1
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Peng R, Rochon K, Hutson AN, Stagg SM, Mears JA. The Structure of the Drp1 Lattice on Membrane. J Mol Biol 2025; 437:169125. [PMID: 40185198 DOI: 10.1016/j.jmb.2025.169125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2025] [Accepted: 03/31/2025] [Indexed: 04/07/2025]
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 mechanisms. 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. We identified two states of the Drp1 lattice among the heterogenous dataset representing conformational changes around hinge 1. Additionally, we observed contact between Drp1 and membrane that can be assigned to the variable domain sequence. 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, FL, USA
| | - Kristy Rochon
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Anelise N Hutson
- 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, FL, USA; Department of Biological Sciences, Florida State University, Tallahassee, FL, 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 Research and Therapeutics, Case Western Reserve University School of Medicine, Cleveland, OH 44106 USA.
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2
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Liu J, Hu J, Duan Y, Tan Y, Gao Q, Wu G. Expanding the phenotypic spectrum of DNM1-related disorders: novel GTPase domain variants and their diverse neurological outcomes. Neurol Sci 2025; 46:2809-2817. [PMID: 39954101 DOI: 10.1007/s10072-024-07974-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2024] [Accepted: 12/23/2024] [Indexed: 02/17/2025]
Abstract
BACKGROUND Pathogenic DNM1 variants cause early-onset developmental and epileptic encephalopathy (DEE). The GTPase domain of the DNM1 protein has the most commonly affected sites. AIM This study aimed to delineate additional patients with DNM1-related disorders harboring novel GTPase domain variants. METHODS Trio whole-exome sequencing was performed on three Chinese probands with suspected encephalopathy, and Sanger sequencing was used to confirm the variants. Detailed evaluations were used to assess clinical features. Variant plasmids were constructed in vitro and transfected into cells, and the expression of mutant proteins was evaluated using western blotting (WB). RESULTS Three de novo heterozygous DNM1 variants were detected in the GTPase domain, namely, NM_004408.4: c.112_120delinsAGCGGCCAC, (p.Gly38_Gln40delinsSerGlyHis), c.457G > A, (p.Glu153Lys), and c.193 A > C, (p.Thr65Pro) in Patients 1, 2, and 3, respectively. Patients 2 and 3 exhibited typical DEE phenotypes with early-onset refractory seizures, profound developmental impairment, intellectual disability, and abnormal electroencephalography findings. However, Patient 1 did not have seizures and her clinical symptoms were autism features, mild hearing loss, subtle changes in the brain, and developmental delays. WB indicated that the expression of plasmids carrying the p.Thr65Pro and p.Glu153Lys variants was not significantly different from that in the wild-type control group and that the expression of the p.Gly38_Gln40delinsSerGlyHis plasmid was elevated. CONCLUSIONS This study expands the genetic and phenotypic spectrum of DNM1-associated disorders and reveals that de novo pathogenic variants in the GTPase domain can lead to divergent neurological outcomes ranging from infantile epileptic encephalopathy syndromes to predominant developmental delays without seizures.
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Affiliation(s)
- Juan Liu
- Department of Rehabilitation, Hunan Children's Hospital, Changsha, China
| | - Jihong Hu
- Department of Rehabilitation, Hunan Children's Hospital, Changsha, China
| | - Yaqin Duan
- Department of Rehabilitation, Hunan Children's Hospital, Changsha, China
| | - Yaqiong Tan
- Department of Rehabilitation, Hunan Children's Hospital, Changsha, China
| | - Quwen Gao
- Department of Neurology, Foresea Life Insurance Shaoguan Hospital, 15th Danxia Road, Shaoguan, Guangdong, 510630, China.
| | - Gefei Wu
- Department of Neurology, Tongji Medical College, Wuhan Children's Hospital, Wuhan Maternal and Child Healthcare Hospital, Huazhong University of Science and Technology, 100th Hong Kong Road, Wuhan, Hubei, 430015, China.
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3
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Pemberton JG, Roy K, Kim YJ, Fischer TD, Joshi V, Ferrer E, Youle RJ, Pucadyil TJ, Balla T. Acute diacylglycerol production activates critical membrane-shaping proteins leading to mitochondrial tubulation and fission. Nat Commun 2025; 16:2685. [PMID: 40102394 PMCID: PMC11920102 DOI: 10.1038/s41467-025-57439-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2024] [Accepted: 02/24/2025] [Indexed: 03/20/2025] Open
Abstract
Mitochondrial dynamics are orchestrated by protein assemblies that directly remodel membrane structure, however the influence of specific lipids on these processes remains poorly understood. Here, using an inducible heterodimerization system to selectively modulate the lipid composition of the outer mitochondrial membrane (OMM), we show that local production of diacylglycerol (DAG) directly leads to transient tubulation and rapid fragmentation of the mitochondrial network, which are mediated by isoforms of endophilin B (EndoB) and dynamin-related protein 1 (Drp1), respectively. Reconstitution experiments on cardiolipin-containing membrane templates mimicking the planar and constricted OMM topologies reveal that DAG facilitates the membrane binding and remodeling activities of both EndoB and Drp1, thereby independently potentiating membrane tubulation and fission events. EndoB and Drp1 do not directly interact with each other, suggesting that DAG production activates multiple pathways for membrane remodeling in parallel. Together, our data emphasizes the importance of OMM lipid composition in regulating mitochondrial dynamics.
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Affiliation(s)
- Joshua G Pemberton
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
- Department of Biology, Western University, London, ON, Canada.
- Division of Development & Genetics, Children's Health Research Institute, London Health Sciences Centre Research Institute, London, ON, Canada.
| | - Krishnendu Roy
- Indian Institute of Science Education and Research, Pune, Maharashtra, India
| | - Yeun Ju Kim
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Tara D Fischer
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Vijay Joshi
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Elizabeth Ferrer
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Richard J Youle
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Thomas J Pucadyil
- Indian Institute of Science Education and Research, Pune, Maharashtra, India.
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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4
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Peng R, Rochon K, Hutson AN, Stagg SM, Mears JA. The Structure of the Drp1 Lattice on Membrane. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2024.04.04.588123. [PMID: 38617273 PMCID: PMC11014616 DOI: 10.1101/2024.04.04.588123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [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 mechanisms. 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. We identified two states of the Drp1 lattice among the heterogenous dataset representing conformational changes around hinge 1. Additionally, we observed contact between Drp1 and membrane that can be assigned to the variable domain sequence. 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
| | - Anelise N Hutson
- 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 Research and Therapeutics, Case Western Reserve University School of Medicine, Cleveland, OH 44106 USA
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5
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Zhang Y, Lillo JV, Mohamed Abdelrasoul MS, Wang Y, Arrasate P, Frolov VA, Noy A. Nanoscale dynamics of Dynamin 1 helices reveals squeeze-twist deformation mode critical for membrane fission. Proc Natl Acad Sci U S A 2024; 121:e2321514121. [PMID: 39602273 PMCID: PMC11626203 DOI: 10.1073/pnas.2321514121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 10/21/2024] [Indexed: 11/29/2024] Open
Abstract
Dynamin 1 (Dyn1) GTPase, a principal driver of membrane fission during synaptic endocytosis, self-assembles into short mechanoactive helices cleaving the necks of endocytic vesicles. While structural information about Dyn1 helix is abundant, little is known about the nanoscale dynamics of the helical scaffolding at the moment of fission, complicating mechanistic understanding of Dyn1 action. To address the role of the helix dynamics in fission, we used High-Speed Atomic Force Microscopy (HS-AFM) and fluorescence microscopy to track and compare the spatiotemporal characteristics of the helices formed by wild-type Dyn1 and its K44A mutant impaired in GTP hydrolysis on minimal lipid membrane templates. In the absence of nucleotide, membrane-bound WTDyn1 and K44ADyn1 self-assembled into tubular protein scaffolding of similar diameter encaging the lipid bilayer. In both cases, the GTP addition caused scaffold constriction coupled with formation of 20 to 30 nm nanogaps in the protein coverage. While both proteins reached scaffold diameters characteristic for membrane superconstriction causing fission, the fission was detected only with WTDyn1. We associated the fission activity with the dynamic evolution of the nanogaps: K44ADyn1 gaps were static, while WTDyn1 gaps actively evolved via repetitive nonaxisymmetric constriction-bending deformations caused by localized GTP hydrolysis. Modeling of the deformations implicated filament twist as an additional deformation mode which combines with superconstriction to facilitate membrane fission. Our results thus show that the dynamics of the Dyn1 helical scaffold goes beyond radial constriction and involves nonaxisymmetric deformations, where filament twist emerges as a critical driver of membrane fission.
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Affiliation(s)
- Yuliang Zhang
- Materials Science Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA94550
| | - Javier Vera Lillo
- Biofisika Institute Consejo Superior de Investigaciones Científicas, Universidad del País Vasco, Euskal Herriko Unibersitatea (CSIC, UPV/EHU), University of the Basque Country, Leioa, 48940, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country, Leioa, 48940, Spain
| | | | - Yaqing Wang
- Materials Science Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA94550
| | - Pedro Arrasate
- Biofisika Institute Consejo Superior de Investigaciones Científicas, Universidad del País Vasco, Euskal Herriko Unibersitatea (CSIC, UPV/EHU), University of the Basque Country, Leioa, 48940, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country, Leioa, 48940, Spain
| | - Vadim A. Frolov
- Biofisika Institute Consejo Superior de Investigaciones Científicas, Universidad del País Vasco, Euskal Herriko Unibersitatea (CSIC, UPV/EHU), University of the Basque Country, Leioa, 48940, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country, Leioa, 48940, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, 48009, Spain
| | - Aleksandr Noy
- Materials Science Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA94550
- School of Natural Sciences, University of California Merced, Merced, CA93434
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6
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Jimah JR, Kundu N, Stanton AE, Sochacki KA, Canagarajah B, Chan L, Strub MP, Wang H, Taraska JW, Hinshaw JE. Cryo-EM structures of membrane-bound dynamin in a post-hydrolysis state primed for membrane fission. Dev Cell 2024; 59:1783-1793.e5. [PMID: 38663399 PMCID: PMC11265984 DOI: 10.1016/j.devcel.2024.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 12/29/2023] [Accepted: 04/04/2024] [Indexed: 07/25/2024]
Abstract
Dynamin assembles as a helical polymer at the neck of budding endocytic vesicles, constricting the underlying membrane as it progresses through the GTPase cycle to sever vesicles from the plasma membrane. Although atomic models of the dynamin helical polymer bound to guanosine triphosphate (GTP) analogs define earlier stages of membrane constriction, there are no atomic models of the assembled state post-GTP hydrolysis. Here, we used cryo-EM methods to determine atomic structures of the dynamin helical polymer assembled on lipid tubules, akin to necks of budding endocytic vesicles, in a guanosine diphosphate (GDP)-bound, super-constricted state. In this state, dynamin is assembled as a 2-start helix with an inner lumen of 3.4 nm, primed for spontaneous fission. Additionally, by cryo-electron tomography, we trapped dynamin helical assemblies within HeLa cells using the GTPase-defective dynamin K44A mutant and observed diverse dynamin helices, demonstrating that dynamin can accommodate a range of assembled complexes in cells that likely precede membrane fission.
