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Tsujii M, Tanudjaja E, Zhang H, Shimizukawa H, Konishi A, Furuta T, Ishimaru Y, Uozumi N. Dissecting structure and function of the monovalent cation/H + antiporters Mdm38 and Ylh47 in Saccharomyces cerevisiae. J Bacteriol 2024; 206:e0018224. [PMID: 39082862 PMCID: PMC11340316 DOI: 10.1128/jb.00182-24] [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: 05/01/2024] [Accepted: 07/09/2024] [Indexed: 08/23/2024] Open
Abstract
Saccharomyces cerevisiae Mdm38 and Ylh47 are homologs of the Ca2+/H+ antiporter Letm1, a candidate gene for seizures associated with Wolf-Hirschhorn syndrome in humans. Mdm38 is important for K+/H+ exchange across the inner mitochondrial membrane and contributes to membrane potential formation and mitochondrial protein translation. Ylh47 also localizes to the inner mitochondrial membrane. However, knowledge of the structures and detailed transport activities of Mdm38 and Ylh47 is limited. In this study, we conducted characterization of the ion transport activities and related structural properties of Mdm38 and Ylh47. Growth tests using Na+/H+ antiporter-deficient Escherichia coli strain TO114 showed that Mdm38 and Ylh47 had Na+ efflux activity. Measurement of transport activity across E. coli-inverted membranes showed that Mdm38 and Ylh47 had K+/H+, Na+/H+, and Li+/H+ antiport activity, but unlike Letm1, they lacked Ca2+/H+ antiport activity. Deletion of the ribosome-binding domain resulted in decreased Na+ efflux activity in Mdm38. Structural models of Mdm38 and Ylh47 identified a highly conserved glutamic acid in the pore-forming membrane-spanning region. Replacement of this glutamic acid with alanine, a non-polar amino acid, significantly impaired the ability of Mdm38 and Ylh47 to complement the salt sensitivity of E. coli TO114. These findings not only provide important insights into the structure and function of the Letm1-Mdm38-Ylh47 antiporter family but by revealing their distinctive properties also shed light on the physiological roles of these transporters in yeast and animals. IMPORTANCE The inner membrane of mitochondria contains numerous ion transporters, including those facilitating H+ transport by the electron transport chain and ATP synthase to maintain membrane potential. Letm1 in the inner membrane of mitochondria in animals functions as a Ca2+/H+ antiporter. However, this study reveals that homologous antiporters in mitochondria of yeast, Mdm38 and Ylh47, do not transport Ca2+ but instead are selective for K+ and Na+. Additionally, the identification of conserved amino acids crucial for antiporter activity further expanded our understanding of the structure and function of the Letm1-Mdm38-Ylh47 antiporter family.
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Affiliation(s)
- Masaru Tsujii
- Graduate School of Engineering, Tohoku University, Aobayama, Sendai, Japan
| | - Ellen Tanudjaja
- Graduate School of Engineering, Tohoku University, Aobayama, Sendai, Japan
| | - Haoyu Zhang
- Graduate School of Engineering, Tohoku University, Aobayama, Sendai, Japan
| | - Haruto Shimizukawa
- Graduate School of Engineering, Tohoku University, Aobayama, Sendai, Japan
| | - Ayumi Konishi
- Graduate School of Engineering, Tohoku University, Aobayama, Sendai, Japan
| | - Tadaomi Furuta
- School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta-cho, Yokohama, Japan
| | - Yasuhiro Ishimaru
- Graduate School of Engineering, Tohoku University, Aobayama, Sendai, Japan
| | - Nobuyuki Uozumi
- Graduate School of Engineering, Tohoku University, Aobayama, Sendai, Japan
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Olsen LF, Lunding A. On the coupling of intracellular K + ${{\rm{K}}}^{+}$ to glycolytic oscillations in yeast. Yeast 2024; 41:486-498. [PMID: 39031655 DOI: 10.1002/yea.3972] [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: 02/09/2024] [Revised: 05/06/2024] [Accepted: 06/05/2024] [Indexed: 07/22/2024] Open
Abstract
We have investigated the interplay between glycolytic oscillations and intracellularK + ${{\rm{K}}}^{+}$ concentration in the yeast Saccharomyces cerevisiae. IntracellularK + ${{\rm{K}}}^{+}$ concentration was measured using the fluorophore potassium-binding benzofuranisophthalate (PBFI). We found thatK + ${{\rm{K}}}^{+}$ is an essential ion for the occurrence of glycolytic oscillations and that intracellularK + ${{\rm{K}}}^{+}$ concentration oscillates synchronously with other variables such as nicotinamide adenine dinucleotide hydride (NADH), intracellular adenosine triphosphate (ATP), and mitochondrial membrane potential. We also investigated if glycolysis and intracellularK + ${{\rm{K}}}^{+}$ concentration oscillate in a number of yeast strains with mutations inK + ${{\rm{K}}}^{+}$ transporters in the plasma membrane, mitochondrial membrane and in the vacuolar membrane. Most of these strains are still capable of showing glycolytic oscillations, but two strains are not: (i) a strain with a deletion in the mitochondrial Mdm38pK + ∕ H + ${{\rm{K}}}^{+}\unicode{x02215}{{\rm{H}}}^{+}$ transporter and (ii) a strain with deletion of the late endosomal Nhx1pK + ∕ H + ${{\rm{K}}}^{+}\unicode{x02215}{{\rm{H}}}^{+}$ (Na + ∕ H + ${\text{Na}}^{+}\unicode{x02215}{{\rm{H}}}^{+}$ ) transporter. In these two mutant strains intracellularK + ${{\rm{K}}}^{+}$ concentration seems to be low, indicating that the two transporters may be involved in transport ofK + ${{\rm{K}}}^{+}$ into the cytosol. In the strain, Mdm38pΔ ${\rm{\Delta }}$ oscillations in glycolysis could be restored by addition of theK + ∕ H + ${{\rm{K}}}^{+}\unicode{x02215}{{\rm{H}}}^{+}$ exchange ionophore nigericin. Furthermore, in two nonoscillating mutant strains with a defective V-ATPase and deletion of the Arp1p protein the intracellularK + ${{\rm{K}}}^{+}$ is relatively high, suggesting that the V-ATPase is essential for transport ofK + ${{\rm{K}}}^{+}$ out of the cytosol and that the cytoskeleton may be involved in bindingK + ${{\rm{K}}}^{+}$ to reduce the concentration of free ion in the cytosol. Analyses of the time series of oscillations of NADH, ATP, mitochondrial membrane potential, and potassium concentration using data-driven modeling corroborate the conjecture thatK + ${{\rm{K}}}^{+}$ ion is essential for the emergence of oscillations and support the experimental findings using mutant strains.
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Affiliation(s)
- Lars F Olsen
- PhyLife, Institute of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Anita Lunding
- PhyLife, Institute of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
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3
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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.
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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
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Hoogstraten CA, Schirris TJJ, Russel FGM. Unlocking mitochondrial drug targets: The importance of mitochondrial transport proteins. Acta Physiol (Oxf) 2024; 240:e14150. [PMID: 38666512 DOI: 10.1111/apha.14150] [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: 10/04/2023] [Revised: 03/02/2024] [Accepted: 04/12/2024] [Indexed: 05/12/2024]
Abstract
A disturbed mitochondrial function contributes to the pathology of many common diseases. These organelles are therefore important therapeutic targets. On the contrary, many adverse effects of drugs can be explained by a mitochondrial off-target effect, in particular, due to an interaction with carrier proteins in the inner membrane. Yet this class of transport proteins remains underappreciated and understudied. The aim of this review is to provide a deeper understanding of the role of mitochondrial carriers in health and disease and their significance as drug targets. We present literature-based evidence that mitochondrial carrier proteins are associated with prevalent diseases and emphasize their potential as drug (off-)target sites by summarizing known mitochondrial drug-transporter interactions. Studying these carriers will enhance our knowledge of mitochondrial drug on- and off-targets and provide opportunities to further improve the efficacy and safety of drugs.
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Affiliation(s)
- Charlotte A Hoogstraten
- Department of Pharmacy, Division of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, the Netherlands
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Tom J J Schirris
- Department of Pharmacy, Division of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, the Netherlands
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Frans G M Russel
- Department of Pharmacy, Division of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, the Netherlands
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
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Paprocka J, Kaminiów K, Yetkin O, Tekturk P, Baykan B, Leiz S, Kluger G, Striano P. Clinical and epilepsy characteristics in Wolf-Hirschhorn syndrome (4p-): A review. Seizure 2024; 116:14-23. [PMID: 36526544 DOI: 10.1016/j.seizure.2022.12.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 11/23/2022] [Accepted: 12/07/2022] [Indexed: 12/13/2022] Open
Abstract
Wolf-Hirschhorn syndrome (WHS) is araredisorderwithan estimated prevalence being around 1 in 50,000 births. The syndrome is caused by the deletion of a critical region (Wolf-Hirschhorn Syndrome Critical region- WHSCR) on chromosome 4p16.3. WHS is clinically characterized by pre-and postnatal growth restriction, hypotonia, intellectual disability, craniofacial dysmorphismand congenital fusion anomalies. The clinical aspects are variable due to the deletion size.Consistently, epilepsy is one of the major concerns for parents and professionals caring for children with WHS. Seizures tend to occur in over 90% of patients, with onset within the first 3 years of life, and a peak incidence at around 6-12 months of age. Approximately 20% of patients had the first seizure onset within the first 6 months of age, almost 50% at 6 to 12 months of age and about 25% later than 12 months of age. The main types of epileptic seizures occurring in patients with WHS were generalized tonic-clonic seizures (around 70%). These were followed by tonic spasms (20%); focal seizures with impaired awareness (12%) and clonicseizures in 7% of patients.Seizures are often triggered by fever, followed by infections of various systems. Particularly, half of WHS patients experience status epilepticus in the first years of life, which can be fatal. Due to limited number of reports on the topic of EEG abnormalities in epilepsy among WHS patients, it is difficult to determine whether there are any characteristic deviations for WHS. Although more than 300 persons with WHS have been reported in the literature, there is sparse knowledge about epilepsy and methods of its anti-seizure medication (ASM) management with an assessment of their effectiveness. The purpose of this systematic review is to briefly summarize achievements and advances in the field of epilepsy in Wolf-Hirschhorn syndrome.
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Affiliation(s)
- Justyna Paprocka
- Pediatric Neurology Department, Faculty of Medical Sciences, Medical University of Silesia, Katowice, Poland.
| | - Konrad Kaminiów
- Students' Scientific Society, Pediatric Neurology Department, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Katowice, Poland
| | - Ozgun Yetkin
- Department of Developmental Neurology, Poznań University of Medical Sciences, Poznań, Poland
| | - Pınar Tekturk
- Child Neurology and Neurology Departments, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiy
| | - Betül Baykan
- Clinical Neurophysiology and Neurology Departments, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Steffen Leiz
- Neuropädiatrie, KinderklinikDritter Orden, München, Germany
| | - Gerhard Kluger
- Institute for Transition, Rehabilitation and Palliation, Paracelsus Medical University, Salzburg, Austria; Center for Pediatric Neurology, Neurorehabilitation and Epileptology, Schoen KlinikVogtareuth, Vogtareuth, Germany
| | - Pasquale Striano
- IRCCS IstitutoGianninaGaslini", Genova, Italy; Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genova, Italy
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6
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Park A, Kim KE, Park I, Lee SH, Park KY, Jung M, Li X, Sleiman MB, Lee SJ, Kim DS, Kim J, Lim DS, Woo EJ, Lee EW, Han BS, Oh KJ, Lee SC, Auwerx J, Mun JY, Rhee HW, Kim WK, Bae KH, Suh JM. Mitochondrial matrix protein LETMD1 maintains thermogenic capacity of brown adipose tissue in male mice. Nat Commun 2023; 14:3746. [PMID: 37353518 PMCID: PMC10290150 DOI: 10.1038/s41467-023-39106-z] [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: 11/03/2021] [Accepted: 05/31/2023] [Indexed: 06/25/2023] Open
Abstract
Brown adipose tissue (BAT) has abundant mitochondria with the unique capability of generating heat via uncoupled respiration. Mitochondrial uncoupling protein 1 (UCP1) is activated in BAT during cold stress and dissipates mitochondrial proton motive force generated by the electron transport chain to generate heat. However, other mitochondrial factors required for brown adipocyte respiration and thermogenesis under cold stress are largely unknown. Here, we show LETM1 domain-containing protein 1 (LETMD1) is a BAT-enriched and cold-induced protein required for cold-stimulated respiration and thermogenesis of BAT. Proximity labeling studies reveal that LETMD1 is a mitochondrial matrix protein. Letmd1 knockout male mice display aberrant BAT mitochondria and fail to carry out adaptive thermogenesis under cold stress. Letmd1 knockout BAT is deficient in oxidative phosphorylation (OXPHOS) complex proteins and has impaired mitochondrial respiration. In addition, BAT-specific Letmd1 deficient mice exhibit phenotypes identical to those observed in Letmd1 knockout mice. Collectively, we demonstrate that the BAT-enriched mitochondrial matrix protein LETMD1 plays a tissue-autonomous role that is essential for BAT mitochondrial function and thermogenesis.
