1
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Peng R, Rochon K, Stagg SM, Mears JA. The Structure of the Drp1 Lattice on Membrane. bioRxiv 2024:2024.04.04.588123. [PMID: 38617273 PMCID: PMC11014616 DOI: 10.1101/2024.04.04.588123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Mitochondrial health relies on the membrane fission mediated by dynamin-related protein 1 (Drp1). Previous structural studies of Drp1 on remodeled membranes were hampered by heterogeneity, leaving a critical gap in the understanding of the mitochondrial fission mechanism. Here we present a cryo-electron microscopy structure of full-length human Drp1 decorated on membrane tubules. Using the reconstruction of average subtracted tubular regions (RASTR) technique, we report that Drp1 forms a locally ordered lattice along the tubule without global helical symmetry. The filaments in the lattice are similar to dynamin rungs with conserved stalk interactions. Adjacent filaments are connected by GTPase domain interactions in a novel stacked conformation. Additionally, we observed contact between Drp1 and membrane that can be assigned to variable domain sequence. We identified two states of the Drp1 lattice representing conformational changes related to membrane curvature differences. Together these structures revealed a putative mechanism by which Drp1 constricts mitochondria membranes in a stepwise, "ratchet" manner.
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Affiliation(s)
- Ruizhi Peng
- Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida, USA
| | - Kristy Rochon
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106 USA
| | - Scott M Stagg
- Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida, USA
- Department of Biological Sciences, Florida State University, Tallahassee, Florida, USA
| | - Jason A Mears
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106 USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106 USA
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106 USA
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2
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Rochon K, Bauer BL, Roethler NA, Buckley Y, Su CC, Huang W, Ramachandran R, Stoll MSK, Yu EW, Taylor DJ, Mears JA. Structural basis for regulated assembly of the mitochondrial fission GTPase Drp1. Nat Commun 2024; 15:1328. [PMID: 38351080 PMCID: PMC10864337 DOI: 10.1038/s41467-024-45524-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 01/26/2024] [Indexed: 02/16/2024] Open
Abstract
Mitochondrial fission is a critical cellular event to maintain organelle function. This multistep process is initiated by the enhanced recruitment and oligomerization of dynamin-related protein 1 (Drp1) at the surface of mitochondria. As such, Drp1 is essential for inducing mitochondrial division in mammalian cells, and homologous proteins are found in all eukaryotes. As a member of the dynamin superfamily of proteins (DSPs), controlled Drp1 self-assembly into large helical polymers stimulates its GTPase activity to promote membrane constriction. Still, little is known about the mechanisms that regulate correct spatial and temporal assembly of the fission machinery. Here we present a cryo-EM structure of a full-length Drp1 dimer in an auto-inhibited state. This dimer reveals two key conformational rearrangements that must be unlocked through intramolecular rearrangements to achieve the assembly-competent state observed in previous structures. This structural insight provides understanding into the mechanism for regulated self-assembly of the mitochondrial fission machinery.
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Affiliation(s)
- Kristy Rochon
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Brianna L Bauer
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Nathaniel A Roethler
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Yuli Buckley
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Chih-Chia Su
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Wei Huang
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Rajesh Ramachandran
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Maria S K Stoll
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Edward W Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Derek J Taylor
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Jason A Mears
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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3
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Pérez-Jover I, Rochon K, Hu D, Mahajan M, Madan Mohan P, Santos-Pérez I, Ormaetxea Gisasola J, Martinez Galvez JM, Agirre J, Qi X, Mears JA, Shnyrova AV, Ramachandran R. Allosteric control of dynamin-related protein 1 through a disordered C-terminal Short Linear Motif. Nat Commun 2024; 15:52. [PMID: 38168038 PMCID: PMC10761769 DOI: 10.1038/s41467-023-44413-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 12/07/2023] [Indexed: 01/05/2024] Open
Abstract
The mechanochemical GTPase dynamin-related protein 1 (Drp1) catalyzes mitochondrial and peroxisomal fission, but the regulatory mechanisms remain ambiguous. Here we find that a conserved, intrinsically disordered, six-residue Short Linear Motif at the extreme Drp1 C-terminus, named CT-SLiM, constitutes a critical allosteric site that controls Drp1 structure and function in vitro and in vivo. Extension of the CT-SLiM by non-native residues, or its interaction with the protein partner GIPC-1, constrains Drp1 subunit conformational dynamics, alters self-assembly properties, and limits cooperative GTP hydrolysis, surprisingly leading to the fission of model membranes in vitro. In vivo, the involvement of the native CT-SLiM is critical for productive mitochondrial and peroxisomal fission, as both deletion and non-native extension of the CT-SLiM severely impair their progression. Thus, contrary to prevailing models, Drp1-catalyzed membrane fission relies on allosteric communication mediated by the CT-SLiM, deceleration of GTPase activity, and coupled changes in subunit architecture and assembly-disassembly dynamics.
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Affiliation(s)
- Isabel Pérez-Jover
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain
- Instituto Biofisika, CSIC, UPV/EHU, 48940, Leioa, Spain
| | - Kristy Rochon
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Di Hu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Mukesh Mahajan
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Pooja Madan Mohan
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Isaac Santos-Pérez
- Electron Microscopy and Crystallography Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology, Park Bld 800, 48160-Derio, Bizkaia, Spain
| | - Julene Ormaetxea Gisasola
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain
- Instituto Biofisika, CSIC, UPV/EHU, 48940, Leioa, Spain
| | - Juan Manuel Martinez Galvez
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain
- Instituto Biofisika, CSIC, UPV/EHU, 48940, Leioa, Spain
| | - Jon Agirre
- York Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, YO10 5DD, York, UK
| | - Xin Qi
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Jason A Mears
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Anna V Shnyrova
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain.
- Instituto Biofisika, CSIC, UPV/EHU, 48940, Leioa, Spain.
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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4
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Zhang Z, Tringides ML, Morgan CE, Miyagi M, Mears JA, Hoppel CL, Yu EW. High-Resolution Structural Proteomics of Mitochondria Using the 'Build and Retrieve' Methodology. Mol Cell Proteomics 2023; 22:100666. [PMID: 37839702 PMCID: PMC10709515 DOI: 10.1016/j.mcpro.2023.100666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 10/06/2023] [Accepted: 10/11/2023] [Indexed: 10/17/2023] Open
Abstract
The application of integrated systems biology to the field of structural biology is a promising new direction, although it is still in the infant stages of development. Here we report the use of single particle cryo-EM to identify multiple proteins from three enriched heterogeneous fractions prepared from human liver mitochondrial lysate. We simultaneously identify and solve high-resolution structures of nine essential mitochondrial enzymes with key metabolic functions, including fatty acid catabolism, reactive oxidative species clearance, and amino acid metabolism. Our methodology also identified multiple distinct members of the acyl-CoA dehydrogenase family. This work highlights the potential of cryo-EM to explore tissue proteomics at the atomic level.
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Affiliation(s)
- Zhemin Zhang
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Marios L Tringides
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Christopher E Morgan
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Masaru Miyagi
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Jason A Mears
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Charles L Hoppel
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Edward W Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA.
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5
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Pérez-Jover I, Rochon K, Hu D, Mohan PM, Santos-Perez I, Gisasola JO, Galvez JMM, Agirre J, Qi X, Mears JA, Shnyrova AV, Ramachandran R. Allosteric control of dynamin-related protein 1-catalyzed mitochondrial fission through a conserved disordered C-terminal Short Linear Motif. Res Sq 2023:rs.3.rs-3161608. [PMID: 37503116 PMCID: PMC10371074 DOI: 10.21203/rs.3.rs-3161608/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
The mechanochemical GTPase dynamin-related protein 1 (Drp1) catalyzes mitochondrial fission, but the regulatory mechanisms remain ambiguous. Here we found that a conserved, intrinsically disordered, six-residue Short Linear Motif at the extreme Drp1 C-terminus, named CT-SLiM, constitutes a critical allosteric site that controls Drp1 structure and function in vitro and in vivo. Extension of the CT-SLiM by non-native residues, or its interaction with the protein partner GIPC-1, constrains Drp1 subunit conformational dynamics, alters self-assembly properties, and limits cooperative GTP hydrolysis, leading to the fission of model membranes in vitro. In vivo, the availability of the native CT-SLiM is a requirement for productive mitochondrial fission, as both non-native extension and deletion of the CT-SLiM severely impair its progression. Thus, contrary to prevailing models, Drp1-catalyzed mitochondrial fission relies on allosteric communication mediated by the CT-SLiM, deceleration of GTPase activity, and coupled changes in subunit architecture and assembly-disassembly dynamics.