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Affiliation(s)
- John R Jimah
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Nidhi Kundu
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Abigail E Stanton
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kem A Sochacki
- Biochemistry and Biophysics Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bertram Canagarajah
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lieza Chan
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Marie-Paule Strub
- Biochemistry and Biophysics Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Huaibin Wang
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Justin W Taraska
- Biochemistry and Biophysics Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jenny E Hinshaw
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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7
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Klenow MB, Vigsø MS, Pezeshkian W, Nylandsted J, Lomholt MA, Simonsen AC. Shape of the membrane neck around a hole during plasma membrane repair. Biophys J 2024; 123:1827-1837. [PMID: 38824389 PMCID: PMC11267432 DOI: 10.1016/j.bpj.2024.05.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 04/05/2024] [Accepted: 05/28/2024] [Indexed: 06/03/2024] Open
Abstract
Plasma membrane damage and rupture occurs frequently in cells, and holes must be sealed rapidly to ensure homeostasis and cell survival. The membrane repair machinery is known to involve recruitment of curvature-inducing annexin proteins, but the connection between membrane remodeling and hole closure is poorly described. The induction of curvature by repair proteins leads to the possible formation of a membrane neck around the hole as a key intermediate structure before sealing. We formulate a theoretical model of equilibrium neck shapes to examine the potential connection to a repair mechanism. Using variational calculus, the shape equations for the membrane near a hole are formulated and solved numerically. The system is described under a condition of fixed area, and a shooting approach is applied to fulfill the boundary conditions at the free membrane edge. A state diagram of neck shapes is produced describing the variation in neck morphology with respect to the membrane area. Two distinct types of necks are predicted, one with conformations curved beyond π existing at positive excess area, whereas flat neck conformations (curved below π) have negative excess area. The results indicate that in cells, the supply of additional membrane area and a change in edge tension is linked to the formation of narrow and curved necks. Such necks may be susceptible to passive or actively induced membrane fission as a possible mechanism for hole sealing during membrane repair in cells.
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Affiliation(s)
- Martin Berg Klenow
- PhyLife - Physical LifeScience, Department of Physics Chemistry and Pharmacy, University of Southern Denmark (SDU), Campusvej 55, Odense M, Denmark
| | - Magnus Staal Vigsø
- PhyLife - Physical LifeScience, Department of Physics Chemistry and Pharmacy, University of Southern Denmark (SDU), Campusvej 55, Odense M, Denmark
| | - Weria Pezeshkian
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Nylandsted
- Danish Cancer Institute (DCI), Copenhagen Ø, Denmark; Department of Molecular Medicine, University of Southern Denmark, Odense C, Denmark
| | - Michael Andersen Lomholt
- PhyLife - Physical LifeScience, Department of Physics Chemistry and Pharmacy, University of Southern Denmark (SDU), Campusvej 55, Odense M, Denmark
| | - Adam Cohen Simonsen
- PhyLife - Physical LifeScience, Department of Physics Chemistry and Pharmacy, University of Southern Denmark (SDU), Campusvej 55, Odense M, Denmark.
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8
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Bussoletti M, Gallo M, Bottacchiari M, Abbondanza D, Casciola CM. Mesoscopic elasticity controls dynamin-driven fission of lipid tubules. Sci Rep 2024; 14:14003. [PMID: 38890460 PMCID: PMC11189461 DOI: 10.1038/s41598-024-64685-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Accepted: 06/12/2024] [Indexed: 06/20/2024] Open
Abstract
Mesoscale physics bridges the gap between the microscopic degrees of freedom of a system and its large-scale continuous behavior and highlights the role of a few key quantities in complex and multiscale phenomena, like dynamin-driven fission of lipid membranes. The dynamin protein wraps the neck formed during clathrin-mediated endocytosis, for instance, and constricts it until severing occurs. Although ubiquitous and fundamental for life, the cooperation between the GTP-consuming conformational changes within the protein and the full-scale response of the underlying lipid substrate is yet to be unraveled. In this work, we build an effective mesoscopic model from constriction to fission of lipid tubules based on continuum membrane elasticity and implicitly accounting for ratchet-like power strokes of dynamins. Localization of the fission event, the overall geometry, and the energy expenditure we predict comply with the major experimental findings. This bolsters the idea that a continuous picture emerges soon enough to relate dynamin polymerization length and membrane rigidity and tension with the optimal pathway to fission. We therefore suggest that dynamins found in in vivo processes may optimize their structure accordingly. Ultimately, we shed light on real-time conductance measurements available in literature and predict the fission time dependency on elastic parameters.
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Affiliation(s)
- Marco Bussoletti
- Department of Mechanical and Aerospace Engineering, Sapienza University of Rome, Rome, Italy
| | - Mirko Gallo
- Department of Mechanical and Aerospace Engineering, Sapienza University of Rome, Rome, Italy
| | - Matteo Bottacchiari
- Department of Mechanical and Aerospace Engineering, Sapienza University of Rome, Rome, Italy
- Department of Basic and Applied Sciences for Engineering, Sapienza University of Rome, Rome, Italy
| | - Dario Abbondanza
- Department of Mechanical and Aerospace Engineering, Sapienza University of Rome, Rome, Italy
| | - Carlo Massimo Casciola
- Department of Mechanical and Aerospace Engineering, Sapienza University of Rome, Rome, Italy.
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9
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Gnyliukh N, Johnson A, Nagel MK, Monzer A, Babić D, Hlavata A, Alotaibi SS, Isono E, Loose M, Friml J. Role of the dynamin-related protein 2 family and SH3P2 in clathrin-mediated endocytosis in Arabidopsis thaliana. J Cell Sci 2024; 137:jcs261720. [PMID: 38506228 PMCID: PMC11112126 DOI: 10.1242/jcs.261720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 03/12/2024] [Indexed: 03/21/2024] Open
Abstract
Clathrin-mediated endocytosis (CME) is vital for the regulation of plant growth and development through controlling plasma membrane protein composition and cargo uptake. CME relies on the precise recruitment of regulators for vesicle maturation and release. Homologues of components of mammalian vesicle scission are strong candidates to be part of the scission machinery in plants, but the precise roles of these proteins in this process are not fully understood. Here, we characterised the roles of the plant dynamin-related protein 2 (DRP2) family (hereafter DRP2s) and SH3-domain containing protein 2 (SH3P2), the plant homologue to recruiters of dynamins, such as endophilin and amphiphysin, in CME by combining high-resolution imaging of endocytic events in vivo and characterisation of the purified proteins in vitro. Although DRP2s and SH3P2 arrive similarly late during CME and physically interact, genetic analysis of the sh3p123 triple mutant and complementation assays with non-SH3P2-interacting DRP2 variants suggest that SH3P2 does not directly recruit DRP2s to the site of endocytosis. These observations imply that, despite the presence of many well-conserved endocytic components, plants have acquired a distinct mechanism for CME.
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Affiliation(s)
- Nataliia Gnyliukh
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | - Alexander Johnson
- Division of Anatomy, Centre for Anatomy & Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
| | | | - Aline Monzer
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | - David Babić
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | - Annamaria Hlavata
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | - Saqer S. Alotaibi
- Department of Biotechnology, College of Science, Taif University, Taif 21944, Saudi Arabia
| | - Erika Isono
- Department of Biology, University of Konstanz, 78464 Konstanz, Germany
| | - Martin Loose
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | - Jiří Friml
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
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10
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Sun G, Hwang C, Jung T, Liu J, Li R. Biased placement of Mitochondria fission facilitates asymmetric inheritance of protein aggregates during yeast cell division. PLoS Comput Biol 2023; 19:e1011588. [PMID: 38011208 PMCID: PMC10703421 DOI: 10.1371/journal.pcbi.1011588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 12/07/2023] [Accepted: 10/10/2023] [Indexed: 11/29/2023] Open
Abstract
Mitochondria are essential and dynamic eukaryotic organelles that must be inherited during cell division. In yeast, mitochondria are inherited asymmetrically based on quality, which is thought to be vital for maintaining a rejuvenated cell population; however, the mechanisms underlying mitochondrial remodeling and segregation during this process are not understood. We used high spatiotemporal imaging to quantify the key aspects of mitochondrial dynamics, including motility, fission, and fusion characteristics, upon aggregation of misfolded proteins in the mitochondrial matrix. Using these measured parameters, we developed an agent-based stochastic model of dynamics of mitochondrial inheritance. Our model predicts that biased mitochondrial fission near the protein aggregates facilitates the clustering of protein aggregates in the mitochondrial matrix, and this process underlies asymmetric mitochondria inheritance. These predictions are supported by live-cell imaging experiments where mitochondrial fission was perturbed. Our findings therefore uncover an unexpected role of mitochondrial dynamics in asymmetric mitochondrial inheritance.
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Affiliation(s)
- Gordon Sun
- Center for Cell Dynamics and Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Biomedical Engineering Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Christine Hwang
- Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Tony Jung
- Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Jian Liu
- Center for Cell Dynamics and Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Biochemistry, Cellular and Molecular Biology Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Rong Li
- Center for Cell Dynamics and Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Biochemistry, Cellular and Molecular Biology Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
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11
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Cossar PJ, Cardoso D, Mathwin D, Russell CC, Chiew B, Hamilton MP, Baker JR, Young KA, Chau N, Robinson PJ, McCluskey A. Wiskostatin and other carbazole scaffolds as off target inhibitors of dynamin I GTPase activity and endocytosis. Eur J Med Chem 2023; 247:115001. [PMID: 36577213 DOI: 10.1016/j.ejmech.2022.115001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/30/2022] [Accepted: 11/30/2022] [Indexed: 12/23/2022]
Abstract
Wiskostatin (1-(3,6-dibromo-9H-carbazol-9-yl)-3-(dimethylamino)propan-2-ol) (1) is a carbazole-based compound reported as a specific and relatively potent inhibitor of the N-WASP actin remodelling complex (S-isomer EC50 = 4.35 μM; R-isomer EC50 = 3.44 μM). An NMR solution structure showed that wiskostatin interacts with a cleft in the regulatory GTPase binding domain of N-WASP. However, numerous studies have reported wiskostatin's actions on membrane transport and cytokinesis that are independent of the N-WASP-Arp2/3 complex pathway, but offer limited alternative explanation. The large GTPase, dynamin has established functional roles in these pathways. This study reveals that wiskostatin and its analogues, as well as other carbazole-based compounds, are inhibitors of helical dynamin GTPase activity and endocytosis. We characterise the effects of wiskostatin on in vitro dynamin GTPase activity, in-cell endocytosis, and determine the importance of wiskostatin functional groups on these activities through design and synthesis of libraries of wiskostatin analogues. We also examine whether other carbazole-based scaffolds frequently used in research or the clinic also modulate dynamin and endocytosis. Understanding off-targets for compounds used as research tools is important to be able to confidently interpret their action on biological systems, particularly when the target and off-targets affect overlapping mechanisms (e.g. cytokinesis and endocytosis). Herein we demonstrate that wiskostatin is a dynamin inhibitor (IC50 20.7 ± 1.2 μM) and a potent inhibitor of clathrin mediated endocytosis (IC50 = 6.9 ± 0.3 μM). Synthesis of wiskostatin analogues gave rise to 1-(9H-carbazol-9-yl)-3-((4-methylbenzyl)amino)propan-2-ol (35) and 1-(9H-carbazol-9-yl)-3-((4-chlorobenzyl)amino)propan-2-ol (43) as potent dynamin inhibitors (IC50 = 1.0 ± 0.2 μM), and (S)-1-(3,6-dibromo-9H-carbazol-9-yl)-3-(dimethylamino)propan-2-ol (8a) and (R)-1-(3,6-dibromo-9H-carbazol-9-yl)-3-(dimethylamino)propan-2-ol (8b) that are amongst the most potent inhibitors of clathrin mediated endocytosis yet reported (IC50 = 2.3 ± 3.3 and 2.1 ± 1.7 μM, respectively).