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Affiliation(s)
- Anna Park
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea
| | - Kwang-Eun Kim
- Graduate School of Medical Science and Engineering, KAIST, Daejeon, 34141, Republic of Korea
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
| | - Isaac Park
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sang Heon Lee
- Graduate School of Medical Science and Engineering, KAIST, Daejeon, 34141, Republic of Korea
| | - Kun-Young Park
- Graduate School of Medical Science and Engineering, KAIST, Daejeon, 34141, Republic of Korea
| | - Minkyo Jung
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu, 41068, Republic of Korea
| | - Xiaoxu Li
- Laboratory of Integrative Systems Physiology, École polytechnique fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Maroun Bou Sleiman
- Laboratory of Integrative Systems Physiology, École polytechnique fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Su Jeong Lee
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, 34141, Republic of Korea
| | - Dae-Soo Kim
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, 34141, Republic of Korea
- Digital Biotech Innovation Center, KRIBB, Daejeon, 34141, Republic of Korea
| | - Jaehoon Kim
- Department of Biological Sciences, KAIST, Daejeon, 34141, Republic of Korea
| | - Dae-Sik Lim
- National Creative Research Center for Cell Plasticity, KAIST Stem Cell Center, Department of Biological Sciences, KAIST, Daejeon, 34141, Republic of Korea
| | - Eui-Jeon Woo
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, 34141, Republic of Korea
- Disease Target Structure Research Center, KRIBB, Daejeon, 34141, Republic of Korea
| | - Eun Woo Lee
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, 34141, Republic of Korea
| | - Baek Soo Han
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, 34141, Republic of Korea
- Biodefense Research Center, KRIBB, Daejeon, 34141, Republic of Korea
| | - Kyoung-Jin Oh
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, 34141, Republic of Korea
| | - Sang Chul Lee
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea
| | - Johan Auwerx
- Laboratory of Integrative Systems Physiology, École polytechnique fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Ji Young Mun
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu, 41068, Republic of Korea
| | - Hyun-Woo Rhee
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
| | - Won Kon Kim
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea.
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, 34141, Republic of Korea.
- School of Medicine, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
| | - Kwang-Hee Bae
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea.
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, CA, 92697, USA.
| | - Jae Myoung Suh
- Graduate School of Medical Science and Engineering, KAIST, Daejeon, 34141, Republic of Korea.
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Austin S, Mekis R, Mohammed SEM, Scalise M, Wang W, Galluccio M, Pfeiffer C, Borovec T, Parapatics K, Vitko D, Dinhopl N, Demaurex N, Bennett KL, Indiveri C, Nowikovsky K. TMBIM5 is the Ca 2+ /H + antiporter of mammalian mitochondria. EMBO Rep 2022; 23:e54978. [PMID: 36321428 PMCID: PMC9724676 DOI: 10.15252/embr.202254978] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 09/07/2022] [Accepted: 10/07/2022] [Indexed: 11/25/2022] Open
Abstract
Mitochondrial Ca2+ ions are crucial regulators of bioenergetics and cell death pathways. Mitochondrial Ca2+ content and cytosolic Ca2+ homeostasis strictly depend on Ca2+ transporters. In recent decades, the major players responsible for mitochondrial Ca2+ uptake and release have been identified, except the mitochondrial Ca2+ /H+ exchanger (CHE). Originally identified as the mitochondrial K+ /H+ exchanger, LETM1 was also considered as a candidate for the mitochondrial CHE. Defining the mitochondrial interactome of LETM1, we identify TMBIM5/MICS1, the only mitochondrial member of the TMBIM family, and validate the physical interaction of TMBIM5 and LETM1. Cell-based and cell-free biochemical assays demonstrate the absence or greatly reduced Na+ -independent mitochondrial Ca2+ release in TMBIM5 knockout or pH-sensing site mutants, respectively, and pH-dependent Ca2+ transport by recombinant TMBIM5. Taken together, we demonstrate that TMBIM5, but not LETM1, is the long-sought mitochondrial CHE, involved in setting and regulating the mitochondrial proton gradient. This finding provides the final piece of the puzzle of mitochondrial Ca2+ transporters and opens the door to exploring its importance in health and disease, and to developing drugs modulating Ca2+ exchange.
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Affiliation(s)
- Shane Austin
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
- Present address:
Department of Biological & Chemical SciencesThe University of the West Indies, Cave Hill CampusCave HillBarbados
| | - Ronald Mekis
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and BiophysicsUniversity of Veterinary Medicine ViennaViennaAustria
| | - Sami E M Mohammed
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and BiophysicsUniversity of Veterinary Medicine ViennaViennaAustria
| | - Mariafrancesca Scalise
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular BiotechnologyUniversity of CalabriaArcavacata di RendeItaly
| | - Wen‐An Wang
- Department of Cell Physiology & MetabolismUniversity of GenevaGenevaSwitzerland
| | - Michele Galluccio
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular BiotechnologyUniversity of CalabriaArcavacata di RendeItaly
| | - Christina Pfeiffer
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
| | - Tamara Borovec
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and BiophysicsUniversity of Veterinary Medicine ViennaViennaAustria
| | - Katja Parapatics
- CeMM Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Dijana Vitko
- CeMM Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Nora Dinhopl
- Department of Pathobiology, Institute of PathologyUniversity of Veterinary MedicineViennaAustria
| | - Nicolas Demaurex
- Department of Cell Physiology & MetabolismUniversity of GenevaGenevaSwitzerland
| | - Keiryn L Bennett
- CeMM Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular BiotechnologyUniversity of CalabriaArcavacata di RendeItaly
- CNR Institute of BiomembranesBioenergetics and Molecular Biotechnologies (IBIOM)BariItaly
| | - Karin Nowikovsky
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and BiophysicsUniversity of Veterinary Medicine ViennaViennaAustria
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8
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Lenzini L, Caroccia B, Seccia TM, Rossi GP. Peptidergic G Protein-Coupled Receptor Regulation of Adrenal Function: Bench to Bedside and Back. Endocr Rev 2022; 43:1038-1050. [PMID: 35436330 DOI: 10.1210/endrev/bnac011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Indexed: 11/19/2022]
Abstract
An altered secretion of adrenocortical and adrenomedullary hormones plays a role in the clinical syndromes of primary aldosteronism (PA), Cushing, and pheochromocytoma. Moreover, an altered production of adrenocortical hormones and/or an abnormal release of factors by the adrenal medulla are involved in several other diseases, including high blood pressure, congestive heart failure, liver cirrhosis, nephrotic syndrome, primary reninism, renovascular hypertension, Addison disease, Bartter, Gitelman, and virilization syndromes. Understanding the regulation of adrenal function and the interactions between adrenal cortex and medulla is, therefore, the prerequisite for mechanistic understanding of these disorders. Accumulating evidence indicates that the modulation of adrenal hormone biosynthesis is a process far more complex than originally thought, as it involves several factors, each cooperating with the other. Moreover, the tight vascular and neural interconnections between the adrenal cortex and medulla underlie physiologically relevant autocrine/paracrine interactions involving several peptides. Besides playing a pathophysiological role in common adrenal diseases, these complex mechanisms could intervene also in rare diseases, such as pheochromocytoma concomitant with adrenal Cushing or with PA, and PA co-occurring with Cushing, through mechanisms that remain to be fully understood at the molecular levels. Heterodimerization of G protein-coupled receptors (GPCRs) induced by peptide signaling is a further emerging new modulatory mechanism capable of finely tuning adrenal hormones synthesis and release. In this review we will examine current knowledge on the role of peptides that act via GPCRs in the regulation of adrenal hormone secretion with a particular focus on autocrine-paracrine signals.
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Affiliation(s)
- Livia Lenzini
- Emergency Medicine Unit, Center for blood pressure disorders -Regione Veneto and Specialized Center of Excellence for Hypertension of the European Society of Hypertension, Department of Medicine-DIMED, University of Padua, 35126 Padua, Italy
| | - Brasilina Caroccia
- Emergency Medicine Unit, Center for blood pressure disorders -Regione Veneto and Specialized Center of Excellence for Hypertension of the European Society of Hypertension, Department of Medicine-DIMED, University of Padua, 35126 Padua, Italy
| | - Teresa Maria Seccia
- Emergency Medicine Unit, Center for blood pressure disorders -Regione Veneto and Specialized Center of Excellence for Hypertension of the European Society of Hypertension, Department of Medicine-DIMED, University of Padua, 35126 Padua, Italy
| | - Gian Paolo Rossi
- Emergency Medicine Unit, Center for blood pressure disorders -Regione Veneto and Specialized Center of Excellence for Hypertension of the European Society of Hypertension, Department of Medicine-DIMED, University of Padua, 35126 Padua, Italy
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Zhang L, Dietsche F, Seitaj B, Rojas-Charry L, Latchman N, Tomar D, Wüst RC, Nickel A, Frauenknecht KB, Schoser B, Schumann S, Schmeisser MJ, Vom Berg J, Buch T, Finger S, Wenzel P, Maack C, Elrod JW, Parys JB, Bultynck G, Methner A. TMBIM5 loss of function alters mitochondrial matrix ion homeostasis and causes a skeletal myopathy. Life Sci Alliance 2022; 5:5/10/e202201478. [PMID: 35715207 PMCID: PMC9206080 DOI: 10.26508/lsa.202201478] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 05/25/2022] [Accepted: 05/31/2022] [Indexed: 01/13/2023] Open
Abstract
TMBIM5 deficiency reduces mitochondrial K+/H+ exchange. Mutation of the channel pore in mice destabilizes the protein and results in increased embryonic lethality and a skeletal myopathy. Ion fluxes across the inner mitochondrial membrane control mitochondrial volume, energy production, and apoptosis. TMBIM5, a highly conserved protein with homology to putative pH-dependent ion channels, is involved in the maintenance of mitochondrial cristae architecture, ATP production, and apoptosis. Here, we demonstrate that overexpressed TMBIM5 can mediate mitochondrial calcium uptake. Under steady-state conditions, loss of TMBIM5 results in increased potassium and reduced proton levels in the mitochondrial matrix caused by attenuated exchange of these ions. To identify the in vivo consequences of TMBIM5 dysfunction, we generated mice carrying a mutation in the channel pore. These mutant mice display increased embryonic or perinatal lethality and a skeletal myopathy which strongly correlates with tissue-specific disruption of cristae architecture, early opening of the mitochondrial permeability transition pore, reduced calcium uptake capability, and mitochondrial swelling. Our results demonstrate that TMBIM5 is an essential and important part of the mitochondrial ion transport system machinery with particular importance for embryonic development and muscle function.
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Affiliation(s)
- Li Zhang
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | | | - Bruno Seitaj
- Department of Cellular and Molecular Medicine, KU Leuven, Laboratory of Molecular and Cellular Signaling, Leuven, Belgium
| | - Liliana Rojas-Charry
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.,Institute of Anatomy, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Nadina Latchman
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Dhanendra Tomar
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Rob Ci Wüst
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Alexander Nickel
- Department of Translational Research, Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, Würzburg, Germany
| | - Katrin Bm Frauenknecht
- Institute of Neuropathology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Benedikt Schoser
- Friedrich-Baur-Institute, Department of Neurology, LMU Clinic, Munich, Germany
| | - Sven Schumann
- Institute of Anatomy, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Michael J Schmeisser
- Institute of Anatomy, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Johannes Vom Berg
- Institute of Laboratory Animal Science, University of Zurich, Zürich, Switzerland
| | - Thorsten Buch
- Institute of Laboratory Animal Science, University of Zurich, Zürich, Switzerland
| | - Stefanie Finger
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Philip Wenzel
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.,Department of Cardiology, Cardiology I, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Rhine-Main, Mainz, Germany
| | - Christoph Maack
- Department of Translational Research, Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, Würzburg, Germany
| | - John W Elrod
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Jan B Parys
- Department of Cellular and Molecular Medicine, KU Leuven, Laboratory of Molecular and Cellular Signaling, Leuven, Belgium
| | - Geert Bultynck
- Department of Cellular and Molecular Medicine, KU Leuven, Laboratory of Molecular and Cellular Signaling, Leuven, Belgium
| | - Axel Methner
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
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10
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Kaiyrzhanov R, Mohammed SEM, Maroofian R, Husain RA, Catania A, Torraco A, Alahmad A, Dutra-Clarke M, Grønborg S, Sudarsanam A, Vogt J, Arrigoni F, Baptista J, Haider S, Feichtinger RG, Bernardi P, Zulian A, Gusic M, Efthymiou S, Bai R, Bibi F, Horga A, Martinez-Agosto JA, Lam A, Manole A, Rodriguez DP, Durigon R, Pyle A, Albash B, Dionisi-Vici C, Murphy D, Martinelli D, Bugiardini E, Allis K, Lamperti C, Reipert S, Risom L, Laugwitz L, Di Nottia M, McFarland R, Vilarinho L, Hanna M, Prokisch H, Mayr JA, Bertini ES, Ghezzi D, Østergaard E, Wortmann SB, Carrozzo R, Haack TB, Taylor RW, Spinazzola A, Nowikovsky K, Houlden H. Bi-allelic LETM1 variants perturb mitochondrial ion homeostasis leading to a clinical spectrum with predominant nervous system involvement. Am J Hum Genet 2022; 109:1692-1712. [PMID: 36055214 PMCID: PMC9502063 DOI: 10.1016/j.ajhg.2022.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 07/01/2022] [Indexed: 11/25/2022] Open
Abstract
Leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) encodes an inner mitochondrial membrane protein with an osmoregulatory function controlling mitochondrial volume and ion homeostasis. The putative association of LETM1 with a human disease was initially suggested in Wolf-Hirschhorn syndrome, a disorder that results from de novo monoallelic deletion of chromosome 4p16.3, a region encompassing LETM1. Utilizing exome sequencing and international gene-matching efforts, we have identified 18 affected individuals from 11 unrelated families harboring ultra-rare bi-allelic missense and loss-of-function LETM1 variants and clinical presentations highly suggestive of mitochondrial disease. These manifested as a spectrum of predominantly infantile-onset (14/18, 78%) and variably progressive neurological, metabolic, and dysmorphic symptoms, plus multiple organ dysfunction associated with neurodegeneration. The common features included respiratory chain complex deficiencies (100%), global developmental delay (94%), optic atrophy (83%), sensorineural hearing loss (78%), and cerebellar ataxia (78%) followed by epilepsy (67%), spasticity (53%), and myopathy (50%). Other features included bilateral cataracts (42%), cardiomyopathy (36%), and diabetes (27%). To better understand the pathogenic mechanism of the identified LETM1 variants, we performed biochemical and morphological studies on mitochondrial K+/H+ exchange activity, proteins, and shape in proband-derived fibroblasts and muscles and in Saccharomyces cerevisiae, which is an important model organism for mitochondrial osmotic regulation. Our results demonstrate that bi-allelic LETM1 variants are associated with defective mitochondrial K+ efflux, swollen mitochondrial matrix structures, and loss of important mitochondrial oxidative phosphorylation protein components, thus highlighting the implication of perturbed mitochondrial osmoregulation caused by LETM1 variants in neurological and mitochondrial pathologies.
