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Mitchell CL, Kurouski D. Novel strategies in Parkinson's disease treatment: a review. Front Mol Neurosci 2024; 17:1431079. [PMID: 39183754 PMCID: PMC11341544 DOI: 10.3389/fnmol.2024.1431079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Accepted: 07/29/2024] [Indexed: 08/27/2024] Open
Abstract
An unprecedented extension of life expectancy observed during the past century drastically increased the number of patients diagnosed with Parkinson's diseases (PD) worldwide. Estimated costs of PD alone reached $52 billion per year, making effective neuroprotective treatments an urgent and unmet need. Current treatments of both AD and PD focus on mitigating the symptoms associated with these pathologies and are not neuroprotective. In this review, we discuss the most advanced therapeutic strategies that can be used to treat PD. We also critically review the shift of the therapeutic paradigm from a small molecule-based inhibition of protein aggregation to the utilization of natural degradation pathways and immune cells that are capable of degrading toxic amyloid deposits in the brain of PD patients.
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Affiliation(s)
- Charles L. Mitchell
- Interdisciplinary Program in Genetics and Genomics, Texas A&M University, College Station, TX, United States
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, United States
| | - Dmitry Kurouski
- Interdisciplinary Program in Genetics and Genomics, Texas A&M University, College Station, TX, United States
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, United States
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2
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Calabresi P, Mechelli A, Natale G, Volpicelli-Daley L, Di Lazzaro G, Ghiglieri V. Alpha-synuclein in Parkinson's disease and other synucleinopathies: from overt neurodegeneration back to early synaptic dysfunction. Cell Death Dis 2023; 14:176. [PMID: 36859484 PMCID: PMC9977911 DOI: 10.1038/s41419-023-05672-9] [Citation(s) in RCA: 94] [Impact Index Per Article: 94.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 01/18/2023] [Accepted: 02/09/2023] [Indexed: 03/03/2023]
Abstract
Although the discovery of the critical role of α-synuclein (α-syn) in the pathogenesis of Parkinson's disease (PD) is now twenty-five years old, it still represents a milestone in PD research. Abnormal forms of α-syn trigger selective and progressive neuronal death through mitochondrial impairment, lysosomal dysfunction, and alteration of calcium homeostasis not only in PD but also in other α-syn-related neurodegenerative disorders such as dementia with Lewy bodies, multiple system atrophy, pure autonomic failure, and REM sleep behavior disorder. Furthermore, α-syn-dependent early synaptic and plastic alterations and the underlying mechanisms preceding overt neurodegeneration have attracted great interest. In particular, the presence of early inflammation in experimental models and PD patients, occurring before deposition and spreading of α-syn, suggests a mechanistic link between inflammation and synaptic dysfunction. The knowledge of these early mechanisms is of seminal importance to support the research on reliable biomarkers to precociously identify the disease and possible disease-modifying therapies targeting α-syn. In this review, we will discuss these critical issues, providing a state of the art of the role of this protein in early PD and other synucleinopathies.
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Affiliation(s)
- Paolo Calabresi
- Sezione di Neurologia, Dipartimento di Neuroscienze, Facoltà di Medicina e Chirurgia, Università Cattolica del Sacro Cuore, Rome, 00168, Italy. .,Neurologia, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, 00168, Italy.