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Affiliation(s)
- Isabel Pérez-Jover
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa, Spain
- Instituto Biofisika, University of the Basque Country, 48940 Leioa, Spain
| | - Kristy Rochon
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Di Hu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Pooja Madan Mohan
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Isaac Santos-Perez
- Electron Microscopy and Crystallography Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park Bld 800, 48160-Derio, Bizkaia, Spain
| | - Julene Ormaetxea Gisasola
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa, Spain
- Instituto Biofisika, University of the Basque Country, 48940 Leioa, Spain
| | - Juan Manuel Martinez Galvez
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa, Spain
- Instituto Biofisika, University of the Basque Country, 48940 Leioa, Spain
| | - Jon Agirre
- York Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, YO10 5DD, York, UK
| | - Xin Qi
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Jason A. Mears
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Anna V. Shnyrova
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa, Spain
- Instituto Biofisika, University of the Basque Country, 48940 Leioa, Spain
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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6
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Bauer BL, Rochon K, Liu JC, Ramachandran R, Mears JA. Disease-associated mutations in Drp1 have fundamentally different effects on the mitochondrial fission machinery. Hum Mol Genet 2023; 32:1975-1987. [PMID: 36795043 PMCID: PMC10244223 DOI: 10.1093/hmg/ddad029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
Patient mutations have been identified throughout dynamin-related protein 1 (Drp1), the key protein mediator of mitochondrial fission. These changes generally impact young children and often result in severe neurological defects and, in some instances, death. Until now, the underlying functional defect leading to patient phenotypes has been largely speculative. We therefore analyzed six disease-associated mutations throughout the GTPase and middle domains (MD) of Drp1. The MD plays a role in Drp1 oligomerization, and three mutations in this region were predictably impaired in self-assembly. However, another mutant in this region (F370C) retained oligomerization capability on pre-curved membranes despite being assembly-limited in solution. Instead, this mutation impaired membrane remodeling of liposomes, which highlights the importance of Drp1 in generating local membrane curvature before fission. Two GTPase domain mutations were also observed in different patients. The G32A mutation was impaired in GTP hydrolysis both in solution and in the presence of lipid but remains capable of self-assembly on these lipid templates. The G223V mutation also exhibited decreased GTPase activity and was able to assemble on pre-curved lipid templates; however, this change impaired membrane remodeling of unilamellar liposomes similar to F370C. This demonstrates that the Drp1 GTPase domain also contributes to self-assembly interactions that drive membrane curvature. Overall, the functional defects caused by mutations in Drp1 are highly variable even for mutations that reside within the same functional domain. This study provides a framework for characterizing additional Drp1 mutations to provide a comprehensive understanding of functional sites within this essential protein.
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Affiliation(s)
- Brianna L Bauer
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Kristy Rochon
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Jasmine C Liu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Jason A Mears
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44016, USA
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7
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Watson DC, Bayik D, Storevik S, Moreino SS, Sprowls SA, Han J, Augustsson MT, Lauko A, Sravya P, Røsland GV, Troike K, Tronstad KJ, Wang S, Sarnow K, Kay K, Lunavat TR, Silver DJ, Dayal S, Joseph JV, Mulkearns-Hubert E, Ystaas LAR, Deshpande G, Guyon J, Zhou Y, Magaut CR, Seder J, Neises L, Williford SE, Meiser J, Scott AJ, Sajjakulnukit P, Mears JA, Bjerkvig R, Chakraborty A, Daubon T, Cheng F, Lyssiotis CA, Wahl DR, Hjelmeland AB, Hossain JA, Miletic H, Lathia JD. GAP43-dependent mitochondria transfer from astrocytes enhances glioblastoma tumorigenicity. Nat Cancer 2023; 4:648-664. [PMID: 37169842 PMCID: PMC10212766 DOI: 10.1038/s43018-023-00556-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 04/06/2023] [Indexed: 05/13/2023]
Abstract
The transfer of intact mitochondria between heterogeneous cell types has been confirmed in various settings, including cancer. However, the functional implications of mitochondria transfer on tumor biology are poorly understood. Here we show that mitochondria transfer is a prevalent phenomenon in glioblastoma (GBM), the most frequent and malignant primary brain tumor. We identified horizontal mitochondria transfer from astrocytes as a mechanism that enhances tumorigenesis in GBM. This transfer is dependent on network-forming intercellular connections between GBM cells and astrocytes, which are facilitated by growth-associated protein 43 (GAP43), a protein involved in neuron axon regeneration and astrocyte reactivity. The acquisition of astrocyte mitochondria drives an increase in mitochondrial respiration and upregulation of metabolic pathways linked to proliferation and tumorigenicity. Functionally, uptake of astrocyte mitochondria promotes cell cycle progression to proliferative G2/M phases and enhances self-renewal and tumorigenicity of GBM. Collectively, our findings reveal a host-tumor interaction that drives proliferation and self-renewal of cancer cells, providing opportunities for therapeutic development.
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Affiliation(s)
- Dionysios C Watson
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Case Comprehensive Cancer Center, Cleveland, OH, USA
- University Hospitals Cleveland Medical Center, Cleveland, OH, USA
- School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Defne Bayik
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Case Comprehensive Cancer Center, Cleveland, OH, USA
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Simon Storevik
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | | | | | - Jianhua Han
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | | | - Adam Lauko
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Medical Scientist Training Program, Case Western Reserve University, Cleveland, OH, USA
| | - Palavalasa Sravya
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | | | - Katie Troike
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Sabrina Wang
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Kristen Kay
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Taral R Lunavat
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Department of Neurology, Molecular Neurogenetics Unit-West, Massachusetts General Hospital, Boston, MA, USA
| | - Daniel J Silver
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Sahil Dayal
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Erin Mulkearns-Hubert
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | | | | | - Joris Guyon
- University of Bordeaux, INSERM, BRIC, Pessac, France
| | - Yadi Zhou
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Juliana Seder
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Laura Neises
- Cancer Metabolism Group, Department of Cancer Research, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | | | - Johannes Meiser
- Cancer Metabolism Group, Department of Cancer Research, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Andrew J Scott
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | | | - Jason A Mears
- Case Comprehensive Cancer Center, Cleveland, OH, USA
- School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Rolf Bjerkvig
- Department of Biomedicine, University of Bergen, Bergen, Norway
- NorLux Neuro-Oncology Laboratory, Department of Cancer Research, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Abhishek Chakraborty
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Case Comprehensive Cancer Center, Cleveland, OH, USA
| | - Thomas Daubon
- University of Bordeaux, CNRS, IBGC, Bordeaux, France
| | - Feixiong Cheng
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Case Comprehensive Cancer Center, Cleveland, OH, USA
| | - Costas A Lyssiotis
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, MI, USA
| | - Daniel R Wahl
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | | | | | - Hrvoje Miletic
- Department of Biomedicine, University of Bergen, Bergen, Norway.
- Department of Pathology, Haukeland University Hospital, Bergen, Norway.
| | - Justin D Lathia
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.
- Case Comprehensive Cancer Center, Cleveland, OH, USA.
- Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, USA.