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Affiliation(s)
- Rauan Kaiyrzhanov
- Department of Neuromuscular Diseases, University College London, Queen Square, Institute of Neurology, London WC1N 3BG, UK
| | - Sami E M Mohammed
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine Vienna, Vienna 1210, Austria
| | - Reza Maroofian
- Department of Neuromuscular Diseases, University College London, Queen Square, Institute of Neurology, London WC1N 3BG, UK
| | - Ralf A Husain
- Department of Neuropediatrics, Jena University Hospital, Jena 07747, Germany; Center for Rare Diseases, Jena University Hospital, Jena 07747, Germany
| | - Alessia Catania
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan 20126, Italy
| | - Alessandra Torraco
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome 00146, Italy
| | - Ahmad Alahmad
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK; Kuwait Medical Genetics Centre, Al-Sabah Medical Area 80901, Kuwait
| | - Marina Dutra-Clarke
- Division of Medical Genetics, Department of Pediatrics, David Geffen School of Medicine, the University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Sabine Grønborg
- Center for Rare Diseases, Department of Pediatrics and Department of Genetics, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, Copenhagen 2100, Denmark
| | - Annapurna Sudarsanam
- West Midlands Regional Genetics Service, Birmingham Women's and Children's Hospital, Birmingham B15 2TG, UK
| | - Julie Vogt
- West Midlands Regional Genetics Service, Birmingham Women's and Children's Hospital, Birmingham B15 2TG, UK
| | - Filippo Arrigoni
- Paediatric Radiology and Neuroradiology Department, V. Buzzi Children's Hospital, Milan 20154, Italy
| | - Julia Baptista
- Peninsula Medical School, Faculty of Health, University of Plymouth, Plymouth PL4 8AA, UK
| | - Shahzad Haider
- Paediatrics Wah Medical College NUMS, Wah Cantonment, Punjab 44000, Pakistan
| | - René G Feichtinger
- University Children's Hospital, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), Salzburg 5020, Austria
| | - Paolo Bernardi
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, Padova 35131, Italy
| | - Alessandra Zulian
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, Padova 35131, Italy
| | - Mirjana Gusic
- Institute of Neurogenomics, Helmholtz Zentrum München, Neuherberg 85764, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich 81675, Germany; Institute of Human Genetics, Technical University of Munich, Munich 81675, Germany
| | - Stephanie Efthymiou
- Department of Neuromuscular Diseases, University College London, Queen Square, Institute of Neurology, London WC1N 3BG, UK
| | | | - Farah Bibi
- Institute of Biochemistry and Biotechnology, Pir Mehar Ali Shah Arid Agriculture University, Rawalpindi 44000, Pakistan
| | - Alejandro Horga
- Department of Neuromuscular Diseases, University College London, Queen Square, Institute of Neurology, London WC1N 3BG, UK; Neuromuscular Diseases Unit, Department of Neurology, Hospital Clinico San Carlos and San Carlos Health Research Institute (IdISSC), Madrid 28040, Spain
| | - Julian A Martinez-Agosto
- Department of Human Genetics, Division of Medical Genetics, Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Amanda Lam
- Neurometabolic Unit, National Hospital for Neurology and Neurosurgery, London, UK; Department of Chemical Pathology, Great Ormond Street Hospital, WC1N 3BG London, UK
| | - Andreea Manole
- Department of Neuromuscular Diseases, University College London, Queen Square, Institute of Neurology, London WC1N 3BG, UK
| | - Diego-Perez Rodriguez
- Department of Clinical Movement Neurosciences, Royal Free Campus, University College of London, Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Romina Durigon
- Department of Clinical Movement Neurosciences, Royal Free Campus, University College of London, Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Angela Pyle
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK
| | - Buthaina Albash
- Kuwait Medical Genetics Centre, Al-Sabah Medical Area 80901, Kuwait
| | - Carlo Dionisi-Vici
- Division of Metabolism, Bambino Gesù Children's Hospital, IRCCS, Rome 00146, Italy
| | - David Murphy
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Diego Martinelli
- Division of Metabolism, Bambino Gesù Children's Hospital, IRCCS, Rome 00146, Italy
| | - Enrico Bugiardini
- Department of Neuromuscular Diseases, University College London, Queen Square, Institute of Neurology, London WC1N 3BG, UK
| | | | - Costanza Lamperti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan 20126, Italy
| | - Siegfried Reipert
- Core Facility of Cell Imaging and Ultrastructure Research, University of Vienna, Djerassiplatz 1, 1030 Wien, Austria
| | - Lotte Risom
- Department of Genetics, Copenhagen University Hospital Rigshospitalet Blegdamsvej, Copenhagen 2100, Denmark
| | - Lucia Laugwitz
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, 72076 Tübingen, Germany; Department of Neuropediatrics, Developmental Neurology and Social Pediatrics, University of Tübingen, Tübingen 72076, Germany
| | - Michela Di Nottia
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome 00146, Italy
| | - Robert McFarland
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK; NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE1 4LP, UK
| | - Laura Vilarinho
- Unit of Neonatal Screening, Metabolism and Genetics, Department of Human Genetics, National Institute of Health Dr Ricardo Jorge, Porto 4000-055, Portugal
| | - Michael Hanna
- Department of Neuromuscular Diseases, University College London, Queen Square, Institute of Neurology, London WC1N 3BG, UK
| | - Holger Prokisch
- Institute of Neurogenomics, Helmholtz Zentrum München, Neuherberg 85764, Germany; Institute of Human Genetics, Technical University of Munich, Munich 81675, Germany
| | - Johannes A Mayr
- University Children's Hospital, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), Salzburg 5020, Austria
| | - Enrico Silvio Bertini
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome 00146, Italy
| | - Daniele Ghezzi
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan 20126, Italy; Department of Pathophysiology and Transplantation, University of Milan, Milan 20122, Italy
| | - Elsebet Østergaard
- Department of Genetics, Copenhagen University Hospital Rigshospitalet Blegdamsvej, Copenhagen 2100, Denmark; Institute for Clinical Medicine, University of Copenhagen, Copenhagen 2200, Denmark
| | - Saskia B Wortmann
- University Children's Hospital, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), Salzburg 5020, Austria; Institute of Neurogenomics, Helmholtz Zentrum München, Neuherberg 85764, Germany; Institute of Human Genetics, Technical University of Munich, Munich 81675, Germany; Radboud Center for Mitochondrial Medicine, Department of Pediatrics, Amalia Children's Hospital, Radboudumc, Nijmegen 6525 EZ, the Netherlands
| | - Rosalba Carrozzo
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome 00146, Italy
| | - Tobias B Haack
- Department of Neuropediatrics, Developmental Neurology and Social Pediatrics, University of Tübingen, Tübingen 72076, Germany; Centre for Rare Diseases, University of Tuebingen, Tübingen 72076, Germany
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK; NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE1 4LP, UK
| | - Antonella Spinazzola
- Department of Clinical Movement Neurosciences, Royal Free Campus, University College of London, Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Karin Nowikovsky
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine Vienna, Vienna 1210, Austria; Department of Internal Medicine I, ASCTR and Comprehensive Cancer Center, Medical University of Vienna, Vienna 1090, Austria.
| | - Henry Houlden
- Department of Neuromuscular Diseases, University College London, Queen Square, Institute of Neurology, London WC1N 3BG, UK.
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11
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Sharma N, Osman C. Yme2, a putative RNA recognition motif and AAA+ domain containing protein, genetically interacts with the mitochondrial protein export machinery. Biol Chem 2022; 403:807-817. [PMID: 35100666 PMCID: PMC9284673 DOI: 10.1515/hsz-2021-0398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/19/2022] [Indexed: 02/04/2023]
Abstract
The mitochondrial respiratory chain is composed of nuclear as well as mitochondrial-encoded subunits. A variety of factors mediate co-translational integration of mtDNA-encoded proteins into the inner membrane. In Saccharomyces cerevisiae, Mdm38 and Mba1 are ribosome acceptors that recruit the mitochondrial ribosome to the inner membrane, where the insertase Oxa1, facilitates membrane integration of client proteins. The protein Yme2 has previously been shown to be localized in the inner mitochondrial membrane and has been implicated in mitochondrial protein biogenesis, but its mode of action remains unclear. Here, we show that multiple copies of Yme2 assemble into a high molecular weight complex. Using a combination of bioinformatics and mutational analyses, we find that Yme2 possesses an RNA recognition motif (RRM), which faces the mitochondrial matrix and a AAA+ domain that is located in the intermembrane space. We further show that YME2 genetically interacts with MDM38, MBA1 and OXA1, which links the function of Yme2 to the mitochondrial protein biogenesis machinery.
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Affiliation(s)
- Nupur Sharma
- Faculty of Biology, Ludwig Maximilian University Munich, D-82152Planegg-Martinsried, Germany
- Graduate School of Life Sciences, Ludwig Maximilian University Munich, D-82152Planegg-Martinsried, Germany
| | - Christof Osman
- Faculty of Biology, Ludwig Maximilian University Munich, D-82152Planegg-Martinsried, Germany
- Graduate School of Life Sciences, Ludwig Maximilian University Munich, D-82152Planegg-Martinsried, Germany
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12
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Ruiz-Castilla FJ, Ruiz Pérez FS, Ramos-Moreno L, Ramos J. Candida albicans Potassium Transporters. Int J Mol Sci 2022; 23:ijms23094884. [PMID: 35563275 PMCID: PMC9105532 DOI: 10.3390/ijms23094884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/26/2022] [Accepted: 04/26/2022] [Indexed: 12/10/2022] Open
Abstract
Potassium is basic for life. All living organisms require high amounts of intracellular potassium, which fulfils multiple functions. To reach efficient potassium homeostasis, eukaryotic cells have developed a complex and tightly regulated system of transporters present both in the plasma membrane and in the membranes of internal organelles that allow correct intracellular potassium content and distribution. We review the information available on the pathogenic yeast Candida albicans. While some of the plasma membrane potassium transporters are relatively well known and experimental data about their nature, function or regulation have been published, in the case of most of the transporters present in intracellular membranes, their existence and even function have just been deduced because of their homology with those present in other yeasts, such as Saccharomyces cerevisiae. Finally, we analyse the possible links between pathogenicity and potassium homeostasis. We comment on the possibility of using some of these transporters as tentative targets in the search for new antifungal drugs.
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13
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Garbincius JF, Elrod JW. Mitochondrial calcium exchange in physiology and disease. Physiol Rev 2022; 102:893-992. [PMID: 34698550 PMCID: PMC8816638 DOI: 10.1152/physrev.00041.2020] [Citation(s) in RCA: 136] [Impact Index Per Article: 68.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 08/16/2021] [Accepted: 10/19/2021] [Indexed: 12/13/2022] Open
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.
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Affiliation(s)
- Joanne F Garbincius
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania
| | - John W Elrod
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania
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14
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Heidorn-Czarna M, Heidorn HM, Fernando S, Sanislav O, Jarmuszkiewicz W, Mutzel R, Fisher PR. Chronic Activation of AMPK Induces Mitochondrial Biogenesis through Differential Phosphorylation and Abundance of Mitochondrial Proteins in Dictyostelium discoideum. Int J Mol Sci 2021; 22:ijms222111675. [PMID: 34769115 PMCID: PMC8584165 DOI: 10.3390/ijms222111675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/22/2021] [Accepted: 10/26/2021] [Indexed: 11/17/2022] Open
Abstract
Mitochondrial biogenesis is a highly controlled process that depends on diverse signalling pathways responding to cellular and environmental signals. AMP-activated protein kinase (AMPK) is a critical metabolic enzyme that acts at a central control point in cellular energy homeostasis. Numerous studies have revealed the crucial roles of AMPK in the regulation of mitochondrial biogenesis; however, molecular mechanisms underlying this process are still largely unknown. Previously, we have shown that, in cellular slime mould Dictyostelium discoideum, the overexpression of the catalytic α subunit of AMPK led to enhanced mitochondrial biogenesis, which was accompanied by reduced cell growth and aberrant development. Here, we applied mass spectrometry-based proteomics of Dictyostelium mitochondria to determine the impact of chronically active AMPKα on the phosphorylation state and abundance of mitochondrial proteins and to identify potential protein targets leading to the biogenesis of mitochondria. Our results demonstrate that enhanced mitochondrial biogenesis is associated with variations in the phosphorylation levels and abundance of proteins related to energy metabolism, protein synthesis, transport, inner membrane biogenesis, and cellular signalling. The observed changes are accompanied by elevated mitochondrial respiratory activity in the AMPK overexpression strain. Our work is the first study reporting on the global phosphoproteome profiling of D. discoideum mitochondria and its changes as a response to constitutively active AMPK. We also propose an interplay between the AMPK and mTORC1 signalling pathways in controlling the cellular growth and biogenesis of mitochondria in Dictyostelium as a model organism.
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Affiliation(s)
- Malgorzata Heidorn-Czarna
- Department of Biology, Chemistry, Pharmacy, Institute for Biology-Microbiology, Freie Universität Berlin, 14195 Berlin, Germany; (H.-M.H.); (R.M.)