| | - Alessandro Mechelli
- Dipartimento di Scienze Mediche e Chirurgiche, Istituto di Neurologia, Università "Magna Graecia", Catanzaro, Italy
| | - Giuseppina Natale
- Sezione di Neurologia, Dipartimento di Neuroscienze, Facoltà di Medicina e Chirurgia, Università Cattolica del Sacro Cuore, Rome, 00168, Italy
| | - Laura Volpicelli-Daley
- Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Giulia Di Lazzaro
- Neurologia, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, 00168, Italy
| | - Veronica Ghiglieri
- Neurologia, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, 00168, Italy.,Università Telematica San Raffaele, Rome, 00166, Italy
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3
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Sathanantham P, Zhao W, He G, Murray A, Fenech E, Diaz A, Schuldiner M, Wang X. A conserved viral amphipathic helix governs the replication site-specific membrane association. PLoS Pathog 2022; 18:e1010752. [PMID: 36048900 PMCID: PMC9473614 DOI: 10.1371/journal.ppat.1010752] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 09/14/2022] [Accepted: 07/19/2022] [Indexed: 11/18/2022] Open
Abstract
Positive-strand RNA viruses assemble their viral replication complexes (VRCs) on specific host organelle membranes, yet it is unclear how viral replication proteins recognize and what motifs or domains in viral replication proteins determine their destinations. We show here that an amphipathic helix, helix B in replication protein 1a of brome mosaic virus (BMV), is necessary for 1a’s localization to the nuclear endoplasmic reticulum (ER) membrane where BMV assembles its VRCs. Helix B is also sufficient to target soluble proteins to the nuclear ER membrane in yeast and plant cells. We further show that an equivalent helix in several plant- and human-infecting viruses of the Alsuviricetes class targets fluorescent proteins to the organelle membranes where they form their VRCs, including ER, vacuole, and Golgi membranes. Our work reveals a conserved helix that governs the localization of VRCs among a group of viruses and points to a possible target for developing broad-spectrum antiviral strategies. Positive-strand RNA viruses [(+)RNA viruses] are the largest viral class that include numerous pathogens causing important diseases in humans, animals, and plants. During their infections, (+)RNA viruses assemble their viral replication complexes (VRCs), where they multiply themselves, at specific organelle membranes. An initial step to form VRCs is to target viral replication proteins to the designated organelle membranes. For brome mosaic virus (BMV), its replication protein 1a is responsible for the VRC formation at the nuclear endoplasmic reticulum (ER) membrane. We show that an amphipathic alpha-helix, helix B, in BMV 1a is necessary for the association of BMV 1a with the nuclear ER membrane and for BMV genome amplification. In addition, Helix B is sufficient to target several soluble proteins to the nuclear ER membrane in yeast and plant cells. BMV belongs to the Alsuviricetes class that includes viruses infecting humans, animals, and plants. We further show that the helix B across members of the Alsuviricetes class is sufficient to target fluorescence proteins to the designated organelle membranes. Our results reveal a conserved feature among a group of viruses in governing the associations with replication site-specific organelle membranes and point to a target to develop broad-spectrum antivirals.
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Affiliation(s)
- Preethi Sathanantham
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Wenhao Zhao
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Key Lab of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Nanjing, China
| | - Guijuan He
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Austin Murray
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Emma Fenech
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Arturo Diaz
- Department of Biology, La Sierra University, Riverside, California, United States of America
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Xiaofeng Wang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
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4
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Rezende L, Couto NFD, Fernandes-Braga W, Epshtein Y, Alvarez-Leite JI, Levitan I, Andrade LDO. OxLDL induces membrane structure rearrangement leading to biomechanics alteration and migration deficiency in macrophage. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - BIOMEMBRANES 2022; 1864:183951. [PMID: 35504320 DOI: 10.1016/j.bbamem.2022.183951] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 04/20/2022] [Accepted: 04/25/2022] [Indexed: 11/30/2022]
Abstract
Cholesterol sequestration from plasma membrane has been shown to induce lipid packing disruption, causing actin cytoskeleton reorganization and polymerization, increasing cell stiffness and inducing lysosomal exocytosis in non-professional phagocytes. Similarly, oxidized form of low-density lipoprotein (oxLDL) has also been shown to disrupt lipid organization and packing in endothelial cells, leading to biomechanics alterations that interfere with membrane injury and repair. For macrophages, much is known about oxLDL effects in cell activation, cytokine production and foam cell formation. However, little is known about its impact in the organization of macrophage membrane structured domains and cellular mechanics, the focus of the present study. Treatment of bone marrow-derived macrophages (BMDM) with oxLDL not only altered membrane structure, and potentially the distribution of raft domains, but also induced actin rearrangement, diffuse integrin distribution and cell shrinkage, similarly to observed upon treatment of these cells with MβCD. Those alterations led to decreased migration efficiency. For both treatments, higher co-localization of actin cytoskeleton and GM1 was observed, indicating a similar mechanism of action involving raft-like domain dynamics. Lastly, like MβCD treatment, oxLDL also induced lysosomal spreading in BMDM. We propose that OxLDL induced re-organization of membrane/cytoskeleton complex in macrophages can be attributed to the insertion of oxysterols into the membrane, which lead to changes in lipid organization and disruption of membrane structure, similar to the effect of cholesterol depletion by MβCD treatment. These results indicate that oxLDL can induce physical alterations in the complex membrane/cytoskeleton of macrophages, leading to significant biomechanical changes that compromise cell behavior.