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8
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Bauer BL, Rochon K, Liu J, Ramachandran R, Mears JA. Disease-associated mutations in Drp1 have fundamentally different effects on the mitochondrial fission machinery. Biophys J 2023; 122:482a. [PMID: 36784482 DOI: 10.1016/j.bpj.2022.11.2581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Brianna L Bauer
- Pharmacology, Case Western Reserve University, Cleveland, OH, USA
| | - Kristy Rochon
- Pharmacology, Case Western Reserve University, Cleveland, OH, USA
| | - Jasmine Liu
- Pharmacology, Case Western Reserve University, Cleveland, OH, USA
| | - Rajesh Ramachandran
- Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - Jason A Mears
- Pharmacology, Case Western Reserve University, Cleveland, OH, USA
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9
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Robertson GL, Riffle S, Patel M, Bodnya C, Marshall A, Beasley HK, Garza-Lopez E, Shao J, Vue Z, Hinton A, Stoll MS, de Wet S, Theart RP, Chakrabarty RP, Loos B, Chandel NS, Mears JA, Gama V. DRP1 mutations associated with EMPF1 encephalopathy alter mitochondrial membrane potential and metabolic programs. J Cell Sci 2023; 136:jcs260370. [PMID: 36763487 PMCID: PMC10657212 DOI: 10.1242/jcs.260370] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 12/22/2022] [Indexed: 02/11/2023] Open
Abstract
Mitochondria and peroxisomes are dynamic signaling organelles that constantly undergo fission, driven by the large GTPase dynamin-related protein 1 (DRP1; encoded by DNM1L). Patients with de novo heterozygous missense mutations in DNM1L present with encephalopathy due to defective mitochondrial and peroxisomal fission (EMPF1) - a devastating neurodevelopmental disease with no effective treatment. To interrogate the mechanisms by which DRP1 mutations cause cellular dysfunction, we used human-derived fibroblasts from patients who present with EMPF1. In addition to elongated mitochondrial morphology and lack of fission, patient cells display lower coupling efficiency, increased proton leak and upregulation of glycolysis. Mitochondrial hyperfusion also results in aberrant cristae structure and hyperpolarized mitochondrial membrane potential. Peroxisomes show a severely elongated morphology in patient cells, which is associated with reduced respiration when cells are reliant on fatty acid oxidation. Metabolomic analyses revealed impaired methionine cycle and synthesis of pyrimidine nucleotides. Our study provides insight into the role of mitochondrial dynamics in cristae maintenance and the metabolic capacity of the cell, as well as the disease mechanism underlying EMPF1.
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Affiliation(s)
| | - Stellan Riffle
- Vanderbilt University, Cell and Developmental Biology, Nashville, TN 37232, USA
| | - Mira Patel
- Vanderbilt University, Cell and Developmental Biology, Nashville, TN 37232, USA
| | - Caroline Bodnya
- Vanderbilt University, Cell and Developmental Biology, Nashville, TN 37232, USA
| | - Andrea Marshall
- Vanderbilt University, Molecular Physiology and Biophysics, Nashville, TN 37232, USA
| | - Heather K. Beasley
- Vanderbilt University, Molecular Physiology and Biophysics, Nashville, TN 37232, USA
| | - Edgar Garza-Lopez
- Vanderbilt University, Molecular Physiology and Biophysics, Nashville, TN 37232, USA
| | - Jianqiang Shao
- Central Microscopy Research Facility, University of Iowa, Iowa City, IA 52246, USA
| | - Zer Vue
- Vanderbilt University, Molecular Physiology and Biophysics, Nashville, TN 37232, USA
| | - Antentor Hinton
- Vanderbilt University, Molecular Physiology and Biophysics, Nashville, TN 37232, USA
| | - Maria S. Stoll
- Case Western Reserve University, Department of Pharmacology and Center for Mitochondrial Diseases, Cleveland, OH 44106, USA
| | - Sholto de Wet
- Stellenbosch University, Department of Physiological Sciences, Matieland, 7602, Stellenbosch, South Africa
| | - Rensu P. Theart
- Stellenbosch University, Department of Electrical and Electronic Engineering, Matieland, 7602, Stellenbosch, South Africa
| | - Ram Prosad Chakrabarty
- Northwestern University, Feinberg School of Medicine Department of Medicine Division of Pulmonary and Critical Care Medicine, Chicago, IL 60611, USA
| | - Ben Loos
- Stellenbosch University, Department of Electrical and Electronic Engineering, Matieland, 7602, Stellenbosch, South Africa
| | - Navdeep S. Chandel
- Northwestern University, Feinberg School of Medicine Department of Medicine Division of Pulmonary and Critical Care Medicine, Chicago, IL 60611, USA
- Northwestern University, Feinberg School of Medicine Department of Biochemistry and Molecular Genetics, Chicago, IL 60611, USA
| | - Jason A. Mears
- Case Western Reserve University, Department of Pharmacology and Center for Mitochondrial Diseases, Cleveland, OH 44106, USA
| | - Vivian Gama
- Vanderbilt University, Cell and Developmental Biology, Nashville, TN 37232, USA
- Vanderbilt University, Vanderbilt Center for Stem Cell Biology, Nashville, TN 37232, USA
- Vanderbilt University, Vanderbilt Brain Institute, Nashville, TN 37232, USA
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10
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Abstract
Dynamin-related protein 1 (Drp1), the master regulator of mitochondrial division (MD), interacts with the cytoskeletal elements, namely filamentous actin (F-actin), microtubules (MT), and septins that coincidentally converge at MD sites. However, the mechanistic contributions of these critical elements to, and their cooperativity in, MD remain poorly characterized. Emergent data indicate that the cytoskeleton plays combinatorial modulator, mediator, and effector roles in MD by 'priming' and 'channeling' Drp1 for mechanoenzymatic membrane remodeling. In this brief review, we will outline our current understanding of Drp1-cytoskeleton interactions, focusing on recent progress in the field and a plausible 'diffusion barrier' role for the cytoskeleton in MD.
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Affiliation(s)
- Jason A. Mears
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Rajesh Ramachandran
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106
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11
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Ducich NH, Mears JA, Bedoyan JK. Solvent accessibility of E1α and E1β residues with known missense mutations causing pyruvate dehydrogenase complex (PDC) deficiency: Impact on PDC-E1 structure and function. J Inherit Metab Dis 2022; 45:557-570. [PMID: 35038180 PMCID: PMC9297371 DOI: 10.1002/jimd.12477] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 11/08/2022]
Abstract
Pyruvate dehydrogenase complex deficiency is a major cause of primary lactic acidemia resulting in high morbidity and mortality, with limited therapeutic options. PDHA1 mutations are responsible for >82% of cases. The E1 component of PDC is a symmetric dimer of heterodimers (αβ/α'β') encoded by PDHA1 and PDHB. We measured solvent accessibility surface area (SASA), utilized nearest-neighbor analysis, incorporated sequence changes using mutagenesis tool in PyMOL, and performed molecular modeling with SWISS-MODEL, to investigate the impact of residues with disease-causing missense variants (DMVs) on E1 structure and function. We reviewed 166 and 13 genetically resolved cases due to PDHA1 and PDHB, respectively, from variant databases. We expanded on 102 E1α and 13 E1β nonduplicate DMVs. DMVs of E1α Arg112-Arg224 stretch (exons 5-7) and of E1α Arg residues constituted 40% and 39% of cases, respectively, with invariant Arg349 accounting for 22% of arginine replacements. SASA analysis showed that 86% and 84% of residues with nonduplicate DMVs of E1α and E1β, respectively, are solvent inaccessible ("buried"). Furthermore, 30% of E1α buried residues with DMVs are deleterious through perturbation of subunit-subunit interface contact (SSIC), with 73% located in the Arg112-Arg224 stretch. E1α Arg349 represented 74% of buried E1α Arg residues involved in SSIC. Structural perturbations resulting from residue replacements in some matched neighboring pairs of amino acids on different subunits involved in SSIC at 2.9-4.0 Å interatomic distance apart, exhibit similar clinical phenotype. Collectively, this work provides insight for future target-based advanced molecular modeling studies, with implications for development of novel therapeutics for specific recurrent DMVs of E1α.