- Department of Cellular Molecular Biology, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland
- Correspondence: ; Tel.: +48-71-375-62-73
| | - Herbert-Michael Heidorn
- Department of Biology, Chemistry, Pharmacy, Institute for Biology-Microbiology, Freie Universität Berlin, 14195 Berlin, Germany; (H.-M.H.); (R.M.)
| | - Sanjanie Fernando
- Discipline of Microbiology, Department of Physiology, Anatomy and Microbiology, School of Life Sciences, College of Science, Health and Engineering, La Trobe University, Bundoora, VIC 3086, Australia; (S.F.); (O.S.); (P.R.F.)
| | - Oana Sanislav
- Discipline of Microbiology, Department of Physiology, Anatomy and Microbiology, School of Life Sciences, College of Science, Health and Engineering, La Trobe University, Bundoora, VIC 3086, Australia; (S.F.); (O.S.); (P.R.F.)
| | - Wieslawa Jarmuszkiewicz
- Laboratory of Mitochondrial Biochemistry, Department of Bioenergetics, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznan, Poland;
| | - Rupert Mutzel
- Department of Biology, Chemistry, Pharmacy, Institute for Biology-Microbiology, Freie Universität Berlin, 14195 Berlin, Germany; (H.-M.H.); (R.M.)
| | - Paul R. Fisher
- Discipline of Microbiology, Department of Physiology, Anatomy and Microbiology, School of Life Sciences, College of Science, Health and Engineering, La Trobe University, Bundoora, VIC 3086, Australia; (S.F.); (O.S.); (P.R.F.)
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15
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Kwok WM, Tajkhorshid E, Camara AKS. Editorial: Mitochondrial Exchangers and Transporters in Cell Survival and Death. Front Physiol 2021; 12:745353. [PMID: 34566705 PMCID: PMC8456120 DOI: 10.3389/fphys.2021.745353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 08/09/2021] [Indexed: 11/23/2022] Open
Affiliation(s)
- Wai-Meng Kwok
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Cancer Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Emad Tajkhorshid
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, United States.,Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States.,Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Amadou K S Camara
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Cancer Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
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16
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Kravenska Y, Checchetto V, Szabo I. Routes for Potassium Ions across Mitochondrial Membranes: A Biophysical Point of View with Special Focus on the ATP-Sensitive K + Channel. Biomolecules 2021; 11:1172. [PMID: 34439838 PMCID: PMC8393992 DOI: 10.3390/biom11081172] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/29/2021] [Accepted: 08/02/2021] [Indexed: 12/18/2022] Open
Abstract
Potassium ions can cross both the outer and inner mitochondrial membranes by means of multiple routes. A few potassium-permeable ion channels exist in the outer membrane, while in the inner membrane, a multitude of different potassium-selective and potassium-permeable channels mediate K+ uptake into energized mitochondria. In contrast, potassium is exported from the matrix thanks to an H+/K+ exchanger whose molecular identity is still debated. Among the K+ channels of the inner mitochondrial membrane, the most widely studied is the ATP-dependent potassium channel, whose pharmacological activation protects cells against ischemic damage and neuronal injury. In this review, we briefly summarize and compare the different hypotheses regarding the molecular identity of this patho-physiologically relevant channel, taking into account the electrophysiological characteristics of the proposed components. In addition, we discuss the characteristics of the other channels sharing localization to both the plasma membrane and mitochondria.
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Affiliation(s)
| | | | - Ildiko Szabo
- Department of Biology, University of Padova, 35131 Padova, Italy; (Y.K.); (V.C.)
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17
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dos Santos GRRM, Leite ACR, Lander N, Chiurillo MA, Vercesi AE, Docampo R. Trypanosoma cruzi Letm1 is involved in mitochondrial Ca 2+ transport, and is essential for replication, differentiation, and host cell invasion. FASEB J 2021; 35:e21685. [PMID: 34085343 PMCID: PMC10437107 DOI: 10.1096/fj.202100120rr] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 04/23/2021] [Accepted: 05/06/2021] [Indexed: 01/08/2023]
Abstract
Leucine zipper-EF-hand containing transmembrane protein 1 (Letm1) is a mitochondrial inner membrane protein involved in Ca2+ and K+ homeostasis in mammalian cells. Here, we demonstrate that the Letm1 orthologue of Trypanosoma cruzi, the etiologic agent of Chagas disease, is important for mitochondrial Ca2+ uptake and release. The results show that both mitochondrial Ca2+ influx and efflux are reduced in TcLetm1 knockdown (TcLetm1-KD) cells and increased in TcLetm1 overexpressing cells, without alterations in the mitochondrial membrane potential. Remarkably, TcLetm1 knockdown or overexpression increases or does not affect mitochondrial Ca2+ levels in epimastigotes, respectively. TcLetm1-KD epimastigotes have reduced growth, and both overexpression and knockdown of TcLetm1 cause a defect in metacyclogenesis. TcLetm1-KD also affected mitochondrial bioenergetics. Invasion of host cells by TcLetm1-KD trypomastigotes and their intracellular replication is greatly impaired. Taken together, our findings indicate that TcLetm1 is important for Ca2+ homeostasis and cell viability in T cruzi.
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Affiliation(s)
| | - Ana Catarina Rezende Leite
- Laboratório de Bioenergética, Instituto de Química e Biotecnologia, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
| | - Noelia Lander
- Center of Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio, USA
| | - Miguel Angel Chiurillo
- Center of Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio, USA
| | - Aníbal Eugênio Vercesi
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil
| | - Roberto Docampo
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil
- Center of Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
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18
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Bernardi P. Looking Back to the Future of Mitochondrial Research. Front Physiol 2021; 12:682467. [PMID: 33995132 PMCID: PMC8119648 DOI: 10.3389/fphys.2021.682467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 04/12/2021] [Indexed: 12/03/2022] Open
Affiliation(s)
- Paolo Bernardi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
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19
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Datta S, Jaiswal M. Mitochondrial calcium at the synapse. Mitochondrion 2021; 59:135-153. [PMID: 33895346 DOI: 10.1016/j.mito.2021.04.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 03/28/2021] [Accepted: 04/13/2021] [Indexed: 12/15/2022]
Abstract
Mitochondria are dynamic organelles, which serve various purposes, including but not limited to the production of ATP and various metabolites, buffering ions, acting as a signaling hub, etc. In recent years, mitochondria are being seen as the central regulators of cellular growth, development, and death. Since neurons are highly specialized cells with a heavy metabolic demand, it is not surprising that neurons are one of the most mitochondria-rich cells in an animal. At synapses, mitochondrial function and dynamics is tightly regulated by synaptic calcium. Calcium influx during synaptic activity causes increased mitochondrial calcium influx leading to an increased ATP production as well as buffering of synaptic calcium. While increased ATP production is required during synaptic transmission, calcium buffering by mitochondria is crucial to prevent faulty neurotransmission and excitotoxicity. Interestingly, mitochondrial calcium also regulates the mobility of mitochondria within synapses causing mitochondria to halt at the synapse during synaptic transmission. In this review, we summarize the various roles of mitochondrial calcium at the synapse.
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Affiliation(s)
- Sayantan Datta
- Tata Institute of Fundamental Research, Hyderabad, India
| | - Manish Jaiswal
- Tata Institute of Fundamental Research, Hyderabad, India.
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20
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Natarajan GK, Mishra J, Camara AKS, Kwok WM. LETM1: A Single Entity With Diverse Impact on Mitochondrial Metabolism and Cellular Signaling. Front Physiol 2021; 12:637852. [PMID: 33815143 PMCID: PMC8012663 DOI: 10.3389/fphys.2021.637852] [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: 12/04/2020] [Accepted: 02/25/2021] [Indexed: 12/11/2022] Open
Abstract
Nearly 2 decades since its discovery as one of the genes responsible for the Wolf-Hirschhorn Syndrome (WHS), the primary function of the leucine-zipper EF-hand containing transmembrane 1 (LETM1) protein in the inner mitochondrial membrane (IMM) or the mechanism by which it regulates mitochondrial Ca2+ handling is unresolved. Meanwhile, LETM1 has been associated with the regulation of fundamental cellular processes, such as development, cellular respiration and metabolism, and apoptosis. This mini-review summarizes the diversity of cellular functions impacted by LETM1 and highlights the multiple roles of LETM1 in health and disease.
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Affiliation(s)
- Gayathri K Natarajan
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Jyotsna Mishra
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Amadou K S Camara
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cancer Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Wai-Meng Kwok
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cancer Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, United States
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21
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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.
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22
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Lin QT, Lee R, Feng AL, Kim MS, Stathopulos PB. The leucine zipper EF-hand containing transmembrane protein-1 EF-hand is a tripartite calcium, temperature, and pH sensor. Protein Sci 2021; 30:855-872. [PMID: 33576522 DOI: 10.1002/pro.4042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/09/2021] [Accepted: 02/09/2021] [Indexed: 12/15/2022]
Abstract
Leucine Zipper EF-hand containing transmembrane protein-1 (LETM1) is an inner mitochondrial membrane protein that mediates mitochondrial calcium (Ca2+ )/proton exchange. The matrix residing carboxyl (C)-terminal domain contains a sequence identifiable EF-hand motif (EF1) that is highly conserved among orthologues. Deletion of EF1 abrogates LETM1 mediated mitochondrial Ca2+ flux, highlighting the requirement of EF1 for LETM1 function. To understand the mechanistic role of this EF-hand in LETM1 function, we characterized the biophysical properties of EF1 in isolation. Our data show that EF1 exhibits α-helical secondary structure that is augmented in the presence of Ca2+ . Unexpectedly, EF1 features a weak (~mM), but specific, apparent Ca2+ -binding affinity, consistent with the canonical Ca2+ coordination geometry, suggested by our solution NMR. The low affinity is, at least in part, due to an Asp at position 12 of the binding loop, where mutation to Glu increases the affinity by ~4-fold. Further, the binding affinity is sensitive to pH changes within the physiological range experienced by mitochondria. Remarkably, EF1 unfolds at high and low temperatures. Despite these unique EF-hand properties, Ca2+ binding increases the exposure of hydrophobic regions, typical of EF-hands; however, this Ca2+ -induced conformational change shifts EF1 from a monomer to higher order oligomers. Finally, we showed that a second, putative EF-hand within LETM1 is unreactive to Ca2+ either in isolation or tandem with EF1. Collectively, our data reveal that EF1 is structurally and biophysically responsive to pH, Ca2+ and temperature, suggesting a role as a multipartite environmental sensor within LETM1.
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Affiliation(s)
- Qi-Tong Lin
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Rachel Lee
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.,Temerty Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Allen L Feng
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.,Faculty of Dentistry, University of Toronto, Toronto, Canada
| | - Michael S Kim
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.,Department of Radiation Oncology, Dalhousie University, Halifax, Canada
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
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23
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Docampo R, Vercesi AE, Huang G, Lander N, Chiurillo MA, Bertolini M. Mitochondrial Ca 2+ homeostasis in trypanosomes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:261-289. [PMID: 34253297 PMCID: PMC10424509 DOI: 10.1016/bs.ircmb.2021.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Mitochondrial calcium ion (Ca2+) uptake is important for buffering cytosolic Ca2+ levels, for regulating cell bioenergetics, and for cell death and autophagy. Ca2+ uptake is mediated by a mitochondrial Ca2+ uniporter (MCU) and the discovery of this channel in trypanosomes has been critical for the identification of the molecular nature of the channel in all eukaryotes. However, the trypanosome uniporter, which has been studied in detail in Trypanosoma cruzi, the agent of Chagas disease, and T. brucei, the agent of human and animal African trypanosomiasis, has lineage-specific adaptations which include the lack of some homologues to mammalian subunits, and the presence of unique subunits. Here, we review newly emerging insights into the role of mitochondrial Ca2+ homeostasis in trypanosomes, the composition of the uniporter, its functional characterization, and its role in general physiology.
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Affiliation(s)
- Roberto Docampo
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States.
| | - Anibal E Vercesi
- Departamento de Patologia Clinica, Universidade Estadual de Campinas, São Paulo, Brazil
| | - Guozhong Huang
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Noelia Lander
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Miguel A Chiurillo
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Mayara Bertolini
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States
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24
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Gyimesi G, Hediger MA. Sequence Features of Mitochondrial Transporter Protein Families. Biomolecules 2020; 10:E1611. [PMID: 33260588 PMCID: PMC7761412 DOI: 10.3390/biom10121611] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/20/2020] [Accepted: 11/22/2020] [Indexed: 02/08/2023] Open
Abstract
Mitochondrial carriers facilitate the transfer of small molecules across the inner mitochondrial membrane (IMM) to support mitochondrial function and core cellular processes. In addition to the classical SLC25 (solute carrier family 25) mitochondrial carriers, the past decade has led to the discovery of additional protein families with numerous members that exhibit IMM localization and transporter-like properties. These include mitochondrial pyruvate carriers, sideroflexins, and mitochondrial cation/H+ exchangers. These transport proteins were linked to vital physiological functions and disease. Their structures and transport mechanisms are, however, still largely unknown and understudied. Protein sequence analysis per se can often pinpoint hotspots that are of functional or structural importance. In this review, we summarize current knowledge about the sequence features of mitochondrial transporters with a special focus on the newly included SLC54, SLC55 and SLC56 families of the SLC solute carrier superfamily. Taking a step further, we combine sequence conservation analysis with transmembrane segment and secondary structure prediction methods to extract residue positions and sequence motifs that likely play a role in substrate binding, binding site gating or structural stability. We hope that our review will help guide future experimental efforts by the scientific community to unravel the transport mechanisms and structures of these novel mitochondrial carriers.
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Affiliation(s)
- Gergely Gyimesi
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension, and Department of Biomedical Research, Inselspital, University of Bern, Kinderklinik, Freiburgstrasse 15, CH-3010 Bern, Switzerland;
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25
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Transmembrane BAX Inhibitor-1 Motif Containing Protein 5 (TMBIM5) Sustains Mitochondrial Structure, Shape, and Function by Impacting the Mitochondrial Protein Synthesis Machinery. Cells 2020; 9:cells9102147. [PMID: 32977469 PMCID: PMC7598220 DOI: 10.3390/cells9102147] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/18/2020] [Accepted: 09/18/2020] [Indexed: 12/15/2022] Open
Abstract
The Transmembrane Bax Inhibitor-1 motif (TMBIM)-containing protein family is evolutionarily conserved and has been implicated in cell death susceptibility. The only member with a mitochondrial localization is TMBIM5 (also known as GHITM or MICS1), which affects cristae organization and associates with the Parkinson's disease-associated protein CHCHD2 in the inner mitochondrial membrane. We here used CRISPR-Cas9-mediated knockout HAP1 cells to shed further light on the function of TMBIM5 in physiology and cell death susceptibility. We found that compared to wild type, TMBIM5-knockout cells were smaller and had a slower proliferation rate. In these cells, mitochondria were more fragmented with a vacuolar cristae structure. In addition, the mitochondrial membrane potential was reduced and respiration was attenuated, leading to a reduced mitochondrial ATP generation. TMBIM5 did not associate with Mic10 and Mic60, which are proteins of the mitochondrial contact site and cristae organizing system (MICOS), nor did TMBIM5 knockout affect their expression levels. TMBIM5-knockout cells were more sensitive to apoptosis elicited by staurosporine and BH3 mimetic inhibitors of Bcl-2 and Bcl-XL. An unbiased proteomic comparison identified a dramatic downregulation of proteins involved in the mitochondrial protein synthesis machinery in TMBIM5-knockout cells. We conclude that TMBIM5 is important to maintain the mitochondrial structure and function possibly through the control of mitochondrial biogenesis.