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Affiliation(s)
- Peter J Cossar
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia
| | - David Cardoso
- Cell Signalling Unit, Children's Medical Research Institute, The University of Sydney, Sydney, NSW, 2145, Australia
| | - Daniel Mathwin
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia
| | - Cecilia C Russell
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia
| | - Beatrice Chiew
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia
| | - Michael P Hamilton
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia
| | - Jennifer R Baker
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia
| | - Kelly A Young
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia
| | - Ngoc Chau
- Cell Signalling Unit, Children's Medical Research Institute, The University of Sydney, Sydney, NSW, 2145, Australia
| | - Phillip J Robinson
- Cell Signalling Unit, Children's Medical Research Institute, The University of Sydney, Sydney, NSW, 2145, Australia
| | - Adam McCluskey
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia.
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12
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Alkafaas SS, Abdallah AM, Ghosh S, Loutfy SA, Elkafas SS, Abdel Fattah NF, Hessien M. Insight into the role of clathrin-mediated endocytosis inhibitors in SARS-CoV-2 infection. Rev Med Virol 2023; 33:e2403. [PMID: 36345157 PMCID: PMC9877911 DOI: 10.1002/rmv.2403] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 10/08/2022] [Accepted: 10/10/2022] [Indexed: 11/10/2022]
Abstract
Emergence of SARS-CoV-2 variants warrants sustainable efforts to upgrade both the diagnostic and therapeutic protocols. Understanding the details of cellular and molecular basis of the virus-host cell interaction is essential for developing variant-independent therapeutic options. The internalization of SARS-CoV-2, into lung epithelial cells, is mediated by endocytosis, especially clathrin-mediated endocytosis (CME). Although vaccination is the gold standard strategy against viral infection, selective inhibition of endocytic proteins, complexes, and associated adaptor proteins may present a variant-independent therapeutic strategy. Although clathrin and/or dynamins are the most important proteins involved in CME, other endocytic mechanisms are clathrin and/or dynamin independent and rely on other proteins. Moreover, endocytosis implicates some subcellular structures, like plasma membrane, actin and lysosomes. Also, physiological conditions, such as pH and ion concentrations, represent an additional factor that mediates these events. Accordingly, endocytosis related proteins are potential targets for small molecules that inhibit endocytosis-mediated viral entry. This review summarizes the potential of using small molecules, targeting key proteins, participating in clathrin-dependent and -independent endocytosis, as variant-independent antiviral drugs against SARS-CoV-2 infection. The review takes two approaches. The first outlines the potential role of endocytic inhibitors in preventing endocytosis-mediated viral entry and its mechanism of action, whereas in the second computational analysis was implemented to investigate the selectivity of common inhibitors against endocytic proteins in SARS-CoV-2 endocytosis. The analysis revealed that remdesivir, methyl-β-cyclodextrin, rottlerin, and Bis-T can effectively inhibit clathrin, HMG-CoA reductase, actin, and dynamin I GTPase and are more potent in inhibiting SARS-CoV-2 than chloroquine. CME inhibitors for SARS-CoV-2 infection remain understudied.
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Affiliation(s)
- Samar Sami Alkafaas
- Molecular Cell Biology UniteDivision of BiochemistryDepartment of ChemistryFaculty of ScienceTanta UniversityTantaEgypt
| | - Abanoub Mosaad Abdallah
- Narcotic Research DepartmentNational Center for Social and Criminological Research (NCSCR)GizaEgypt
| | - Soumya Ghosh
- Department of GeneticsFaculty of Natural and Agricultural SciencesUniversity of the Free StateBloemfonteinSouth Africa
| | - Samah A. Loutfy
- Virology and Immunology UnitCancer Biology DepartmentNational Cancer Institute (NCI)Cairo UniversityCairoEgypt
- Nanotechnology Research CenterBritish UniversityCairoEgypt
| | - Sara Samy Elkafas
- Production Engineering and Mechanical Design DepartmentFaculty of EngineeringMenofia UniversityMenofiaEgypt
| | - Nasra F. Abdel Fattah
- Virology and Immunology UnitCancer Biology DepartmentNational Cancer Institute (NCI)Cairo UniversityCairoEgypt
| | - Mohamed Hessien
- Molecular Cell Biology UniteDivision of BiochemistryDepartment of ChemistryFaculty of ScienceTanta UniversityTantaEgypt
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13
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Odell LR, Robertson MJ, Young KA, McGeachie AB, Quan A, Robinson PJ, McCluskey A. Prodrugs of the Archetypal Dynamin Inhibitor Bis-T-22. ChemMedChem 2022; 17:e202200400. [PMID: 36351775 PMCID: PMC10947042 DOI: 10.1002/cmdc.202200400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 10/06/2022] [Indexed: 11/11/2022]
Abstract
The Bis-T series of compounds comprise some of the most potent inhibitors of dynamin GTPase activity yet reported, e. g., (2E,2'E)-N,N'-(propane-1,3-diyl)bis(2-cyano-3-(3,4-dihydroxyphenyl)acrylamide) (2), Bis-T-22. The catechol moieties are believed to limit cell permeability, rendering these compounds largely inactive in cells. To solve this problem, a prodrug strategy was envisaged and eight ester analogues were synthesised. The shortest and bulkiest esters (acetate and butyl/tert-butyl) were found to be insoluble under physiological conditions, whilst the remaining five were soluble and stable under these conditions. These five were analysed for plasma stability and half-lives ranged from ∼2.3 min (propionic ester 4), increasing with size and bulk, to greater than 24 hr (dimethyl carbamate 10). Similar profiles where observed with the rate of formation of Bis-T-22 with half-lives ranging from ∼25 mins (propionic ester 4). Propionic ester 4 was chosen to undergo further testing and was found to inhibit endocytosis in a dose-dependent manner with IC50 ∼8 μM, suggesting this compound is able to effectively cross the cell membrane where it is rapidly hydrolysed to the desired Bis-T-22 parent compound.
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Affiliation(s)
- Luke R. Odell
- The University of NewcastleUniversity DriveCallaghanNSW 2308Australia
- Present address: Department of Medicinal ChemistryUppsala UniversityBox 57475123UppsalaSweden
| | - Mark J Robertson
- The University of NewcastleUniversity DriveCallaghanNSW 2308Australia
- Present address: Chemistry, College of Science & EngineeringJames Cook UniversityTownsvilleQLD 4814Australia
| | - Kelly A Young
- The University of NewcastleUniversity DriveCallaghanNSW 2308Australia
| | - Andrew B. McGeachie
- Cell Signalling UnitChildren's Medical Research InstituteThe University of Sydney214 Hawkesbury RoadWestmeadNSW 2145Australia
| | - Annie Quan
- Cell Signalling UnitChildren's Medical Research InstituteThe University of Sydney214 Hawkesbury RoadWestmeadNSW 2145Australia
| | - Phillip J. Robinson
- Cell Signalling UnitChildren's Medical Research InstituteThe University of Sydney214 Hawkesbury RoadWestmeadNSW 2145Australia
| | - Adam McCluskey
- The University of NewcastleUniversity DriveCallaghanNSW 2308Australia
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14
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Abstract
Monitoring the proteins and lipids that mediate all cellular processes requires imaging methods with increased spatial and temporal resolution. STED (stimulated emission depletion) nanoscopy enables fast imaging of nanoscale structures in living cells but is limited by photobleaching. Here, we present event-triggered STED, an automated multiscale method capable of rapidly initiating two-dimensional (2D) and 3D STED imaging after detecting cellular events such as protein recruitment, vesicle trafficking and second messengers activity using biosensors. STED is applied in the vicinity of detected events to maximize the temporal resolution. We imaged synaptic vesicle dynamics at up to 24 Hz, 40 ms after local calcium activity; endocytosis and exocytosis events at up to 11 Hz, 40 ms after local protein recruitment or pH changes; and the interaction between endosomal vesicles at up to 3 Hz, 70 ms after approaching one another. Event-triggered STED extends the capabilities of live nanoscale imaging, enabling novel biological observations in real time.
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Affiliation(s)
- Jonatan Alvelid
- Department of Applied Physics and Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Martina Damenti
- Department of Applied Physics and Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Chiara Sgattoni
- Department of Applied Physics and Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Ilaria Testa
- Department of Applied Physics and Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden.
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15
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Synthesis and Effect of Conformationally Locked Carbocyclic Guanine Nucleotides on Dynamin. Biomolecules 2022; 12:biom12040584. [PMID: 35454173 PMCID: PMC9031165 DOI: 10.3390/biom12040584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/14/2022] [Accepted: 04/14/2022] [Indexed: 11/16/2022] Open
Abstract
Guanine nucleotides can flip between a North and South conformation in the ribose moiety. To test the enzymatic activity of GTPases bound to nucleotides in the two conformations, we generated methanocarba guanine nucleotides in the North or South envelope conformations, i.e., (N)-GTP and (S)-GTP, respectively. With dynamin as a model system, we examined the effects of (N)-GTP and (S)-GTP on dynamin-mediated membrane constriction, an activity essential for endocytosis. Dynamin membrane constriction and fission activity are dependent on GTP binding and hydrolysis, but the effect of the conformational state of the GTP nucleotide on dynamin activity is not known. After reconstituting dynamin-mediated lipid tubulation and membrane constriction in vitro, we observed via cryo-electron microscopy (cryo-EM) that (N)-GTP, but not (S)-GTP, enables the constriction of dynamin-decorated lipid tubules. These findings suggest that the activity of dynamin is dependent on the conformational state of the GTP nucleotide. However, a survey of nucleotide ribose conformations associated with dynamin structures in nature shows almost exclusively the (S)-conformation. The explanation for this mismatch of (N) vs. (S) required for GTP analogues in a dynamin-mediated process will be addressed in future studies.
