1
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Shivangi, Khan Y, Ekka MK, Meena LS. Structural and functional characterization of mycobacterial PhoH2 and identification of potential inhibitor of its enzymatic activity. Braz J Microbiol 2024; 55:1033-1051. [PMID: 38386260 PMCID: PMC11153397 DOI: 10.1007/s42770-024-01267-4] [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: 11/09/2023] [Accepted: 01/30/2024] [Indexed: 02/23/2024] Open
Abstract
Mycobacterium tuberculosis is composed of a cumbersome signaling and protein network which partakes in bacterial survival and augments its pathogenesis. Mycobacterial PhoH2 (Mt-PhoH2) is a signaling element and a predictive phosphate starvation protein that works in an ATP-dependent manner. Here, we elaborated the characterization of Mt-PhoH2 through biophysical, biochemical, and computational methods. In addition to its intrinsic ATPase activity, the biochemical experiments revealed its GTPase activity and both activities are metal ion dependent. Magnesium, manganese, copper, iron, nickel, zinc, cesium, calcium, and lithium were examined for their effect on activity, and the optimum activity was found with 10 mM of Mg2+ ions. The kinetic parameters of 3 µM Mt-PhoH2 were observed as Km 4.873 ± 0.44 µM, Vmax 12.3817 ± 0.084 µM/min/mg, Kcat 0.0075 ± 0.00005 s-1, and Kcat/Km 0.0015 ± 0.000001 µM-1 s-1 with GTP. In the case of GTP as a substrate, a 20% decrease in enzymatic activity and a 50% increase in binding affinity of Mt-PhoH2 were observed. The substrates ADP and GDP inhibit the ATPase and GTPase activity of Mt-PhoH2. CD spectroscopy showed the dominance of alpha helix in the secondary structure of Mt-PhoH2, and this structural pattern was altered upon addition of ATP and GTP. In silico inhibitor screening revealed ML141 and NAV_2729 as two potential inhibitors of the catalytic activity of Mt-PhoH2. Mt-PhoH2 is essential for mycobacterial growth as its knockdown strain showed a decreased growth effect. Overall, the present article emphasizes the factors essential for the proper functioning of Mt-PhoH2 which is a participant in the toxin-antitoxin machinery and may also play an important role in phosphate starvation.
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Affiliation(s)
- Shivangi
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC, Ghaziabad, Uttar Pradesh, 201 002, India
| | - Yasmeen Khan
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC, Ghaziabad, Uttar Pradesh, 201 002, India
| | - Mary Krishna Ekka
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC, Ghaziabad, Uttar Pradesh, 201 002, India
| | - Laxman S Meena
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India.
- Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC, Ghaziabad, Uttar Pradesh, 201 002, India.
- CSIR-Central Drug Research Institute, Lucknow, 226031, India.
- CSIR-Institute of Genomics and Integrative Biology, Academy of Scientific & Innovative Research (AcSIR), Mall Road, Delhi, 110007, India.
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2
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Matsubayashi HT, Mountain J, Takahashi N, Deb Roy A, Yao T, Peterson AF, Saez Gonzalez C, Kawamata I, Inoue T. Non-catalytic role of phosphoinositide 3-kinase in mesenchymal cell migration through non-canonical induction of p85β/AP2-mediated endocytosis. Nat Commun 2024; 15:2612. [PMID: 38521786 PMCID: PMC10960865 DOI: 10.1038/s41467-024-46855-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: 01/11/2023] [Accepted: 03/13/2024] [Indexed: 03/25/2024] Open
Abstract
Class IA phosphoinositide 3-kinase (PI3K) galvanizes fundamental cellular processes such as migration, proliferation, and differentiation. To enable these multifaceted roles, the catalytic subunit p110 utilizes the multi-domain, regulatory subunit p85 through its inter SH2 domain (iSH2). In cell migration, its product PI(3,4,5)P3 generates locomotive activity. While non-catalytic roles are also implicated, underlying mechanisms and their relationship to PI(3,4,5)P3 signaling remain elusive. Here, we report that a disordered region of iSH2 contains AP2 binding motifs which can trigger clathrin and dynamin-mediated endocytosis independent of PI3K catalytic activity. The AP2 binding motif mutants of p85 aberrantly accumulate at focal adhesions and increase both velocity and persistency in fibroblast migration. We thus propose the dual functionality of PI3K in the control of cell motility, catalytic and non-catalytic, arising distinctly from juxtaposed regions within iSH2.
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Affiliation(s)
- Hideaki T Matsubayashi
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
- Center for Cell Dynamics, Institute of Basic Biomedical Sciences, Johns Hopkins University, Baltimore, MD, USA.
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Tohoku, Japan.
| | - Jack Mountain
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Center for Cell Dynamics, Institute of Basic Biomedical Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Nozomi Takahashi
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Tohoku, Japan
| | - Abhijit Deb Roy
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Center for Cell Dynamics, Institute of Basic Biomedical Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Tony Yao
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Center for Cell Dynamics, Institute of Basic Biomedical Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Amy F Peterson
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Center for Cell Dynamics, Institute of Basic Biomedical Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Cristian Saez Gonzalez
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Center for Cell Dynamics, Institute of Basic Biomedical Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Ibuki Kawamata
- Department of Robotics, Tohoku University, Tohoku, Japan
- Natural Science Division, Ochanomizu University, Kyoto, Japan
- Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Takanari Inoue
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
- Center for Cell Dynamics, Institute of Basic Biomedical Sciences, Johns Hopkins University, Baltimore, MD, USA.
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3
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Pérez-Jover I, Rochon K, Hu D, Mahajan M, Madan Mohan P, Santos-Pérez I, Ormaetxea Gisasola J, Martinez Galvez JM, Agirre J, Qi X, Mears JA, Shnyrova AV, Ramachandran R. Allosteric control of dynamin-related protein 1 through a disordered C-terminal Short Linear Motif. Nat Commun 2024; 15:52. [PMID: 38168038 PMCID: PMC10761769 DOI: 10.1038/s41467-023-44413-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 12/07/2023] [Indexed: 01/05/2024] Open
Abstract
The mechanochemical GTPase dynamin-related protein 1 (Drp1) catalyzes mitochondrial and peroxisomal fission, but the regulatory mechanisms remain ambiguous. Here we find that a conserved, intrinsically disordered, six-residue Short Linear Motif at the extreme Drp1 C-terminus, named CT-SLiM, constitutes a critical allosteric site that controls Drp1 structure and function in vitro and in vivo. Extension of the CT-SLiM by non-native residues, or its interaction with the protein partner GIPC-1, constrains Drp1 subunit conformational dynamics, alters self-assembly properties, and limits cooperative GTP hydrolysis, surprisingly leading to the fission of model membranes in vitro. In vivo, the involvement of the native CT-SLiM is critical for productive mitochondrial and peroxisomal fission, as both deletion and non-native extension of the CT-SLiM severely impair their progression. Thus, contrary to prevailing models, Drp1-catalyzed membrane fission relies on allosteric communication mediated by the CT-SLiM, deceleration of GTPase activity, and coupled changes in subunit architecture and assembly-disassembly dynamics.
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Affiliation(s)
- Isabel Pérez-Jover
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain
- Instituto Biofisika, CSIC, UPV/EHU, 48940, Leioa, Spain
| | - Kristy Rochon
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Di Hu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Mukesh Mahajan
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Pooja Madan Mohan
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Isaac Santos-Pérez
- Electron Microscopy and Crystallography Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology, Park Bld 800, 48160-Derio, Bizkaia, Spain
| | - Julene Ormaetxea Gisasola
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain
- Instituto Biofisika, CSIC, UPV/EHU, 48940, Leioa, Spain
| | - Juan Manuel Martinez Galvez
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain
- Instituto Biofisika, CSIC, UPV/EHU, 48940, Leioa, Spain
| | - Jon Agirre
- York Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, YO10 5DD, York, UK
| | - Xin Qi
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Jason A Mears
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Anna V Shnyrova
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain.
- Instituto Biofisika, CSIC, UPV/EHU, 48940, Leioa, Spain.
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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4
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Okuma H, Saijo-Hamano Y, Yamada H, Sherif AA, Hashizaki E, Sakai N, Kato T, Imasaki T, Kikkawa S, Nitta E, Sasai M, Abe T, Sugihara F, Maniwa Y, Kosako H, Takei K, Standley DM, Yamamoto M, Nitta R. Structural basis of Irgb6 inactivation by Toxoplasma gondii through the phosphorylation of switch I. Genes Cells 2024; 29:17-38. [PMID: 37984375 DOI: 10.1111/gtc.13080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/12/2023] [Accepted: 10/29/2023] [Indexed: 11/22/2023]
Abstract
Irgb6 is a priming immune-related GTPase (IRG) that counteracts Toxoplasma gondii. It is known to be recruited to the low virulent type II T. gondii parasitophorous vacuole (PV), initiating cell-autonomous immunity. However, the molecular mechanism by which immunity-related GTPases become inactivated after the parasite infection remains obscure. Here, we found that Thr95 of Irgb6 is prominently phosphorylated in response to low virulent type II T. gondii infection. We observed that a phosphomimetic T95D mutation in Irgb6 impaired its localization to the PV and exhibited reduced GTPase activity in vitro. Structural analysis unveiled an atypical conformation of nucleotide-free Irgb6-T95D, resulting from a conformational change in the G-domain that allosterically modified the PV membrane-binding interface. In silico docking corroborated the disruption of the physiological membrane binding site. These findings provide novel insights into a T. gondii-induced allosteric inactivation mechanism of Irgb6.
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Affiliation(s)
- Hiromichi Okuma
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yumiko Saijo-Hamano
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroshi Yamada
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Aalaa Alrahman Sherif
- Department of Genome Informatics, Research Institute for Microbial Diseases, Osaka, Japan
- Laboratory of Systems Immunology, WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Emi Hashizaki
- Laboratory of Immunoparasitology, Osaka University, Osaka, Japan
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka, Japan
| | | | - Takaaki Kato
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tsuyoshi Imasaki
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Satoshi Kikkawa
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Eriko Nitta
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Miwa Sasai
- Laboratory of Immunoparasitology, Osaka University, Osaka, Japan
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka, Japan
| | - Tadashi Abe
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Fuminori Sugihara
- Core Instrumentation Facility, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Yoshimasa Maniwa
- Division of Thoracic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hidetaka Kosako
- Division of Cell Signaling, Fujii Memorial Institute of Medical Sciences, Tokushima University, Tokushima, Japan
| | - Kohji Takei
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Daron M Standley
- Department of Genome Informatics, Research Institute for Microbial Diseases, Osaka, Japan
- Laboratory of Systems Immunology, WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Masahiro Yamamoto
- Laboratory of Immunoparasitology, Osaka University, Osaka, Japan
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka, Japan
| | - Ryo Nitta
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
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5
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Bonnycastle K, Dobson KL, Blumrich EM, Gajbhiye A, Davenport EC, Pronot M, Steinruecke M, Trost M, Gonzalez-Sulser A, Cousin MA. Reversal of cell, circuit and seizure phenotypes in a mouse model of DNM1 epileptic encephalopathy. Nat Commun 2023; 14:5285. [PMID: 37648685 PMCID: PMC10468497 DOI: 10.1038/s41467-023-41035-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 08/17/2023] [Indexed: 09/01/2023] Open
Abstract
Dynamin-1 is a large GTPase with an obligatory role in synaptic vesicle endocytosis at mammalian nerve terminals. Heterozygous missense mutations in the dynamin-1 gene (DNM1) cause a novel form of epileptic encephalopathy, with pathogenic mutations clustering within regions required for its essential GTPase activity. We reveal the most prevalent pathogenic DNM1 mutation, R237W, disrupts dynamin-1 enzyme activity and endocytosis when overexpressed in central neurons. To determine how this mutation impacted cell, circuit and behavioural function, we generated a mouse carrying the R237W mutation. Neurons from heterozygous mice display dysfunctional endocytosis, in addition to altered excitatory neurotransmission and seizure-like phenotypes. Importantly, these phenotypes are corrected at the cell, circuit and in vivo level by the drug, BMS-204352, which accelerates endocytosis. Here, we demonstrate a credible link between dysfunctional endocytosis and epileptic encephalopathy, and importantly reveal that synaptic vesicle recycling may be a viable therapeutic target for monogenic intractable epilepsies.
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Affiliation(s)
- Katherine Bonnycastle
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK.
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK.
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK.