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26
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Natarajan GK, Glait L, Mishra J, Stowe DF, Camara AKS, Kwok WM. Total Matrix Ca 2+ Modulates Ca 2+ Efflux via the Ca 2+/H + Exchanger in Cardiac Mitochondria. Front Physiol 2020; 11:510600. [PMID: 33041851 PMCID: PMC7526510 DOI: 10.3389/fphys.2020.510600] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 08/13/2020] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial Ca2+ handling is accomplished by balancing Ca2+ uptake, primarily via the Ru360-sensitive mitochondrial calcium uniporter (MCU), Ca2+ buffering in the matrix and Ca2+ efflux mainly via Ca2+ ion exchangers, such as the Na+/Ca2+ exchanger (NCLX) and the Ca2+/H+ exchanger (CHE). The mechanism of CHE in cardiac mitochondria is not well-understood and its contribution to matrix Ca2+ regulation is thought to be negligible, despite higher expression of the putative CHE protein, LETM1, compared to hepatic mitochondria. In this study, Ca2+ efflux via the CHE was investigated in isolated rat cardiac mitochondria and permeabilized H9c2 cells. Mitochondria were exposed to (a) increasing matrix Ca2+ load via repetitive application of a finite CaCl2 bolus to the external medium and (b) change in the pH gradient across the inner mitochondrial membrane (IMM). Ca2+ efflux at different matrix Ca2+ loads was revealed by inhibiting Ca2+ uptake or reuptake with Ru360 after increasing number of CaCl2 boluses. In Na+-free experimental buffer and with Ca2+ uptake inhibited, the rate of Ca2+ efflux and steady-state free matrix Ca2+ [mCa2+]ss increased as the number of administered CaCl2 boluses increased. ADP and cyclosporine A (CsA), which are known to increase Ca2+ buffering while maintaining a constant [mCa2+]ss, decreased the rate of Ca2+ efflux via the CHE, with a significantly greater decrease in the presence of ADP. ADP also increased Ca2+ buffering rate and decreased [mCa2+]ss. A change in the pH of the external medium to a more acidic value from 7.15 to 6.8∼6.9 caused a twofold increase in the Ca2+ efflux rate, while an alkaline change in pH from 7.15 to 7.4∼7.5 did not change the Ca2+ efflux rate. In addition, CHE activation was associated with membrane depolarization. Targeted transient knockdown of LETM1 in permeabilized H9c2 cells modulated Ca2+ efflux. The results indicate that Ca2+ efflux via the CHE in cardiac mitochondria is modulated by acidic buffer pH and by total matrix Ca2+. A mechanism is proposed whereby activation of CHE is sensitive to changes in both the matrix Ca2+ buffering system and the matrix free Ca2+ concentration.
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Affiliation(s)
- Gayathri K Natarajan
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Lyall Glait
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Jyotsna Mishra
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - David F Stowe
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, Milwaukee, WI, United States.,Research Service, Veteran Affairs Medical Center, Milwaukee, WI, United States
| | - Amadou K S Camara
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Cancer Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Wai-Meng Kwok
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Cancer Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Pharmacology & Toxicology, Medical College of Wisconsin, Milwaukee, WI, United States
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27
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Li S, Wu Z, Li Y, Tantray I, De Stefani D, Mattarei A, Krishnan G, Gao FB, Vogel H, Lu B. Altered MICOS Morphology and Mitochondrial Ion Homeostasis Contribute to Poly(GR) Toxicity Associated with C9-ALS/FTD. Cell Rep 2020; 32:107989. [PMID: 32755582 PMCID: PMC7433775 DOI: 10.1016/j.celrep.2020.107989] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 05/20/2020] [Accepted: 07/14/2020] [Indexed: 12/31/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) manifests pathological changes in motor neurons and various other cell types. Compared to motor neurons, the contribution of the other cell types to the ALS phenotypes is understudied. G4C2 repeat expansion in C9ORF72 is the most common genetic cause of ALS along with frontotemporal dementia (C9-ALS/FTD), with increasing evidence supporting repeat-encoded poly(GR) in disease pathogenesis. Here, we show in Drosophila muscle that poly(GR) enters mitochondria and interacts with components of the Mitochondrial Contact Site and Cristae Organizing System (MICOS), altering MICOS dynamics and intra-subunit interactions. This impairs mitochondrial inner membrane structure, ion homeostasis, mitochondrial metabolism, and muscle integrity. Similar mitochondrial defects are observed in patient fibroblasts. Genetic manipulation of MICOS components or pharmacological restoration of ion homeostasis with nigericin effectively rescue the mitochondrial pathology and disease phenotypes in both systems. These results implicate MICOS-regulated ion homeostasis in C9-ALS pathogenesis and suggest potential new therapeutic strategies.
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Affiliation(s)
- Shuangxi Li
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA,These authors contributed equally
| | - Zhihao Wu
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA,These authors contributed equally,Present address: Department of Biological Sciences, Dedman College of Humanities and Sciences, Southern Methodist University, Dallas TX 75275, USA
| | - Yu Li
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Ishaq Tantray
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Diego De Stefani
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy
| | - Andrea Mattarei
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Via F. Marzolo 5, 35131 Padova, Italy
| | - Gopinath Krishnan
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Fen-Biao Gao
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Hannes Vogel
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Bingwei Lu
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA,Lead Contact,Correspondence:
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28
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Zhang F, Bian J, Chen X, Huang J, Smith N, Lu W, Xu Y, Lee J, Wu X. Roles for intracellular cation transporters in respiratory growth of yeast. Metallomics 2020; 11:1667-1678. [PMID: 31402362 DOI: 10.1039/c9mt00145j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Potassium is involved in copper and iron metabolism in eukaryotic Golgi apparatus, but it is not clear yet whether potassium distributions in other vesicles also affect copper and iron metabolism. Here we show that respiratory growth and iron acquisition by the yeast Saccharomyces cerevisiae relies on potassium (K+) compartmentalization to the mitochondria, as well as the vacuole and late endosome via K+/H+ exchangers Mdm38p, Vnx1p and Nhx1p, respectively. The data indicate that NHX1 and VNX1 knock-out cells grow better than wild type cells on non-fermentable YPEG media, while MDM38 knock-out cells display a growth defect on YPEG media. The over expression of the KHA1 gene located on the Golgi apparatus partially compensates for the growth defect of the MDM38 knock-out strain. The results suggest that the vacuole and late endosome are important potassium storage vesicles and Mdm38p affects the mitochondrial function by regulating copper and iron metabolism. Our study reveals potassium compartmentalization to the subcellular vesicles is relevant for respiratory growth by improving copper utilization and promoting iron absorption.
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Affiliation(s)
- Feng Zhang
- College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China.
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29
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Channels and transporters for inorganic ions in plant mitochondria: Prediction and facts. Mitochondrion 2020; 53:224-233. [PMID: 32540403 DOI: 10.1016/j.mito.2020.05.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 05/01/2020] [Accepted: 05/22/2020] [Indexed: 02/07/2023]
Abstract
Mitochondria are crucial bioenergetic organelles for providing different metabolites, including ATP, to sustain cell growth both in animals and in plants. These organelles, delimited by two membranes (outer and inner mitochondrial membrane), maintain their function by an intensive communication with other organelles as well as with the cytosol. Transport of metabolites across the two membranes, but also that of inorganic ions, takes place through specific ion channels and transporters and plays a crucial role in ensuring an adequate ionic milieu within the mitochondria. In the present review we briefly summarize the current knowledge about plant mitochondrial ion channels and transporters in comparison to those of animal mitochondria and examine the possible molecular identity of the so far unidentified transport systems taking into account subcellular targeting predictions and data from literature.
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30
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Nakamura S, Matsui A, Akabane S, Tamura Y, Hatano A, Miyano Y, Omote H, Kajikawa M, Maenaka K, Moriyama Y, Endo T, Oka T. The mitochondrial inner membrane protein LETM1 modulates cristae organization through its LETM domain. Commun Biol 2020; 3:99. [PMID: 32139798 PMCID: PMC7058069 DOI: 10.1038/s42003-020-0832-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 02/17/2020] [Indexed: 11/26/2022] Open
Abstract
LETM1 is a mitochondrial inner membrane protein that is required for maintaining the mitochondrial morphology and cristae structures, and regulates mitochondrial ion homeostasis. Here we report a role of LETM1 in the organization of cristae structures. We identified four amino acid residues of human LETM1 that are crucial for complementation of the growth deficiency caused by gene deletion of a yeast LETM1 orthologue. Substituting amino acid residues with alanine disrupts the correct assembly of a protein complex containing LETM1 and prevents changes in the mitochondrial morphology induced by exogenous LETM1 expression. Moreover, the LETM1 protein changes the shapes of the membranes of in vitro-reconstituted proteoliposomes, leading to the formation of invaginated membrane structures on artificial liposomes. LETM1 mutant proteins with alanine substitutions fail to facilitate the formation of invaginated membrane structures, suggesting that LETM1 plays a fundamental role in the organization of mitochondrial membrane morphology. Nakamura et al find that the mitochondrial protein LETM1 can directly modulate membrane structure in vitro and identify a conserved domain involved in modulating mitochondrial membrane morphology. This study enhances our understanding of how mitochondrial cristae are organised.
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Affiliation(s)
- Seiko Nakamura
- Department of Molecular Biology, Graduate School of Medical Science, Kyushu University, Fukuoka, 812-8582, Japan
| | - Aiko Matsui
- Department of Life Science, Rikkyo University, Tokyo, 171-8501, Japan
| | - Shiori Akabane
- Department of Life Science, Rikkyo University, Tokyo, 171-8501, Japan
| | - Yasushi Tamura
- Department of Material and Biological Chemistry, Faculty of Science, Yamagata University, Yamagata, 990-8560, Japan
| | - Azumi Hatano
- Department of Life Science, Rikkyo University, Tokyo, 171-8501, Japan
| | - Yuriko Miyano
- Department of Life Science, Rikkyo University, Tokyo, 171-8501, Japan
| | - Hiroshi Omote
- Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, 700-8530, Japan
| | - Mizuho Kajikawa
- Laboratory for Infectious Immunity, RIKEN Research Center for Allergy and Immunology, Kanagawa, 230-0045, Japan
| | - Katsumi Maenaka
- Laboratory of Biomolecular Science, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, 060-0812, Japan
| | - Yoshinori Moriyama
- Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, 700-8530, Japan
| | - Toshiya Endo
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, 603-8555, Japan
| | - Toshihiko Oka
- Department of Life Science, Rikkyo University, Tokyo, 171-8501, Japan.
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31
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Abstract
Adult cardiomyocytes are postmitotic cells that undergo very limited cell division. Thus, cardiomyocyte death as occurs during myocardial infarction has very detrimental consequences for the heart. Mitochondria have emerged as an important regulator of cardiovascular health and disease. Mitochondria are well established as bioenergetic hubs for generating ATP but have also been shown to regulate cell death pathways. Indeed many of the same signals used to regulate metabolism and ATP production, such as calcium and reactive oxygen species, are also key regulators of mitochondrial cell death pathways. It is widely hypothesized that an increase in calcium and reactive oxygen species activate a large conductance channel in the inner mitochondrial membrane known as the PTP (permeability transition pore) and that opening of this pore leads to necroptosis, a regulated form of necrotic cell death. Strategies to reduce PTP opening either by inhibition of PTP or inhibiting the rise in mitochondrial calcium or reactive oxygen species that activate PTP have been proposed. A major limitation of inhibiting the PTP is the lack of knowledge about the identity of the protein(s) that form the PTP and how they are activated by calcium and reactive oxygen species. This review will critically evaluate the candidates for the pore-forming unit of the PTP and discuss recent data suggesting that assumption that the PTP is formed by a single molecular identity may need to be reconsidered.
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Affiliation(s)
- Tyler M Bauer
- Laboratory of Cardiac Physiology, National Heart, Lung and Blood Institute, Bethesda, MD
| | - Elizabeth Murphy
- Laboratory of Cardiac Physiology, National Heart, Lung and Blood Institute, Bethesda, MD
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Alcántar-Fernández J, González-Maciel A, Reynoso-Robles R, Pérez Andrade ME, Hernández-Vázquez ADJ, Velázquez-Arellano A, Miranda-Ríos J. High-glucose diets induce mitochondrial dysfunction in Caenorhabditis elegans. PLoS One 2019; 14:e0226652. [PMID: 31846489 PMCID: PMC6917275 DOI: 10.1371/journal.pone.0226652] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 11/29/2019] [Indexed: 01/20/2023] Open
Abstract
Glucose is an important nutrient that dictates the development, fertility and lifespan of all organisms. In humans, a deficit in its homeostatic control might lead to hyperglucemia and the development of obesity and type 2 diabetes, which show a decreased ability to respond to and metabolize glucose. Previously, we have reported that high-glucose diets (HGD) induce alterations in triglyceride content, body size, progeny, and the mRNA accumulation of key regulators of carbohydrate and lipid metabolism, and longevity in Caenorhabditis elegans (PLoS ONE 13(7): e0199888). Herein, we show that increasing amounts of glucose in the diet induce the swelling of both mitochondria in germ and muscle cells. Additionally, HGD alter the enzymatic activities of the different respiratory complexes in an intricate pattern. Finally, we observed a downregulation of ceramide synthases (hyl-1 and hyl-2) and antioxidant genes (gcs-1 and gst-4), while mitophagy genes (pink-1 and dct-1) were upregulated, probably as part of a mitohormetic mechanism in response to glucose toxicity.