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16
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Helical self-assembly of a mucin segment suggests an evolutionary origin for von Willebrand factor tubules. Proc Natl Acad Sci U S A 2022; 119:e2116790119. [PMID: 35377815 PMCID: PMC9169620 DOI: 10.1073/pnas.2116790119] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Extracellular proteins with mechanical functions often require specialized assembly processes to form covalent oligomers. Progress in tissue bioengineering and repair will benefit from an understanding of how to harness and manipulate these processes. Here, we show that a particular supramolecular assembly mode was pre-encoded in the ancient domain organization common to gel-forming mucins and von Willebrand factor, glycoproteins that are deceptively different due to their divergence for distinct mechanical tasks. This finding highlights symmetry principles and building blocks retooled in nature to construct polymers with wide-ranging properties. These building blocks and knowledge of their self-assembly can be used to design new polymeric structures. The glycoprotein von Willebrand factor (VWF) contributes to hemostasis by stanching injuries in blood vessel walls. A distinctive feature of VWF is its assembly into long, helical tubules in endothelial cells prior to secretion. When VWF is released into the bloodstream, these tubules unfurl to release linear polymers that bind subendothelial collagen at wound sites, recruit platelets, and initiate the clotting cascade. VWF evolved from gel-forming mucins, the polymeric glycoproteins that coat and protect exposed epithelia. Despite the divergent function of VWF in blood vessel repair, sequence conservation and shared domain organization imply that VWF retained key aspects of the mucin bioassembly mechanism. Here, we show using cryo-electron microscopy that the ability to form tubules, a property hitherto thought to have arisen as a VWF adaptation to the vasculature, is a feature of the amino-terminal region of mucin. This segment of the human intestinal gel-forming mucin (MUC2) was found to self-assemble into tubules with a striking resemblance to those of VWF itself. To facilitate a comparison, we determined the residue-resolution structure of tubules formed by the homologous segment of VWF. The structures of the MUC2 and VWF tubules revealed the flexible joints and the intermolecular interactions required for tubule formation. Steric constraints in full-length MUC2 suggest that linear filaments, a previously observed supramolecular assembly form, are more likely than tubules to be the physiological mucin storage intermediate. Nevertheless, MUC2 tubules indicate a possible evolutionary origin for VWF tubules and elucidate design principles present in mucins and VWF.
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17
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Baker JR, O'Brien NS, Prichard KL, Robinson PJ, McCluskey A, Russell CC. Dynole 34-2 and Acrylo-Dyn 2-30, Novel Dynamin GTPase Chemical Biology Probes. Methods Mol Biol 2022; 2417:221-238. [PMID: 35099803 DOI: 10.1007/978-1-0716-1916-2_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
This protocol describes the chemical synthesis of the dynamin inhibitors Dynole 34-2 and Acrylo-Dyn 2-30, and their chemical scaffold matched partner inactive compounds. The chosen active and inactive paired compounds represent potent dynamin inhibitors and very closely related dynamin-inactive compounds, with the synthesis of three of the four compounds readily possible via a common intermediate. Combined with the assay data provided, this allows the interrogation of dynamin in vitro and potentially in vivo.
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Affiliation(s)
- Jennifer R Baker
- Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, Australia
| | - Nicholas S O'Brien
- Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, Australia
| | - Kate L Prichard
- Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, Australia
| | - Phillip J Robinson
- Cell Signaling Unit, Children's Medical Research Institute, The University of Sydney, Sydney, NSW, Australia
| | - Adam McCluskey
- Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, Australia
| | - Cecilia C Russell
- Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, Australia.
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18
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Odell LR, Chau N, Russell CC, Young KA, Gilbert J, Robinson PJ, Sakoff JA, McCluskey A. Pyrimidyn-Based Dynamin Inhibitors as Novel Cytotoxic Agents. ChemMedChem 2021; 17:e202100560. [PMID: 34590434 DOI: 10.1002/cmdc.202100560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/28/2021] [Indexed: 11/06/2022]
Abstract
Five focused libraries of pyrimidine-based dynamin GTPase inhibitors, in total 69 compounds were synthesised, and their dynamin inhibition and broad-spectrum cytotoxicity examined. Dynamin plays a crucial role in mitosis, and as such inhibition of dynamin was expected to broadly correlate with the observed cytotoxicity. The pyrimidines synthesised ranged from mono-substituted to trisubstituted. The highest levels of dynamin inhibition were noted with di- and tri- substituted pyrimidines, especially those with pendent amino alkyl chains. Short chains and simple heterocyclic rings reduced dynamin activity. There were three levels of dynamin activity noted: 1-10, 10-25 and 25-60 μM. Screening of these compounds in a panel of cancer cell lines: SW480 (colon), HT29 (colon), SMA (spontaneous murine astrocytoma), MCF-7 (breast), BE2-C (glioblastoma), SJ-G2 (neuroblastoma), MIA (pancreas), A2780 (ovarian), A431 (skin), H460 (lung), U87 (glioblastoma) and DU145 (prostate) cell lines reveal a good correlation between the observed dynamin inhibition and the observed cytotoxicity. The most active analogues (31 a,b) developed returned average GI50 values of 1.0 and 0.78 μM across the twelve cell lines examined. These active analogues were: N2 -(3-dimethylaminopropyl)-N4 -dodecyl-6-methylpyrimidine-2,4-diamine (31 a) and N4 -(3-dimethylaminopropyl)-N2 -dodecyl-6-methylpyrimidine-2,4-diamine (31 b).
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Affiliation(s)
- Luke R Odell
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia
| | - Ngoc Chau
- Cell Signalling Unit Children's Medical Research Institute, The University of Sydney, Sydney, 2145 Hawkesbury Road, NSW 2145, Australia
| | - Cecilia C Russell
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia
| | - Kelly A Young
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia
| | - Jayne Gilbert
- Experimental Therapeutics Group, Department of Medical Oncology, Calvary Mater Newcastle Hospital, Edith Street, Waratah, NSW 2298, Australia
| | - Phillip J Robinson
- Cell Signalling Unit Children's Medical Research Institute, The University of Sydney, Sydney, 2145 Hawkesbury Road, NSW 2145, Australia
| | - Jennette A Sakoff
- Experimental Therapeutics Group, Department of Medical Oncology, Calvary Mater Newcastle Hospital, Edith Street, Waratah, NSW 2298, Australia
| | - Adam McCluskey
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia
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19
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Liu J, Alvarez FJD, Clare DK, Noel JK, Zhang P. CryoEM structure of the super-constricted two-start dynamin 1 filament. Nat Commun 2021; 12:5393. [PMID: 34518553 PMCID: PMC8437954 DOI: 10.1038/s41467-021-25741-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 08/26/2021] [Indexed: 11/23/2022] Open
Abstract
Dynamin belongs to the large GTPase superfamily, and mediates the fission of vesicles during endocytosis. Dynamin molecules are recruited to the neck of budding vesicles to assemble into a helical collar and to constrict the underlying membrane. Two helical forms were observed: the one-start helix in the constricted state and the two-start helix in the super-constricted state. Here we report the cryoEM structure of a super-constricted two-start dynamin 1 filament at 3.74 Å resolution. The two strands are joined by the conserved GTPase dimeric interface. In comparison with the one-start structure, a rotation around Hinge 1 is observed, essential for communicating the chemical power of the GTPase domain and the mechanical force of the Stalk and PH domain onto the underlying membrane. The Stalk interfaces are well conserved and serve as fulcrums for adapting to changing curvatures. Relative to one-start, small rotations per interface accumulate to bring a drastic change in the helical pitch. Elasticity theory rationalizes the diversity of dynamin helical symmetries and suggests corresponding functional significance.
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Affiliation(s)
- Jiwei Liu
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Frances Joan D Alvarez
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA
| | - Daniel K Clare
- Electron Bio-Imaging Centre, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | | | - Peijun Zhang
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA.
- Electron Bio-Imaging Centre, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
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20
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Cheng X, Chen K, Dong B, Yang M, Filbrun SL, Myoung Y, Huang TX, Gu Y, Wang G, Fang N. Dynamin-dependent vesicle twist at the final stage of clathrin-mediated endocytosis. Nat Cell Biol 2021; 23:859-869. [PMID: 34253896 PMCID: PMC8355216 DOI: 10.1038/s41556-021-00713-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 06/09/2021] [Indexed: 12/11/2022]
Abstract
Dynamin plays an important role in clathrin-mediated endocytosis (CME) by cutting the neck of nascent vesicles from the cell membrane. Here through using gold nanorods as cargos to image dynamin action during live CME, we show that near the peak of dynamin accumulation, the cargo-containing vesicles always exhibit abrupt, right-handed rotations that finish in a short time (~0.28 s). The large and quick twist, herein named the super twist, is the result of the coordinated dynamin helix action upon GTP hydrolysis. After the super twist, the rotational freedom of the vesicle drastically increases, accompanied with simultaneous or delayed translational movement, indicating that it detaches from the cell membrane. These observations suggest that dynamin-mediated scission involves a large torque generated by coordinated actions of multiple dynamins in the helix, which is the main driving force for vesicle scission.
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Affiliation(s)
- Xiaodong Cheng
- Department of Chemistry, Georgia State University, Atlanta, GA, USA.,State Key Laboratory of Physical Chemistry of Solid Surfaces, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Kuangcai Chen
- Department of Chemistry, Georgia State University, Atlanta, GA, USA
| | - Bin Dong
- Department of Chemistry, Georgia State University, Atlanta, GA, USA
| | - Meek Yang
- Department of Chemistry, Georgia State University, Atlanta, GA, USA
| | - Seth L Filbrun
- Department of Chemistry, Georgia State University, Atlanta, GA, USA
| | - Yong Myoung
- Department of Chemistry, Georgia State University, Atlanta, GA, USA
| | - Teng-Xiang Huang
- Department of Chemistry, Georgia State University, Atlanta, GA, USA
| | - Yan Gu
- The Bristol-Myers Squibb Company, Devens, MA, USA
| | - Gufeng Wang
- Department of Chemistry, Georgia State University, Atlanta, GA, USA.
| | - Ning Fang
- Department of Chemistry, Georgia State University, Atlanta, GA, USA. .,State Key Laboratory of Physical Chemistry of Solid Surfaces, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China.
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21
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Liu J, Tassinari M, Souza DP, Naskar S, Noel JK, Bohuszewicz O, Buck M, Williams TA, Baum B, Low HH. Bacterial Vipp1 and PspA are members of the ancient ESCRT-III membrane-remodeling superfamily. Cell 2021; 184:3660-3673.e18. [PMID: 34166615 PMCID: PMC8281802 DOI: 10.1016/j.cell.2021.05.041] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 11/24/2020] [Accepted: 05/25/2021] [Indexed: 12/31/2022]
Abstract
Membrane remodeling and repair are essential for all cells. Proteins that perform these functions include Vipp1/IM30 in photosynthetic plastids, PspA in bacteria, and ESCRT-III in eukaryotes. Here, using a combination of evolutionary and structural analyses, we show that these protein families are homologous and share a common ancient evolutionary origin that likely predates the last universal common ancestor. This homology is evident in cryo-electron microscopy structures of Vipp1 rings from the cyanobacterium Nostoc punctiforme presented over a range of symmetries. Each ring is assembled from rungs that stack and progressively tilt to form dome-shaped curvature. Assembly is facilitated by hinges in the Vipp1 monomer, similar to those in ESCRT-III proteins, which allow the formation of flexible polymers. Rings have an inner lumen that is able to bind and deform membranes. Collectively, these data suggest conserved mechanistic principles that underlie Vipp1, PspA, and ESCRT-III-dependent membrane remodeling across all domains of life.