- Service de Génétique Médicale, Centre Hospitalier Universitaire (CHU) Sainte-Justine, Université de Montréal, Montreal, QC, Canada.
| | - Katharine L Dobson
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
| | - Eva-Maria Blumrich
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
| | - Akshada Gajbhiye
- Newcastle University Biosciences Institute, Faculty of Medical Sciences, NE2 4HH, Newcastle upon Tyne, UK
| | - Elizabeth C Davenport
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
| | - Marie Pronot
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
| | - Moritz Steinruecke
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
| | - Matthias Trost
- Newcastle University Biosciences Institute, Faculty of Medical Sciences, NE2 4HH, Newcastle upon Tyne, UK
| | - Alfredo Gonzalez-Sulser
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK
| | - Michael A Cousin
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK.
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK.
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK.
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6
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He J, Liu K, Wu Y, Zhao C, Yan S, Chen JH, Hu L, Wang D, Zheng F, Wei W, Xu C, Huang C, Liu X, Yao X, Ding L, Fang Z, Tang AH, Fu C. The AAA-ATPase Yta4/ATAD1 interacts with the mitochondrial divisome to inhibit mitochondrial fission. PLoS Biol 2023; 21:e3002247. [PMID: 37590302 PMCID: PMC10465003 DOI: 10.1371/journal.pbio.3002247] [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: 02/25/2022] [Revised: 08/29/2023] [Accepted: 07/12/2023] [Indexed: 08/19/2023] Open
Abstract
Mitochondria are in a constant balance of fusion and fission. Excessive fission or deficient fusion leads to mitochondrial fragmentation, causing mitochondrial dysfunction and physiological disorders. How the cell prevents excessive fission of mitochondria is not well understood. Here, we report that the fission yeast AAA-ATPase Yta4, which is the homolog of budding yeast Msp1 responsible for clearing mistargeted tail-anchored (TA) proteins on mitochondria, plays a critical role in preventing excessive mitochondrial fission. The absence of Yta4 leads to mild mitochondrial fragmentation in a Dnm1-dependent manner but severe mitochondrial fragmentation upon induction of mitochondrial depolarization. Overexpression of Yta4 delocalizes the receptor proteins of Dnm1, i.e., Fis1 (a TA protein) and Mdv1 (the bridging protein between Fis1 and Dnm1), from mitochondria and reduces the localization of Dnm1 to mitochondria. The effect of Yta4 overexpression on Fis1 and Mdv1, but not Dnm1, depends on the ATPase and translocase activities of Yta4. Moreover, Yta4 interacts with Dnm1, Mdv1, and Fis1. In addition, Yta4 competes with Dnm1 for binding Mdv1 and decreases the affinity of Dnm1 for GTP and inhibits Dnm1 assembly in vitro. These findings suggest a model, in which Yta4 inhibits mitochondrial fission by inhibiting the function of the mitochondrial divisome composed of Fis1, Mdv1, and Dnm1. Therefore, the present work reveals an uncharacterized molecular mechanism underlying the inhibition of mitochondrial fission.
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Affiliation(s)
- Jiajia He
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology & Hefei National Research Center for Interdisciplinary Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Ke Liu
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology & Hefei National Research Center for Interdisciplinary Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Yifan Wu
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Chenhui Zhao
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Shuaijie Yan
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Jia-Hui Chen
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
| | - Lizhu Hu
- Anhui Province Key Laboratory of Medical Physics and Technology, Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Dongmei Wang
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Fan Zheng
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Wenfan Wei
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Chao Xu
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology & Hefei National Research Center for Interdisciplinary Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Chengdong Huang
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology & Hefei National Research Center for Interdisciplinary Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Xing Liu
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology & Hefei National Research Center for Interdisciplinary Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Xuebiao Yao
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology & Hefei National Research Center for Interdisciplinary Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Lijun Ding
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China
| | - Zhiyou Fang
- Anhui Province Key Laboratory of Medical Physics and Technology, Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Ai-Hui Tang
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
| | - Chuanhai Fu
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology & Hefei National Research Center for Interdisciplinary Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
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7
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Nyenhuis SB, Wu X, Strub MP, Yim YI, Stanton AE, Baena V, Syed ZA, Canagarajah B, Hammer JA, Hinshaw JE. OPA1 helical structures give perspective to mitochondrial dysfunction. Nature 2023; 620:1109-1116. [PMID: 37612506 DOI: 10.1038/s41586-023-06462-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 07/19/2023] [Indexed: 08/25/2023]
Abstract
Dominant optic atrophy is one of the leading causes of childhood blindness. Around 60-80% of cases1 are caused by mutations of the gene that encodes optic atrophy protein 1 (OPA1), a protein that has a key role in inner mitochondrial membrane fusion and remodelling of cristae and is crucial for the dynamic organization and regulation of mitochondria2. Mutations in OPA1 result in the dysregulation of the GTPase-mediated fusion process of the mitochondrial inner and outer membranes3. Here we used cryo-electron microscopy methods to solve helical structures of OPA1 assembled on lipid membrane tubes, in the presence and absence of nucleotide. These helical assemblies organize into densely packed protein rungs with minimal inter-rung connectivity, and exhibit nucleotide-dependent dimerization of the GTPase domains-a hallmark of the dynamin superfamily of proteins4. OPA1 also contains several unique secondary structures in the paddle domain that strengthen its membrane association, including membrane-inserting helices. The structural features identified in this study shed light on the effects of pathogenic point mutations on protein folding, inter-protein assembly and membrane interactions. Furthermore, mutations that disrupt the assembly interfaces and membrane binding of OPA1 cause mitochondrial fragmentation in cell-based assays, providing evidence of the biological relevance of these interactions.
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Affiliation(s)
- Sarah B Nyenhuis
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA
| | - Xufeng Wu
- Light Microscopy Facility, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Marie-Paule Strub
- Protein Expression Facility, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Yang-In Yim
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Abigail E Stanton
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA
- Molecular Biology Department, Princeton University, Princeton, NJ, USA
| | - Valentina Baena
- Electron Microscopy Core, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Zulfeqhar A Syed
- Electron Microscopy Core, National Heart, Lung, and Blood Institute, 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
| | - John A Hammer
- Cell and Developmental Biology Center, 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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8
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Yang J, Chen P, Cao Y, Liu S, Wang W, Li L, Li J, Jiang Z, Ma Y, Chen S, Zheng S, Qi X, Jiang H. Chemical inhibition of mitochondrial fission via targeting the DRP1-receptor interaction. Cell Chem Biol 2023; 30:278-294.e11. [PMID: 36827981 DOI: 10.1016/j.chembiol.2023.02.002] [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: 05/19/2022] [Revised: 09/14/2022] [Accepted: 02/03/2023] [Indexed: 02/25/2023]
Abstract
Mitochondrial fission is critical for mitochondrial dynamics and homeostasis. The dynamin superfamily GTPase DRP1 is recruited by three functionally redundant receptors, MFF, MiD49, and MiD51, to mitochondria to drive fission. Here, we exploit high-content live-cell imaging to screen for mitochondrial fission inhibitors and have developed a covalent compound, mitochondrial division inhibitor (MIDI). MIDI treatment potently blocks mitochondrial fragmentation induced by mitochondrial toxins and restores mitochondrial morphology in fusion-defective cells carrying pathogenic mitofusin and OPA1 mutations. Mechanistically, MIDI does not affect DRP1 tetramerization nor DRP1 GTPase activity but does block DRP1 recruitment to mitochondria. Subsequent biochemical and cellular characterizations reveal an unexpected mechanism that MIDI targets DRP1 interaction with multiple receptors via covalent interaction with DRP1-C367. Taken together, beyond developing a potent mitochondrial fission inhibitor that profoundly impacts mitochondrial morphogenesis, our study establishes proof of concept for developing protein-protein interaction inhibitors targeting DRP1.
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Affiliation(s)
- Jun Yang
- School of Life Sciences, Tsinghua University, Beijing 100084, China; National Institute of Biological Sciences, Beijing 102206, China
| | - Peihao Chen
- National Institute of Biological Sciences, Beijing 102206, China; School of Life Sciences, Peking University, Beijing, China
| | - Yu Cao
- National Institute of Biological Sciences, Beijing 102206, China; College of Life Sciences, Beijing Normal University, Beijing, China
| | - Shanshan Liu
- National Institute of Biological Sciences, Beijing 102206, China
| | - Wei Wang
- National Institute of Biological Sciences, Beijing 102206, China; School of Life Sciences, Peking University, Beijing, China
| | - Lin Li
- National Institute of Biological Sciences, Beijing 102206, China
| | - Jiaojiao Li
- National Institute of Biological Sciences, Beijing 102206, China
| | - Zhaodi Jiang
- National Institute of Biological Sciences, Beijing 102206, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - Yan Ma
- National Institute of Biological Sciences, Beijing 102206, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - She Chen
- National Institute of Biological Sciences, Beijing 102206, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - Sanduo Zheng
- National Institute of Biological Sciences, Beijing 102206, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - Xiangbing Qi
- National Institute of Biological Sciences, Beijing 102206, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China.
| | - Hui Jiang
- School of Life Sciences, Tsinghua University, Beijing 100084, China; National Institute of Biological Sciences, Beijing 102206, China; Beijing Key Laboratory of Cell Biology for Animal Aging, Beijing 102206, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China.
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9
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Matsubayashi HT, Mountain J, Yao T, Peterson AF, Deb Roy A, Inoue T. Non-catalytic role of phosphoinositide 3-kinase in mesenchymal cell migration through non-canonical induction of p85β/AP-2-mediated endocytosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2022.12.31.522383. [PMID: 36712134 PMCID: PMC9881872 DOI: 10.1101/2022.12.31.522383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Class IA phosphoinositide 3-kinase (PI3K) galvanizes fundamental cellular processes such as migration, proliferation, and differentiation. To enable multifaceted roles, the catalytic subunit p110 utilizes a multidomain, regulatory subunit p85 through its inter SH2 domain (iSH2). In cell migration, their product PI(3,4,5)P3 generates locomotive activity. While non-catalytic roles are also implicated, underlying mechanisms and its relationship to PI(3,4,5)P3 signaling remain elusive. Here, we report that a disordered region of iSH2 contains previously uncharacterized AP-2 binding motifs which can trigger clathrin and dynamin-mediated endocytosis independent of PI3K catalytic activity. The AP-2 binding motif mutants of p85 aberrantly accumulate at focal adhesions and upregulate both velocity and persistency in fibroblast migration. We thus propose the dual functionality of PI3K in the control of cell motility, catalytic and non-catalytic, arising distinctly from juxtaposed regions within iSH2.
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Affiliation(s)
- Hideaki T. Matsubayashi
- Department of Cell Biology, School of Medicine, Johns Hopkins University
- Center for Cell Dynamics, Institute of Basic Biomedical Sciences, Johns Hopkins University
| | - Jack Mountain
- Department of Cell Biology, School of Medicine, Johns Hopkins University
- Center for Cell Dynamics, Institute of Basic Biomedical Sciences, Johns Hopkins University
| | - Tony Yao
- Department of Cell Biology, School of Medicine, Johns Hopkins University
- Center for Cell Dynamics, Institute of Basic Biomedical Sciences, Johns Hopkins University
| | - Amy F. Peterson
- Department of Cell Biology, School of Medicine, Johns Hopkins University
- Center for Cell Dynamics, Institute of Basic Biomedical Sciences, Johns Hopkins University
| | - Abhijit Deb Roy
- Department of Cell Biology, School of Medicine, Johns Hopkins University
- Center for Cell Dynamics, Institute of Basic Biomedical Sciences, Johns Hopkins University
| | - Takanari Inoue
- Department of Cell Biology, School of Medicine, Johns Hopkins University
- Center for Cell Dynamics, Institute of Basic Biomedical Sciences, Johns Hopkins University
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10
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Laiman J, Hsu YJ, Loh J, Tang WC, Chuang MC, Liu HK, Yang WS, Chen BC, Chuang LM, Chang YC, Liu YW. GSK3α phosphorylates dynamin-2 to promote GLUT4 endocytosis in muscle cells. J Cell Biol 2022; 222:213725. [PMID: 36445308 PMCID: PMC9712776 DOI: 10.1083/jcb.202102119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 08/17/2022] [Accepted: 10/31/2022] [Indexed: 12/02/2022] Open
Abstract
Insulin-stimulated translocation of glucose transporter 4 (GLUT4) to plasma membrane of skeletal muscle is critical for postprandial glucose uptake; however, whether the internalization of GLUT4 is also regulated by insulin signaling remains unclear. Here, we discover that the activity of dynamin-2 (Dyn2) in catalyzing GLUT4 endocytosis is negatively regulated by insulin signaling in muscle cells. Mechanistically, the fission activity of Dyn2 is inhibited by binding with the SH3 domain of Bin1. In the absence of insulin, GSK3α phosphorylates Dyn2 to relieve the inhibition of Bin1 and promotes endocytosis. Conversely, insulin signaling inactivates GSK3α and leads to attenuated GLUT4 internalization. Furthermore, the isoform-specific pharmacological inhibition of GSK3α significantly improves insulin sensitivity and glucose tolerance in diet-induced insulin-resistant mice. Together, we identify a new role of GSK3α in insulin-stimulated glucose disposal by regulating Dyn2-mediated GLUT4 endocytosis in muscle cells. These results highlight the isoform-specific function of GSK3α on membrane trafficking and its potential as a therapeutic target for metabolic disorders.