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Affiliation(s)
- Jonathan Alcántar-Fernández
- Programa de Doctorado en Ciencias Biomédicas, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, México
- Unidad de Genética de la Nutrición, Depto. de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, UNAM e Instituto Nacional de Pediatría, Ciudad de México, México
| | - Angélica González-Maciel
- Laboratorio de Morfología Celular y Tisular, Instituto Nacional de Pediatría, Ciudad de México, México
| | - Rafael Reynoso-Robles
- Laboratorio de Morfología Celular y Tisular, Instituto Nacional de Pediatría, Ciudad de México, México
| | - Martha Elva Pérez Andrade
- Unidad de Genética de la Nutrición, Depto. de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, UNAM e Instituto Nacional de Pediatría, Ciudad de México, México
| | - Alain de J. Hernández-Vázquez
- Unidad de Genética de la Nutrición, Depto. de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, UNAM e Instituto Nacional de Pediatría, Ciudad de México, México
| | - Antonio Velázquez-Arellano
- Unidad de Genética de la Nutrición, Depto. de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, UNAM e Instituto Nacional de Pediatría, Ciudad de México, México
| | - Juan Miranda-Ríos
- Unidad de Genética de la Nutrición, Depto. de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, UNAM e Instituto Nacional de Pediatría, Ciudad de México, México
- * E-mail:
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33
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LETM1: Essential for Mitochondrial Biology and Cation Homeostasis? Trends Biochem Sci 2019; 44:648-658. [DOI: 10.1016/j.tibs.2019.04.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 02/28/2019] [Accepted: 04/03/2019] [Indexed: 12/28/2022]
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34
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Durigon R, Mitchell AL, Jones AW, Manole A, Mennuni M, Hirst EM, Houlden H, Maragni G, Lattante S, Doronzio PN, Dalla Rosa I, Zollino M, Holt IJ, Spinazzola A. LETM1 couples mitochondrial DNA metabolism and nutrient preference. EMBO Mol Med 2019; 10:emmm.201708550. [PMID: 30012579 PMCID: PMC6127893 DOI: 10.15252/emmm.201708550] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The diverse clinical phenotypes of Wolf–Hirschhorn syndrome (WHS) are the result of haploinsufficiency of several genes, one of which, LETM1, encodes a protein of the mitochondrial inner membrane of uncertain function. Here, we show that LETM1 is associated with mitochondrial ribosomes, is required for mitochondrial DNA distribution and expression, and regulates the activity of an ancillary metabolic enzyme, pyruvate dehydrogenase. LETM1 deficiency in WHS alters mitochondrial morphology and DNA organization, as does substituting ketone bodies for glucose in control cells. While this change in nutrient availability leads to the death of fibroblasts with normal amounts of LETM1, WHS‐derived fibroblasts survive on ketone bodies, which can be attributed to their reduced dependence on glucose oxidation. Thus, remodeling of mitochondrial nucleoprotein complexes results from the inability of mitochondria to use specific substrates for energy production and is indicative of mitochondrial dysfunction. However, the dysfunction could be mitigated by a modified diet—for WHS, one high in lipids and low in carbohydrates.
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Affiliation(s)
- Romina Durigon
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | - Alice L Mitchell
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | - Aleck We Jones
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | - Andreea Manole
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK.,Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Mara Mennuni
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | | | - Henry Houlden
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK.,Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | | | - Serena Lattante
- Institute of Genomic Medicine, Catholic University, Rome, Italy
| | | | - Ilaria Dalla Rosa
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | | | - Ian J Holt
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK.,Biodonostia Health Research Institute, San Sebastián, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Antonella Spinazzola
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK .,MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
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35
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Locascio A, Andrés-Colás N, Mulet JM, Yenush L. Saccharomyces cerevisiae as a Tool to Investigate Plant Potassium and Sodium Transporters. Int J Mol Sci 2019; 20:E2133. [PMID: 31052176 PMCID: PMC6539216 DOI: 10.3390/ijms20092133] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 04/26/2019] [Accepted: 04/29/2019] [Indexed: 12/20/2022] Open
Abstract
Sodium and potassium are two alkali cations abundant in the biosphere. Potassium is essential for plants and its concentration must be maintained at approximately 150 mM in the plant cell cytoplasm including under circumstances where its concentration is much lower in soil. On the other hand, sodium must be extruded from the plant or accumulated either in the vacuole or in specific plant structures. Maintaining a high intracellular K+/Na+ ratio under adverse environmental conditions or in the presence of salt is essential to maintain cellular homeostasis and to avoid toxicity. The baker's yeast, Saccharomyces cerevisiae, has been used to identify and characterize participants in potassium and sodium homeostasis in plants for many years. Its utility resides in the fact that the electric gradient across the membrane and the vacuoles is similar to plants. Most plant proteins can be expressed in yeast and are functional in this unicellular model system, which allows for productive structure-function studies for ion transporting proteins. Moreover, yeast can also be used as a high-throughput platform for the identification of genes that confer stress tolerance and for the study of protein-protein interactions. In this review, we summarize advances regarding potassium and sodium transport that have been discovered using the yeast model system, the state-of-the-art of the available techniques and the future directions and opportunities in this field.
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Affiliation(s)
- Antonella Locascio
- Instituto de Biología Molecular y Celular de Plantas, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, 46022 Valencia, Spain.
| | - Nuria Andrés-Colás
- Instituto de Biología Molecular y Celular de Plantas, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, 46022 Valencia, Spain.
| | - José Miguel Mulet
- Instituto de Biología Molecular y Celular de Plantas, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, 46022 Valencia, Spain.
| | - Lynne Yenush
- Instituto de Biología Molecular y Celular de Plantas, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, 46022 Valencia, Spain.
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36
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Li Y, Tran Q, Shrestha R, Piao L, Park S, Park J, Park J. LETM1 is required for mitochondrial homeostasis and cellular viability (Review). Mol Med Rep 2019; 19:3367-3375. [PMID: 30896806 PMCID: PMC6471456 DOI: 10.3892/mmr.2019.10041] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 03/12/2019] [Indexed: 12/13/2022] Open
Abstract
Leucine zipper/EF-hand-containing transmembrane protein 1 (LETM1) has been identified as the gene responsible for Wolf-Hirschhorn syndrome (WHS), which is characterized by intellectual disability, epilepsy, growth delay and craniofacial dysgenesis. LETM1 is a mitochondrial inner membrane protein that encodes a homolog of the yeast protein Mdm38, which is involved in mitochondrial morphology. In the present review, the importance of LETM1 in WHS and its role within the mitochondrion was explored. LETM1 governs the mitochondrion ion channel and is involved in mitochondrial respiration. Recent studies have reported that LETM1 acts as a mitochondrial Ca2+/H+ antiporter. LETM1 has also been identified as a K+/H+ exchanger, and serves a role in Mg2+ homeostasis. The function of LETM1 in mitochondria regulation is regulated by its binding partners, carboxyl-terminal modulator protein and mitochondrial ribosomal protein L36. Therefore, we describe the remarkable role of LETM1 in mitochondrial network physiology and its function in mitochondrion-mediated cell death. In the context of these findings, we suggest that the participation of LETM1 in tumorigenesis through the alteration of cancer metabolism should be investigated. This review provides a comprehensive description of LETM1 function, which is required for mitochondrial homeostasis and cellular viability.
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Affiliation(s)
- Yuwen Li
- Department of Pharmacology, Metabolic Syndrome and Cell Signaling Laboratory, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Quangdon Tran
- Department of Pharmacology, Metabolic Syndrome and Cell Signaling Laboratory, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Robin Shrestha
- Department of Pharmacology, Metabolic Syndrome and Cell Signaling Laboratory, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Longzhen Piao
- Department of Oncology, Affiliated Hospital of Yanbian University, Yanji, Jilin 133000, P.R. China
| | - Sungjin Park
- Department of Pharmacology, Metabolic Syndrome and Cell Signaling Laboratory, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Jisoo Park
- Department of Pharmacology, Metabolic Syndrome and Cell Signaling Laboratory, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
| | - Jongsun Park
- Department of Pharmacology, Metabolic Syndrome and Cell Signaling Laboratory, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea
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37
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Hawrysh PJ, Buck LT. Mitochondrial matrix pH acidifies during anoxia and is maintained by the F 1F o-ATPase in anoxia-tolerant painted turtle cortical neurons. FEBS Open Bio 2019; 9:571-581. [PMID: 30984533 PMCID: PMC6443863 DOI: 10.1002/2211-5463.12612] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 01/18/2019] [Accepted: 02/05/2019] [Indexed: 12/19/2022] Open
Abstract
The western painted turtle (Chrysemys picta bellii) can survive extended periods of anoxia via a series of mechanisms that serve to reduce its energetic needs. Central to these mechanisms is the response of mitochondria, which depolarize in response to anoxia in turtle pyramidal neurons due to an influx of K+. It is currently unknown how mitochondrial matrix pH is affected by this response and we hypothesized that matrix pH acidifies during anoxia due to increased K+/H+ exchanger activity. Inhibition of K+/H+ exchange via quinine led to a collapse of mitochondrial membrane potential (Ψm) during oxygenated conditions in turtle cortical neurons, as indicated by rhodamine‐123 fluorescence, and this occurred twice as quickly during anoxia which indicates an elevation in K+ conductance. Mitochondrial matrix pH acidified during anoxia, as indicated by SNARF‐1 fluorescence imaged via confocal microscopy, and further acidification occurred during anoxia when the F1Fo‐ATPase was inhibited with oligomycin‐A, indicating that ΔpH collapse is prevented during anoxic conditions. Collectively, these results indicate that the mitochondrial proton electrochemical gradient is actively preserved during anoxia to prevent a collapse of Ψm and ΔpH.
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Affiliation(s)
| | - Leslie Thomas Buck
- Department of Cell and Systems Biology University of Toronto Canada.,Department of Ecology and Evolutionary Biology University of Toronto Canada
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38
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Haumann J, Camara AKS, Gadicherla AK, Navarro CD, Boelens AD, Blomeyer CA, Dash RK, Boswell MR, Kwok WM, Stowe DF. Slow Ca 2+ Efflux by Ca 2+/H + Exchange in Cardiac Mitochondria Is Modulated by Ca 2+ Re-uptake via MCU, Extra-Mitochondrial pH, and H + Pumping by F OF 1-ATPase. Front Physiol 2019; 9:1914. [PMID: 30804812 PMCID: PMC6378946 DOI: 10.3389/fphys.2018.01914] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 12/18/2018] [Indexed: 02/04/2023] Open
Abstract
Mitochondrial (m) Ca2+ influx is largely dependent on membrane potential (ΔΨm), whereas mCa2+ efflux occurs primarily via Ca2+ ion exchangers. We probed the kinetics of Ca2+/H+ exchange (CHEm) in guinea pig cardiac muscle mitochondria. We tested if net mCa2+ flux is altered during a matrix inward H+ leak that is dependent on matrix H+ pumping by ATPm hydrolysis at complex V (FOF1-ATPase). We measured [Ca2+]m, extra-mitochondrial (e) [Ca2+]e, ΔΨm, pHm, pHe, NADH, respiration, ADP/ATP ratios, and total [ATP]m in the presence or absence of protonophore dinitrophenol (DNP), mitochondrial uniporter (MCU) blocker Ru360, and complex V blocker oligomycin (OMN). We proposed that net slow influx/efflux of Ca2+ after adding DNP and CaCl2 is dependent on whether the ΔpHm gradient is/is not maintained by reciprocal outward H+ pumping by complex V. We found that adding CaCl2 enhanced DNP-induced increases in respiration and decreases in ΔΨm while [ATP]m decreased, ΔpHm gradient was maintained, and [Ca2+]m continued to increase slowly, indicating net mCa2+ influx via MCU. In contrast, with complex V blocked by OMN, adding DNP and CaCl2 caused larger declines in ΔΨm as well as a slow fall in pHm to near pHe while [Ca2+]m continued to decrease slowly, indicating net mCa2+ efflux in exchange for H+ influx (CHEm) until the ΔpHm gradient was abolished. The kinetics of slow mCa2+ efflux with slow H+ influx via CHEm was also observed at pHe 6.9 vs. 7.6 by the slow fall in pHm until ΔpHm was abolished; if Ca2+ reuptake via the MCU was also blocked, mCa2+ efflux via CHEm became more evident. Of the two components of the proton electrochemical gradient, our results indicate that CHEm activity is driven largely by the ΔpHm chemical gradient with H+ leak, while mCa2+ entry via MCU depends largely on the charge gradient ΔΨm. A fall in ΔΨm with excess mCa2+ loading can occur during cardiac cell stress. Cardiac cell injury due to mCa2+ overload may be reduced by temporarily inhibiting FOF1-ATPase from pumping H+ due to ΔΨm depolarization. This action would prevent additional slow mCa2+ loading via MCU and permit activation of CHEm to mediate efflux of mCa2+. HIGHLIGHTSWe examined how slow mitochondrial (m) Ca2+ efflux via Ca2+/H+ exchange (CHEm) is triggered by matrix acidity after a rapid increase in [Ca2+]m by adding CaCl2 in the presence of dinitrophenol (DNP) to permit H+ influx, and oligomycin (OMN) to block H+ pumping via FOF1-ATP synthase/ase (complex V). Declines in ΔΨm and pHm after DNP and added CaCl2 were larger when complex V was blocked. [Ca2+]m slowly increased despite a fall in ΔΨm but maintained pHm when H+ pumping by complex V was permitted. [Ca2+]m slowly decreased and external [Ca2+]e increased with declines in both ΔΨm and pHm when complex V was blocked. ATPm hydrolysis supports a falling pHm and redox state and promotes a slow increase in [Ca2+]m. After rapid Ca2+ influx due to a bolus of CaCl2, slow mCa2+ efflux by CHEm occurs directly if pHe is low.
