporter research has grown stably over the last decade. Current studies focus on the structure of the mitochondrial calcium uniporter complex and its regulatory effect on mitochondrial calcium homeostasis. In addition, the potential role of mitochondrial calcium uniporter in different diseases has been explored. Current studies mostly involve investigations of cancer and neurodegenerative diseases. Our analysis provides guidance and new insights into further mitochondrial calcium uniporter research.
| S-EPMC9895098 | biostudies-literature
Project description:Mitochondria from many eukaryotic clades take up large amounts of calcium (Ca(2+)) via an inner membrane transporter called the uniporter. Transport by the uniporter is membrane potential dependent and sensitive to ruthenium red or its derivative Ru360 (ref. 1). Electrophysiological studies have shown that the uniporter is an ion channel with remarkably high conductance and selectivity. Ca(2+) entry into mitochondria is also known to activate the tricarboxylic acid cycle and seems to be crucial for matching the production of ATP in mitochondria with its cytosolic demand. Mitochondrial calcium uniporter (MCU) is the pore-forming and Ca(2+)-conducting subunit of the uniporter holocomplex, but its primary sequence does not resemble any calcium channel studied to date. Here we report the structure of the pore domain of MCU from Caenorhabditis elegans, determined using nuclear magnetic resonance (NMR) and electron microscopy (EM). MCU is a homo-oligomer in which the second transmembrane helix forms a hydrophilic pore across the membrane. The channel assembly represents a new solution of ion channel architecture, and is stabilized by a coiled-coil motif protruding into the mitochondrial matrix. The critical DXXE motif forms the pore entrance, which features two carboxylate rings; based on the ring dimensions and functional mutagenesis, these rings appear to form the selectivity filter. To our knowledge, this is one of the largest membrane protein structures characterized by NMR, and provides a structural blueprint for understanding the function of this channel.
| S-EPMC4874835 | biostudies-literature
Project description:T-cell receptor (TCR)-induced Ca2+ signals are essential for T-cell activation and function. In this context, mitochondria play an important role and take up Ca2+ to support elevated bioenergetic demands. However, the functional relevance of the mitochondrial-Ca2+-uniporter (MCU) complex in T-cells was not fully understood. Here, we demonstrate that TCR activation causes rapid mitochondrial Ca2+ (mCa2+) uptake in primary naive and effector human CD4+ T-cells. Compared to naive T-cells, effector T-cells display elevated mCa2+ and increased bioenergetic and metabolic output. Transcriptome and proteome analyses reveal molecular determinants involved in the TCR induced functional reprogramming and identify signalling pathways and cellular functions regulated by MCU. Knockdown of MCUa (MCUaKD), diminishes mCa2+ uptake, mitochondrial respiration and ATP production, as well as T-cell migration and cytokine secretion. Moreover, MCUaKD in rat CD4+ T-cells suppresses autoimmune responses in an experimental autoimmune encephalomyelitis (EAE) multiple sclerosis model. In summary, we demonstrate that mCa2+ uptake through MCU is essential for proper T-cell function and has a crucial role in autoimmunity. T-cell specific MCU inhibition is thus a potential tool for targeting autoimmune disorders.
| S-SCDT-10_1038-S44319-024-00313-4 | biostudies-other