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Affiliation(s)
- Jessica Laiman
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yen-Jung Hsu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Julie Loh
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Wei-Chun Tang
- ResearchCenter for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - Mei-Chun Chuang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hui-Kang Liu
- National Research Institute of Chinese Medicine, Ministry of Health and Welfare, Taipei, Taiwan,Program in the Clinical Drug Development of Herbal Medicine, Taipei Medical University, Taipei, Taiwan
| | - Wei-Shun Yang
- Division of Nephrology, Department of Internal Medicine, National Taiwan University Hospital, Hsin-Chu Branch, Hsin-Chu, Taiwan
| | - Bi-Chang Chen
- ResearchCenter for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - Lee-Ming Chuang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan,Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Yi-Cheng Chang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan,Institute of Medical Genomics and Proteomics, College of Medicine, National Taiwan University, Taipei, Taiwan,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan,Yi-Cheng Chang:
| | - Ya-Wen Liu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan,Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan,Correspondence to Ya-Wen Liu:
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11
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Yamada H, Abe T, Nagaoka H, Takashima E, Nitta R, Yamamoto M, Takei K. Recruitment of Irgb6 to the membrane is a direct trigger for membrane deformation. Front Cell Infect Microbiol 2022; 12:992198. [PMID: 36159643 PMCID: PMC9504060 DOI: 10.3389/fcimb.2022.992198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 08/12/2022] [Indexed: 11/13/2022] Open
Abstract
Irgb6 is a member of interferon γ-induced immunity related GTPase (IRG), and one of twenty “effector” IRGs, which coordinately attack parasitophorous vacuole membrane (PVM), causing death of intracellular pathogen. Although Irgb6 plays a pivotal role as a pioneer in the process of PVM disruption, the direct effect of Irgb6 on membrane remained to be elucidated. Here, we utilized artificial lipid membranes to reconstitute Irgb6-membrane interaction in vitro, and revealed that Irgb6 directly deformed the membranes. Liposomes incubated with recombinant Irgb6 were drastically deformed generating massive tubular protrusions in the absence of guanine nucleotide, or with GMP-PNP. Liposome deformation was abolished by incubating with Irgb6-K275A/R371A, point mutations at membrane targeting residues. The membrane tubules generated by Irgb6 were mostly disappeared by the addition of GTP or GDP, which are caused by detachment of Irgb6 from membrane. Binding of Irgb6 to the membrane, which was reconstituted in vitro using lipid monolayer, was stimulated at GTP-bound state. Irgb6 GTPase activity was stimulated by the presence of liposomes more than eightfold. Irgb6 GTPase activity in the absence of membrane was also slightly stimulated, by lowering ionic strength, or by increasing protein concentration, indicating synergistic stimulation of the GTPase activity. These results suggest that membrane targeting of Irgb6 and resulting membrane deformation does not require GTP, but converting into GTP-bound state is crucial for detaching Irgb6 from the membrane, which might coincident with local membrane disruption.
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Affiliation(s)
- Hiroshi Yamada
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
- *Correspondence: Hiroshi Yamada, ; Kohji Takei,
| | - Tadashi Abe
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Hikaru Nagaoka
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Ryo Nitta
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masahiro Yamamoto
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Kohji Takei
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
- *Correspondence: Hiroshi Yamada, ; Kohji Takei,
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12
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Molecular and Functional Interactions of Alpha-Synuclein with Rab3a. J Biol Chem 2022; 298:102239. [PMID: 35809645 PMCID: PMC9396396 DOI: 10.1016/j.jbc.2022.102239] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 11/23/2022] Open
Abstract
Alpha-synuclein (a-Syn) is a presynaptic protein, the misfolding of which is associated with Parkinson’s disease. Rab GTPases are small guanine nucleotide binding proteins that play key roles in vesicle trafficking and have been associated with a-Syn function and dysfunction. a-Syn is enriched on synaptic vesicles, where it has been reported to interact with GTP-bound Rab3a, a master regulator of synaptic vesicle trafficking. a-Syn is known to bind weakly to Rab8a in solution via a positively charged patch, but the physiological implications of such interactions have not been explored. Here, we investigate direct interactions between a-Syn and Rab3a in solution and on lipid membranes using NMR spectroscopy. We find that the C terminus of a-Syn interacts with Rab3a in a manner similar to its previously reported interaction with Rab8a. While weak in solution, we demonstrate that this interaction becomes stronger when the proteins are bound to a membrane surface. The Rab3a binding site for a-Syn is similar to the surface that contacts the Rab3a effector rabphilin-3A, which modulates the enzymatic activity of Rab3a. Accordingly, we show that a-Syn inhibits GTP hydrolysis by Rab3a and that inhibition is more potent on the membrane surface, suggesting that their interaction may be functionally relevant. Finally, we show that phosphorylation of a-Syn residue Ser 129, a modification associated with Parkinson’s disease pathology, enhances its interactions with Rab3a and increases its ability to inhibit Rab3a GTP hydrolysis. These results represent the first observation of a functional role for synuclein-Rab interactions and for a-Syn Ser 129 phosphorylation.
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13
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Hamasaki E, Wakita N, Yasuoka H, Nagaoka H, Morita M, Takashima E, Uchihashi T, Takeda T, Abe T, Lee JW, Iimura T, Saleem MA, Ogo N, Asai A, Narita A, Takei K, Yamada H. The Lipid-Binding Defective Dynamin 2 Mutant in Charcot-Marie-Tooth Disease Impairs Proper Actin Bundling and Actin Organization in Glomerular Podocytes. Front Cell Dev Biol 2022; 10:884509. [PMID: 35620056 PMCID: PMC9127447 DOI: 10.3389/fcell.2022.884509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 04/06/2022] [Indexed: 11/13/2022] Open
Abstract
Dynamin is an endocytic protein that functions in vesicle formation by scission of invaginated membranes. Dynamin maintains the structure of foot processes in glomerular podocytes by directly and indirectly interacting with actin filaments. However, molecular mechanisms underlying dynamin-mediated actin regulation are largely unknown. Here, biochemical and cell biological experiments were conducted to uncover how dynamin modulates interactions between membranes and actin in human podocytes. Actin-bundling, membrane tubulating, and GTPase activities of dynamin were examined in vitro using recombinant dynamin 2-wild-type (WT) or dynamin 2-K562E, which is a mutant found in Charcot-Marie-Tooth patients. Dynamin 2-WT and dynamin 2-K562E led to the formation of prominent actin bundles with constant diameters. Whereas liposomes incubated with dynamin 2-WT resulted in tubule formation, dynamin 2-K562E reduced tubulation. Actin filaments and liposomes stimulated dynamin 2-WT GTPase activity by 6- and 20-fold, respectively. Actin-filaments, but not liposomes, stimulated dynamin 2-K562E GTPase activity by 4-fold. Self-assembly-dependent GTPase activity of dynamin 2-K562E was reduced to one-third compared to that of dynamin 2-WT. Incubation of liposomes and actin with dynamin 2-WT led to the formation of thick actin bundles, which often bound to liposomes. The interaction between lipid membranes and actin bundles by dynamin 2-K562E was lower than that by dynamin 2-WT. Dynamin 2-WT partially colocalized with stress fibers and actin bundles based on double immunofluorescence of human podocytes. Dynamin 2-K562E expression resulted in decreased stress fiber density and the formation of aberrant actin clusters. Dynamin 2-K562E colocalized with α-actinin-4 in aberrant actin clusters. Reformation of stress fibers after cytochalasin D-induced actin depolymerization and washout was less effective in dynamin 2-K562E-expressing cells than that in dynamin 2-WT. Bis-T-23, a dynamin self-assembly enhancer, was unable to rescue the decreased focal adhesion numbers and reduced stress fiber density induced by dynamin 2-K562E expression. These results suggest that the low affinity of the K562E mutant for lipid membranes, and atypical self-assembling properties, lead to actin disorganization in HPCs. Moreover, lipid-binding and self-assembly of dynamin 2 along actin filaments are required for podocyte morphology and functions. Finally, dynamin 2-mediated interactions between actin and membranes are critical for actin bundle formation in HPCs.
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Affiliation(s)
- Eriko Hamasaki
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Natsuki Wakita
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Hiroki Yasuoka
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Hikaru Nagaoka
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Masayuki Morita
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | | | - Tetsuya Takeda
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Tadashi Abe
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Ji-Won Lee
- Department of Pharmacology, Faculty and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Tadahiro Iimura
- Department of Pharmacology, Faculty and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Moin A Saleem
- Bristol Renal, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Naohisa Ogo
- Center for Drug Discovery, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Akira Asai
- Center for Drug Discovery, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Akihiro Narita
- Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Kohji Takei
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Hiroshi Yamada
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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14
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Metal-Binding Propensity in the Mitochondrial Dynamin-Related Protein 1. J Membr Biol 2022; 255:143-150. [PMID: 35218392 DOI: 10.1007/s00232-022-00221-5] [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: 01/16/2022] [Accepted: 02/14/2022] [Indexed: 10/19/2022]
Abstract
Dynamin-related protein1 (Drp1) functions to divide mitochondria and peroxisomes by binding specific adaptor proteins and lipids, both of which are integral to the limiting organellar membrane. In efforts to understand how such multivalent interactions regulate Drp1 functions, in vitro reconstitution schemes rely on recruiting soluble portions of the adaptors appended with genetically encoded polyhistidine tags onto membranes containing Ni2+-bound chelator lipids. These strategies are facile and circumvent the challenge in working with membrane proteins but assume that binding is specific to proteins carrying the polyhistidine tag. Here, we find using chelator lipids and chelator beads that both native and recombinant Drp1 directly bind Ni2+ ions. Metal binding, therefore, represents a potential strategy to deplete or purify Drp1 from native tissue lysates. Importantly, high concentrations of the metal in solution inhibit GTP hydrolysis and renders Drp1 inactive in membrane fission. Together, our results emphasize a metal-binding propensity, which could significantly impact Drp1 functions.
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15
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Bharambe N, Ramachandran R. Microscale Thermophoresis (MST ) as a Tool for Measuring Dynamin Superfamily Protein (DSP)-Lipid Interactions. Methods Mol Biol 2021; 2159:85-92. [PMID: 32529365 DOI: 10.1007/978-1-0716-0676-6_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Microscale thermophoresis (MST ) is a robust new fluorescence-based technology that enables measurement of biomolecular interactions and binding affinities (KD). MST is an immobilization-free alternative to surface plasmon resonance (SPR ) and is cost-effective relative to isothermal titration calorimetry (ITC ). In this chapter, using Drp1 as an example, we demonstrate for the first time, the application of MST to the determination of DSP-lipid interactions and the accurate measurement of KD under physiologically relevant solution conditions.