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Affiliation(s)
- Nicole H. Ducich
- Case Western Reserve University (CWRU) School of Medicine, Cleveland, Ohio, USA
| | - Jason A. Mears
- Department of Pharmacology, CWRU, Cleveland, Ohio, USA
- Center for Mitochondrial Diseases, CWRU, Cleveland, Ohio, USA
| | - Jirair K. Bedoyan
- Division of Genetic and Genomic Medicine, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Pediatrics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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12
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Akinbiyi EO, Abramowitz LK, Bauer BL, Stoll MSK, Hoppel CL, Hsiao CP, Hanover JA, Mears JA. Blocked O-GlcNAc cycling alters mitochondrial morphology, function, and mass. Sci Rep 2021; 11:22106. [PMID: 34764359 PMCID: PMC8586252 DOI: 10.1038/s41598-021-01512-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/18/2021] [Indexed: 12/24/2022] Open
Abstract
O-GlcNAcylation is a prevalent form of glycosylation that regulates proteins within the cytosol, nucleus, and mitochondria. The O-GlcNAc modification can affect protein cellular localization, function, and signaling interactions. The specific impact of O-GlcNAcylation on mitochondrial morphology and function has been elusive. In this manuscript, the role of O-GlcNAcylation on mitochondrial fission, oxidative phosphorylation (Oxphos), and the activity of electron transport chain (ETC) complexes were evaluated. In a cellular environment with hyper O-GlcNAcylation due to the deletion of O-GlcNAcase (OGA), mitochondria showed a dramatic reduction in size and a corresponding increase in number and total mitochondrial mass. Because of the increased mitochondrial content, OGA knockout cells exhibited comparable coupled mitochondrial Oxphos and ATP levels when compared to WT cells. However, we observed reduced protein levels for complex I and II when comparing normalized mitochondrial content and reduced linked activity for complexes I and III when examining individual ETC complex activities. In assessing mitochondrial fission, we observed increased amounts of O-GlcNAcylated dynamin-related protein 1 (Drp1) in cells genetically null for OGA and in glioblastoma cells. Individual regions of Drp1 were evaluated for O-GlcNAc modifications, and we found that this post-translational modification (PTM) was not limited to the previously characterized residues in the variable domain (VD). Additional modification sites are predicted in the GTPase domain, which may influence enzyme activity. Collectively, these results highlight the impact of O-GlcNAcylation on mitochondrial dynamics and ETC function and mimic the changes that may occur during glucose toxicity from hyperglycemia.
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Affiliation(s)
- Elizabeth O Akinbiyi
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Lara K Abramowitz
- Laboratory of Cellular and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Brianna L Bauer
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Maria S K Stoll
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Charles L Hoppel
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Chao-Pin Hsiao
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- Frances Payne Bolton School of Nursing, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - John A Hanover
- Laboratory of Cellular and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jason A Mears
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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13
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Sha Z, Montano MM, Rochon K, Mears JA, Deredge D, Wintrode P, Szweda L, Mikita N, Lee I. A structure and function relationship study to identify the impact of the R721G mutation in the human mitochondrial lon protease. Arch Biochem Biophys 2021; 710:108983. [PMID: 34228963 DOI: 10.1016/j.abb.2021.108983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 10/20/2022]
Abstract
Lon is an ATP-dependent protease belonging to the "ATPase associated with diverse cellular activities" (AAA+) protein family. In humans, Lon is translated as a precursor and imported into the mitochondria matrix through deletion of the first 114 amino acid residues. In mice, embryonic knockout of lon is lethal. In humans, some dysfunctional lon mutations are tolerated but they cause a developmental disorder known as the CODAS syndrome. To gain a better understanding on the enzymology of human mitochondrial Lon, this study compares the structure-function relationship of the WT versus one of the CODAS mutants R721G to identify the mechanistic features in Lon catalysis that are affected. To this end, steady-state kinetics were used to quantify the difference in ATPase and ATP-dependent peptidase activities between WT and R721G. The Km values for the intrinsic as well as protein-stimulated ATPase were increased whereas the kcat value for ATP-dependent peptidase activity was decreased in the R721G mutant. The mutant protease also displayed substrate inhibition kinetics. In vitro studies revealed that R721G did not degrade the endogenous mitochondrial Lon substrate pyruvate dehydrogenase kinase isoform 4 (PDK4) effectively like WT hLon. Furthermore, the pyruvate dehydrogenase complex (PDH) protected PDK4 from hLon degradation. Using hydrogen deuterium exchange/mass spectrometry and negative stain electron microscopy, structural perturbations associated with the R721G mutation were identified. To validate the in vitro findings under a physiologically relevant condition, the intrinsic stability as well as proteolytic activity of WT versus R721G mutant towards PDK 4 were compared in cell lysates prepared from immortalized B lymphocytes expressing the respective protease. The lifetime of PDK4 is longer in the mutant cells, but the lifetime of Lon protein is longer in the WT cells, which corroborate the in vitro structure-functional relationship findings.
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Affiliation(s)
- Zhou Sha
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Monica M Montano
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Kristy Rochon
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Jason A Mears
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA; Center for Mitochondrial Diseases, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Daniel Deredge
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, 21201, USA
| | - Patrick Wintrode
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, 21201, USA
| | - Luke Szweda
- Department of Internal Medicine, Division of Cardiology, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Natalie Mikita
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA; Department of Chemistry, Missouri Western State University, St. Joseph, MO, 64507, USA.
| | - Irene Lee
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA.
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14
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Montecinos-Franjola F, Bauer BL, Mears JA, Ramachandran R. GFP fluorescence tagging alters dynamin-related protein 1 oligomerization dynamics and creates disassembly-refractory puncta to mediate mitochondrial fission. Sci Rep 2020; 10:14777. [PMID: 32901052 PMCID: PMC7479153 DOI: 10.1038/s41598-020-71655-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 08/19/2020] [Indexed: 01/22/2023] Open
Abstract
Green fluorescent protein (GFP)-tagging is the prevalent strategy to monitor protein dynamics in living cells. However, the consequences of appending the bulky GFP moiety to the protein of interest are rarely investigated. Here, using a powerful combination of quantitative fluorescence spectroscopic and imaging techniques, we have examined the oligomerization dynamics of the GFP-tagged mitochondrial fission GTPase dynamin-related protein 1 (Drp1) both in vitro and in vivo. We find that GFP-tagged Drp1 exhibits impaired oligomerization equilibria in solution that corresponds to a greatly diminished cooperative GTPase activity in comparison to native Drp1. Consequently, GFP-tagged Drp1 constitutes aberrantly stable, GTP-resistant supramolecular assemblies both in vitro and in vivo, neither of which reflects a more dynamic native Drp1 oligomerization state. Indeed, GFP-tagged Drp1 is detected more frequently per unit length over mitochondria in Drp1-null mouse embryonic fibroblasts (MEFs) compared to wild-type (wt) MEFs, indicating that the drastically reduced GTP turnover restricts oligomer disassembly from the mitochondrial surface relative to mixed oligomers comprising native and GFP-tagged Drp1. Yet, GFP-tagged Drp1 retains the capacity to mediate membrane constriction in vitro and mitochondrial division in vivo. These findings suggest that instead of robust assembly-disassembly dynamics, persistent Drp1 higher-order oligomerization over membranes is sufficient for mitochondrial fission.
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Affiliation(s)
- Felipe Montecinos-Franjola
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Brianna L Bauer
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Jason A Mears
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA. .,Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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15
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Abstract
Mitochondria are required for cell survival and are best known for their role in energy production. These organelles also participate in many other biological processes that are critical for cellular function, and thus, play a central role in cellular life and death decisions. In a majority of cell types, mitochondria form highly dynamic, reticular networks. Maintaining the shape of these complex, ever-changing networks is critical for mitochondrial and cellular function, and requires the conserved activities of mitochondrial fission and fusion. Great advances in our knowledge about the molecular machines that mediate these dynamic activities have been made over the past 2 decades. These advances have been driven by the use of highly complementary in vitro and in vivo approaches that have proven extremely powerful for studying the complex membrane remodeling processes that drive fission and fusion of the organelle. In this chapter, we detail current methods used to examine the mechanisms and regulation of mitochondrial fission and fusion in vitro and in vivo.
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Affiliation(s)
- Suzanne Hoppins
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA, United States.
| | - Laura L Lackner
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, United States.
| | - Jason E Lee
- Department of Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Boulder, CO, United States.
| | - Jason A Mears
- Department of Pharmacology, Center for Mitochondrial Diseases, and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, United States.