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Affiliation(s)
- Luisa Rezende
- Department of Morphology/Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Natalia Fernanda Do Couto
- Department of Morphology/Federal University of Minas Gerais, Belo Horizonte, MG, Brazil; Department of Medicine, University of Illinois at Chicago, Chicago, USA
| | - Weslley Fernandes-Braga
- Department of Biochemistry and Immunology/Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Yulia Epshtein
- Department of Medicine, University of Illinois at Chicago, Chicago, USA
| | | | - Irena Levitan
- Department of Medicine, University of Illinois at Chicago, Chicago, USA
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Single-molecule manipulation of macromolecules on GUV or SUV membranes using optical tweezers. Biophys J 2021; 120:5454-5465. [PMID: 34813728 DOI: 10.1016/j.bpj.2021.11.2884] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 10/16/2021] [Accepted: 11/19/2021] [Indexed: 11/23/2022] Open
Abstract
Despite their wide applications in soluble macromolecules, optical tweezers have rarely been used to characterize the dynamics of membrane proteins, mainly due to the lack of model membranes compatible with optical trapping. Here, we examined optical trapping and mechanical properties of two potential model membranes, giant and small unilamellar vesicles (GUVs and SUVs, respectively) for studies of membrane protein dynamics. We found that optical tweezers can stably trap GUVs containing iodixanol with controlled membrane tension. The trapped GUVs with high membrane tension can serve as a force sensor to accurately detect reversible folding of a DNA hairpin or membrane binding of synaptotagmin-1 C2AB domain attached to the GUV. We also observed that SUVs are rigid enough to resist large pulling forces and are suitable for detecting protein conformational changes induced by force. Our methodologies may facilitate single-molecule manipulation studies of membrane proteins using optical tweezers.
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6
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Ge J, Bian X, Ma L, Cai Y, Li Y, Yang J, Karatekin E, De Camilli P, Zhang Y. Stepwise membrane binding of extended synaptotagmins revealed by optical tweezers. Nat Chem Biol 2021; 18:313-320. [PMID: 34916620 DOI: 10.1038/s41589-021-00914-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 09/29/2021] [Indexed: 12/15/2022]
Abstract
Extended synaptotagmins (E-Syts) mediate lipid exchange between the endoplasmic reticulum (ER) and the plasma membrane (PM). Anchored on the ER, E-Syts bind the PM via an array of C2 domains in a Ca2+- and lipid-dependent manner, drawing the two membranes close to facilitate lipid exchange. How these C2 domains bind the PM and regulate the ER-PM distance is not well understood. Here, we applied optical tweezers to dissect PM binding by E-Syt1 and E-Syt2. We detected Ca2+- and lipid-dependent membrane-binding kinetics of both E-Syts and determined the binding energies and rates of individual C2 domains or pairs. We incorporated these parameters in a theoretical model to recapitulate salient features of E-Syt-mediated membrane contacts observed in vivo, including their equilibrium distances and probabilities. Our methods can be applied to study other proteins containing multiple membrane-binding domains linked by disordered polypeptides.