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Affiliation(s)
- Nikhil Bharambe
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
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16
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Ekka MK, Meena LS. Essential biochemical, biophysical and computational inputs on efficient functioning of Mycobacterium tuberculosis H 37Rv FtsY. Int J Biol Macromol 2021; 171:59-73. [PMID: 33412199 DOI: 10.1016/j.ijbiomac.2020.12.182] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/23/2020] [Accepted: 12/23/2020] [Indexed: 11/19/2022]
Abstract
Mycobacterium tuberculosis (M. tuberculosis H37Rv) utilizes the signal recognition particle pathway (SRP pathway) system for secretion of various proteins from ribosomes to the extracellular surface which plays an important role in the machinery running inside the bacterium. This system comprises of three major components FtsY, FfH and 4.5S rRNA. This manuscript highlights essential factors responsible for the optimized enzymatic activity of FtsY. Kinetic parameters include Vmax and Km for the hydrolysis of GTP by ftsY which were 20.25±5.16 μM/min/mg and 39.95±7.7 μM respectively. kcat and catalytic efficiency of the reaction were 0.012±0.003 s-1 and 0.00047±0.0001 μM/s-1 respectively. These values were affected upon changing the standard conditions. Cations (Mg2+ and Mn2+) play important role in FtsY enzymatic activity as increasing Mg2+ decrease the activity. Mn2+on the other hand is required at higher concentration around 60 mM for carrying optimum GTPase activity. FtsY is hydrolyzing ATP and GDP as well and GDP acts as an inhibitor of the reaction. MD simulation shows effective binding and stabilization of the FtsY complexed structure with GTP, GDP and ATP. Mutational analysis was done at two important residues of GTP binding motif of FtsY, namely, GXXXXGK (K236) and DXXG (D367) and showed that these mutations significantly decrease FtsY GTPase activity. FtsY is comprised of α helices, but this structural pattern was shown to change with increasing concentrations of GTP and ATP which symbolize that these ligands cause significant conformational change by variating the secondary structure to transduce signals required by downstream effectors. This binding favors the functional stabilization of FtsY by destabilization of α-helix integrity. Revealing the hidden aspects of the functioning of FtsY might be an essential part for the understanding of the SRP pathway which is one of the important contributors of M. tuberculosis virulence.
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Affiliation(s)
- Mary Krishna Ekka
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC, Ghaziabad, Uttar Pradesh 201 002, India
| | - Laxman S Meena
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC, Ghaziabad, Uttar Pradesh 201 002, India.
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17
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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: 22] [Impact Index Per Article: 7.3] [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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18
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Niu Y, Suzuki H, Hosford CJ, Walz T, Chappie JS. Structural asymmetry governs the assembly and GTPase activity of McrBC restriction complexes. Nat Commun 2020; 11:5907. [PMID: 33219217 PMCID: PMC7680126 DOI: 10.1038/s41467-020-19735-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 10/26/2020] [Indexed: 01/21/2023] Open
Abstract
McrBC complexes are motor-driven nucleases functioning in bacterial self-defense by cleaving foreign DNA. The GTP-specific AAA + protein McrB powers translocation along DNA and its hydrolysis activity is stimulated by its partner nuclease McrC. Here, we report cryo-EM structures of Thermococcus gammatolerans McrB and McrBC, and E. coli McrBC. The McrB hexamers, containing the necessary catalytic machinery for basal GTP hydrolysis, are intrinsically asymmetric. This asymmetry directs McrC binding so that it engages a single active site, where it then uses an arginine/lysine-mediated hydrogen-bonding network to reposition the asparagine in the McrB signature motif for optimal catalytic function. While the two McrBC complexes use different DNA-binding domains, these contribute to the same general GTP-recognition mechanism employed by all G proteins. Asymmetry also induces distinct inter-subunit interactions around the ring, suggesting a coordinated and directional GTP-hydrolysis cycle. Our data provide insights into the conserved molecular mechanisms governing McrB family AAA + motors. The bacterial defense system McrBC is a two-component motor-driven nuclease complex that cleaves foreign DNA. Here, the authors present the structures of the GTP-specific AAA + motor protein McrB and two McrBC complexes and discuss the molecular mechanism of how McrC binding stimulates McrB GTP hydrolysis.
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Affiliation(s)
- Yiming Niu
- Department of Molecular Medicine, Cornell University, Ithaca, NY, USA.,Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, NY, USA.,Laboratory Molecular Neurobiology and Biophysics, The Rockefeller University, New York, NY, USA
| | - Hiroshi Suzuki
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, NY, USA.,Advanced Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Christopher J Hosford
- Department of Molecular Medicine, Cornell University, Ithaca, NY, USA.,New England Biolabs, Inc., Ipswich, MA, USA
| | - Thomas Walz
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, NY, USA.
| | - Joshua S Chappie
- Department of Molecular Medicine, Cornell University, Ithaca, NY, USA.
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19
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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: 48] [Impact Index Per Article: 12.0] [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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20
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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: 31] [Impact Index Per Article: 7.8] [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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21
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Schiltz CJ, Adams MC, Chappie JS. The full-length structure of Thermus scotoductus OLD defines the ATP hydrolysis properties and catalytic mechanism of Class 1 OLD family nucleases. Nucleic Acids Res 2020; 48:2762-2776. [PMID: 32009148 PMCID: PMC7049728 DOI: 10.1093/nar/gkaa059] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 12/28/2019] [Accepted: 01/20/2020] [Indexed: 12/15/2022] Open
Abstract
OLD family nucleases contain an N-terminal ATPase domain and a C-terminal Toprim domain. Homologs segregate into two classes based on primary sequence length and the presence/absence of a unique UvrD/PcrA/Rep-like helicase gene immediately downstream in the genome. Although we previously defined the catalytic machinery controlling Class 2 nuclease cleavage, degenerate conservation of the C-termini between classes precludes pinpointing the analogous residues in Class 1 enzymes by sequence alignment alone. Our Class 2 structures also provide no information on ATPase domain architecture and ATP hydrolysis. Here we present the full-length structure of the Class 1 OLD nuclease from Thermus scotoductus (Ts) at 2.20 Å resolution, which reveals a dimerization domain inserted into an N-terminal ABC ATPase fold and a C-terminal Toprim domain. Structural homology with genome maintenance proteins identifies conserved residues responsible for Ts OLD ATPase activity. Ts OLD lacks the C-terminal helical domain present in Class 2 OLD homologs yet preserves the spatial organization of the nuclease active site, arguing that OLD proteins use a conserved catalytic mechanism for DNA cleavage. We also demonstrate that mutants perturbing ATP hydrolysis or DNA cleavage in vitro impair P2 OLD-mediated killing of recBC-Escherichia coli hosts, indicating that both the ATPase and nuclease activities are required for OLD function in vivo.
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Affiliation(s)
- Carl J Schiltz
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Myfanwy C Adams
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Joshua S Chappie
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
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22
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Beattie SR, Schnicker NJ, Murante T, Kettimuthu K, Williams NS, Gakhar L, Krysan DJ. Benzothiourea Derivatives Target the Secretory Pathway of the Human Fungal Pathogen Cryptococcus neoformans. ACS Infect Dis 2020; 6:529-539. [PMID: 32070095 DOI: 10.1021/acsinfecdis.9b00478] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cryptococcus neoformans is one of the most important human fungal pathogens and causes life-threatening meningoencephalitis in immunocompromised patients. The current gold standard therapy for C. neoformans meningoencephalitis is based on medications that are over 50 years old and is not readily available in regions with high disease burden. Here, we report the mycologic, mechanistic, and pharmacologic characterization of a set of benzothioureas with highly selective fungicidal activity against C. neoformans. In addition, to direct antifungal activity, benzothioureas inhibit C. neoformans virulence traits. On the basis of a set of phenotypic, biochemical, and biophysical assays, the benzothioureas (BTUs) inhibit the late secretory pathway (post-Golgi), possibly through a direct interaction with Sav1, an orthologue of the Sec4-class small GTPase. Importantly, pharmacological characterization of the BTUs indicates it readily penetrates the blood-brain barrier. Together, our data support the further development of this scaffold as an antifungal agent with a novel mechanism of action against C. neoformans.
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Affiliation(s)
- Sarah R. Beattie
- Department of Pediatrics, Carver College of Medicine, University of Iowa, 25 South Grand Avenue, Iowa City, Iowa 52245, United States
| | - Nicholas J. Schnicker
- Protein and Crystallography Facility, Carver College of Medicine, University of Iowa, 51 Newton Road, Iowa City, Iowa 52245, United States
| | - Thomas Murante
- Department of Pediatrics, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642, United States
| | - Kavitha Kettimuthu
- Department of Biochemistry, University of Texas Southwestern, 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
| | - Noelle S. Williams
- Department of Biochemistry, University of Texas Southwestern, 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
| | - Lokesh Gakhar
- Protein and Crystallography Facility, Carver College of Medicine, University of Iowa, 51 Newton Road, Iowa City, Iowa 52245, United States
- Department of Biochemistry, Carver College of Medicine, University of Iowa, 51 Newton Road, Iowa City, Iowa 52245, United States
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, 25 South Grand Avenue, Iowa City, Iowa 52245, United States
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, 25 South Grand Avenue, Iowa City, Iowa 52245, United States
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23
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Kennedy NW, Picton LK, Hill RB. Isolation and Analysis of Mitochondrial Fission Enzyme DNM1 from Saccharomyces cerevisiae. Methods Mol Biol 2020; 2159:3-15. [PMID: 32529359 PMCID: PMC8040746 DOI: 10.1007/978-1-0716-0676-6_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Mitochondrial fission, an essential process for mitochondrial and cellular homeostasis, is accomplished by evolutionarily conserved members of the dynamin superfamily of large GTPases. These enzymes couple the hydrolysis of guanosine triphosphate to the mechanical work of membrane remodeling that ultimately leads to membrane scission. The importance of mitochondrial dynamins is exemplified by mutations in the human family member that causes neonatal lethality. In this chapter, we describe the subcloning, purification, and preliminary characterization of the budding yeast mitochondrial dynamin, DNM1, from Saccharomyces cerevisiae, which is the first mitochondrial dynamin isolated from native sources. The yeast-purified enzyme exhibits assembly-stimulated hydrolysis of GTP similar to other fission dynamins, but differs from the enzyme isolated from non-native sources.
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Affiliation(s)
- Nolan W Kennedy
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Lora K Picton
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA
| | - R Blake Hill
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA.
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24
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Abstract
Purification of dynamin-related proteins is complicated by their oligomeric tendencies. In this chapter, we describe an established purification regime to isolate the mitochondrial fission protein Drp1 using bacterial expression. Key attributes of dynamins include their ability to hydrolyze GTP and self-assemble into larger polymers under specific conditions. Therefore, the GTPase activity of Drp1 should be examined to confirm isolation of functional protein, and we describe a conventional colorimetric assay to assess enzyme activity. To determine the ability of Drp1 to self-assemble, we induce Drp1 polymerization through addition of a non-hydrolyzable GTP analogue. A sedimentation assay provides a quantitative measure of polymerization that complements a qualitative assessment through visualization of Drp1 oligomers using negative-stain electron microscopy (EM). Importantly, we highlight the caveats of affinity tags and the influence that these peptide sequences can have on Drp1 function given their proximity to functional domains.
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25
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Walker BC, Tempel W, Zhu H, Park H, Cochran JC. Chromokinesins NOD and KID Use Distinct ATPase Mechanisms and Microtubule Interactions To Perform a Similar Function. Biochemistry 2019; 58:2326-2338. [PMID: 30973712 DOI: 10.1021/acs.biochem.9b00011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Chromokinesins NOD and KID have similar DNA binding domains and functions during cell division, while their motor domain sequences show significant variations. It has been unclear whether these motors have the similar structure, chemistry, and microtubule interactions necessary to follow a similar mechanism of force generation. We used biochemical rate measurements, cosedimentation, and structural analysis to investigate the ATPase mechanisms of the NOD and KID core domains. These studies revealed that NOD and KID have different ATPase mechanisms, microtubule interactions, and catalytic domain structures. The ATPase cycles of NOD and KID have different rate-limiting steps. The ATPase rate of NOD was robustly stimulated by microtubules, and its microtubule affinity was weakened in all nucleotide-bound states. KID bound microtubules tightly in all nucleotide states and remained associated with the microtubule for more than 100 cycles of ATP hydrolysis before dissociating. The structure of KID was most like that of conventional kinesin (KIF5). Key differences in the microtubule binding region and allosteric communication pathway between KID and NOD are consistent with our biochemical data. Our results support the model in which NOD and KID utilize distinct mechanistic pathways to achieve the same function during cell division.