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16
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Abstract
Primary ovarian insufficiency (POI) is defined by the loss or dysfunction of ovarian follicles associated with amenorrhea before the age of 40. Symptoms include hot flashes, sleep disturbances, and depression, as well as reduced fertility and increased long-term risk of cardiovascular disease. POI occurs in ∼1% to 2% of women, although the etiology of most cases remains unexplained. Approximately 10% to 20% of POI cases are due to mutations in a single gene or a chromosomal abnormality, which has provided considerable molecular insight into the biological underpinnings of POI. Many of the genes for which mutations have been associated with POI, either isolated or syndromic cases, function within mitochondria, including MRPS22, POLG, TWNK, LARS2, HARS2, AARS2, CLPP, and LRPPRC. Collectively, these genes play roles in mitochondrial DNA replication, gene expression, and protein synthesis and degradation. Although mutations in these genes clearly implicate mitochondrial dysfunction in rare cases of POI, data are scant as to whether these genes in particular, and mitochondrial dysfunction in general, contribute to most POI cases that lack a known etiology. Further studies are needed to better elucidate the contribution of mitochondria to POI and determine whether there is a common molecular defect in mitochondrial function that distinguishes mitochondria-related genes that when mutated cause POI vs those that do not. Nonetheless, the clear implication of mitochondrial dysfunction in POI suggests that manipulation of mitochondrial function represents an important therapeutic target for the treatment or prevention of POI.
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Affiliation(s)
- Dov Tiosano
- Division of Pediatric Endocrinology, Ruth Rappaport Children’s Hospital, Rambam Medical Center, Haifa, Israel
- Rappaport Family Faculty of Medicine, Technion—Israel Institute of Technology, Haifa, Israel
- Correspondence: David A. Buchner, PhD, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, Ohio 44106. E-mail: ; or Dov Tiosano, MD, Division of Pediatric Endocrinology, Ruth Rappaport Children’s Hospital, Rambam Medical Center, HaAliya HaShniya Street 8, Haifa 3109601, Israel. E-mail:
| | - Jason A Mears
- Center for Mitochondrial Diseases, Case Western Reserve University, Cleveland, Ohio
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio
| | - David A Buchner
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio
- Research Institute for Children’s Health, Case Western Reserve University, Cleveland, Ohio
- Correspondence: David A. Buchner, PhD, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, Ohio 44106. E-mail: ; or Dov Tiosano, MD, Division of Pediatric Endocrinology, Ruth Rappaport Children’s Hospital, Rambam Medical Center, HaAliya HaShniya Street 8, Haifa 3109601, Israel. E-mail:
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17
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Lu B, Kennedy B, Clinton RW, Wang EJ, McHugh D, Stepanyants N, Macdonald PJ, Mears JA, Qi X, Ramachandran R. Steric interference from intrinsically disordered regions controls dynamin-related protein 1 self-assembly during mitochondrial fission. Sci Rep 2018; 8:10879. [PMID: 30022112 PMCID: PMC6051998 DOI: 10.1038/s41598-018-29001-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 07/04/2018] [Indexed: 12/19/2022] Open
Abstract
The self-assembling, mechanoenzymatic dynamin superfamily GTPase, dynamin-related protein 1 (Drp1), catalyzes mitochondrial and peroxisomal fission. Distinct intrinsically disordered regions (IDRs) in Drp1 substitute for the canonical pleckstrin homology (PH) domain and proline-rich domain (PRD) of prototypical dynamin, which cooperatively regulate endocytic vesicle scission. Whether the Drp1 IDRs function analogously to the corresponding dynamin domains however remains unknown. We show that an IDR unique to the Drp1 GTPase (G) domain, the 'extended 80-loop', albeit dissimilar in location, structure, and mechanism, functions akin to the dynamin PRD by enabling stable Drp1 mitochondrial recruitment and by suppressing Drp1 cooperative GTPase activity in the absence of specific partner-protein interactions. Correspondingly, we find that another IDR, the Drp1 variable domain (VD), in conjunction with the conserved stalk L1N loop, functions akin to the dynamin PH domain; first, in an 'auto-inhibitory' capacity that restricts Drp1 activity through a long-range steric inhibition of helical inter-rung G-domain dimerization, and second, as a 'fulcrum' for Drp1 self-assembly in the proper helical register. We show that the Drp1 VD is necessary and sufficient for specific Drp1-phospholipid interactions. We further demonstrate that the membrane-dependent VD conformational rearrangement essential for the alleviation of Drp1 auto-inhibition is contingent upon the basal GTP hydrolysis-dependent generation of Drp1 dimers from oligomers in solution. IDRs thus conformationally couple the enzymatic and membrane activities of Drp1 toward membrane fission.
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Affiliation(s)
- Bin Lu
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Bridget Kennedy
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Ryan W Clinton
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Emily Jue Wang
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Daniel McHugh
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Natalia Stepanyants
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Patrick J Macdonald
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Jason A Mears
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Xin Qi
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Rajesh Ramachandran
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA. .,Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA. .,Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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18
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Tandler B, Hoppel CL, Mears JA. Morphological Pathways of Mitochondrial Division. Antioxidants (Basel) 2018; 7:antiox7020030. [PMID: 29462856 PMCID: PMC5836020 DOI: 10.3390/antiox7020030] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 02/12/2018] [Accepted: 02/14/2018] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial fission is essential for distributing cellular energy throughout cells and for isolating damaged regions of the organelle that are targeted for degradation. Excessive fission is associated with the progression of cell death as well. Therefore, this multistep process is tightly regulated and several physiologic cues directly impact mitochondrial division. The double membrane structure of mitochondria complicates this process, and protein factors that drive membrane scission need to coordinate the separation of both the outer and inner mitochondrial membranes. In this review, we discuss studies that characterize distinct morphological changes associated with mitochondrial division. Specifically, coordinated partitioning and pinching of mitochondria have been identified as alternative mechanisms associated with fission. Additionally, we highlight the major protein constituents that drive mitochondrial fission and the role of connections with the endoplasmic reticulum in establishing sites of membrane division. Collectively, we review decades of research that worked to define the molecular framework of mitochondrial fission. Ongoing studies will continue to sort through the complex network of interactions that drive this critical event.
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Affiliation(s)
- Bernard Tandler
- Center for Mitochondrial Disease, Cleveland, OH 44106, USA.
- Department of Biological Sciences, School of Dental Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Charles L Hoppel
- Center for Mitochondrial Disease, Cleveland, OH 44106, USA.
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
- Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Jason A Mears
- Center for Mitochondrial Disease, Cleveland, OH 44106, USA.
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
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19
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Mears JA, Francy CA, Clinton RW, Lee S. Structural Studies that Define Regulatory Interactions Within the Mitochondrial Fission Machinery. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.2066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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20
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Abstract
Studies of integral membrane proteins in vitro are frequently complicated by the presence of a hydrophobic transmembrane domain. Further complicating these studies, reincorporation of detergent-solubilized membrane proteins into liposomes is a stochastic process where protein topology is impossible to enforce. This paper offers an alternative method to these challenging techniques that utilizes a liposome-based scaffold. Protein solubility is enhanced by deletion of the transmembrane domain, and these amino acids are replaced with a tethering moiety, such as a His-tag. This tether interacts with an anchoring group (Ni2+ coordinated by nitrilotriacetic acid (NTA(Ni2+)) for His-tagged proteins), which enforces a uniform protein topology at the surface of the liposome. An example is presented wherein the interaction between Dynamin-related protein 1 (Drp1) with an integral membrane protein, Mitochondrial Fission Factor (Mff), was investigated using this scaffold liposome method. In this work, we have demonstrated the ability of Mff to efficiently recruit soluble Drp1 to the surface of liposomes, which stimulated its GTPase activity. Moreover, Drp1 was able to tubulate the Mff-decorated lipid template in the presence of specific lipids. This example demonstrates the effectiveness of scaffold liposomes using structural and functional assays and highlights the role of Mff in regulating Drp1 activity.