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Affiliation(s)
- Jinghua Ge
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Xin Bian
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT, USA.,State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Lu Ma
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.,Nanobiology Institute, Yale University, West Haven, CT, USA.,Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Yiying Cai
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT, USA
| | - Yanghui Li
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,College of Optical and Electronic Technology, China Jiliang University, Hangzhou, China
| | - Jie Yang
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Erdem Karatekin
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.,Nanobiology Institute, Yale University, West Haven, CT, USA.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Université de Paris, Saints-Pères Paris Institute for the Neurosciences (SPPIN), Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Pietro De Camilli
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT, USA.,Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Yongli Zhang
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA. .,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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7
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Sarchione A, Marchand A, Taymans JM, Chartier-Harlin MC. Alpha-Synuclein and Lipids: The Elephant in the Room? Cells 2021; 10:2452. [PMID: 34572099 PMCID: PMC8467310 DOI: 10.3390/cells10092452] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/10/2021] [Accepted: 09/12/2021] [Indexed: 12/17/2022] Open
Abstract
Since the initial identification of alpha-synuclein (α-syn) at the synapse, numerous studies demonstrated that α-syn is a key player in the etiology of Parkinson's disease (PD) and other synucleinopathies. Recent advances underline interactions between α-syn and lipids that also participate in α-syn misfolding and aggregation. In addition, increasing evidence demonstrates that α-syn plays a major role in different steps of synaptic exocytosis. Thus, we reviewed literature showing (1) the interplay among α-syn, lipids, and lipid membranes; (2) advances of α-syn synaptic functions in exocytosis. These data underscore a fundamental role of α-syn/lipid interplay that also contributes to synaptic defects in PD. The importance of lipids in PD is further highlighted by data showing the impact of α-syn on lipid metabolism, modulation of α-syn levels by lipids, as well as the identification of genetic determinants involved in lipid homeostasis associated with α-syn pathologies. While questions still remain, these recent developments open the way to new therapeutic strategies for PD and related disorders including some based on modulating synaptic functions.
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Affiliation(s)
| | | | | | - Marie-Christine Chartier-Harlin
- Univ. Lille, Inserm, CHU Lille, UMR-S 1172—LilNCog—Lille Neuroscience and Cognition, F-59000 Lille, France; (A.S.); (A.M.); (J.-M.T.)
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8
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Bozelli JC, Epand RM. Membrane Shape and the Regulation of Biological Processes. J Mol Biol 2020; 432:5124-5136. [DOI: 10.1016/j.jmb.2020.03.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/25/2020] [Accepted: 03/27/2020] [Indexed: 01/06/2023]
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9
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Athanasopoulos A, André B, Sophianopoulou V, Gournas C. Fungal plasma membrane domains. FEMS Microbiol Rev 2020; 43:642-673. [PMID: 31504467 DOI: 10.1093/femsre/fuz022] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/25/2019] [Indexed: 12/11/2022] Open
Abstract
The plasma membrane (PM) performs a plethora of physiological processes, the coordination of which requires spatial and temporal organization into specialized domains of different sizes, stability, protein/lipid composition and overall architecture. Compartmentalization of the PM has been particularly well studied in the yeast Saccharomyces cerevisiae, where five non-overlapping domains have been described: The Membrane Compartments containing the arginine permease Can1 (MCC), the H+-ATPase Pma1 (MCP), the TORC2 kinase (MCT), the sterol transporters Ltc3/4 (MCL), and the cell wall stress mechanosensor Wsc1 (MCW). Additional cortical foci at the fungal PM are the sites where clathrin-dependent endocytosis occurs, the sites where the external pH sensing complex PAL/Rim localizes, and sterol-rich domains found in apically grown regions of fungal membranes. In this review, we summarize knowledge from several fungal species regarding the organization of the lateral PM segregation. We discuss the mechanisms of formation of these domains, and the mechanisms of partitioning of proteins there. Finally, we discuss the physiological roles of the best-known membrane compartments, including the regulation of membrane and cell wall homeostasis, apical growth of fungal cells and the newly emerging role of MCCs as starvation-protective membrane domains.