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Affiliation(s)
- Benjamin C Walker
- Department of Molecular & Cellular Biochemistry , Indiana University , Simon Hall Room 405C, 212 South Hawthorne Drive , Bloomington , Indiana 47405 , United States
| | - Wolfram Tempel
- Structural Genomics Consortium , University of Toronto , Toronto , Ontario M5G 1L7 , Canada
| | - Haizhong Zhu
- Structural Genomics Consortium , University of Toronto , Toronto , Ontario M5G 1L7 , Canada
| | - Heewon Park
- Department of Biochemistry and Molecular Biology , Tulane School of Medicine , New Orleans , Louisiana 70112 , United States
| | - Jared C Cochran
- Department of Molecular & Cellular Biochemistry , Indiana University , Simon Hall Room 405C, 212 South Hawthorne Drive , Bloomington , Indiana 47405 , United States
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26
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Zhao Y, Sun X, Hu D, Prosdocimo DA, Hoppel C, Jain MK, Ramachandran R, Qi X. ATAD3A oligomerization causes neurodegeneration by coupling mitochondrial fragmentation and bioenergetics defects. Nat Commun 2019; 10:1371. [PMID: 30914652 PMCID: PMC6435701 DOI: 10.1038/s41467-019-09291-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 03/01/2019] [Indexed: 12/13/2022] Open
Abstract
Mitochondrial fragmentation and bioenergetic failure manifest in Huntington’s disease (HD), a fatal neurodegenerative disease. The factors that couple mitochondrial fusion/fission with bioenergetics and their impacts on neurodegeneration however remain poorly understood. Our proteomic analysis identifies mitochondrial protein ATAD3A as an interactor of mitochondrial fission GTPase, Drp1, in HD. Here we show that, in HD, ATAD3A dimerization due to deacetylation at K135 residue is required for Drp1-mediated mitochondrial fragmentation. Disturbance of ATAD3A steady state impairs mtDNA maintenance by disrupting TFAM/mtDNA binding. Blocking Drp1/ATAD3A interaction with a peptide, DA1, abolishes ATAD3A oligomerization, suppresses mitochondrial fragmentation and mtDNA lesion, and reduces bioenergetic deficits and cell death in HD mouse- and patient-derived cells. DA1 treatment reduces behavioral and neuropathological phenotypes in HD transgenic mice. Our findings demonstrate that ATAD3A plays a key role in neurodegeneration by linking Drp1-induced mitochondrial fragmentation to defective mtDNA maintenance, suggesting that DA1 might be useful for developing HD therapeutics. Huntington’s disease leads to mitochondrial fragmentation and bioenergetic failure, although how the two events are connected is poorly understood. Here, Zhao et al. identify ATAD3A as a molecular linker and show that a peptide inhibitor of ATAD3A oligomerization suppresses HD phenotypes.
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Affiliation(s)
- Yuanyuan Zhao
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Xiaoyan Sun
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Di Hu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Domenick A Prosdocimo
- Case Cardiovascular Research Institute and Harrington Heart and Vascular Institute, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Department of Medicine, University Hospitals Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Charles Hoppel
- Center for Mitochondrial Disease, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Mukesh K Jain
- Case Cardiovascular Research Institute and Harrington Heart and Vascular Institute, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Department of Medicine, University Hospitals Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Xin Qi
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA. .,Center for Mitochondrial Disease, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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27
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Chuang MC, Lin SS, Ohniwa RL, Lee GH, Su YA, Chang YC, Tang MJ, Liu YW. Tks5 and Dynamin-2 enhance actin bundle rigidity in invadosomes to promote myoblast fusion. J Cell Biol 2019; 218:1670-1685. [PMID: 30894403 PMCID: PMC6504888 DOI: 10.1083/jcb.201809161] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/22/2019] [Accepted: 03/04/2019] [Indexed: 12/12/2022] Open
Abstract
Skeletal muscle development requires the cell-cell fusion of differentiated myoblasts to form muscle fibers. The actin cytoskeleton is known to be the main driving force for myoblast fusion; however, how actin is organized to direct intercellular fusion remains unclear. Here we show that an actin- and dynamin-2-enriched protrusive structure, the invadosome, is required for the fusion process of myogenesis. Upon differentiation, myoblasts acquire the ability to form invadosomes through isoform switching of a critical invadosome scaffold protein, Tks5. Tks5 directly interacts with and recruits dynamin-2 to the invadosome and regulates its assembly around actin filaments to strengthen the stiffness of dynamin-actin bundles and invadosomes. These findings provide a mechanistic framework for the acquisition of myogenic fusion machinery during myogenesis and reveal a novel structural function for Tks5 and dynamin-2 in organizing actin filaments in the invadosome to drive membrane fusion.
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Affiliation(s)
- Mei-Chun Chuang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Shan-Shan Lin
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ryosuke L Ohniwa
- Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.,Center for Biotechnology, National Taiwan University, Taipei, Taiwan
| | - Gang-Hui Lee
- International Center of Wound Repair and Regeneration, National Cheng Kung University, Tainan, Taiwan
| | - You-An Su
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yu-Chen Chang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ming-Jer Tang
- International Center of Wound Repair and Regeneration, National Cheng Kung University, Tainan, Taiwan.,Department of Physiology, Medical College, National Cheng Kung University, Tainan, Taiwan
| | - Ya-Wen Liu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan .,Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
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28
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Chatterjee A, Acharjee A, Das S, Datta PP. Deletion analyses reveal insights into the domain specific activities of an essential GTPase CgtA in Vibrio cholerae. Arch Biochem Biophys 2019; 665:143-151. [PMID: 30894284 DOI: 10.1016/j.abb.2019.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 03/08/2019] [Accepted: 03/10/2019] [Indexed: 10/27/2022]
Abstract
CgtA is an essential bacterial GTPase protein involved in multiple cellular activities. In the presence of 50S ribosome, its GTPase activity increases significantly. Through sequential deletions of CgtA protein of Vibrio cholerae (CgtAvc) we found that its N terminal Obg domain is essential for ribosome binding and augmenting the ribosome mediated GTPase activity. Strategic deletions of the three glycine rich loops of Obg domain revealed that loop 1 of Obg domain is involved in anchoring the protein into the 50S, whereas, loop 2 & loop 3 are involved in conveying the effect of interaction of the Obg domain with the 50S to the GTPase domain through an interdomain linker, followed by GTP hydrolysis. On the other hand, the non-conserved C-terminal domain (CTD) is not directly involved in ribosome binding but shows negative impact on GTPase activity.
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Affiliation(s)
- Ananya Chatterjee
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia, 741246, West Bengal, India; Viral Research and Diagnostic Laboratories, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme XM, Beliaghata, P.O. Box-177, Kolkata, 700 010, West Bengal, India
| | - Arita Acharjee
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia, 741246, West Bengal, India
| | - Sagarika Das
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia, 741246, West Bengal, India
| | - Partha P Datta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia, 741246, West Bengal, India.
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29
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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: 1.3] [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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30
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Lu B, Kennedy B, Clinton RW, Wang EJ, McHugh D, Stepanyants N, Macdonald PJ, Mears JA, Qi X, Ramachandran R. Steric interference from intrinsically disordered regions controls dynamin-related protein 1 self-assembly during mitochondrial fission. Sci Rep 2018; 8:10879. [PMID: 30022112 PMCID: PMC6051998 DOI: 10.1038/s41598-018-29001-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [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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31
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Manni MM, Tiberti ML, Pagnotta S, Barelli H, Gautier R, Antonny B. Acyl chain asymmetry and polyunsaturation of brain phospholipids facilitate membrane vesiculation without leakage. eLife 2018. [PMID: 29543154 PMCID: PMC5903860 DOI: 10.7554/elife.34394] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Phospholipid membranes form cellular barriers but need to be flexible enough to divide by fission. Phospholipids generally contain a saturated fatty acid (FA) at position sn1 whereas the sn2-FA is saturated, monounsaturated or polyunsaturated. Our understanding of the impact of phospholipid unsaturation on membrane flexibility and fission is fragmentary. Here, we provide a comprehensive view of the effects of the FA profile of phospholipids on membrane vesiculation by dynamin and endophilin. Coupled to simulations, this analysis indicates that: (i) phospholipids with two polyunsaturated FAs make membranes prone to vesiculation but highly permeable; (ii) asymmetric sn1-saturated-sn2-polyunsaturated phospholipids provide a tradeoff between efficient membrane vesiculation and low membrane permeability; (iii) When incorporated into phospholipids, docosahexaenoic acid (DHA; omega-3) makes membranes more deformable than arachidonic acid (omega-6). These results suggest an explanation for the abundance of sn1-saturated-sn2-DHA phospholipids in synaptic membranes and for the importance of the omega-6/omega-3 ratio on neuronal functions. Surrounding each living cell is a membrane that is mainly made of fat molecules called phospholipids. Similar membranes also surround many of the structures inside cells. It is important for life that these membranes are impermeable to many molecules; for example, they do not allow ions to cross them freely. The membranes also need to be flexible and allow cells to form different shapes. Flexible membranes also allow cells to move molecules around and to divide to produce new cells. Each phospholipid includes two long chains of atoms called fatty acids. There are many fatty acids but they are typically grouped into saturated and unsaturated based on their chemical structures. The omega-3 and omega-6 fats are both groups of unsaturated fatty acids that are found in brain cells. Many phospholipids in cell membranes contain one saturated and one unsaturated fatty acid but it is not clear why. By studying fat molecules in the laboratory and combining this with simulations, Manni et al. have now examined the effects of fatty acids on membranes. The investigation showed that phospholipids with both saturated and unsaturated fatty acids strike a balance between impermeable and flexible membranes. More unsaturated fatty acids make more flexible membranes but they are too permeable to be used in cells. The experiments also revealed that omega-3 unsaturated fats aid flexibility more than omega-6. This finding may help to explain why the relative amounts of omega-3 and -6 are so important in the membranes of brain cells. The connection between the fats we eat and the fatty acids in our cells is complex. Yet, findings like these serve to remind us that we need a balanced diet of different fats to keep all our cells healthy.
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Affiliation(s)
- Marco M Manni
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur et CNRS, Valbonne, France.,Instituto Biofisika (UPV/EHU, CSIC), Leioa, Spain
| | - Marion L Tiberti
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur et CNRS, Valbonne, France
| | - Sophie Pagnotta
- Centre Commun de Microscopie Appliquée, Université Côte d'Azur, Nice, France
| | - Hélène Barelli
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur et CNRS, Valbonne, France
| | - Romain Gautier
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur et CNRS, Valbonne, France
| | - Bruno Antonny
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur et CNRS, Valbonne, France
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32
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A highly-sensitive high throughput assay for dynamin's basal GTPase activity. PLoS One 2017; 12:e0185639. [PMID: 28957392 PMCID: PMC5619819 DOI: 10.1371/journal.pone.0185639] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 09/15/2017] [Indexed: 11/19/2022] Open
Abstract
Clathrin-mediated endocytosis is the major pathway by which cells internalize materials from the external environment. Dynamin, a large multidomain GTPase, is a key regulator of clathrin-mediated endocytosis. It assembles at the necks of invaginated clathrin-coated pits and, through GTP hydrolysis, catalyzes scission and release of clathrin-coated vesicles from the plasma membrane. Several small molecule inhibitors of dynamin's GTPase activity, such as Dynasore and Dyngo-4a, are currently available, although their specificity has been brought into question. Previous screens for these inhibitors measured dynamin's stimulated GTPase activity due to lack of sufficient sensitivity, hence the mechanisms by which they inhibit dynamin are uncertain. We report a highly sensitive fluorescence-based assay capable of detecting dynamin's basal GTPase activity under conditions compatible with high throughput screening. Utilizing this optimized assay, we conducted a pilot screen of 8000 compounds and identified several "hits" that inhibit the basal GTPase activity of dynamin-1. Subsequent dose-response curves were used to validate the activity of these compounds. Interestingly, we found neither Dynasore nor Dyngo-4a inhibited dynamin's basal GTPase activity, although both inhibit assembly-stimulated GTPase activity. This assay provides the basis for a more extensive search for more potent and chemically desirable dynamin inhibitors.
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33
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Cryo-EM Studies of Drp1 Reveal Cardiolipin Interactions that Activate the Helical Oligomer. Sci Rep 2017; 7:10744. [PMID: 28878368 PMCID: PMC5587723 DOI: 10.1038/s41598-017-11008-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 07/19/2017] [Indexed: 12/18/2022] Open
Abstract
Dynamins are mechano-chemical GTPases involved in the remodeling of cellular membranes. In this study, we have investigated the mechanism of dynamin-related protein 1 (Drp1), a key mediator of mitochondrial fission. To date, it is unclear how Drp1 assembles on the mitochondrial outer membrane in response to different lipid signals to induce membrane fission. Here, we present cryo-EM structures of Drp1 helices on nanotubes with distinct lipid compositions to mimic membrane interactions with the fission machinery. These Drp1 polymers assemble exclusively through stalk and G-domain dimerizations, which generates an expanded helical symmetry when compared to other dynamins. Interestingly, we found the characteristic gap between Drp1 and the lipid bilayer was lost when the mitochondrial specific lipid cardiolipin was present, as Drp1 directly interacted with the membrane. Moreover, this interaction leads to a change in the helical structure, which alters G-domain interactions to enhance GTPase activity. These results demonstrate how lipid cues at the mitochondrial outer membrane (MOM) can alter Drp1 structure to activate the fission machinery.