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Affiliation(s)
- Jiwei Liu
- Department of Infectious Disease, Imperial College, London, UK
| | | | - Diorge P Souza
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK; Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Souvik Naskar
- Department of Infectious Disease, Imperial College, London, UK
| | - Jeffrey K Noel
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | | | - Martin Buck
- Department of Life Sciences, Imperial College, London, UK
| | - Tom A Williams
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK; Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, UK; Institute for the Physics of Living Systems, University College London, London, UK.
| | - Harry H Low
- Department of Infectious Disease, Imperial College, London, UK.
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22
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Baratam K, Jha K, Srivastava A. Flexible pivoting of dynamin pleckstrin homology domain catalyzes fission: insights into molecular degrees of freedom. Mol Biol Cell 2021; 32:1306-1319. [PMID: 33979205 PMCID: PMC8351549 DOI: 10.1091/mbc.e20-12-0794] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The neuronal dynamin1 functions in the release of synaptic vesicles by orchestrating the process of GTPase-dependent membrane fission. Dynamin1 associates with the plasma membrane–localized phosphatidylinositol-4,5-bisphosphate (PIP2) through the centrally located pleckstrin homology domain (PHD). The PHD is dispensable as fission (in model membranes) can be managed, even when the PHD-PIP2 interaction is replaced by a generic polyhistidine- or polylysine-lipid interaction. However, the absence of the PHD renders a dramatic dampening of the rate of fission. These observations suggest that the PHD-PIP2–containing membrane interaction could have evolved to expedite fission to fulfill the requirement of rapid kinetics of synaptic vesicle recycling. Here, we use a suite of multiscale modeling approaches to explore PHD–membrane interactions. Our results reveal that 1) the binding of PHD to PIP2-containing membranes modulates the lipids toward fission-favoring conformations and softens the membrane, and 2) PHD associates with membrane in multiple orientations using variable loops as pivots. We identify a new loop (VL4), which acts as an auxiliary pivot and modulates the orientation flexibility of PHD on the membrane—a mechanism that we believe may be important for high-fidelity dynamin collar assembly. Together, these insights provide a molecular-level understanding of the catalytic role of PHD in dynamin-mediated membrane fission.
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Affiliation(s)
| | - Kirtika Jha
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore-560012, India
| | - Anand Srivastava
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore-560012, India
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23
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Lee CT, Akamatsu M, Rangamani P. Value of models for membrane budding. Curr Opin Cell Biol 2021; 71:38-45. [PMID: 33706232 DOI: 10.1016/j.ceb.2021.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/27/2021] [Accepted: 01/30/2021] [Indexed: 12/16/2022]
Abstract
The budding of membranes and curvature generation is common to many forms of trafficking in cells. Clathrin-mediated endocytosis, as a prototypical example of trafficking, has been studied in great detail using a variety of experimental systems and methods. Recently, advances in experimental methods have led to great strides in insights on the molecular mechanisms and the spatiotemporal dynamics of the protein machinery associated with membrane curvature generation. These advances have been ably supported by computational models, which have given us insights into the underlying mechanical principles of clathrin-mediated endocytosis. On the other hand, targeted experimental perturbation of membranes has lagged behind that of proteins in cells. In this area, modeling is especially critical to interpret experimental measurements in a mechanistic context. Here, we discuss the contributions made by these models to our understanding of endocytosis and identify opportunities to strengthen the connections between models and experiments.
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Affiliation(s)
- Christopher T Lee
- Department of Mechanical and Aerospace Engineering, University of California San Diego Jacobs School of Engineering, 9500 Gilman Drive #0411, La Jolla, CA, 92093, USA
| | - Matthew Akamatsu
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego Jacobs School of Engineering, 9500 Gilman Drive #0411, La Jolla, CA, 92093, USA.
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24
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Mass photometry enables label-free tracking and mass measurement of single proteins on lipid bilayers. Nat Methods 2021; 18:1247-1252. [PMID: 34608319 PMCID: PMC8490153 DOI: 10.1038/s41592-021-01261-w] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 08/04/2021] [Indexed: 02/08/2023]
Abstract
The quantification of membrane-associated biomolecular interactions is crucial to our understanding of various cellular processes. State-of-the-art single-molecule approaches rely largely on the addition of fluorescent labels, which complicates the quantification of the involved stoichiometries and dynamics because of low temporal resolution and the inherent limitations associated with labeling efficiency, photoblinking and photobleaching. Here, we demonstrate dynamic mass photometry, a method for label-free imaging, tracking and mass measurement of individual membrane-associated proteins diffusing on supported lipid bilayers. Application of this method to the membrane remodeling GTPase, dynamin-1, reveals heterogeneous mixtures of dimer-based oligomers, oligomer-dependent mobilities, membrane affinities and (dis)association of individual complexes. These capabilities, together with assay-based advances for studying integral membrane proteins, will enable the elucidation of biomolecular mechanisms in and on lipid bilayers.
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25
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S Mogre S, Brown AI, Koslover EF. Getting around the cell: physical transport in the intracellular world. Phys Biol 2020; 17:061003. [PMID: 32663814 DOI: 10.1088/1478-3975/aba5e5] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Eukaryotic cells face the challenging task of transporting a variety of particles through the complex intracellular milieu in order to deliver, distribute, and mix the many components that support cell function. In this review, we explore the biological objectives and physical mechanisms of intracellular transport. Our focus is on cytoplasmic and intra-organelle transport at the whole-cell scale. We outline several key biological functions that depend on physically transporting components across the cell, including the delivery of secreted proteins, support of cell growth and repair, propagation of intracellular signals, establishment of organelle contacts, and spatial organization of metabolic gradients. We then review the three primary physical modes of transport in eukaryotic cells: diffusive motion, motor-driven transport, and advection by cytoplasmic flow. For each mechanism, we identify the main factors that determine speed and directionality. We also highlight the efficiency of each transport mode in fulfilling various key objectives of transport, such as particle mixing, directed delivery, and rapid target search. Taken together, the interplay of diffusion, molecular motors, and flows supports the intracellular transport needs that underlie a broad variety of biological phenomena.
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Affiliation(s)
- Saurabh S Mogre
- Department of Physics, University of California, San Diego, San Diego, California 92093, United States of America
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26
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Abstract
We present an approach for preparing cryo-electron microscopy (cryo-EM) grids to study short-lived molecular states. Using piezoelectric dispensing, two independent streams of ~50-pl droplets of sample are deposited within 10 ms of each other onto the surface of a nanowire EM grid, and the mixing reaction stops when the grid is vitrified in liquid ethane ~100 ms later. We demonstrate this approach for four biological systems where short-lived states are of high interest.
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27
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Jaumouillé V, Waterman CM. Physical Constraints and Forces Involved in Phagocytosis. Front Immunol 2020; 11:1097. [PMID: 32595635 PMCID: PMC7304309 DOI: 10.3389/fimmu.2020.01097] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/06/2020] [Indexed: 01/02/2023] Open
Abstract
Phagocytosis is a specialized process that enables cellular ingestion and clearance of microbes, dead cells and tissue debris that are too large for other endocytic routes. As such, it is an essential component of tissue homeostasis and the innate immune response, and also provides a link to the adaptive immune response. However, ingestion of large particulate materials represents a monumental task for phagocytic cells. It requires profound reorganization of the cell morphology around the target in a controlled manner, which is limited by biophysical constraints. Experimental and theoretical studies have identified critical aspects associated with the interconnected biophysical properties of the receptors, the membrane, and the actin cytoskeleton that can determine the success of large particle internalization. In this review, we will discuss the major physical constraints involved in the formation of a phagosome. Focusing on two of the most-studied types of phagocytic receptors, the Fcγ receptors and the complement receptor 3 (αMβ2 integrin), we will describe the complex molecular mechanisms employed by phagocytes to overcome these physical constraints.
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Affiliation(s)
- Valentin Jaumouillé
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Clare M Waterman
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States
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28
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Tornabene BA, Varlakhanova NV, Hosford CJ, Chappie JS, Ford MGJ. Structural and functional characterization of the dominant negative P-loop lysine mutation in the dynamin superfamily protein Vps1. Protein Sci 2020; 29:1416-1428. [PMID: 31981262 PMCID: PMC7255512 DOI: 10.1002/pro.3830] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/16/2020] [Accepted: 01/16/2020] [Indexed: 12/15/2022]
Abstract
Dynamin-superfamily proteins (DSPs) are large self-assembling mechanochemical GTPases that harness GTP hydrolysis to drive membrane remodeling events needed for many cellular processes. Mutation to alanine of a fully conserved lysine within the P-loop of the DSP GTPase domain results in abrogation of GTPase activity. This mutant has been widely used in the context of several DSPs as a dominant-negative to impair DSP-dependent processes. However, the precise deficit of the P-loop K to A mutation remains an open question. Here, we use biophysical, biochemical and structural approaches to characterize this mutant in the context of the endosomal DSP Vps1. We show that the Vps1 P-loop K to A mutant binds nucleotide with an affinity similar to wild type but exhibits defects in the organization of the GTPase active site that explain the lack of hydrolysis. In cells, Vps1 and Dnm1 bearing the P-loop K to A mutation are defective in disassembly. These mutants become trapped in assemblies at the typical site of action of the DSP. This work provides mechanistic insight into the widely-used DSP P-loop K to A mutation and the basis of its dominant-negative effects in the cell.
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Affiliation(s)
- Bryan A. Tornabene
- Department of Cell BiologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvania
| | | | | | | | - Marijn G. J. Ford
- Department of Cell BiologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvania
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29
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Dynamin regulates the dynamics and mechanical strength of the actin cytoskeleton as a multifilament actin-bundling protein. Nat Cell Biol 2020; 22:674-688. [PMID: 32451441 PMCID: PMC7953826 DOI: 10.1038/s41556-020-0519-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 04/07/2020] [Indexed: 01/28/2023]
Abstract
The dynamin GTPase is known to bundle actin filaments, but the underlying molecular mechanism and physiological relevance remain unclear. Our genetic analyses revealed a function of dynamin in propelling invasive membrane protrusions during myoblast fusion in vivo. Using biochemistry, total internal reflection fluorescence microscopy, electron microscopy and cryo-electron tomography, we show that dynamin bundles actin while forming a helical structure. At its full capacity, each dynamin helix captures 12-16 actin filaments on the outer rim of the helix. GTP hydrolysis by dynamin triggers disassembly of fully assembled dynamin helices, releasing free dynamin dimers/tetramers and facilitating Arp2/3-mediated branched actin polymerization. The assembly/disassembly cycles of dynamin promote continuous actin bundling to generate mechanically stiff actin super-bundles. Super-resolution and immunogold platinum replica electron microscopy revealed dynamin along actin bundles at the fusogenic synapse. These findings implicate dynamin as a unique multifilament actin-bundling protein that regulates the dynamics and mechanical strength of the actin cytoskeletal network.
