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Peñalva DA, Monnappa AK, Natale P, López-Montero I. Mfn2-dependent fusion pathway of PE-enriched micron-sized vesicles. Proc Natl Acad Sci U S A 2024; 121:e2313609121. [PMID: 39012824 PMCID: PMC11287154 DOI: 10.1073/pnas.2313609121] [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: 08/07/2023] [Accepted: 06/17/2024] [Indexed: 07/18/2024] Open
Abstract
Mitofusins (Mfn1 and Mfn2) are the mitochondrial outer-membrane fusion proteins in mammals and belong to the dynamin superfamily of multidomain GTPases. Recent structural studies of truncated variants lacking alpha helical transmembrane domains suggested that Mfns dimerize to promote the approximation and the fusion of the mitochondrial outer membranes upon the hydrolysis of guanine 5'-triphosphate disodium salt (GTP). However, next to the presence of GTP, the fusion activity seems to require multiple regulatory factors that control the dynamics and kinetics of mitochondrial fusion through the formation of Mfn1-Mfn2 heterodimers. Here, we purified and reconstituted the full-length murine Mfn2 protein into giant unilamellar vesicles (GUVs) with different lipid compositions. The incubation with GTP resulted in the fusion of Mfn2-GUVs. High-speed video-microscopy showed that the Mfn2-dependent membrane fusion pathway progressed through a zipper mechanism where the formation and growth of an adhesion patch eventually led to the formation of a membrane opening at the rim of the septum. The presence of physiological concentration (up to 30 mol%) of dioleoyl-phosphatidylethanolamine (DOPE) was shown to be a requisite to observe GTP-induced Mfn2-dependent fusion. Our observations show that Mfn2 alone can promote the fusion of micron-sized DOPE-enriched vesicles without the requirement of regulatory cofactors, such as membrane curvature, or the assistance of other proteins.
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Affiliation(s)
- Daniel A. Peñalva
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional del Sur, Bahía BlancaB8000, Argentina
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía BlancaB8000, Argentina
| | - Ajay K. Monnappa
- Instituto de Investigación Biomédica Hospital Doce de Octubre (imas12), Madrid28041, Spain
| | - Paolo Natale
- Instituto de Investigación Biomédica Hospital Doce de Octubre (imas12), Madrid28041, Spain
- Departamento Química Física, Universidad Complutense de Madrid, Madrid28041, Spain
- Instituto Pluridisciplinar, Universidad Complutense de Madrid, Madrid28041, Spain
| | - Iván López-Montero
- Instituto de Investigación Biomédica Hospital Doce de Octubre (imas12), Madrid28041, Spain
- Departamento Química Física, Universidad Complutense de Madrid, Madrid28041, Spain
- Instituto Pluridisciplinar, Universidad Complutense de Madrid, Madrid28041, Spain
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Chen YX, Zhao AR, Wei TW, Wang H, Wang LS. Progress of Mitochondrial Function Regulation in Cardiac Regeneration. J Cardiovasc Transl Res 2024:10.1007/s12265-024-10514-w. [PMID: 38647881 DOI: 10.1007/s12265-024-10514-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 04/11/2024] [Indexed: 04/25/2024]
Abstract
Heart failure and myocardial infarction, global health concerns, stem from limited cardiac regeneration post-injury. Myocardial infarction, typically caused by coronary artery blockage, leads to cardiac muscle cell damage, progressing to heart failure. Addressing the adult heart's minimal self-repair capability is crucial, highlighting cardiac regeneration research's importance. Studies reveal a metabolic shift from anaerobic glycolysis to oxidative phosphorylation in neonates as a key factor in impaired cardiac regeneration, with mitochondria being central. The heart's high energy demands rely on a robust mitochondrial network, essential for cellular energy, cardiac health, and regenerative capacity. Mitochondria's influence extends to redox balance regulation, signaling molecule interactions, and apoptosis. Changes in mitochondrial morphology and quantity also impact cardiac cell regeneration. This article reviews mitochondria's multifaceted role in cardiac regeneration, particularly in myocardial infarction and heart failure models. Understanding mitochondrial function in cardiac regeneration aims to enhance myocardial infarction and heart failure treatment methods and insights.
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Affiliation(s)
- Yi-Xi Chen
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - An-Ran Zhao
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Tian-Wen Wei
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Hao Wang
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Lian-Sheng Wang
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China.