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Clinton RW, Mears JA. Using Scaffold Liposomes to Reconstitute Lipid-proximal Protein-protein Interactions In Vitro. J Vis Exp 2017. [PMID: 28117823 DOI: 10.3791/54971] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Studies of integral membrane proteins in vitro are frequently complicated by the presence of a hydrophobic transmembrane domain. Further complicating these studies, reincorporation of detergent-solubilized membrane proteins into liposomes is a stochastic process where protein topology is impossible to enforce. This paper offers an alternative method to these challenging techniques that utilizes a liposome-based scaffold. Protein solubility is enhanced by deletion of the transmembrane domain, and these amino acids are replaced with a tethering moiety, such as a His-tag. This tether interacts with an anchoring group (Ni2+ coordinated by nitrilotriacetic acid (NTA(Ni2+)) for His-tagged proteins), which enforces a uniform protein topology at the surface of the liposome. An example is presented wherein the interaction between Dynamin-related protein 1 (Drp1) with an integral membrane protein, Mitochondrial Fission Factor (Mff), was investigated using this scaffold liposome method. In this work, we have demonstrated the ability of Mff to efficiently recruit soluble Drp1 to the surface of liposomes, which stimulated its GTPase activity. Moreover, Drp1 was able to tubulate the Mff-decorated lipid template in the presence of specific lipids. This example demonstrates the effectiveness of scaffold liposomes using structural and functional assays and highlights the role of Mff in regulating Drp1 activity.
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Affiliation(s)
- Ryan W Clinton
- Department of Pharmacology, Center for Mitochondrial Diseases, The Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine
| | - Jason A Mears
- Department of Pharmacology, Center for Mitochondrial Diseases, The Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine;
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35
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Leija C, Rijo-Ferreira F, Kinch LN, Grishin NV, Nischan N, Kohler JJ, Hu Z, Phillips MA. Pyrimidine Salvage Enzymes Are Essential for De Novo Biosynthesis of Deoxypyrimidine Nucleotides in Trypanosoma brucei. PLoS Pathog 2016; 12:e1006010. [PMID: 27820863 PMCID: PMC5098729 DOI: 10.1371/journal.ppat.1006010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 10/18/2016] [Indexed: 01/17/2023] Open
Abstract
The human pathogenic parasite Trypanosoma brucei possess both de novo and salvage routes for the biosynthesis of pyrimidine nucleotides. Consequently, they do not require salvageable pyrimidines for growth. Thymidine kinase (TK) catalyzes the formation of dTMP and dUMP and is one of several salvage enzymes that appear redundant to the de novo pathway. Surprisingly, we show through analysis of TK conditional null and RNAi cells that TK is essential for growth and for infectivity in a mouse model, and that a catalytically active enzyme is required for its function. Unlike humans, T. brucei and all other kinetoplastids lack dCMP deaminase (DCTD), which provides an alternative route to dUMP formation. Ectopic expression of human DCTD resulted in full rescue of the RNAi growth phenotype and allowed for selection of viable TK null cells. Metabolite profiling by LC-MS/MS revealed a buildup of deoxypyrimidine nucleosides in TK depleted cells. Knockout of cytidine deaminase (CDA), which converts deoxycytidine to deoxyuridine led to thymidine/deoxyuridine auxotrophy. These unexpected results suggested that T. brucei encodes an unidentified 5'-nucleotidase that converts deoxypyrimidine nucleotides to their corresponding nucleosides, leading to their dead-end buildup in TK depleted cells at the expense of dTTP pools. Bioinformatics analysis identified several potential candidate genes that could encode 5'-nucleotidase activity including an HD-domain protein that we show catalyzes dephosphorylation of deoxyribonucleotide 5'-monophosphates. We conclude that TK is essential for synthesis of thymine nucleotides regardless of whether the nucleoside precursors originate from the de novo pathway or through salvage. Reliance on TK in the absence of DCTD may be a shared vulnerability among trypanosomatids and may provide a unique opportunity to selectively target a diverse group of pathogenic single-celled eukaryotes with a single drug.
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Affiliation(s)
- Christopher Leija
- Department of Pharmacology University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Filipa Rijo-Ferreira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- Department of Neuroscience, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
- Graduate Program in Areas of Basic and Applied Biology, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Lisa N. Kinch
- Department of Biophysics, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Nick V. Grishin
- Department of Biophysics, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Nicole Nischan
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Jennifer J. Kohler
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Zeping Hu
- Children’s Medical Center Research Institute, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Margaret A. Phillips
- Department of Pharmacology University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
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36
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Fast, Temperature-Sensitive and Clathrin-Independent Endocytosis at Central Synapses. Neuron 2016; 90:492-8. [PMID: 27146271 DOI: 10.1016/j.neuron.2016.03.013] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 02/29/2016] [Accepted: 03/15/2016] [Indexed: 11/24/2022]
Abstract
The fusion of neurotransmitter-filled vesicles during synaptic transmission is balanced by endocytotic membrane retrieval. Despite extensive research, the speed and mechanisms of synaptic vesicle endocytosis have remained controversial. Here, we establish low-noise time-resolved membrane capacitance measurements that allow monitoring changes in surface membrane area elicited by single action potentials and stronger stimuli with high-temporal resolution at physiological temperature in individual bona-fide mature central synapses. We show that single action potentials trigger very rapid endocytosis, retrieving presynaptic membrane with a time constant of 470 ms. This fast endocytosis is independent of clathrin but mediated by dynamin and actin. In contrast, stronger stimuli evoke a slower mode of endocytosis that is clathrin, dynamin, and actin dependent. Furthermore, the speed of endocytosis is highly temperature dependent with a Q10 of ∼3.5. These results demonstrate that distinct molecular modes of endocytosis with markedly different kinetics operate at central synapses.
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37
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Srinivasan S, Dharmarajan V, Reed DK, Griffin PR, Schmid SL. Identification and function of conformational dynamics in the multidomain GTPase dynamin. EMBO J 2016; 35:443-57. [PMID: 26783363 DOI: 10.15252/embj.201593477] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 12/11/2015] [Indexed: 01/13/2023] Open
Abstract
Vesicle release upon endocytosis requires membrane fission, catalyzed by the large GTPase dynamin. Dynamin contains five domains that together orchestrate its mechanochemical activity. Hydrogen-deuterium exchange coupled with mass spectrometry revealed global nucleotide- and membrane-binding-dependent conformational changes, as well as the existence of an allosteric relay element in the α2(S) helix of the dynamin stalk domain. As predicted from structural studies, FRET analyses detect large movements of the pleckstrin homology domain (PHD) from a 'closed' conformation docked near the stalk to an 'open' conformation able to interact with membranes. We engineered dynamin constructs locked in either the closed or open state by chemical cross-linking or deletion mutagenesis and showed that PHD movements function as a conformational switch to regulate dynamin self-assembly, membrane binding, and fission. This PHD conformational switch is impaired by a centronuclear myopathy-causing disease mutation, S619L, highlighting the physiological significance of its role in regulating dynamin function. Together, these data provide new insight into coordinated conformational changes that regulate dynamin function and couple membrane binding, oligomerization, and GTPase activity during dynamin-catalyzed membrane fission.
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Affiliation(s)
| | | | - Dana Kim Reed
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Patrick R Griffin
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL, USA
| | - Sandra L Schmid
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA
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38
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Macdonald PJ, Francy CA, Stepanyants N, Lehman L, Baglio A, Mears JA, Qi X, Ramachandran R. Distinct Splice Variants of Dynamin-related Protein 1 Differentially Utilize Mitochondrial Fission Factor as an Effector of Cooperative GTPase Activity. J Biol Chem 2015; 291:493-507. [PMID: 26578513 DOI: 10.1074/jbc.m115.680181] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Indexed: 02/02/2023] Open
Abstract
Multiple isoforms of the mitochondrial fission GTPase dynamin-related protein 1 (Drp1) arise from the alternative splicing of its single gene-encoded pre-mRNA transcript. Among these, the longer Drp1 isoforms, expressed selectively in neurons, bear unique polypeptide sequences within their GTPase and variable domains, known as the A-insert and the B-insert, respectively. Their functions remain unresolved. A comparison of the various biochemical and biophysical properties of the neuronally expressed isoforms with that of the ubiquitously expressed, and shortest, Drp1 isoform (Drp1-short) has revealed the effect of these inserts on Drp1 function. Utilizing various biochemical, biophysical, and cellular approaches, we find that the A- and B-inserts distinctly alter the oligomerization propensity of Drp1 in solution as well as the preferred curvature of helical Drp1 self-assembly on membranes. Consequently, these sequences also suppress Drp1 cooperative GTPase activity. Mitochondrial fission factor (Mff), a tail-anchored membrane protein of the mitochondrial outer membrane that recruits Drp1 to sites of ensuing fission, differentially stimulates the disparate Drp1 isoforms and alleviates the autoinhibitory effect imposed by these sequences on Drp1 function. Moreover, the differential stimulatory effects of Mff on Drp1 isoforms are dependent on the mitochondrial lipid, cardiolipin (CL). Although Mff stimulation of the intrinsically cooperative Drp1-short isoform is relatively modest, CL-independent, and even counter-productive at high CL concentrations, Mff stimulation of the much less cooperative longest Drp1 isoform (Drp1-long) is robust and occurs synergistically with increasing CL content. Thus, membrane-anchored Mff differentially regulates various Drp1 isoforms by functioning as an allosteric effector of cooperative GTPase activity.
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Affiliation(s)
| | - Christopher A Francy
- Department of Pharmacology, Center for Mitochondrial Diseases, and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | | | - Lance Lehman
- From the Department of Physiology and Biophysics
| | | | - Jason A Mears
- Department of Pharmacology, Center for Mitochondrial Diseases, and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Xin Qi
- From the Department of Physiology and Biophysics, Center for Mitochondrial Diseases, and
| | - Rajesh Ramachandran
- From the Department of Physiology and Biophysics, Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
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39
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Clinton RW, Francy CA, Ramachandran R, Qi X, Mears JA. Dynamin-related Protein 1 Oligomerization in Solution Impairs Functional Interactions with Membrane-anchored Mitochondrial Fission Factor. J Biol Chem 2015; 291:478-92. [PMID: 26578514 DOI: 10.1074/jbc.m115.680025] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Indexed: 11/06/2022] Open
Abstract
Mitochondrial fission is a crucial cellular process mediated by the mechanoenzymatic GTPase, dynamin-related protein 1 (Drp1). During mitochondrial division, Drp1 is recruited from the cytosol to the outer mitochondrial membrane by one, or several, integral membrane proteins. One such Drp1 partner protein, mitochondrial fission factor (Mff), is essential for mitochondrial division, but its mechanism of action remains unexplored. Previous studies have been limited by a weak interaction between Drp1 and Mff in vitro. Through refined in vitro reconstitution approaches and multiple independent assays, we show that removal of the regulatory variable domain (VD) in Drp1 enhances formation of a functional Drp1-Mff copolymer. This protein assembly exhibits greatly stimulated cooperative GTPase activity in solution. Moreover, when Mff was anchored to a lipid template, to mimic a more physiologic environment, significant stimulation of GTPase activity was observed with both WT and ΔVD Drp1. Contrary to recent findings, we show that premature Drp1 self-assembly in solution impairs functional interactions with membrane-anchored Mff. Instead, dimeric Drp1 species are selectively recruited by Mff to initiate assembly of a functional fission complex. Correspondingly, we also found that the coiled-coil motif in Mff is not essential for Drp1 interactions, but rather serves to augment cooperative self-assembly of Drp1 proximal to the membrane. Taken together, our findings provide a mechanism wherein the multimeric states of both Mff and Drp1 regulate their collaborative interaction.