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Affiliation(s)
- Ryan W Clinton
- Department of Pharmacology, Center for Mitochondrial Diseases, The Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine
| | - Jason A Mears
- Department of Pharmacology, Center for Mitochondrial Diseases, The Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine;
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21
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Francy CA, Frohlich C, Daumke O, Mears JA. Defining Membrane Interactions that Drive Dynamin Related Protein 1 (Drp1) Oligomerization using cryo-EM. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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22
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Macdonald PJ, Francy CA, Stepanyants N, Lehman L, Baglio A, Mears JA, Qi X, Ramachandran R. Distinct Splice Variants of Dynamin-related Protein 1 Differentially Utilize Mitochondrial Fission Factor as an Effector of Cooperative GTPase Activity. J Biol Chem 2015; 291:493-507. [PMID: 26578513 DOI: 10.1074/jbc.m115.680181] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Indexed: 02/02/2023] Open
Abstract
Multiple isoforms of the mitochondrial fission GTPase dynamin-related protein 1 (Drp1) arise from the alternative splicing of its single gene-encoded pre-mRNA transcript. Among these, the longer Drp1 isoforms, expressed selectively in neurons, bear unique polypeptide sequences within their GTPase and variable domains, known as the A-insert and the B-insert, respectively. Their functions remain unresolved. A comparison of the various biochemical and biophysical properties of the neuronally expressed isoforms with that of the ubiquitously expressed, and shortest, Drp1 isoform (Drp1-short) has revealed the effect of these inserts on Drp1 function. Utilizing various biochemical, biophysical, and cellular approaches, we find that the A- and B-inserts distinctly alter the oligomerization propensity of Drp1 in solution as well as the preferred curvature of helical Drp1 self-assembly on membranes. Consequently, these sequences also suppress Drp1 cooperative GTPase activity. Mitochondrial fission factor (Mff), a tail-anchored membrane protein of the mitochondrial outer membrane that recruits Drp1 to sites of ensuing fission, differentially stimulates the disparate Drp1 isoforms and alleviates the autoinhibitory effect imposed by these sequences on Drp1 function. Moreover, the differential stimulatory effects of Mff on Drp1 isoforms are dependent on the mitochondrial lipid, cardiolipin (CL). Although Mff stimulation of the intrinsically cooperative Drp1-short isoform is relatively modest, CL-independent, and even counter-productive at high CL concentrations, Mff stimulation of the much less cooperative longest Drp1 isoform (Drp1-long) is robust and occurs synergistically with increasing CL content. Thus, membrane-anchored Mff differentially regulates various Drp1 isoforms by functioning as an allosteric effector of cooperative GTPase activity.
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Affiliation(s)
| | - Christopher A Francy
- Department of Pharmacology, Center for Mitochondrial Diseases, and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | | | - Lance Lehman
- From the Department of Physiology and Biophysics
| | | | - Jason A Mears
- Department of Pharmacology, Center for Mitochondrial Diseases, and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Xin Qi
- From the Department of Physiology and Biophysics, Center for Mitochondrial Diseases, and
| | - Rajesh Ramachandran
- From the Department of Physiology and Biophysics, Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
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Clinton RW, Francy CA, Ramachandran R, Qi X, Mears JA. Dynamin-related Protein 1 Oligomerization in Solution Impairs Functional Interactions with Membrane-anchored Mitochondrial Fission Factor. J Biol Chem 2015; 291:478-92. [PMID: 26578514 DOI: 10.1074/jbc.m115.680025] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Indexed: 11/06/2022] Open
Abstract
Mitochondrial fission is a crucial cellular process mediated by the mechanoenzymatic GTPase, dynamin-related protein 1 (Drp1). During mitochondrial division, Drp1 is recruited from the cytosol to the outer mitochondrial membrane by one, or several, integral membrane proteins. One such Drp1 partner protein, mitochondrial fission factor (Mff), is essential for mitochondrial division, but its mechanism of action remains unexplored. Previous studies have been limited by a weak interaction between Drp1 and Mff in vitro. Through refined in vitro reconstitution approaches and multiple independent assays, we show that removal of the regulatory variable domain (VD) in Drp1 enhances formation of a functional Drp1-Mff copolymer. This protein assembly exhibits greatly stimulated cooperative GTPase activity in solution. Moreover, when Mff was anchored to a lipid template, to mimic a more physiologic environment, significant stimulation of GTPase activity was observed with both WT and ΔVD Drp1. Contrary to recent findings, we show that premature Drp1 self-assembly in solution impairs functional interactions with membrane-anchored Mff. Instead, dimeric Drp1 species are selectively recruited by Mff to initiate assembly of a functional fission complex. Correspondingly, we also found that the coiled-coil motif in Mff is not essential for Drp1 interactions, but rather serves to augment cooperative self-assembly of Drp1 proximal to the membrane. Taken together, our findings provide a mechanism wherein the multimeric states of both Mff and Drp1 regulate their collaborative interaction.
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Affiliation(s)
- Ryan W Clinton
- From the Department of Pharmacology, the Center for Mitochondrial Diseases, the Cleveland Center for Membrane and Structural Biology, and
| | - Christopher A Francy
- From the Department of Pharmacology, the Center for Mitochondrial Diseases, the Cleveland Center for Membrane and Structural Biology, and
| | - Rajesh Ramachandran
- the Cleveland Center for Membrane and Structural Biology, and the Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Xin Qi
- the Center for Mitochondrial Diseases, the Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Jason A Mears
- From the Department of Pharmacology, the Center for Mitochondrial Diseases, the Cleveland Center for Membrane and Structural Biology, and
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Stepanyants N, Macdonald PJ, Francy CA, Mears JA, Qi X, Ramachandran R. Cardiolipin's propensity for phase transition and its reorganization by dynamin-related protein 1 form a basis for mitochondrial membrane fission. Mol Biol Cell 2015; 26:3104-16. [PMID: 26157169 PMCID: PMC4551322 DOI: 10.1091/mbc.e15-06-0330] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 07/01/2015] [Indexed: 01/01/2023] Open
Abstract
Fluid cardiolipin (CL) promotes self-assembly of Drp1, a dynamin-family GTPase involved in mitochondrial fission. Drp1 sequesters CL into condensed membrane platforms and in a GTP-dependent manner increases the propensity of the lipid to undergo a nonbilayer phase transition. CL reorganization generates local membrane constriction for fission. Cardiolipin (CL) is an atypical, dimeric phospholipid essential for mitochondrial dynamics in eukaryotic cells. Dynamin-related protein 1 (Drp1), a cytosolic member of the dynamin superfamily of large GTPases, interacts with CL and functions to sustain the balance of mitochondrial division and fusion by catalyzing mitochondrial fission. Although recent studies have indicated a role for CL in stimulating Drp1 self-assembly and GTPase activity at the membrane surface, the mechanism by which CL functions in membrane fission, if at all, remains unclear. Here, using a variety of fluorescence spectroscopic and imaging approaches together with model membranes, we demonstrate that Drp1 and CL function cooperatively in effecting membrane constriction toward fission in three distinct steps. These involve 1) the preferential association of Drp1 with CL localized at a high spatial density in the membrane bilayer, 2) the reorganization of unconstrained, fluid-phase CL molecules in concert with Drp1 self-assembly, and 3) the increased propensity of CL to transition from a lamellar, bilayer arrangement to an inverted hexagonal, nonbilayer configuration in the presence of Drp1 and GTP, resulting in the creation of localized membrane constrictions that are primed for fission. Thus we propose that Drp1 and CL function in concert to catalyze mitochondrial division.
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Affiliation(s)
- Natalia Stepanyants
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Patrick J Macdonald
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Christopher A Francy
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106 Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106 Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Jason A Mears
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106 Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106 Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Xin Qi
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106 Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106 Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106
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Francy CA, Alvarez FJD, Zhou L, Ramachandran R, Mears JA. The mechanoenzymatic core of dynamin-related protein 1 comprises the minimal machinery required for membrane constriction. J Biol Chem 2015; 290:11692-703. [PMID: 25770210 DOI: 10.1074/jbc.m114.610881] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Indexed: 11/06/2022] Open
Abstract
Mitochondria are dynamic organelles that continually undergo cycles of fission and fusion. Dynamin-related protein 1 (Drp1), a large GTPase of the dynamin superfamily, is the main mediator of mitochondrial fission. Like prototypical dynamin, Drp1 is composed of a mechanochemical core consisting of the GTPase, middle, and GTPase effector domain regions. In place of the pleckstrin homology domain in dynamin, however, Drp1 contains an unstructured variable domain, whose function is not yet fully resolved. Here, using time-resolved EM and rigorous statistical analyses, we establish the ability of full-length Drp1 to constrict lipid bilayers through a GTP hydrolysis-dependent mechanism. We also show the variable domain limits premature Drp1 assembly in solution and promotes membrane curvature. Furthermore, the mechanochemical core of Drp1, absent of the variable domain, is sufficient to mediate GTP hydrolysis-dependent membrane constriction.