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30
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Zhang D, Zhang Y, Ma J, Zhu C, Niu T, Chen W, Pang X, Zhai Y, Sun F. Cryo-EM structures of S-OPA1 reveal its interactions with membrane and changes upon nucleotide binding. eLife 2020; 9:50294. [PMID: 32228866 PMCID: PMC7156267 DOI: 10.7554/elife.50294] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 03/30/2020] [Indexed: 02/05/2023] Open
Abstract
Mammalian mitochondrial inner membrane fusion is mediated by optic atrophy 1 (OPA1). Under physiological conditions, OPA1 undergoes proteolytic processing to form a membrane-anchored long isoform (L-OPA1) and a soluble short isoform (S-OPA1). A combination of L-OPA1 and S-OPA1 is essential for efficient membrane fusion; however, the relevant mechanism is not well understood. In this study, we investigate the cryo-electron microscopic structures of S-OPA1–coated liposomes in nucleotide-free and GTPγS-bound states. S-OPA1 exhibits a general dynamin-like structure and can assemble onto membranes in a helical array with a dimer building block. We reveal that hydrophobic residues in its extended membrane-binding domain are critical for its tubulation activity. The binding of GTPγS triggers a conformational change and results in a rearrangement of the helical lattice and tube expansion similar to that of S-Mgm1. These observations indicate that S-OPA1 adopts a dynamin-like power stroke membrane remodeling mechanism during mitochondrial inner membrane fusion.
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Affiliation(s)
- Danyang Zhang
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yan Zhang
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Jun Ma
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Chunmei Zhu
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Tongxin Niu
- Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Wenbo Chen
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoyun Pang
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yujia Zhai
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Fei Sun
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China.,Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
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31
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Cao H, Krueger EW, Chen J, Drizyte-Miller K, Schulz ME, McNiven MA. The anti-viral dynamin family member MxB participates in mitochondrial integrity. Nat Commun 2020; 11:1048. [PMID: 32102993 PMCID: PMC7044337 DOI: 10.1038/s41467-020-14727-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/23/2020] [Indexed: 12/19/2022] Open
Abstract
The membrane deforming dynamin family members MxA and MxB are large GTPases that convey resistance to a variety of infectious viruses. During viral infection, Mx proteins are known to show markedly increased expression via an interferon-responsive promoter to associate with nuclear pores. In this study we report that MxB is an inner mitochondrial membrane GTPase that plays an important role in the morphology and function of this organelle. Expression of mutant MxB or siRNA knockdown of MxB leads to fragmented mitochondria with disrupted inner membranes that are unable to maintain a proton gradient, while expelling their nucleoid-based genome into the cytoplasm. These findings implicate a dynamin family member in mitochondrial-based changes frequently observed during an interferon-based, anti-viral response. Mx proteins belong to the dynamin family of large GTPases and are highly induced by interferon in virally infected cells. The authors show that uninfected immune cells and hepatocytes also express MxB protein that associates with mitochondria to alter the morphology and genome of this organelle.
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Affiliation(s)
- Hong Cao
- Department of Biochemistry and Molecular Biology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA.,Center for Basic Research in Digestive Diseases, Division of Gastroenterology & Hepatology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA
| | - E W Krueger
- Center for Basic Research in Digestive Diseases, Division of Gastroenterology & Hepatology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA
| | - Jing Chen
- Center for Basic Research in Digestive Diseases, Division of Gastroenterology & Hepatology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA
| | - Kristina Drizyte-Miller
- Biochemistry and Molecular Biology Program, Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA
| | - Mary E Schulz
- Center for Basic Research in Digestive Diseases, Division of Gastroenterology & Hepatology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA
| | - Mark A McNiven
- Department of Biochemistry and Molecular Biology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA. .,Center for Basic Research in Digestive Diseases, Division of Gastroenterology & Hepatology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA.
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32
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Abstract
Phagocytosis is a specialized process that enables cellular ingestion and clearance of microbes, dead cells and tissue debris that are too large for other endocytic routes. As such, it is an essential component of tissue homeostasis and the innate immune response, and also provides a link to the adaptive immune response. However, ingestion of large particulate materials represents a monumental task for phagocytic cells. It requires profound reorganization of the cell morphology around the target in a controlled manner, which is limited by biophysical constraints. Experimental and theoretical studies have identified critical aspects associated with the interconnected biophysical properties of the receptors, the membrane, and the actin cytoskeleton that can determine the success of large particle internalization. In this review, we will discuss the major physical constraints involved in the formation of a phagosome. Focusing on two of the most-studied types of phagocytic receptors, the Fcγ receptors and the complement receptor 3 (αMβ2 integrin), we will describe the complex molecular mechanisms employed by phagocytes to overcome these physical constraints.
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Affiliation(s)
- Valentin Jaumouillé
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Clare M Waterman
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States
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33
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Polymer-like Model to Study the Dynamics of Dynamin Filaments on Deformable Membrane Tubes. Biophys J 2019; 117:1870-1891. [PMID: 31672269 DOI: 10.1016/j.bpj.2019.09.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 09/08/2019] [Accepted: 09/24/2019] [Indexed: 01/30/2023] Open
Abstract
Peripheral membrane proteins with intrinsic curvature can act both as sensors of membrane curvature and shape modulators of the underlying membranes. A well-studied example of such proteins is the mechanochemical GTPase dynamin, which assembles into helical filaments around membrane tubes and catalyzes their scission in a GTPase-dependent manner. It is known that the dynamin coat alone, without GTP, can constrict membrane tubes to radii of ∼10 nm, indicating that the intrinsic shape and elasticity of dynamin filaments should play an important role in membrane remodeling. However, molecular and dynamic understanding of the process is lacking. Here, we develop a dynamical polymer-chain model for a helical elastic filament bound on a deformable membrane tube of conserved mass, accounting for thermal fluctuations in the filament and lipid flows in the membrane. The model is based on the locally cylindrical helix approximation for dynamin. We obtain the elastic parameters of the dynamin filament by molecular dynamics simulations of its tetrameric building block and also from coarse-grained structure-based simulations of a 17-dimer filament. The results show that the stiffness of dynamin is comparable to that of the membrane. We determine equilibrium shapes of the filament and the membrane and find that mostly the pitch of the filament, not its radius, is sensitive to variations in membrane tension and stiffness. The close correspondence between experimental estimates of the inner tube radius and those predicted by the model suggests that dynamin's "stalk" region is responsible for its GTP-independent membrane-shaping ability. The model paves the way for future mesoscopic modeling of dynamin with explicit motor function.
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34
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Functional recruitment of dynamin requires multimeric interactions for efficient endocytosis. Nat Commun 2019; 10:4462. [PMID: 31575863 PMCID: PMC6773865 DOI: 10.1038/s41467-019-12434-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 09/10/2019] [Indexed: 02/06/2023] Open
Abstract
During clathrin mediated endocytosis (CME), the concerted action of dynamin and its interacting partners drives membrane scission. Essential interactions occur between the proline/arginine-rich domain of dynamin (dynPRD) and the Src-homology domain 3 (SH3) of various proteins including amphiphysins. Here we show that multiple SH3 domains must bind simultaneously to dynPRD through three adjacent motifs for dynamin’s efficient recruitment and function. First, we show that mutant dynamins modified in a single motif, including the central amphiphysin SH3 (amphSH3) binding motif, partially rescue CME in dynamin triple knock-out cells. However, mutating two motifs largely prevents that ability. Furthermore, we designed divalent dynPRD-derived peptides. These ligands bind multimers of amphSH3 with >100-fold higher affinity than monovalent ones in vitro. Accordingly, dialyzing living cells with these divalent peptides through a patch-clamp pipette blocks CME much more effectively than with monovalent ones. We conclude that dynamin drives vesicle scission via multivalent interactions in cells. During clathrin mediated endocytosis (CME), membrane scission is achieved by the concerted action of dynamin and its interacting partners such as amphiphysins. Here authors show that efficient recruitment and function of dynamin requires simultaneous binding of multiple amphiphysin SH3 domains.
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35
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Ford MGJ, Chappie JS. The structural biology of the dynamin-related proteins: New insights into a diverse, multitalented family. Traffic 2019; 20:717-740. [PMID: 31298797 DOI: 10.1111/tra.12676] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 07/10/2019] [Accepted: 07/10/2019] [Indexed: 12/13/2022]
Abstract
Dynamin-related proteins are multidomain, mechanochemical GTPases that self-assemble and orchestrate a wide array of cellular processes. Over the past decade, structural insights from X-ray crystallography and cryo-electron microscopy have reshaped our mechanistic understanding of these proteins. Here, we provide a historical perspective on these advances that highlights the structural attributes of different dynamin family members and explores how these characteristics affect GTP hydrolysis, conformational coupling and oligomerization. We also discuss a number of lingering challenges remaining in the field that suggest future directions of study.
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Affiliation(s)
- Marijn G J Ford
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Joshua S Chappie
- Department of Molecular Medicine, Cornell University, Ithaca, New York
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36
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Kalia R, Frost A. Open and cut: allosteric motion and membrane fission by dynamin superfamily proteins. Mol Biol Cell 2019; 30:2097-2104. [PMID: 31365329 PMCID: PMC6743466 DOI: 10.1091/mbc.e16-10-0709] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 06/07/2019] [Accepted: 06/18/2019] [Indexed: 12/20/2022] Open
Abstract
Cells have evolved diverse protein-based machinery to reshape, cut, or fuse their membrane-delimited compartments. Dynamin superfamily proteins are principal components of this machinery and use their ability to hydrolyze GTP and to polymerize into helices and rings to achieve these goals. Nucleotide-binding, hydrolysis, and exchange reactions drive significant conformational changes across the dynamin family, and these changes alter the shape and stability of supramolecular dynamin oligomers, as well as the ability of dynamins to bind receptors and membranes. Mutations that interfere with the conformational repertoire of these enzymes, and hence with membrane fission, exist in several inherited human diseases. Here, we discuss insights from new x-ray crystal structures and cryo-EM reconstructions that have enabled us to infer some of the allosteric dynamics for these proteins. Together, these studies help us to understand how dynamins perform mechanical work, as well as how specific mutants of dynamin family proteins exhibit pathogenic properties.
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Affiliation(s)
- Raghav Kalia
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84132
| | - Adam Frost
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84132
- Chan-Zuckerberg Biohub, San Francisco, CA 94158
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37
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Abstract
Dynamin proteins assemble into characteristic helical structures around necks of clathrin-coated membrane buds. Hydrolysis of dynamin-bound GTP results in both fission of the membrane neck and partial disruption of the dynamin oligomer. Imaging by atomic force microscopy reveals that, on GTP hydrolysis, dynamin oligomers undergo a dynamic remodeling and lose their distinctive helical shape. While breakup of the dynamin helix is a critical stage in clathrin-mediated endocytosis, the mechanism for this remodeling of the oligomer has not been resolved. In this paper, we formulate an analytical, elasticity-based model for the reshaping and disassembly of the dynamin scaffold. We predict that the shape of the oligomer is modulated by the orientation of dynamin's pleckstrin homology (PH) domain relative to the underlying membrane. Our results indicate that tilt of the PH domain drives deformation and fragmentation of the oligomer, in agreement with experimental observations. This model motivated the introduction of the tilted helix: a curve that maintains a fixed angle between its normal and the normal of the embedding surface. Our findings highlight the importance of tilt as a key regulator of size and morphology of membrane-bound oligomers.