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Affiliation(s)
- Ryan W Clinton
- From the Department of Pharmacology, the Center for Mitochondrial Diseases, the Cleveland Center for Membrane and Structural Biology, and
| | - Christopher A Francy
- From the Department of Pharmacology, the Center for Mitochondrial Diseases, the Cleveland Center for Membrane and Structural Biology, and
| | - Rajesh Ramachandran
- the Cleveland Center for Membrane and Structural Biology, and the Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Xin Qi
- the Center for Mitochondrial Diseases, the Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Jason A Mears
- From the Department of Pharmacology, the Center for Mitochondrial Diseases, the Cleveland Center for Membrane and Structural Biology, and
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40
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Liu Z, Mobley JA, DeLucas LJ, Kahn RA, West AB. LRRK2 autophosphorylation enhances its GTPase activity. FASEB J 2015; 30:336-47. [PMID: 26396237 DOI: 10.1096/fj.15-277095] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 09/08/2015] [Indexed: 12/17/2022]
Abstract
The leucine-rich repeat kinase (LRRK)-2 protein contains nonoverlapping GTPase and kinase domains, and mutation in either domain can cause Parkinson disease. GTPase proteins are critical upstream modulators of many effector protein kinases. In LRRK2, this paradigm may be reversed, as the kinase domain phosphorylates its own GTPase domain. In this study, we found that the ameba LRRK2 ortholog ROCO4 phosphorylates the GTPase domain [termed Ras-of-complex (ROC) domain in this family] of human LRRK2 on the same residues as the human LRRK2 kinase. Phosphorylation of ROC enhances its rate of GTP hydrolysis [from kcat (catalytic constant) 0.007 to 0.016 min(-1)], without affecting GTP or GDP dissociation kinetics [koff = 0.093 and 0.148 min(-1) for GTP and GDP, respectively). Phosphorylation also promotes the formation of ROC dimers, although GTPase activity appears to be equivalent between purified dimers and monomers. Modeling experiments show that phosphorylation induces conformational changes at the critical p-loop structure. Finally, ROC appears to be one of many GTPases phosphorylated in p-loop residues, as revealed by alignment of LRRK2 autophosphorylation sites with GTPases annotated in the phosphoproteome database. These results provide an example of a novel mechanism for kinase-mediated control of GTPase activity.
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Affiliation(s)
- Zhiyong Liu
- *Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, Center for Structural Biology, Department of Optometry, and Department of Surgery, The University of Alabama at Birmingham, Birmingham, Alabama, USA; and Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - James A Mobley
- *Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, Center for Structural Biology, Department of Optometry, and Department of Surgery, The University of Alabama at Birmingham, Birmingham, Alabama, USA; and Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Lawrence J DeLucas
- *Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, Center for Structural Biology, Department of Optometry, and Department of Surgery, The University of Alabama at Birmingham, Birmingham, Alabama, USA; and Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Richard A Kahn
- *Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, Center for Structural Biology, Department of Optometry, and Department of Surgery, The University of Alabama at Birmingham, Birmingham, Alabama, USA; and Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Andrew B West
- *Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, Center for Structural Biology, Department of Optometry, and Department of Surgery, The University of Alabama at Birmingham, Birmingham, Alabama, USA; and Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
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Wilkes MC, Repellin CE, Kang JH, Andrianifahanana M, Yin X, Leof EB. Sorting nexin 9 differentiates ligand-activated Smad3 from Smad2 for nuclear import and transforming growth factor β signaling. Mol Biol Cell 2015; 26:3879-91. [PMID: 26337383 PMCID: PMC4626071 DOI: 10.1091/mbc.e15-07-0545] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 08/27/2015] [Indexed: 01/23/2023] Open
Abstract
Sorting nexin 9 (SNX9) is shown to differentiate Smad3 from Smad2 nuclear delivery by mediating the association of phosphorylated Smad3 with importin 8 and the nuclear membrane. While the absence of SNX9 had negligible effects on transforming growth factor β receptor activity or Smad2 signaling, Smad3-dependent targets and phenotypes were inhibited. Transforming growth factor β (TGFβ) is a pleiotropic protein secreted from essentially all cell types and primary tissues. While TGFβ’s actions reflect the activity of a number of signaling networks, the primary mediator of TGFβ responses are the Smad proteins. Following receptor activation, these cytoplasmic proteins form hetero-oligomeric complexes that translocate to the nucleus and affect gene transcription. Here, through biological, biochemical, and immunofluorescence approaches, sorting nexin 9 (SNX9) is identified as being required for Smad3-dependent responses. SNX9 interacts with phosphorylated (p) Smad3 independent of Smad2 or Smad4 and promotes more rapid nuclear delivery than that observed independent of ligand. Although SNX9 does not bind nucleoporins Nup153 or Nup214 or some β importins (Imp7 or Impβ), it mediates the association of pSmad3 with Imp8 and the nuclear membrane. This facilitates nuclear translocation of pSmad3 but not SNX9.
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Affiliation(s)
- Mark C Wilkes
- Thoracic Diseases Research Unit, Department of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Claire E Repellin
- Thoracic Diseases Research Unit, Department of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Jeong-Han Kang
- Thoracic Diseases Research Unit, Department of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Mahefatiana Andrianifahanana
- Thoracic Diseases Research Unit, Department of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Xueqian Yin
- Thoracic Diseases Research Unit, Department of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Edward B Leof
- Thoracic Diseases Research Unit, Department of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
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Nithianantham S, Le S, Seto E, Jia W, Leary J, Corbett KD, Moore JK, Al-Bassam J. Tubulin cofactors and Arl2 are cage-like chaperones that regulate the soluble αβ-tubulin pool for microtubule dynamics. eLife 2015. [PMID: 26208336 PMCID: PMC4574351 DOI: 10.7554/elife.08811] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Microtubule dynamics and polarity stem from the polymerization of
αβ-tubulin heterodimers. Five conserved tubulin cofactors/chaperones
and the Arl2 GTPase regulate α- and β-tubulin assembly into
heterodimers and maintain the soluble tubulin pool in the cytoplasm, but their
physical mechanisms are unknown. Here, we reconstitute a core tubulin chaperone
consisting of tubulin cofactors TBCD, TBCE, and Arl2, and reveal a cage-like
structure for regulating αβ-tubulin. Biochemical assays and electron
microscopy structures of multiple intermediates show the sequential binding of
αβ-tubulin dimer followed by tubulin cofactor TBCC onto this chaperone,
forming a ternary complex in which Arl2 GTP hydrolysis is activated to alter
αβ-tubulin conformation. A GTP-state locked Arl2 mutant inhibits
ternary complex dissociation in vitro and causes severe defects in microtubule
dynamics in vivo. Our studies suggest a revised paradigm for tubulin cofactors and
Arl2 functions as a catalytic chaperone that regulates soluble
αβ-tubulin assembly and maintenance to support microtubule
dynamics. DOI:http://dx.doi.org/10.7554/eLife.08811.001 Cells contain a network of protein filaments called microtubules. These filaments are
involved in many biological processes; for example, they help cells keep the right
shape, and they help to transport proteins and other materials inside cells. Two proteins called α-tubulin and β-tubulin are the building blocks of
microtubules. The filaments are very dynamic structures that can rapidly change
length as individual tubulin units are either added or removed to the filament ends.
Several proteins known as tubulin cofactors and an enzyme called Arl2 help to build a
vast pool of tubulin units that are able attach to the microtubules. These
units—called αβ-tubulin—are formed by α-tubulin
and β-tubulin binding to each other, but it not clear exactly what roles the
tubulin cofactors and Arl2 play in this process. Nithianantham et al. used a combination of microscopy and biochemical techniques to
study how the tubulin cofactors and Arl2 are organised, and their role in the
assembly of microtubules in yeast. The experiments show that Arl2 and two tubulin
cofactors associate with each other to form a stable ‘complex’ that has
a cage-like structure. A molecule of αβ-tubulin binds to the complex,
followed by another cofactor called TBCC. This activates the enzyme activity of Arl2,
which releases the energy needed to alter the shape of the αβ-tubulin.
Nithianantham et al. also found that yeast cells with a mutant form of Arl2 that
lacked enzyme activity had problems forming microtubules. Together, these findings show that the tubulin cofactors and Arl2 form a complex that
regulates the assembly and maintenance of αβ-tubulin. The next
challenge is to understand how this regulation influences the way that microtubules
grow and shrink inside cells. DOI:http://dx.doi.org/10.7554/eLife.08811.002
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Affiliation(s)
- Stanley Nithianantham
- Department of Molecular Cellular Biology, University of California, Davis, Davis, United States
| | - Sinh Le
- Department of Molecular Cellular Biology, University of California, Davis, Davis, United States
| | - Elbert Seto
- Department of Molecular Cellular Biology, University of California, Davis, Davis, United States
| | - Weitao Jia
- Department of Molecular Cellular Biology, University of California, Davis, Davis, United States
| | - Julie Leary
- Department of Molecular Cellular Biology, University of California, Davis, Davis, United States
| | - Kevin D Corbett
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, United States
| | - Jawdat Al-Bassam
- Department of Molecular Cellular Biology, University of California, Davis, Davis, United States
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Stepanyants N, Macdonald PJ, Francy CA, Mears JA, Qi X, Ramachandran R. Cardiolipin's propensity for phase transition and its reorganization by dynamin-related protein 1 form a basis for mitochondrial membrane fission. Mol Biol Cell 2015; 26:3104-16. [PMID: 26157169 PMCID: PMC4551322 DOI: 10.1091/mbc.e15-06-0330] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 07/01/2015] [Indexed: 01/01/2023] Open
Abstract
Fluid cardiolipin (CL) promotes self-assembly of Drp1, a dynamin-family GTPase involved in mitochondrial fission. Drp1 sequesters CL into condensed membrane platforms and in a GTP-dependent manner increases the propensity of the lipid to undergo a nonbilayer phase transition. CL reorganization generates local membrane constriction for fission. Cardiolipin (CL) is an atypical, dimeric phospholipid essential for mitochondrial dynamics in eukaryotic cells. Dynamin-related protein 1 (Drp1), a cytosolic member of the dynamin superfamily of large GTPases, interacts with CL and functions to sustain the balance of mitochondrial division and fusion by catalyzing mitochondrial fission. Although recent studies have indicated a role for CL in stimulating Drp1 self-assembly and GTPase activity at the membrane surface, the mechanism by which CL functions in membrane fission, if at all, remains unclear. Here, using a variety of fluorescence spectroscopic and imaging approaches together with model membranes, we demonstrate that Drp1 and CL function cooperatively in effecting membrane constriction toward fission in three distinct steps. These involve 1) the preferential association of Drp1 with CL localized at a high spatial density in the membrane bilayer, 2) the reorganization of unconstrained, fluid-phase CL molecules in concert with Drp1 self-assembly, and 3) the increased propensity of CL to transition from a lamellar, bilayer arrangement to an inverted hexagonal, nonbilayer configuration in the presence of Drp1 and GTP, resulting in the creation of localized membrane constrictions that are primed for fission. Thus we propose that Drp1 and CL function in concert to catalyze mitochondrial division.
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Affiliation(s)
- Natalia Stepanyants
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Patrick J Macdonald
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Christopher A Francy
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106 Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106 Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Jason A Mears
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106 Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106 Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Xin Qi
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106 Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106 Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106
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Gurel PS, A M, Guo B, Shu R, Mierke DF, Higgs HN. Assembly and turnover of short actin filaments by the formin INF2 and profilin. J Biol Chem 2015; 290:22494-506. [PMID: 26124273 DOI: 10.1074/jbc.m115.670166] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Indexed: 11/06/2022] Open
Abstract
INF2 (inverted formin 2) is a formin protein with unique biochemical effects on actin. In addition to the common formin ability to accelerate actin nucleation and elongation, INF2 can also sever filaments and accelerate their depolymerization. Although we understand key attributes of INF2-mediated severing, we do not understand the mechanism by which INF2 accelerates depolymerization subsequent to severing. Here, we show that INF2 can create short filaments (<60 nm) that continuously turn over actin subunits through a combination of barbed end elongation, severing, and WH2 motif-mediated depolymerization. This pseudo-steady state condition occurs whether starting from actin filaments or monomers. The rate-limiting step of the cycle is nucleotide exchange of ADP for ATP on actin monomers after release from the INF2/actin complex. Profilin addition has two effects: 1) to accelerate filament turnover 6-fold by accelerating nucleotide exchange and 2) to shift the equilibrium toward polymerization, resulting in longer filaments. In sum, our findings show that the combination of multiple interactions of INF2 with actin can work in concert to increase the ATP turnover rate of actin. Depending on the ratio of INF2:actin, this increased flux can result in rapid filament depolymerization or maintenance of short filaments. We also show that high concentrations of cytochalasin D accelerate ATP turnover by actin but through a different mechanism from that of INF2.