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Affiliation(s)
- Christopher A Francy
- From the Department of Pharmacology, Center for Mitochondrial Diseases, and Cleveland Center for Membrane and Structural Biology, and
| | - Frances J D Alvarez
- From the Department of Pharmacology, Center for Mitochondrial Diseases, and Cleveland Center for Membrane and Structural Biology, and
| | - Louie Zhou
- From the Department of Pharmacology, Center for Mitochondrial Diseases, and Cleveland Center for Membrane and Structural Biology, and
| | - Rajesh Ramachandran
- Cleveland Center for Membrane and Structural Biology, and the Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Jason A Mears
- From the Department of Pharmacology, Center for Mitochondrial Diseases, and Cleveland Center for Membrane and Structural Biology, and
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Francy CA, Alvarez FJ, Zhou L, Mears JA. The Mechanoenzymatic Properties of Drp1 in Nucleotide Induced Constriction of Lipid Bilayers. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.2039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Macdonald PJ, Stepanyants N, Mehrotra N, Mears JA, Qi X, Sesaki H, Ramachandran R. A dimeric equilibrium intermediate nucleates Drp1 reassembly on mitochondrial membranes for fission. Mol Biol Cell 2014; 25:1905-15. [PMID: 24790094 PMCID: PMC4055269 DOI: 10.1091/mbc.e14-02-0728] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Drp1 catalyzes mitochondrial division, but the mechanisms remain elusive. The mitochondrial lipid cardiolipin stimulates Drp1 activity and supports membrane constriction. In addition, Drp1 populates two polymeric states that equilibrate via a dimeric intermediate. Dimers nucleate Drp1 reassembly on mitochondria for fission. The GTPase dynamin-related protein 1 (Drp1) catalyzes mitochondrial division, but the mechanisms remain poorly understood. Much of what is attributed to Drp1’s mechanism of action in mitochondrial membrane fission parallels that of prototypical dynamin in endocytic vesicle scission. Unlike the case for dynamin, however, no lipid target for Drp1 activation at the mitochondria has been identified. In addition, the oligomerization properties of Drp1 have not been well established. We show that the mitochondria-specific lipid cardiolipin is a potent stimulator of Drp1 GTPase activity, as well as of membrane tubulation. We establish further that under physiological conditions, Drp1 coexists as two morphologically distinct polymeric species, one nucleotide bound in solution and the other membrane associated, which equilibrate via a dimeric assembly intermediate. With two mutations, C300A and C505A, that shift Drp1 polymerization equilibria in opposite directions, we demonstrate that dimers, and not multimers, potentiate the reassembly and reorganization of Drp1 for mitochondrial membrane remodeling both in vitro and in vivo.
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Affiliation(s)
- Patrick J Macdonald
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Natalia Stepanyants
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Niharika Mehrotra
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Jason A Mears
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Xin Qi
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106
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Alvarez F, Zhou L, Mears JA. Structural Studies of Dynamin-Related Protein 1 (DRP1) Provide Mechanistic Insight into Mitochondrial Fission. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.1948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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29
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Alvarez FJD, Zhou L, Mears JA. Structural studies of Dnm1/Drp1 provide mechanistic insight into mitochondrial fission. Mitochondrion 2012. [DOI: 10.1016/j.mito.2012.07.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Hinshaw JE, Chappie JS, Mears JA, Fang S, Leonard M, Schmid SL, Milligan RA, Dyda F. Structural Analysis of Dynamin Reveals Power Stroke. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.1764] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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31
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Chappie JS, Mears JA, Fang S, Leonard M, Schmid SL, Milligan RA, Hinshaw JE, Dyda F. A pseudoatomic model of the dynamin polymer identifies a hydrolysis-dependent powerstroke. Cell 2011; 147:209-22. [PMID: 21962517 DOI: 10.1016/j.cell.2011.09.003] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 07/26/2011] [Accepted: 09/01/2011] [Indexed: 11/28/2022]
Abstract
The GTPase dynamin catalyzes membrane fission by forming a collar around the necks of clathrin-coated pits, but the specific structural interactions and conformational changes that drive this process remain a mystery. We present the GMPPCP-bound structures of the truncated human dynamin 1 helical polymer at 12.2 Å and a fusion protein, GG, linking human dynamin 1's catalytic G domain to its GTPase effector domain (GED) at 2.2 Å. The structures reveal the position and connectivity of dynamin fragments in the assembled structure, showing that G domain dimers only form between tetramers in sequential rungs of the dynamin helix. Using chemical crosslinking, we demonstrate that dynamin tetramers are made of two dimers, in which the G domain of one molecule interacts in trans with the GED of another. Structural comparison of GG(GMPPCP) to the GG transition-state complex identifies a hydrolysis-dependent powerstroke that may play a role in membrane-remodeling events necessary for fission.
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Affiliation(s)
- Joshua S Chappie
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
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Jomaa A, Stewart G, Mears JA, Kireeva I, Brown ED, Ortega J. Cryo-electron microscopy structure of the 30S subunit in complex with the YjeQ biogenesis factor. RNA 2011; 17:2026-38. [PMID: 21960487 PMCID: PMC3198595 DOI: 10.1261/rna.2922311] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Accepted: 08/26/2011] [Indexed: 05/22/2023]
Abstract
YjeQ is a protein broadly conserved in bacteria containing an N-terminal oligonucleotide/oligosaccharide fold (OB-fold) domain, a central GTPase domain, and a C-terminal zinc-finger domain. YjeQ binds tightly and stoichiometrically to the 30S subunit, which stimulates its GTPase activity by 160-fold. Despite growing evidence for the involvement of the YjeQ protein in bacterial 30S subunit assembly, the specific function and mechanism of this protein remain unclear. Here, we report the costructure of YjeQ with the 30S subunit obtained by cryo-electron microscopy. The costructure revealed that YjeQ interacts simultaneously with helix 44, the head and the platform of the 30S subunit. This binding location of YjeQ in the 30S subunit suggests a chaperone role in processing of the 3' end of the rRNA as well as in mediating the correct orientation of the main domains of the 30S subunit. In addition, the YjeQ binding site partially overlaps with the interaction site of initiation factors 2 and 3, and upon binding, YjeQ covers three inter-subunit bridges that are important for the association of the 30S and 50S subunits. Hence, our structure suggests that YjeQ may assist in ribosome maturation by preventing premature formation of the translation initiation complex and association with the 50S subunit. Together, these results support a role for YjeQ in the late stages of 30S maturation.
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Affiliation(s)
- Ahmad Jomaa
- Department of Biochemistry and Biomedical Sciences and Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, L8N3Z5, Canada
| | - Geordie Stewart
- Department of Biochemistry and Biomedical Sciences and Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, L8N3Z5, Canada
| | - Jason A. Mears
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Inga Kireeva
- Department of Biochemistry and Biomedical Sciences and Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, L8N3Z5, Canada
| | - Eric D. Brown
- Department of Biochemistry and Biomedical Sciences and Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, L8N3Z5, Canada
| | - Joaquin Ortega
- Department of Biochemistry and Biomedical Sciences and Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, L8N3Z5, Canada
- Corresponding author.E-mail .
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Schulz TA, Choi MG, Raychaudhuri S, Mears JA, Ghirlando R, Hinshaw JE, Prinz WA. Lipid-regulated sterol transfer between closely apposed membranes by oxysterol-binding protein homologues. ACTA ACUST UNITED AC 2010; 187:889-903. [PMID: 20008566 PMCID: PMC2806323 DOI: 10.1083/jcb.200905007] [Citation(s) in RCA: 175] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The ORP lipid-binding domain can contact two membranes simultaneously to facilitate sterol extraction or delivery at one membrane in response to the lipid composition of the other. Sterols are transferred between cellular membranes by vesicular and poorly understood nonvesicular pathways. Oxysterol-binding protein–related proteins (ORPs) have been implicated in sterol sensing and nonvesicular transport. In this study, we show that yeast ORPs use a novel mechanism that allows regulated sterol transfer between closely apposed membranes, such as organelle contact sites. We find that the core lipid-binding domain found in all ORPs can simultaneously bind two membranes. Using Osh4p/Kes1p as a representative ORP, we show that ORPs have at least two membrane-binding surfaces; one near the mouth of the sterol-binding pocket and a distal site that can bind a second membrane. The distal site is required for the protein to function in cells and, remarkably, regulates the rate at which Osh4p extracts and delivers sterols in a phosphoinositide-dependent manner. Together, these findings suggest a new model of how ORPs could sense and regulate the lipid composition of adjacent membranes.