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Affiliation(s)
- Johan Haumann
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Amadou K S Camara
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Cancer Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Ashish K Gadicherla
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Christopher D Navarro
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Age D Boelens
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Christoph A Blomeyer
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Ranjan K Dash
- Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, Milwaukee, WI, United States
| | - Michael R Boswell
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Wai-Meng Kwok
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Cancer Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - David F Stowe
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, Milwaukee, WI, United States.,Research Service, Veterans Affairs Medical Center, Milwaukee, WI, United States
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39
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Molecular Mechanisms of Leucine Zipper EF-Hand Containing Transmembrane Protein-1 Function in Health and Disease. Int J Mol Sci 2019; 20:ijms20020286. [PMID: 30642051 PMCID: PMC6358941 DOI: 10.3390/ijms20020286] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 01/08/2019] [Accepted: 01/09/2019] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial calcium (Ca2+) uptake shapes cytosolic Ca2+ signals involved in countless cellular processes and more directly regulates numerous mitochondrial functions including ATP production, autophagy and apoptosis. Given the intimate link to both life and death processes, it is imperative that mitochondria tightly regulate intramitochondrial Ca2+ levels with a high degree of precision. Among the Ca2+ handling tools of mitochondria, the leucine zipper EF-hand containing transmembrane protein-1 (LETM1) is a transporter protein localized to the inner mitochondrial membrane shown to constitute a Ca2+/H+ exchanger activity. The significance of LETM1 to mitochondrial Ca2+ regulation is evident from Wolf-Hirschhorn syndrome patients that harbor a haplodeficiency in LETM1 expression, leading to dysfunctional mitochondrial Ca2+ handling and from numerous types of cancer cells that show an upregulation of LETM1 expression. Despite the significance of LETM1 to cell physiology and pathophysiology, the molecular mechanisms of LETM1 function remain poorly defined. In this review, we aim to provide an overview of the current understanding of LETM1 structure and function and pinpoint the knowledge gaps that need to be filled in order to unravel the underlying mechanistic basis for LETM1 function.
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40
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Chang L, Zhang X, Gong P, Wang Y, Du B, Li J. Identification and characterization of Letm1 gene in Toxoplasma gondii. Acta Biochim Biophys Sin (Shanghai) 2019; 51:78-87. [PMID: 30423025 DOI: 10.1093/abbs/gmy138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/11/2018] [Indexed: 01/22/2023] Open
Abstract
Toxoplasma gondii is an obligate intracellular protozoan that causes toxoplasmosis. Previous studies have shown that the perturbation of mitochondrial metabolism in T. gondii results in growth deficiency in host cells and lack of virulence in animals. Members of this Letm1 protein family are inner mitochondrial membrane proteins which play a role in potassium and hydrogen ion exchange. Letm1 has not been characterized in T. gondii. In this study, a potential TgLetm1 gene (TgGT1_288400) with Letm1-like protein domain coding sequence was identified in T. gondii. Indirect immunofluorescence assays suggested that TgLetm1 localized to the mitochondria in tachyzoites, as indicated by the colocalization with mitochondrial marker Mitotracker. TgLetm1 was found in the membrane fraction by western blot analysis. To investigate the role of TgLetm1 in T. gondii, we generated a tetracycline-inducible TgLetm1-knock-down mutant. The conditional deletion of TgLetm1 resulted in mitochondrial swelling. Functional studies showed that the conditional deletion of TgLetm1 resulted in growth inhibition, deficiency in invasion and replication, and lack of virulence in mice.
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Affiliation(s)
- Le Chang
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xichen Zhang
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Pengtao Gong
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Yuru Wang
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Boya Du
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Jianhua Li
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
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41
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Wang C, Ren H, Dong H, Liang M, Wu Q, Liao Y. 18q22.1-qter deletion and 4p16.3 microduplication in a boy with speech delay and mental retardation: case report and review of the literature. Mol Cytogenet 2018; 11:55. [PMID: 30377449 PMCID: PMC6194714 DOI: 10.1186/s13039-018-0404-2] [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] [Received: 08/31/2018] [Accepted: 10/01/2018] [Indexed: 11/13/2022] Open
Abstract
Background Deletions involving the long arm of chromosome 18 have been associated with a highly variable phenotypic spectrum that is related to the extent of the deleted region. Duplications in chromosomal region 4p16.3 have also been shown to cause 4p16.3 microduplication syndrome. Most reported patients of trisomy 4p16.3 have more duplications, including the Wolf-Hirschhorn critical region (WHSCR). Here, we present a patient with speech delay and mental retardation caused by a deletion of 18q (18q22.1-qter) and terminal microduplication of 4p (4p16.3-pter) distal to WHSCR. Case presentation The patient was a 23-month-old boy with moderate growth retardation, severe speech delay, mental retardation, and dysmorphic features. Single nucleotide polymorphism (SNP) array analysis confirmed an 11.2-Mb terminal deletion at 18q22.1 and revealed a 1.8-Mb terminal duplication of 4p16.3. Our patient showed clinical overlap with these two syndromes, although his overall features were milder than what had been previously described. Some dosage-sensitive genes on the 18q terminal deleted region and 4p16.3 duplicated region of the present case may have contributed to his phenotype. Conclusions This is the first report of a patient with combined terminal deletion of 18q22.1 and duplication of 4p16.3. In this report, we provide clinical and molecular evidence supporting that the microduplication in 4p16.3, distal to WHSCR, is pathogenic. The coexistence of two chromosome aberrations complicates the clinical picture and creates a chimeric phenotype. This report provides further information on the genotype-phenotype correlation of 18q terminal deletion and 4p microduplication.
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Affiliation(s)
- Chunjing Wang
- 1Department of Life Sciences, Bengbu Medical College, 2600 Donghai Avenue, Bengbu, Anhui 233030 People's Republic of China
| | - Huanhuan Ren
- 1Department of Life Sciences, Bengbu Medical College, 2600 Donghai Avenue, Bengbu, Anhui 233030 People's Republic of China
| | - Huaifu Dong
- 2Department of Paediatrics, The First Affiliated Hospital of Bengbu Medical College, 2600 Donghai Avenue, Bengbu, Anhui China
| | - Meng Liang
- 1Department of Life Sciences, Bengbu Medical College, 2600 Donghai Avenue, Bengbu, Anhui 233030 People's Republic of China
| | - Qi Wu
- 1Department of Life Sciences, Bengbu Medical College, 2600 Donghai Avenue, Bengbu, Anhui 233030 People's Republic of China
| | - Yaping Liao
- 1Department of Life Sciences, Bengbu Medical College, 2600 Donghai Avenue, Bengbu, Anhui 233030 People's Republic of China
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42
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Xu J, Huang B, Li S, Zhang X, Xie T, Xu Y. Knockdown of LETM1 inhibits proliferation and metastasis of human renal cell carcinoma cells. Oncol Lett 2018; 16:6377-6382. [PMID: 30405774 PMCID: PMC6202556 DOI: 10.3892/ol.2018.9449] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 08/30/2018] [Indexed: 01/01/2023] Open
Abstract
The leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) has been reported to serve an important role in a number of human malignancies and is correlated with poor prognosis. However, little is known about the role of LETM1 in renal cell carcinoma (RCC). In the present study, the expression levels of LETM1 were investigated in RCC cell lines (Caki-1, 786-O, OS-RC-2, A498 and ACHN) and the HK-2 normal human renal tubular epithelial cell line. Short interfering RNA (siRNA) was used to knock down the expression of LETM1 in 786-O and A498 cells. The results indicated that the constitutive expression of LETM1 was notably upregulated in RCC cell lines. Knockdown of LETM1 significantly decreased cell proliferation, migration and invasion. Mechanistically, it was revealed that the knockdown of LETM1 expression sharply downregulated the protein expression of β-Catenin, Cyclin D1 and c-Myc in 786-O and A498 cells. In conclusion, these results suggest that knockdown of LETM1 exhibits tumor suppressive effects, at least in part by controlling the downstream Wnt/β-Catenin signaling pathway. Therefore, LETM1 may act as a novel therapeutic target for the treatment of RCC.
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Affiliation(s)
- Jie Xu
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P.R. China.,Department of Urology, Pudong New Area People's Hospital, Shanghai 201299, P.R. China
| | - Bisheng Huang
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P.R. China
| | - Saiyang Li
- Department of First Clinical Medical College, Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Xiaolu Zhang
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P.R. China
| | - Tiancheng Xie
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P.R. China
| | - Yunfei Xu
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P.R. China.,Department of First Clinical Medical College, Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
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43
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Giorgi C, Marchi S, Pinton P. The machineries, regulation and cellular functions of mitochondrial calcium. Nat Rev Mol Cell Biol 2018; 19:713-730. [PMID: 30143745 DOI: 10.1038/s41580-018-0052-8] [Citation(s) in RCA: 481] [Impact Index Per Article: 80.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Calcium ions (Ca2+) are some of the most versatile signalling molecules, and they have many physiological functions, prominently including muscle contraction, neuronal excitability, cell migration and cell growth. By sequestering and releasing Ca2+, mitochondria serve as important regulators of cellular Ca2+. Mitochondrial Ca2+ also has other important functions, such as regulation of mitochondrial metabolism, ATP production and cell death. In recent years, identification of the molecular machinery regulating mitochondrial Ca2+ accumulation and efflux has expanded the number of (patho)physiological conditions that rely on mitochondrial Ca2+ homeostasis. Thus, expanding the understanding of the mechanisms of mitochondrial Ca2+ regulation and function in different cell types is an important task in biomedical research, which offers the possibility of targeting mitochondrial Ca2+ machinery for the treatment of several disorders.
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Affiliation(s)
- Carlotta Giorgi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Saverio Marchi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy. .,Maria Cecilia Hospital, GVM Care and Research, Cotignola, Ravenna, Italy.
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44
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Abstract
Mitochondrial Ca2+ regulation is crucial for bioenergetics and cellular signaling. The mechanisms controlling mitochondrial calcium homeostasis have been recently unraveled with the discovery of mitochondrial inner membrane proteins that regulate mitochondrial Ca2+ uptake and extrusion. Mitochondrial Ca2+ uptake depends on a large complex of proteins centered around the Ca2+ channel protein, mitochondrial Ca2+ uniporter (MCU) in close interactions with several regulatory subunits (MCUb, EMRE, MICU1, MICU2). Mitochondrial Ca2+ extrusion is mainly mediated by the mitochondrial Na+/Ca2+/Li+ exchanger (NCLX). Here, we review the major players of mitochondrial Ca2+ homeostasis and their physiological functions.
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Affiliation(s)
- Trayambak Pathak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Mohamed Trebak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, United States.
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45
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Tang G, Zhang C, Ju Z, Zheng S, Wen Z, Xu S, Chen Y, Ma Z. The mitochondrial membrane protein FgLetm1 regulates mitochondrial integrity, production of endogenous reactive oxygen species and mycotoxin biosynthesis in Fusarium graminearum. MOLECULAR PLANT PATHOLOGY 2018; 19:1595-1611. [PMID: 29077257 PMCID: PMC6637989 DOI: 10.1111/mpp.12633] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/10/2017] [Accepted: 10/23/2017] [Indexed: 05/14/2023]
Abstract
Deoxynivalenol (DON) is a mycotoxin produced in cereal crops infected with Fusarium graminearum. DON poses a serious threat to human and animal health, and is a critical virulence factor. Various environmental factors, including reactive oxygen species (ROS), have been shown to interfere with DON biosynthesis in this pathogen. The regulatory mechanisms of how ROS trigger DON production have been investigated extensively in F. graminearum. However, the role of the endogenous ROS-generating system in DON biosynthesis is largely unknown. In this study, we genetically analysed the function of leucine zipper-EF-hand-containing transmembrane 1 (LETM1) superfamily proteins and evaluated the role of the mitochondrial-produced ROS in DON biosynthesis. Our results show that there are two Letm1 orthologues, FgLetm1 and FgLetm2, in F. graminearum. FgLetm1 is localized to the mitochondria and is essential for mitochondrial integrity, whereas FgLetm2 plays a minor role in the maintenance of mitochondrial integrity. The ΔFgLetm1 mutant demonstrated a vegetative growth defect, abnormal conidia and increased sensitivity to various stress agents. More importantly, the ΔFgLetm1 mutant showed significantly reduced levels of endogenous ROS, decreased DON biosynthesis and attenuated virulence in planta. To our knowledge, this is the first report showing that mitochondrial integrity and endogenous ROS production by mitochondria are important for DON production and virulence in Fusarium species.
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Affiliation(s)
- Guangfei Tang
- Institute of BiotechnologyZhejiang UniversityHangzhou 310058China
| | - Chengqi Zhang
- Institute of BiotechnologyZhejiang UniversityHangzhou 310058China
- College of Plant ProtectionAnhui Agricultural UniversityHefei 230036China
| | - Zhenzhen Ju
- Institute of BiotechnologyZhejiang UniversityHangzhou 310058China
| | - Shiyu Zheng
- Institute of BiotechnologyZhejiang UniversityHangzhou 310058China
| | - Ziyue Wen
- Institute of BiotechnologyZhejiang UniversityHangzhou 310058China
| | - Sunde Xu
- Institute of BiotechnologyZhejiang UniversityHangzhou 310058China
| | - Yun Chen
- Institute of BiotechnologyZhejiang UniversityHangzhou 310058China
| | - Zhonghua Ma
- Institute of BiotechnologyZhejiang UniversityHangzhou 310058China
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46
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Arduino DM, Perocchi F. Pharmacological modulation of mitochondrial calcium homeostasis. J Physiol 2018; 596:2717-2733. [PMID: 29319185 DOI: 10.1113/jp274959] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 12/13/2017] [Indexed: 12/26/2022] Open
Abstract
Mitochondria are pivotal organelles in calcium (Ca2+ ) handling and signalling, constituting intracellular checkpoints for numerous processes that are vital for cell life. Alterations in mitochondrial Ca2+ homeostasis have been linked to a variety of pathological conditions and are critical in the aetiology of several human diseases. Efforts have been taken to harness mitochondrial Ca2+ transport mechanisms for therapeutic intervention, but pharmacological compounds that direct and selectively modulate mitochondrial Ca2+ homeostasis are currently lacking. New avenues have, however, emerged with the breakthrough discoveries on the genetic identification of the main players involved in mitochondrial Ca2+ influx and efflux pathways and with recent hints towards a deep understanding of the function of these molecular systems. Here, we review the current advances in the understanding of the mechanisms and regulation of mitochondrial Ca2+ homeostasis and its contribution to physiology and human disease. We also introduce and comment on the recent progress towards a systems-level pharmacological targeting of mitochondrial Ca2+ homeostasis.