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Affiliation(s)
- Pinar S Gurel
- From the Department of Biochemistry, Geisel School of Medicine and
| | - Mu A
- From the Department of Biochemistry, Geisel School of Medicine and
| | - Bingqian Guo
- the Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755
| | - Rui Shu
- From the Department of Biochemistry, Geisel School of Medicine and
| | - Dale F Mierke
- the Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755
| | - Henry N Higgs
- From the Department of Biochemistry, Geisel School of Medicine and
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Mattila JP, Shnyrova AV, Sundborger AC, Hortelano ER, Fuhrmans M, Neumann S, Müller M, Hinshaw JE, Schmid SL, Frolov VA. A hemi-fission intermediate links two mechanistically distinct stages of membrane fission. Nature 2015; 524:109-113. [PMID: 26123023 PMCID: PMC4529379 DOI: 10.1038/nature14509] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 05/05/2015] [Indexed: 12/22/2022]
Abstract
Fusion and fission drive all vesicular transport. Although topologically opposite, these reactions pass through the same hemi-fusion/fission intermediate1,2, characterized by a ‘stalk’ in which only the inner monolayers of the two compartments have merged to form a localized non-bilayer connection1-3. Formation of the hemi-fission intermediate requires energy input from proteins catalyzing membrane remodeling; however the relationship between protein conformational rearrangements and hemi-fusion/fission remains obscure. Here we analyzed how the GTPase cycle of dynamin, the prototypical membrane fission catalyst4-6, is directly coupled to membrane remodeling. We used intra-molecular chemical cross-linking to stabilize dynamin in its GDP•AlF4--bound transition-state. In the absence of GTP this conformer produced stable hemi-fission, but failed to progress to complete fission, even in the presence of GTP. Further analysis revealed that the pleckstrin homology domain (PHD) locked in its membrane-inserted state facilitated hemi-fission. A second mode of dynamin activity, fueled by GTP hydrolysis, couples dynamin disassembly with cooperative diminishing of the PHD wedging, thus destabilizing the hemi-fission intermediate to complete fission. Molecular simulations corroborate the bimodal character of dynamin action and indicate radial and axial forces as dominant, although not independent drivers of hemi-fission and fission transformations, respectively. Mirrored in the fusion reaction7-8, the force bimodality might constitute a general paradigm for leakage-free membrane remodeling.
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Affiliation(s)
- Juha-Pekka Mattila
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75201
| | - Anna V Shnyrova
- Biophysics Unit (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of The Basque Country, Leioa, Spain
| | - Anna C Sundborger
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892
| | - Eva Rodriguez Hortelano
- Biophysics Unit (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of The Basque Country, Leioa, Spain
| | - Marc Fuhrmans
- Institute for Theoretical Physics, Georg-August University, 37077 Göttingen, Germany
| | - Sylvia Neumann
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Marcus Müller
- Institute for Theoretical Physics, Georg-August University, 37077 Göttingen, Germany
| | - Jenny E Hinshaw
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892
| | - Sandra L Schmid
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75201
| | - Vadim A Frolov
- Biophysics Unit (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of The Basque Country, Leioa, Spain.,IKERBASQUE, Basque Foundation of Science, Bilbao, Spain
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46
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Pharmacological targeting of actin-dependent dynamin oligomerization ameliorates chronic kidney disease in diverse animal models. Nat Med 2015; 21:601-9. [PMID: 25962121 PMCID: PMC4458177 DOI: 10.1038/nm.3843] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 03/18/2015] [Indexed: 12/11/2022]
Abstract
Dysregulation of the actin cytoskeleton in podocytes represents a common pathway in the pathogenesis of proteinuria across a spectrum of chronic kidney diseases (CKD). The GTPase dynamin has been implicated in the maintenance of cellular architecture in podocytes through its direct interaction with actin. Furthermore, the propensity of dynamin to oligomerize into higher-order structures in an actin-dependent manner and to crosslink actin microfilaments into higher order structures have been correlated with increased actin polymerization and global organization of the actin cytoskeleton in the cell. We found that use of the small molecule Bis-T-23, which promotes actin-dependent dynamin oligomerization and thus increased actin polymerization in injured podocytes, was sufficient to improve renal health in diverse models of both transient kidney disease and of CKD. In particular, administration of Bis-T-23 in these renal disease models restored the normal ultrastructure of podocyte foot processes, lowered proteinuria, lowered collagen IV deposits in the mesangial matrix, diminished mesangial matrix expansion and extended lifespan. These results further establish that alterations in the actin cytoskeleton of kidney podocytes is a common hallmark of CKD, while also underscoring the significant regenerative potential of injured glomeruli and that targeting the oligomerization cycle of dynamin represents an attractive potential therapeutic target to treat CKD.
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47
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Chatterjee A, Datta PP. Two conserved amino acids of juxtaposed domains of a ribosomal maturation protein CgtA sustain its optimal GTPase activity. Biochem Biophys Res Commun 2015; 461:636-41. [PMID: 25912137 DOI: 10.1016/j.bbrc.2015.04.079] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 04/15/2015] [Indexed: 11/19/2022]
Abstract
CgtA is a highly conserved ribosome binding protein involved in ribosome biogenesis and associated with stringent response. It is a 55 KDa GTPase protein consisting of GTPase, Obg and C-terminal domains. The function of the latter two domains was not clear and despite the importance, the mode of action of CgtA is still largely unknown. Knocking out of CgtA gene is lethal and mutations lead to growth, sporulation and developmental defects in bacteria. It was found that a growth defect and pinhole size colony morphology of Bacillus subtilis was associated with a Gly92Asp point mutation on the Obg domain of its CgtA protein, instead of its GTPase domain. CgtA is an important and essential protein of the deadly diarrhea causing bacteria Vibrio cholerae and in order to investigate the mode of action of the V. cholerae CgtA we have utilized this information. We measured the GTPase activity of V. cholerae CgtA (CgtAvc) protein in the presence of purified ribosome. Our results showed 5-fold increased GTP hydrolysis activity compared to its intrinsic activity. Then we explored the GTPase activity of the mutated CgtAvc (Gly98Asp) located at the Obg domain, which reduced the GTP hydrolysis rate to half. The double point mutations (Gly98Asp, and Tyr194Gly) encompassing another conserved residue, Tyr194, located at the diagonally opposite position in the GTPase domain largely restored (about 82%) the reduced GTPase activity, revealing a fine-tuned inter-domain movement readily associated with the GTPase activity of CgtA and thus maintaining the proper functioning of the CgtA protein.
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Affiliation(s)
- Ananya Chatterjee
- Department of Biological Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur, Nadia, West Bengal, India
| | - Partha P Datta
- Department of Biological Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur, Nadia, West Bengal, India.
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48
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Ugarte-Uribe B, Müller HM, Otsuki M, Nickel W, García-Sáez AJ. Dynamin-related protein 1 (Drp1) promotes structural intermediates of membrane division. J Biol Chem 2014; 289:30645-30656. [PMID: 25237193 DOI: 10.1074/jbc.m114.575779] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Drp1 is a dynamin-like GTPase that mediates mitochondrial and peroxisomal division in a process dependent on self-assembly and coupled to GTP hydrolysis. Despite the link between Drp1 malfunction and human disease, the molecular details of its membrane activity remain poorly understood. Here we reconstituted and directly visualized Drp1 activity in giant unilamellar vesicles. We quantified the effect of lipid composition and GTP on membrane binding and remodeling activity by fluorescence confocal microscopy and flow cytometry. In contrast to other dynamin relatives, Drp1 bound to both curved and flat membranes even in the absence of nucleotides. We also found that Drp1 induced membrane tubulation that was stimulated by cardiolipin. Moreover, Drp1 promoted membrane tethering dependent on the intrinsic curvature of the membrane lipids and on GTP. Interestingly, Drp1 concentrated at membrane contact surfaces and, in the presence of GTP, formed discrete clusters on the vesicles. Our findings support a role of Drp1 not only in the formation of lipid tubes but also on the stabilization of tightly apposed membranes, which are intermediate states in the process of mitochondrial fission.
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Affiliation(s)
- Begoña Ugarte-Uribe
- Max-Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany,; Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany, and
| | | | - Miki Otsuki
- Max-Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Walter Nickel
- Heidelberg University Biochemistry Center, 69120 Heidelberg, Germany
| | - Ana J García-Sáez
- Max-Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany,; Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany, and.
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49
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Pinot M, Vanni S, Pagnotta S, Lacas-Gervais S, Payet LA, Ferreira T, Gautier R, Goud B, Antonny B, Barelli H. Lipid cell biology. Polyunsaturated phospholipids facilitate membrane deformation and fission by endocytic proteins. Science 2014; 345:693-7. [PMID: 25104391 DOI: 10.1126/science.1255288] [Citation(s) in RCA: 236] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Phospholipids (PLs) with polyunsaturated acyl chains are extremely abundant in a few specialized cellular organelles such as synaptic vesicles and photoreceptor discs, but their effect on membrane properties is poorly understood. Here, we found that polyunsaturated PLs increased the ability of dynamin and endophilin to deform and vesiculate synthetic membranes. When cells incorporated polyunsaturated fatty acids into PLs, the plasma membrane became more amenable to deformation by a pulling force and the rate of endocytosis was accelerated, in particular, under conditions in which cholesterol was limiting. Molecular dynamics simulations and biochemical measurements indicated that polyunsaturated PLs adapted their conformation to membrane curvature. Thus, by reducing the energetic cost of membrane bending and fission, polyunsaturated PLs may help to support rapid endocytosis.
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Affiliation(s)
- Mathieu Pinot
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Nice Sophia Antipolis and CNRS, 06560 Valbonne, France. Unité Mixte de Recherche 144, Institut Curie and CNRS, F-75248 Paris, France
| | - Stefano Vanni
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Nice Sophia Antipolis and CNRS, 06560 Valbonne, France
| | - Sophie Pagnotta
- Centre Commun de Microscopie Appliquée, Université Nice Sophia Antipolis, Parc Valrose, 06000 Nice, France
| | - Sandra Lacas-Gervais
- Centre Commun de Microscopie Appliquée, Université Nice Sophia Antipolis, Parc Valrose, 06000 Nice, France
| | - Laurie-Anne Payet
- Signalisation et Transports Ioniques Membranaires, Université de Poitiers and CNRS, Poitiers, France
| | - Thierry Ferreira
- Signalisation et Transports Ioniques Membranaires, Université de Poitiers and CNRS, Poitiers, France
| | - Romain Gautier
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Nice Sophia Antipolis and CNRS, 06560 Valbonne, France
| | - Bruno Goud
- Unité Mixte de Recherche 144, Institut Curie and CNRS, F-75248 Paris, France
| | - Bruno Antonny
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Nice Sophia Antipolis and CNRS, 06560 Valbonne, France.
| | - Hélène Barelli
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Nice Sophia Antipolis and CNRS, 06560 Valbonne, France
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50
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Bustillo-Zabalbeitia I, Montessuit S, Raemy E, Basañez G, Terrones O, Martinou JC. Specific interaction with cardiolipin triggers functional activation of Dynamin-Related Protein 1. PLoS One 2014; 9:e102738. [PMID: 25036098 PMCID: PMC4103857 DOI: 10.1371/journal.pone.0102738] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 06/23/2014] [Indexed: 11/18/2022] Open
Abstract
Dynamin-Related Protein 1 (Drp1), a large GTPase of the dynamin superfamily, is required for mitochondrial fission in healthy and apoptotic cells. Drp1 activation is a complex process that involves translocation from the cytosol to the mitochondrial outer membrane (MOM) and assembly into rings/spirals at the MOM, leading to membrane constriction/division. Similar to dynamins, Drp1 contains GTPase (G), bundle signaling element (BSE) and stalk domains. However, instead of the lipid-interacting Pleckstrin Homology (PH) domain present in the dynamins, Drp1 contains the so-called B insert or variable domain that has been suggested to play an important role in Drp1 regulation. Different proteins have been implicated in Drp1 recruitment to the MOM, although how MOM-localized Drp1 acquires its fully functional status remains poorly understood. We found that Drp1 can interact with pure lipid bilayers enriched in the mitochondrion-specific phospholipid cardiolipin (CL). Building on our previous study, we now explore the specificity and functional consequences of this interaction. We show that a four lysine module located within the B insert of Drp1 interacts preferentially with CL over other anionic lipids. This interaction dramatically enhances Drp1 oligomerization and assembly-stimulated GTP hydrolysis. Our results add significantly to a growing body of evidence indicating that CL is an important regulator of many essential mitochondrial functions.
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Affiliation(s)
- Itsasne Bustillo-Zabalbeitia
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Sylvie Montessuit
- Department of Cell Biology, University of Geneva, Geneva, Switzerland
| | - Etienne Raemy
- Department of Cell Biology, University of Geneva, Geneva, Switzerland
| | - Gorka Basañez
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Oihana Terrones
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
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