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Affiliation(s)
- Timothy A Schulz
- Laboratory of Cell Biochemistry and Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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Mears JA, Ray P, Fang S, Lackner L, Nunnari J, Hinshaw JE. The Role of Dynamin Family Members in Membrane Fission. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.82.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - Laura Lackner
- Section of Molecular and Cellular BiologyUC DavisDavisCA
| | - Jodi Nunnari
- Section of Molecular and Cellular BiologyUC DavisDavisCA
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Mears JA, Lackner LL, Fang S, Nunnari JM, Hinshaw JE. Mitochondrial Fission is Mediated by Conformational Changes in the Dynamin-related Protein, Dnm1. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.2105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Affiliation(s)
- Jason A Mears
- Laboratory of Cell Biochemistry and Biology, NIDDK, NIH, Bethesda, Maryland 20892, USA
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Mears JA, Sharma MR, Gutell RR, McCook AS, Richardson PE, Caulfield TR, Agrawal RK, Harvey SC. A structural model for the large subunit of the mammalian mitochondrial ribosome. J Mol Biol 2006; 358:193-212. [PMID: 16510155 PMCID: PMC3495566 DOI: 10.1016/j.jmb.2006.01.094] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2005] [Revised: 01/25/2006] [Accepted: 01/27/2006] [Indexed: 11/30/2022]
Abstract
Protein translation is essential for all forms of life and is conducted by a macromolecular complex, the ribosome. Evolutionary changes in protein and RNA sequences can affect the 3D organization of structural features in ribosomes in different species. The most dramatic changes occur in animal mitochondria, whose genomes have been reduced and altered significantly. The RNA component of the mitochondrial ribosome (mitoribosome) is reduced in size, with a compensatory increase in protein content. Until recently, it was unclear how these changes affect the 3D structure of the mitoribosome. Here, we present a structural model of the large subunit of the mammalian mitoribosome developed by combining molecular modeling techniques with cryo-electron microscopic data at 12.1A resolution. The model contains 93% of the mitochondrial rRNA sequence and 16 mitochondrial ribosomal proteins in the large subunit of the mitoribosome. Despite the smaller mitochondrial rRNA, the spatial positions of RNA domains known to be involved directly in protein synthesis are essentially the same as in bacterial and archaeal ribosomes. However, the dramatic reduction in rRNA content necessitates evolution of unique structural features to maintain connectivity between RNA domains. The smaller rRNA sequence also limits the likelihood of tRNA binding at the E-site of the mitoribosome, and correlates with the reduced size of D-loops and T-loops in some animal mitochondrial tRNAs, suggesting co-evolution of mitochondrial rRNA and tRNA structures.
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Affiliation(s)
- Jason A Mears
- Department of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA
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Abstract
Dynamin-related proteins (DRPs) are large self-assembling GTPases whose common function is to regulate membrane dynamics in a variety of cellular processes. Dnm1, which is a yeast DRP (Drp1/Dlp1 in humans), is required for mitochondrial division, but its mechanism is unknown. We provide evidence that Dnm1 likely functions through self-assembly to drive the membrane constriction event that is associated with mitochondrial division. Two regulatory features of Dnm1 self-assembly were also identified. Dnm1 self-assembly proceeded through a rate-limiting nucleation step, and nucleotide hydrolysis by assembled Dnm1 structures was highly cooperative with respect to GTP. Dnm1 formed extended spirals, which possessed diameters greater than those of dynamin-1 spirals but whose sizes, remarkably, were equal to those of mitochondrial constriction sites in vivo. These data suggest that Dnm1 has evolved to form structures that fit the dimensions of mitochondria.
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Affiliation(s)
- Elena Ingerman
- Department of Molecular and Cellular Biology, Center for Genetics and Development, University of California, Davis, Davis, CA 95616, USA
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Ivanov VI, Mears JA. Using cross-links to study ribosomal dynamics. J Biomol Struct Dyn 2004; 21:691-8. [PMID: 14769062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
After publications of 3-D models of a static ribosome and its large and small subunits, one of the next tasks is to recognize movable ribosomal elements responsible for mechanical shifts during protein synthesis. Statistic analysis of available cross-linking data allowed us to reveal three well separated groups of motions in the ribosome: I, mean magnitude of 10 A; II, most abundant, centered at 20 A and of wide dispersion, and III, sparsely populated, with large distances up to 95 A. The last group, III, comprises elements, like the L7/12-stalk and the L1- protuberance, that adopt different positions in crystallographic or electron micrographic structures, and neighboring hairpins 88 and 89, indicating mobility. We demonstrate that the cross-linking method can be applied to study ribosomal dynamics, including large-scale functional movements and, in particular, to estimate which structures participate in molecular switches.
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Affiliation(s)
- Valery I Ivanov
- VA Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia.
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Abstract
The order in which proteins bind to 16S rRNA, the assembly map, was determined by Nomura and co-workers in the early 1970s. The assembly map shows the dependencies of binding of successive proteins but fails to address the relationship of these dependencies to the three-dimensional folding of the ribosome. Here, using molecular mechanics techniques, we rationalize the order of protein binding in terms of ribosomal folding. We determined the specific contacts between the ribosomal proteins and 16S rRNA from a crystal structure of the 30S subunit (1FJG). We then used these contacts as restraints in a rigid body Monte-Carlo simulation with reduced-representation models of the RNA and proteins. Proteins were added sequentially to the RNA in the order that they appear in the assembly map. Our results show that proteins nucleate the folding of the head, platform, and body domains, but they do not strongly restrict the orientations of the domains relative to one another. We also examined the contributions of individual proteins to the formation of binding sites for sequential proteins in the assembly process. Binding sites for the primary binding proteins are generally more ordered in the naked RNA than those for other proteins. Furthermore, we examined one pathway in the assembly map and found that the addition of early binding proteins helps to organize the RNA around the binding sites of proteins that bind later. It appears that the order of assembly depends on the degree of pre-organization of each protein's binding site at a given stage of assembly, and the impact that the binding of each protein has on the organization of the remaining unoccupied binding sites.
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Affiliation(s)
- Scott M Stagg
- Department of Biochemistry and Molecular Genetics, The University of Alabama at Birmingham, 1918 University Blvd, 552 Basic Health Sciences Bldg, Birmingham, AL 35294-0005, USA
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Abstract
We have determined the three-dimensional organization of ribosomal RNAs and proteins essential for minimal ribosome function. Comparative sequence analysis identifies regions of the ribosome that have been evolutionarily conserved, and the spatial organization of conserved domains is determined by mapping these onto structures of the 30S and 50S subunits determined by X-ray crystallography. Several functional domains of the ribosome are conserved in their three-dimensional organization in the Archaea, Bacteria, Eucaryotic nuclear, mitochondria and chloroplast ribosomes. In contrast, other regions from both subunits have shifted their position in three-dimensional space during evolution, including the L11 binding domain and the alpha-sarcin-ricin loop (SRL). We examined conserved bridge interactions between the two ribosomal subunits, giving an indication of which contacts are more significant. The tRNA contacts that are conserved were also determined, highlighting functional interactions as the tRNA moves through the ribosome during protein synthesis. To augment these studies of a large collection of comparative structural models sampled from all major branches on the phylogenetic tree, Caenorhabditis elegans mitochondrial rRNA is considered individually because it is among the smallest rRNA sequences known. The C.elegans model supports the large collection of comparative structure models while providing insight into the evolution of mitochondrial ribosomes.
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Affiliation(s)
- Jason A Mears
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35295-0005, USA
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43
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Abstract
The distribution of 34 flavonoids detected in the North American species of Parthenium L. is presented. Of the 27 flavonoids identified (some tentatively) all are flavonols: eight are based on kaempferol, seven on quercetin, four on 6-hydroxykaempferol and eight on the quercetagetin skeleton. Of the 34 flavonoids detected, 19 are glycosides and 15 are aglycones, primarily highly methylated compounds.
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Affiliation(s)
- J A Mears
- Phytochemistry Laboratory, Academy of Natural Sciences of Philadelphia, USA
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Lee OS, Mears JA, Miller DD, Feller DR. Evaluation of the optical isomers of tetrahydroisoquinolines in rat adipose tissue and guinea pig aorta. Eur J Pharmacol 1974; 28:225-9. [PMID: 4430326 DOI: 10.1016/0014-2999(74)90137-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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