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38
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Jimah JR, Hinshaw JE. Structural Insights into the Mechanism of Dynamin Superfamily Proteins. Trends Cell Biol 2019; 29:257-273. [DOI: 10.1016/j.tcb.2018.11.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 10/30/2018] [Accepted: 11/02/2018] [Indexed: 12/28/2022]
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39
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Pannuzzo M, McDargh ZA, Deserno M. The role of scaffold reshaping and disassembly in dynamin driven membrane fission. eLife 2018; 7:39441. [PMID: 30561335 PMCID: PMC6355196 DOI: 10.7554/elife.39441] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 12/13/2018] [Indexed: 12/11/2022] Open
Abstract
The large GTPase dynamin catalyzes membrane fission in eukaryotic cells, but despite three decades of experimental work, competing and partially conflicting models persist regarding some of its most basic actions. Here we investigate the mechanical and functional consequences of dynamin scaffold shape changes and disassembly with the help of a geometrically and elastically realistic simulation model of helical dynamin-membrane complexes. Beyond changes of radius and pitch, we emphasize the crucial role of a third functional motion: an effective rotation of the filament around its longitudinal axis, which reflects alternate tilting of dynamin’s PH binding domains and creates a membrane torque. We also show that helix elongation impedes fission, hemifission is reached via a small transient pore, and coat disassembly assists fission. Our results have several testable structural consequences and help to reconcile mutual conflicting aspects between the two main present models of dynamin fission—the two-stage and the constrictase model. When cells take up material from their surroundings, they must first transport this cargo across their outer membrane, a flexible sheet of tightly organized fat molecules that act as a barrier to the environment. Cells can achieve this by letting their membrane surround the object, pulling it inwards until it is contained in a pouch that bulges into the cell. This bag is then corded up so it splits off from the outer membrane. The ‘cord’ is a protein called dynamin, which is thought to form a tight spiral around the bag’s neck, closing it over and pinching it away. The structure of dynamin is fairly well known, and yet several theories compete to explain how it may snap the bag off the outer membrane. Here, Pannuzzo et al. have created a computer simulation that faithfully replicates the geometry and the elasticity of the membrane and of dynamin, and used it to test different ways the protein could work. The first test featured simple constriction, where the dynamin spiral contracts around the membrane to pinch it; this only separated the bag from the membrane after implausibly tight constriction. The second test added elongation, with the spiral lengthening as well as reducing its diameter, but this further reduced the ability for the protein to snap off the membrane. The final test combined constriction and rotation, whereby dynamin ‘twirls’ as it presses on the neck of the bag: this succeeded in efficiently severing the membrane once the dynamin spiral disassembled. Indeed, the simulations suggested that dynamin might start to dismantle while it constricts, without compromising its role. In fact, getting rid of excess length as the protein contracts helps to dissolve any remnants of a membrane connection. Defects in dynamin are associated with conditions such as centronuclear myopathy and Charcot‐Marie‐Tooth peripheral neuropathy. Recent research also indicates that the protein is involved in a much wider range of neurological disorders that include Alzheimer's, Parkinson's, Huntington's, and amyotrophic lateral sclerosis. The models created by Pannuzzo et al. are useful tools to understand how dynamin and similar proteins work and sometimes fail.
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Affiliation(s)
- Martina Pannuzzo
- Department of Physics, Carnegie Mellon University, Pittsburgh, United States
| | - Zachary A McDargh
- Department of Physics, Carnegie Mellon University, Pittsburgh, United States
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, Pittsburgh, United States
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40
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Kamerkar SC, Kraus F, Sharpe AJ, Pucadyil TJ, Ryan MT. Dynamin-related protein 1 has membrane constricting and severing abilities sufficient for mitochondrial and peroxisomal fission. Nat Commun 2018; 9:5239. [PMID: 30531964 PMCID: PMC6286342 DOI: 10.1038/s41467-018-07543-w] [Citation(s) in RCA: 163] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 11/07/2018] [Indexed: 12/12/2022] Open
Abstract
Dynamin-related protein 1 (Drp1) is essential for mitochondrial and peroxisomal fission. Recent studies propose that Drp1 does not sever but rather constricts mitochondrial membranes allowing dynamin 2 (Dnm2) to execute final scission. Here, we report that unlike Drp1, Dnm2 is dispensable for peroxisomal and mitochondrial fission, as these events occurred in Dnm2 knockout cells. Fission events were also observed in mouse embryonic fibroblasts lacking Dnm1, 2 and 3. Using reconstitution experiments on preformed membrane tubes, we show that Drp1 alone both constricts and severs membrane tubes. Scission required the membrane binding, self-assembling and GTPase activities of Drp1 and occurred on tubes up to 250 nm in radius. In contrast, Dnm2 exhibited severely restricted fission capacity with occasional severing of tubes below 50 nm in radius. We conclude that Drp1 has both membrane constricting and severing abilities and is the dominant dynamin performing mitochondrial and peroxisomal fission. Drp1 and Dnm2 have been implicated in mitochondrial fission events, although their specific activities in constriction and scission have been unclear. Here, the authors demonstrate that Drp1 is sufficient to constrict and sever mitochondrial and peroxisomal membranes in the absence of Dnm proteins.
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Affiliation(s)
- Sukrut C Kamerkar
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune, 411008, Maharashtra, India
| | - Felix Kraus
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, 3800, Melbourne, Australia
| | - Alice J Sharpe
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, 3800, Melbourne, Australia
| | - Thomas J Pucadyil
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune, 411008, Maharashtra, India.
| | - Michael T Ryan
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, 3800, Melbourne, Australia.
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41
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Varlakhanova NV, Alvarez FJD, Brady TM, Tornabene BA, Hosford CJ, Chappie JS, Zhang P, Ford MGJ. Structures of the fungal dynamin-related protein Vps1 reveal a unique, open helical architecture. J Cell Biol 2018; 217:3608-3624. [PMID: 30087125 PMCID: PMC6168280 DOI: 10.1083/jcb.201712021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 05/26/2018] [Accepted: 07/17/2018] [Indexed: 12/19/2022] Open
Abstract
How specific dynamin-related proteins (DRPs) are tailored to their cellular targets is an open question. Varlakhanova et al. present structures of the fungal DRP Vps1, which functions at the endosomal compartment. The crystal and cryoEM structures reveal a unique DRP architecture that highlights structural flexibilities of DRP self-assembly. Dynamin-related proteins (DRPs) are large multidomain GTPases required for diverse membrane-remodeling events. DRPs self-assemble into helical structures, but how these structures are tailored to their cellular targets remains unclear. We demonstrate that the fungal DRP Vps1 primarily localizes to and functions at the endosomal compartment. We present crystal structures of a Vps1 GTPase–bundle signaling element (BSE) fusion in different nucleotide states to capture GTP hydrolysis intermediates and concomitant conformational changes. Using cryoEM, we determined the structure of full-length GMPPCP-bound Vps1. The Vps1 helix is more open and flexible than that of dynamin. This is due to further opening of the BSEs away from the GTPase domains. A novel interface between adjacent GTPase domains forms in Vps1 instead of the contacts between the BSE and adjacent stalks and GTPase domains as seen in dynamin. Disruption of this interface abolishes Vps1 function in vivo. Hence, Vps1 exhibits a unique helical architecture, highlighting structural flexibilities of DRP self-assembly.
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Affiliation(s)
| | - Frances J D Alvarez
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Tyler M Brady
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Bryan A Tornabene
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | | | - Joshua S Chappie
- Department of Molecular Medicine, Cornell University, Ithaca, NY
| | - Peijun Zhang
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA.,Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK.,Electron Bio-Imaging Centre, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Marijn G J Ford
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
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Kong L, Sochacki KA, Wang H, Fang S, Canagarajah B, Kehr AD, Rice WJ, Strub MP, Taraska JW, Hinshaw JE. Cryo-EM of the dynamin polymer assembled on lipid membrane. Nature 2018; 560:258-262. [PMID: 30069048 PMCID: PMC6121775 DOI: 10.1038/s41586-018-0378-6] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 06/20/2018] [Indexed: 12/17/2022]
Abstract
Membrane fission is a fundamental process in the regulation and remodeling of cell membranes. Dynamin, a large GTPase, mediates membrane fission by assembling around, constricting and cleaving the necks of budding vesicles1. Here, we report a 3.75 Å resolution cryo-EM structure of the membrane-associated helical polymer of human dynamin-1 in the GMPPCP bound state. The structure defines the helical symmetry of the dynamin polymer and the positions of the oligomeric interfaces, which were validated by cell-based endocytosis assays. Compared to the lipid-free tetramer form2, membrane-associated dynamin binds to the lipid bilayer with its pleckstrin homology domain (PHD) and self-assembles across the helical rungs via the GTPase domain3. Notably, interaction with the membrane and helical assembly is accommodated by a severely bent bundle signaling element (BSE), which connects the GTPase domain with the rest of the protein. The BSE conformation is asymmetric across the inter-rung GTPase interface, and is unique compared to all known nucleotide-bound states of dynamin. The structure suggests that the BSE bends from forces generated from the GTPase dimer interaction that are transferred across the stalk to the PHD and lipid membrane. Mutations disrupting the BSE kink impaired endocytosis. We also report a 10.1 Å resolution cryo-EM map of a super-constricted dynamin polymer showing localized conformational changes at the BSE and GTPase domains induced by GTP hydrolysis that drive membrane constriction. Altogether, the results provide a structural basis for dynamin’s mechanism of action on lipid membrane.
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Affiliation(s)
- Leopold Kong
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA
| | - Kem A Sochacki
- Laboratory of Molecular Biophysics, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Huaibin Wang
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA
| | - Shunming Fang
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA
| | - Bertram Canagarajah
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA
| | - Andrew D Kehr
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA
| | - William J Rice
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Marie-Paule Strub
- Laboratory of Molecular Biophysics, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Justin W Taraska
- Laboratory of Molecular Biophysics, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Jenny E Hinshaw
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA.
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43
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Bassereau P, Jin R, Baumgart T, Deserno M, Dimova R, Frolov VA, Bashkirov PV, Grubmüller H, Jahn R, Risselada HJ, Johannes L, Kozlov MM, Lipowsky R, Pucadyil TJ, Zeno WF, Stachowiak JC, Stamou D, Breuer A, Lauritsen L, Simon C, Sykes C, Voth GA, Weikl TR. The 2018 biomembrane curvature and remodeling roadmap. JOURNAL OF PHYSICS D: APPLIED PHYSICS 2018; 51:343001. [PMID: 30655651 PMCID: PMC6333427 DOI: 10.1088/1361-6463/aacb98] [Citation(s) in RCA: 188] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The importance of curvature as a structural feature of biological membranes has been recognized for many years and has fascinated scientists from a wide range of different backgrounds. On the one hand, changes in membrane morphology are involved in a plethora of phenomena involving the plasma membrane of eukaryotic cells, including endo- and exocytosis, phagocytosis and filopodia formation. On the other hand, a multitude of intracellular processes at the level of organelles rely on generation, modulation, and maintenance of membrane curvature to maintain the organelle shape and functionality. The contribution of biophysicists and biologists is essential for shedding light on the mechanistic understanding and quantification of these processes. Given the vast complexity of phenomena and mechanisms involved in the coupling between membrane shape and function, it is not always clear in what direction to advance to eventually arrive at an exhaustive understanding of this important research area. The 2018 Biomembrane Curvature and Remodeling Roadmap of Journal of Physics D: Applied Physics addresses this need for clarity and is intended to provide guidance both for students who have just entered the field as well as established scientists who would like to improve their orientation within this fascinating area.