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Mai TL, Derreumaux P, Nguyen PH. Structure and Elasticity of Mitochondrial Membranes: A Molecular Dynamics Simulation Study. J Phys Chem B 2023; 127:10778-10791. [PMID: 38084584 DOI: 10.1021/acs.jpcb.3c05112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Mitochondria are known as the powerhouse of the cell because they produce energy in the form of adenosine triphosphate. They also have other crucial functions such as regulating apoptosis, calcium homeostasis, and reactive oxygen species production. To perform these diverse functions, mitochondria adopt specific structures and frequently undergo dynamic shape changes, indicating that their mechanical properties play an essential role in their functions. To gain a detailed understanding at the molecular level of the structure and mechanical properties of mitochondria, we carry out atomistic molecular dynamics simulations for three inner mitochondrial membranes and three outer mitochondrial membrane models. These models take into account variations in cardiolipin and cholesterol concentrations as well as the symmetry/asymmetry between the two leaflets. Our simulations allow us to calculate various structural quantities and the bending, twisting, and tilting elastic moduli of the membrane models. Our results indicate that the structures of the inner and outer mitochondrial membranes are quite similar and do not depend much on the variation in lipid compositions. However, the bending modulus of the membranes increases with increasing concentrations of cardiolipin or cholesterol but decreases with a membrane asymmetry. Notably, we found that the dipole potential of the membrane increases with an increasing cardiolipin concentration. Finally, possible roles of cardiolipin in regulating ion and proton currents and maintaining the cristate are discussed in some details.
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Affiliation(s)
- Thi Ly Mai
- CNRS, Université Paris Cité, UPR9080, Laboratoire de Biochimie Théorique, Institute de Biologie Physico-Chimique, Fondation Edmond de Rothschild, 13 rue Pierre et Marie Curie, Paris 75005, France
| | - Philippe Derreumaux
- CNRS, Université Paris Cité, UPR9080, Laboratoire de Biochimie Théorique, Institute de Biologie Physico-Chimique, Fondation Edmond de Rothschild, 13 rue Pierre et Marie Curie, Paris 75005, France
- Institut Universitaire de France (IUF), Paris 75005, France
| | - Phuong H Nguyen
- CNRS, Université Paris Cité, UPR9080, Laboratoire de Biochimie Théorique, Institute de Biologie Physico-Chimique, Fondation Edmond de Rothschild, 13 rue Pierre et Marie Curie, Paris 75005, France
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Venkatraman K, Lee CT, Garcia GC, Mahapatra A, Milshteyn D, Perkins G, Kim KY, Pasolli HA, Phan S, Lippincott-Schwartz J, Ellisman MH, Rangamani P, Budin I. Cristae formation is a mechanical buckling event controlled by the inner membrane lipidome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.13.532310. [PMID: 36993370 PMCID: PMC10054968 DOI: 10.1101/2023.03.13.532310] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Cristae are high curvature structures in the inner mitochondrial membrane (IMM) that are crucial for ATP production. While cristae-shaping proteins have been defined, analogous mechanisms for lipids have yet to be elucidated. Here we combine experimental lipidome dissection with multi-scale modeling to investigate how lipid interactions dictate IMM morphology and ATP generation. When modulating phospholipid (PL) saturation in engineered yeast strains, we observed a surprisingly abrupt breakpoint in IMM topology driven by a continuous loss of ATP synthase organization at cristae ridges. We found that cardiolipin (CL) specifically buffers the IMM against curvature loss, an effect that is independent of ATP synthase dimerization. To explain this interaction, we developed a continuum model for cristae tubule formation that integrates both lipid and protein-mediated curvatures. The model highlighted a snapthrough instability, which drives IMM collapse upon small changes in membrane properties. We also showed that CL is essential in low oxygen conditions that promote PL saturation. These results demonstrate that the mechanical function of CL is dependent on the surrounding lipid and protein components of the IMM.
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Affiliation(s)
- Kailash Venkatraman
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093
| | - Christopher T Lee
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093
| | - Guadalupe C Garcia
- Computational Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla CA 92097
| | - Arijit Mahapatra
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093
| | - Daniel Milshteyn
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093
| | - Guy Perkins
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, La Jolla, CA 92093
| | - Keun-Young Kim
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, La Jolla, CA 92093
| | - H Amalia Pasolli
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn VA 20147
| | - Sebastien Phan
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, La Jolla, CA 92093
| | | | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, La Jolla, CA 92093
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093
| | - Itay Budin
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093
- Lead contact
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