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Affiliation(s)
- Daniela M Arduino
- Gene Center, Department of Biochemistry, Ludwig-Maximilians Universität München, Munich, 81377, Germany.,Institute for Diabetes and Obesity, Helmholtz Diabetes Center (HDC), Helmholtz Zentrum München and German National Diabetes Center (DZD), Neuherberg, 85764, Germany
| | - Fabiana Perocchi
- Gene Center, Department of Biochemistry, Ludwig-Maximilians Universität München, Munich, 81377, Germany.,Institute for Diabetes and Obesity, Helmholtz Diabetes Center (HDC), Helmholtz Zentrum München and German National Diabetes Center (DZD), Neuherberg, 85764, Germany
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47
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Austin S, Tavakoli M, Pfeiffer C, Seifert J, Mattarei A, De Stefani D, Zoratti M, Nowikovsky K. LETM1-Mediated K + and Na + Homeostasis Regulates Mitochondrial Ca 2+ Efflux. Front Physiol 2017; 8:839. [PMID: 29204122 PMCID: PMC5698270 DOI: 10.3389/fphys.2017.00839] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 10/09/2017] [Indexed: 12/13/2022] Open
Abstract
Ca2+ transport across the inner membrane of mitochondria (IMM) is of major importance for their functions in bioenergetics, cell death and signaling. It is therefore tightly regulated. It has been recently proposed that LETM1—an IMM protein with a crucial role in mitochondrial K+/H+ exchange and volume homeostasis—also acts as a Ca2+/H+ exchanger. Here we show for the first time that lowering LETM1 gene expression by shRNA hampers mitochondrial K+/H+ and Na+/H+ exchange. Decreased exchange activity resulted in matrix K+ accumulation in these mitochondria. Furthermore, LETM1 depletion selectively decreased Na+/Ca2+ exchange mediated by NCLX, as observed in the presence of ruthenium red, a blocker of the Mitochondrial Ca2+ Uniporter (MCU). These data confirm a key role of LETM1 in monovalent cation homeostasis, and suggest that the effects of its modulation on mitochondrial transmembrane Ca2+ fluxes may reflect those on Na+/H+ exchange activity.
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Affiliation(s)
- Shane Austin
- Department of Internal Medicine I and Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
| | - Mojtaba Tavakoli
- Department of Internal Medicine I and Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
| | - Christina Pfeiffer
- Department of Internal Medicine I and Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
| | - Julia Seifert
- Department of Internal Medicine I and Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
| | - Andrea Mattarei
- Department of Chemical Sciences, Università di Padova, Padova, Italy
| | - Diego De Stefani
- Department of Biomedical Sciences, Università di Padova, Padova, Italy
| | - Mario Zoratti
- Department of Biomedical Sciences, Università di Padova, Padova, Italy.,Institute of Neuroscience (CNR), Padova, Italy
| | - Karin Nowikovsky
- Department of Internal Medicine I and Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
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48
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Huang E, Qu D, Huang T, Rizzi N, Boonying W, Krolak D, Ciana P, Woulfe J, Klein C, Slack RS, Figeys D, Park DS. PINK1-mediated phosphorylation of LETM1 regulates mitochondrial calcium transport and protects neurons against mitochondrial stress. Nat Commun 2017; 8:1399. [PMID: 29123128 PMCID: PMC5680261 DOI: 10.1038/s41467-017-01435-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 09/18/2017] [Indexed: 01/04/2023] Open
Abstract
Mutations in PTEN-induced kinase 1 (PINK1) result in a recessive familial form of Parkinson’s disease (PD). PINK1 loss is associated with mitochondrial Ca2+ mishandling, mitochondrial dysfunction, as well as increased neuronal vulnerability. Here we demonstrate that PINK1 directly interacts with and phosphorylates LETM1 at Thr192 in vitro. Phosphorylated LETM1 or the phospho-mimetic LETM1-T192E increase calcium release in artificial liposomes and facilitates calcium transport in intact mitochondria. Expression of LETM1-T192E but not LETM1-wild type (WT) rescues mitochondrial calcium mishandling in PINK1-deficient neurons. Expression of both LETM1-WT and LETM1-T192E protects neurons against MPP+–MPTP-induced neuronal death in PINK1 WT neurons, whereas only LETM1-T192E protects neurons under conditions of PINK1 loss. Our findings delineate a mechanism by which PINK1 regulates mitochondrial Ca2+ level through LETM1 and suggest a model by which PINK1 loss leads to deficient phosphorylation of LETM1 and impaired mitochondrial Ca2+ transport.. Mutations in the mitochondrial kinase PINK1 result in familial Parkinson’s disease. Here the authors show that LETM1, a mitochondrial inner membrane protein, is a substrate of PINK1 that regulates Ca2+ handling in mitochondria in response to mitochondrial toxins.
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Affiliation(s)
- En Huang
- University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - Dianbo Qu
- University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - Tianwen Huang
- University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - Nicoletta Rizzi
- Center of Excellence on Neurodegenerative Diseases, Department of Pharmacological Sciences, University of Milan, Via Balzaretti 9, 20133, Milan, Italy
| | - Wassamon Boonying
- University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - Dorothy Krolak
- University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - Paolo Ciana
- Center of Excellence on Neurodegenerative Diseases, Department of Oncology and Hemato-Oncology, University of Milan, Via Balzaretti 9, 20133, Milan, Italy
| | - John Woulfe
- Centre for Cancer Therapeutics, Ottawa Hospital Research Institute and Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - Christine Klein
- Institute of Neurogenetics, University of Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Ruth S Slack
- University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - Daniel Figeys
- Department of Biochemistry, Microbiology and Immunology, Department of Chemistry and Biomolecular Sciences, and Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - David S Park
- University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5.
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49
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Yemelin A, Brauchler A, Jacob S, Laufer J, Heck L, Foster AJ, Antelo L, Andresen K, Thines E. Identification of factors involved in dimorphism and pathogenicity of Zymoseptoria tritici. PLoS One 2017; 12:e0183065. [PMID: 28829795 PMCID: PMC5568738 DOI: 10.1371/journal.pone.0183065] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 07/28/2017] [Indexed: 01/20/2023] Open
Abstract
A forward genetics approach was applied in order to investigate the molecular basis of morphological transition in the wheat pathogenic fungus Zymoseptoria tritici. Z. tritici is a dimorphic plant pathogen displaying environmentally regulated morphogenetic transition between yeast-like and hyphal growth. Considering the infection mode of Z. tritici, the switching to hyphal growth is essential for pathogenicity allowing the fungus the host invasion through natural openings like stomata. We exploited a previously developed Agrobacterium tumefaciens-mediated transformation (ATMT) to generate a mutant library by insertional mutagenesis including more than 10,000 random mutants. To identify genes involved in dimorphic switch, a plate-based screening system was established. With this approach eleven dimorphic switch deficient random mutants were recovered, ten of which exhibited a yeast-like mode of growth and one mutant predominantly growing filamentously, producing high amount of mycelium under different incubation conditions. Using genome walking approach previously established, the T-DNA integration sites were recovered and the disrupted genomic loci of corresponding mutants were identified and validated within reverse genetics approach. As prove of concept, two of the random mutants obtained were selected for further investigation using targeted gene inactivation. Both genes deduced were found to encode known factors, previously characterized in other fungi: Ssk1p being constituent of HOG pathway and Ade5,7p involved in de novo purine biosynthesis. The targeted mutant strains defective in these genes exhibit a drastically impaired virulence within infection assays on whole wheat plants. Moreover exploiting further physiological assays the predicted function for both gene products could be confirmed in concordance with conserved biological role of homologous proteins previously described in other fungal organisms.
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Affiliation(s)
- Alexander Yemelin
- Institute for Biotechnology and Drug Research (IBWF gGmbH), Kaiserslautern, Germany
| | - Annamaria Brauchler
- Institute of Molecular Physiology, Microbiology and Wine Research, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Stefan Jacob
- Institute for Biotechnology and Drug Research (IBWF gGmbH), Kaiserslautern, Germany
| | - Julian Laufer
- Institute for Biotechnology and Drug Research (IBWF gGmbH), Kaiserslautern, Germany
| | - Larissa Heck
- Institute for Biotechnology and Drug Research (IBWF gGmbH), Kaiserslautern, Germany
| | - Andrew J. Foster
- Institute for Biotechnology and Drug Research (IBWF gGmbH), Kaiserslautern, Germany
| | - Luis Antelo
- Institute of Molecular Physiology, Microbiology and Wine Research, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Karsten Andresen
- Institute of Molecular Physiology, Microbiology and Wine Research, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Eckhard Thines
- Institute for Biotechnology and Drug Research (IBWF gGmbH), Kaiserslautern, Germany
- Institute of Molecular Physiology, Microbiology and Wine Research, Johannes Gutenberg University Mainz, Mainz, Germany
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50
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Hou Y, Kitaguchi T, Kriszt R, Tseng YH, Raghunath M, Suzuki M. Ca 2+-associated triphasic pH changes in mitochondria during brown adipocyte activation. Mol Metab 2017; 6:797-808. [PMID: 28752044 PMCID: PMC5518710 DOI: 10.1016/j.molmet.2017.05.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/19/2017] [Accepted: 05/25/2017] [Indexed: 12/31/2022] Open
Abstract
Objective Brown adipocytes (BAs) are endowed with a high metabolic capacity for energy expenditure due to their high mitochondria content. While mitochondrial pH is dynamically regulated in response to stimulation and, in return, affects various metabolic processes, how mitochondrial pH is regulated during adrenergic stimulation-induced thermogenesis is unknown. We aimed to reveal the spatial and temporal dynamics of mitochondrial pH in stimulated BAs and the mechanisms behind the dynamic pH changes. Methods A mitochondrial targeted pH-sensitive protein, mito-pHluorin, was constructed and transfected to BAs. Transfected BAs were stimulated by an adrenergic agonist, isoproterenol. The pH changes in mitochondria were characterized by dual-color imaging with indicators that monitor mitochondrial membrane potential and heat production. The mechanisms of pH changes were studied by examining the involvement of electron transport chain (ETC) activity and Ca2+ profiles in mitochondria and the intracellular Ca2+ store, the endoplasmic reticulum (ER). Results A triphasic mitochondrial pH change in BAs upon adrenergic stimulation was revealed. In comparison to a thermosensitive dye, we reveal that phases 1 and 2 of the pH increase precede thermogenesis, while phase 3, characterized by a pH decrease, occurs during thermogenesis. The mechanism of pH increase is partially related to ETC. In addition, the pH increase occurs concurrently with an increase in mitochondrial Ca2+. This Ca2+ increase is contributed to by an influx from the ER, and it is further involved in mitochondrial pH regulation. Conclusions We demonstrate that an increase in mitochondrial pH is implicated as an early event in adrenergically stimulated BAs. We further suggest that this pH increase may play a role in the potentiation of thermogenesis. A triphasic mitochondrial pH changes in adrenergically stimulated BAs was revealed. Phases 1 and 2 of the pH increase precede thermogenesis. The pH increase is partially related to electron transport chain activity. Ca2+ was transmitted from endoplasmic reticulum to mitochondria during phase 1. The transmitted Ca2+ regulates pH increase in mitochondria.
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Key Words
- AMA, antimycin A
- BAs, brown adipocytes
- Brown adipocytes
- Ca2+
- Confocal microscopy
- EGTA, ethylene glycol tetraacetic acid
- ER, endoplasmic reticulum
- ETC, electron transport chain
- Endoplasmic reticulum
- FFAs, free fatty acids
- Fluorescence imaging
- IMS, intermembrane space
- ISO, isoproterenol
- MAM, mitochondria-associated ER membrane
- MCU, mitochondrial calcium uniporter
- Mitochondria-associated ER membrane
- Rot, rotenone
- SERCA, sarco/endoplasmic reticulum Ca2+-ATPase
- TG, thapsigargin
- TMRM, tetramethylrhodamine methyl ester
- UCP1, uncoupling protein 1
- β-AR, β-adrenergic receptor
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Affiliation(s)
- Yanyan Hou
- WASEDA Bioscience Research Institute in Singapore (WABIOS), 11 Biopolis Way, #05-02 Helios, Singapore 138667, Singapore
| | - Tetsuya Kitaguchi
- WASEDA Bioscience Research Institute in Singapore (WABIOS), 11 Biopolis Way, #05-02 Helios, Singapore 138667, Singapore; Comprehensive Research Organization, Waseda University, Tokyo, 162-0041, Japan
| | - Rókus Kriszt
- Department of Biomedical Engineering, National University of Singapore, 117583, Singapore; NUS Tissue Engineering Program, Life Sciences Institute, National University of Singapore, 117510, Singapore; Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, 117456, Singapore
| | - Yu-Hua Tseng
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Michael Raghunath
- Department of Biomedical Engineering, National University of Singapore, 117583, Singapore; NUS Tissue Engineering Program, Life Sciences Institute, National University of Singapore, 117510, Singapore; Department of Biochemistry, Yong Loo Ling School of Medicine, National University of Singapore, 117597, Singapore
| | - Madoka Suzuki
- WASEDA Bioscience Research Institute in Singapore (WABIOS), 11 Biopolis Way, #05-02 Helios, Singapore 138667, Singapore; Comprehensive Research Organization, Waseda University, Tokyo, 162-0041, Japan; PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
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