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Affiliation(s)
- Patricia Bassereau
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
| | - Rui Jin
- Chemistry Department, University of Pennsylvania, Philadelphia, PA 19104-6323, United States of America
| | - Tobias Baumgart
- Chemistry Department, University of Pennsylvania, Philadelphia, PA 19104-6323, United States of America
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, United States of America
| | - Rumiana Dimova
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
| | - Vadim A Frolov
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country, Leioa 48940, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Spain
| | - Pavel V Bashkirov
- Federal Research and Clinical Centre of Physical-Chemical Medicine, Moscow 119435, Russia
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow 119071, Russia
| | - Helmut Grubmüller
- Department of Theoretical and Computational Biophysics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Reinhard Jahn
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - H Jelger Risselada
- Department of Theoretical Physics, Georg-August University, Göttingen, Germany
| | - Ludger Johannes
- Cellular and Chemical Biology Unit, Institut Curie, PSL Research University, U1143 INSERM, UMR3666 CNRS, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | - Michael M Kozlov
- Sackler Faculty of Medicine, Department of Physiology and Pharmacology, Tel Aviv University
| | - Reinhard Lipowsky
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
| | | | - Wade F Zeno
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, United States of America
| | - Jeanne C Stachowiak
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, United States of America
- University of Texas at Austin, Institute for Cellular and Molecular Biology, Austin, TX, United States of America
| | - Dimitrios Stamou
- Bionanotechnology and Nanomedicine Laboratory, Department of Chemistry, Nano-Science Center, University of Copenhagen, Denmark
| | - Artú Breuer
- Bionanotechnology and Nanomedicine Laboratory, Department of Chemistry, Nano-Science Center, University of Copenhagen, Denmark
| | - Line Lauritsen
- Bionanotechnology and Nanomedicine Laboratory, Department of Chemistry, Nano-Science Center, University of Copenhagen, Denmark
| | - Camille Simon
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
| | - Cécile Sykes
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
| | - Gregory A Voth
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, United States of America
| | - Thomas R Weikl
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
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44
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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: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [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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45
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Snead WT, Stachowiak JC. Structure Versus Stochasticity-The Role of Molecular Crowding and Intrinsic Disorder in Membrane Fission. J Mol Biol 2018; 430:2293-2308. [PMID: 29627460 DOI: 10.1016/j.jmb.2018.03.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/22/2018] [Accepted: 03/26/2018] [Indexed: 01/07/2023]
Abstract
Cellular membranes must undergo remodeling to facilitate critical functions including membrane trafficking, organelle biogenesis, and cell division. An essential step in membrane remodeling is membrane fission, in which an initially continuous membrane surface is divided into multiple, separate compartments. The established view has been that membrane fission requires proteins with conserved structural features such as helical scaffolds, hydrophobic insertions, and polymerized assemblies. In this review, we discuss these structure-based fission mechanisms and highlight recent findings from several groups that support an alternative, structure-independent mechanism of membrane fission. This mechanism relies on lateral collisions among crowded, membrane-bound proteins to generate sufficient steric pressure to drive membrane vesiculation. As a stochastic process, this mechanism contrasts with the paradigm that deterministic protein structures are required to drive fission, raising the prospect that many more proteins may participate in fission than previously thought. Paradoxically, our recent work suggests that intrinsically disordered domains may be among the most potent drivers of membrane fission, owing to their large hydrodynamic radii and substantial chain entropy. This stochastic view of fission also suggests new roles for the structure-based fission proteins. Specifically, we hypothesize that in addition to driving fission directly, the canonical fission machines may facilitate the enrichment and organization of bulky disordered protein domains in order to promote membrane fission by locally amplifying protein crowding.
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Affiliation(s)
- Wilton T Snead
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Jeanne C Stachowiak
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA.
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46
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Increasing Diversity of Biological Membrane Fission Mechanisms. Trends Cell Biol 2018; 28:274-286. [DOI: 10.1016/j.tcb.2017.12.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 12/06/2017] [Accepted: 12/12/2017] [Indexed: 12/19/2022]
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47
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48
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Makaraci P, Kim K. trans-Golgi network-bound cargo traffic. Eur J Cell Biol 2018; 97:137-149. [PMID: 29398202 DOI: 10.1016/j.ejcb.2018.01.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/15/2017] [Accepted: 01/16/2018] [Indexed: 12/19/2022] Open
Abstract
Cargo following the retrograde trafficking are sorted at endosomes to be targeted the trans-Golgi network (TGN), a central receiving organelle. Though molecular requirements and their interaction networks have been somewhat established, the complete understanding of the intricate nature of their action mechanisms in every step of the retrograde traffic pathway remains unachieved. This review focuses on elucidating known functions of key regulators, including scission factors at the endosome and tethering/fusion mediators at the receiving dock, TGN, as well as a diverse range of cargo.
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Affiliation(s)
- Pelin Makaraci
- Department of Biology, Missouri State University, 901 S National Ave., Springfield, MO 65807, USA
| | - Kyoungtae Kim
- Department of Biology, Missouri State University, 901 S National Ave., Springfield, MO 65807, USA.
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49
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Takeda T, Kozai T, Yang H, Ishikuro D, Seyama K, Kumagai Y, Abe T, Yamada H, Uchihashi T, Ando T, Takei K. Dynamic clustering of dynamin-amphiphysin helices regulates membrane constriction and fission coupled with GTP hydrolysis. eLife 2018; 7:30246. [PMID: 29357276 PMCID: PMC5780043 DOI: 10.7554/elife.30246] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 12/18/2017] [Indexed: 01/16/2023] Open
Abstract
Dynamin is a mechanochemical GTPase essential for membrane fission during clathrin-mediated endocytosis. Dynamin forms helical complexes at the neck of clathrin-coated pits and their structural changes coupled with GTP hydrolysis drive membrane fission. Dynamin and its binding protein amphiphysin cooperatively regulate membrane remodeling during the fission, but its precise mechanism remains elusive. In this study, we analyzed structural changes of dynamin-amphiphysin complexes during the membrane fission using electron microscopy (EM) and high-speed atomic force microscopy (HS-AFM). Interestingly, HS-AFM analyses show that the dynamin-amphiphysin helices are rearranged to form clusters upon GTP hydrolysis and membrane constriction occurs at protein-uncoated regions flanking the clusters. We also show a novel function of amphiphysin in size control of the clusters to enhance biogenesis of endocytic vesicles. Our approaches using combination of EM and HS-AFM clearly demonstrate new mechanistic insights into the dynamics of dynamin-amphiphysin complexes during membrane fission. The nerve cells that make up a nervous system connect at junctions known as synapses. When a nerve impulse reaches the end of the cell, membrane-bound packages called vesicles fuse with the surface membrane and release their contents to the outside. The contents, namely chemicals called neurotransmitters, then travels across the synapse, relaying the signal to the next cell. Nerve cells can fire many times per second. The membrane from fused vesicles must be retrieved from the surface membrane and recycled to make new vesicles, ready to transmit more signals across the synapse. Many proteins at these sites are involved in folding the fused membrane back into the cell, constricting the opening, and eventually pinching off the new vesicles – a process known as endocytosis. Two proteins named dynamin and amphiphysin cooperate in this process, but their precise mechanism remained elusive. Dynamin is a protein that acts like a motor; it breaks down a molecule called GTP to release energy. Previous studies have seen that dynamin-amphiphysin complexes join end to end to form long helical structures. Takeda et al. have now looked at how the structure of the helices changes during endocytosis. This revealed that the dynamin-amphiphysin helices rearrange to form clusters when the GTP is broken down. Further analysis showed that the folded membrane becomes constricted at regions that are not coated with the clusters of dynamin-amphiphysin helices. Takeda et al. also discovered that amphiphysin controls the size of the clusters to help make the new vesicles more uniform. The gene for dynamin is altered in a number of disorders affecting the nervous system and muscles, including epileptic encephalopathy, Charcot-Marie-Tooth disease and congenital myopathy. Moreover, a neurological disorder characterized by muscle stiffness (known as Stiff-person syndrome) occurs when an individual’s immune system mistakenly attacks the amphiphysin protein. As such, these new findings will not only help scientists to better understand the process of endocytosis, but they will also give new insight into a number of human diseases.
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Affiliation(s)
- Tetsuya Takeda
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Toshiya Kozai
- Department of Physics, College of Science and Engineering, Kanazawa University, Kanazawa, Japan
| | - Huiran Yang
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Daiki Ishikuro
- Department of Physics, College of Science and Engineering, Kanazawa University, Kanazawa, Japan
| | - Kaho Seyama
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Yusuke Kumagai
- Department of Physics, College of Science and Engineering, Kanazawa University, Kanazawa, Japan
| | - Tadashi Abe
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Hiroshi Yamada
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Takayuki Uchihashi
- CREST, JST, Saitama, Japan.,Department of Physics, School of Science, Nagoya University, Nagoya, Japan
| | - Toshio Ando
- CREST, JST, Saitama, Japan.,Bio-AFM Frontier Research Center, College of Science and Engineering, Kanazawa University, Kanazawa, Japan
| | - Kohji Takei
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.,CREST, JST, Saitama, Japan
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Galli V, Sebastian R, Moutel S, Ecard J, Perez F, Roux A. Uncoupling of dynamin polymerization and GTPase activity revealed by the conformation-specific nanobody dynab. eLife 2017; 6:25197. [PMID: 29022874 PMCID: PMC5658065 DOI: 10.7554/elife.25197] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 10/11/2017] [Indexed: 01/28/2023] Open
Abstract
Dynamin is a large GTPase that forms a helical collar at the neck of endocytic pits, and catalyzes membrane fission (Schmid and Frolov, 2011; Ferguson and De Camilli, 2012). Dynamin fission reaction is strictly dependent on GTP hydrolysis, but how fission is mediated is still debated (Antonny et al., 2016): GTP energy could be spent in membrane constriction required for fission, or in disassembly of the dynamin polymer to trigger fission. To follow dynamin GTP hydrolysis at endocytic pits, we generated a conformation-specific nanobody called dynab, that binds preferentially to the GTP hydrolytic state of dynamin-1. Dynab allowed us to follow the GTPase activity of dynamin-1 in real-time. We show that in fibroblasts, dynamin GTP hydrolysis occurs as stochastic bursts, which are randomly distributed relatively to the peak of dynamin assembly. Thus, dynamin disassembly is not coupled to GTPase activity, supporting that the GTP energy is primarily spent in constriction.
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Affiliation(s)
- Valentina Galli
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Rafael Sebastian
- Department of Computer Sciences, Universidad de Valencia, Valencia, Spain
| | - Sandrine Moutel
- Institut Curie, PSL Research University, Paris, France.,Translational Department, Institut Curie, Paris, France
| | - Jason Ecard
- Institut Curie, PSL Research University, Paris, France
| | - Franck Perez
- Institut Curie, PSL Research University, Paris, France
| | - Aurélien Roux
- Department of Biochemistry, University of Geneva, Geneva, Switzerland.,Swiss National Centre for Competence in Research Programme Chemical Biology, Geneva, Switzerland
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