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Affiliation(s)
- Alexandros Athanasopoulos
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research 'Demokritos,' Patr. Grigoriou E & 27 Neapoleos St. 15341, Agia Paraskevi, Greece
| | - Bruno André
- Molecular Physiology of the Cell laboratory, Université Libre de Bruxelles (ULB), Institut de Biologie et de Médecine Moléculaires, rue des Pr Jeener et Brachet 12, 6041, Gosselies, Belgium
| | - Vicky Sophianopoulou
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research 'Demokritos,' Patr. Grigoriou E & 27 Neapoleos St. 15341, Agia Paraskevi, Greece
| | - Christos Gournas
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research 'Demokritos,' Patr. Grigoriou E & 27 Neapoleos St. 15341, Agia Paraskevi, Greece
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10
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The roles of the diversity of amphipathic lipids in shaping membranes by membrane-shaping proteins. Biochem Soc Trans 2020; 48:837-851. [PMID: 32597479 DOI: 10.1042/bst20190376] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/02/2020] [Accepted: 06/05/2020] [Indexed: 12/23/2022]
Abstract
Lipid compositions of cells differ according to cell types and intracellular organelles. Phospholipids are major cell membrane lipids and have hydrophilic head groups and hydrophobic fatty acid tails. The cellular lipid membrane without any protein adapts to spherical shapes, and protein binding to the membrane is thought to be required for shaping the membrane for various cellular events. Until recently, modulation of cellular lipid membranes was initially shown to be mediated by proteins recognizing lipid head groups, including the negatively charged ones of phosphatidylserine and phosphoinositides. Recent studies have shown that the abilities of membrane-deforming proteins are also regulated by the composition of fatty acid tails, which cause different degrees of packing defects. The binding of proteins to cellular lipid membranes is affected by the packing defects, presumably through modulation of their interactions with hydrophobic amino acid residues. Therefore, lipid composition can be characterized by both packing defects and charge density. The lipid composition regarding fatty acid tails affects membrane bending via the proteins with amphipathic helices, including those with the ArfGAP1 lipid packing sensor (ALPS) motif and via membrane-deforming proteins with structural folding, including those with the Bin-Amphiphysin-Rvs167 (BAR) domains. This review focuses on how the fatty acid tails, in combination with the head groups of phospholipids, affect protein-mediated membrane deformation.
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11
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Manzetti J, Weissbach FH, Graf FE, Unterstab G, Wernli M, Hopfer H, Drachenberg CB, Rinaldo CH, Hirsch HH. BK Polyomavirus Evades Innate Immune Sensing by Disrupting the Mitochondrial Network and Promotes Mitophagy. iScience 2020; 23:101257. [PMID: 32599557 PMCID: PMC7326741 DOI: 10.1016/j.isci.2020.101257] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 03/16/2020] [Accepted: 06/05/2020] [Indexed: 12/12/2022] Open
Abstract
Immune escape contributes to viral persistence, yet little is known about human polyomaviruses. BK-polyomavirus (BKPyV) asymptomatically infects 90% of humans but causes premature allograft failure in kidney transplant patients. Despite virus-specific T cells and neutralizing antibodies, BKPyV persists in kidneys and evades immune control as evidenced by urinary shedding in immunocompetent individuals. Here, we report that BKPyV disrupts the mitochondrial network and membrane potential when expressing the 66aa-long agnoprotein during late replication. Agnoprotein is necessary and sufficient, using its amino-terminal and central domain for mitochondrial targeting and network disruption, respectively. Agnoprotein impairs nuclear IRF3-translocation, interferon-beta expression, and promotes p62/SQSTM1-mitophagy. Agnoprotein-mutant viruses unable to disrupt mitochondria show reduced replication and increased interferon-beta expression but can be rescued by type-I interferon blockade, TBK1-inhibition, or CoCl2-treatment. Mitochondrial fragmentation and p62/SQSTM1-autophagy occur in allograft biopsies of kidney transplant patients with BKPyV nephropathy. JCPyV and SV40 infection similarly disrupt mitochondrial networks, indicating a conserved mechanism facilitating polyomavirus persistence and post-transplant disease. BK polyomavirus agnoprotein disrupts mitochondrial membrane potential and network Agnoprotein impairs nucleus IRF3 translocation and interferon-β expression Agnoprotein facilitates innate immune evasion during the late viral replication phase Damaged mitochondria are targeted for p62/SQSTM1 autophagy
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Affiliation(s)
- Julia Manzetti
- Transplantation & Clinical Virology, Department Biomedicine (Haus Petersplatz), University of Basel, Petersplatz 10, CH-4009 Basel, Switzerland
| | - Fabian H Weissbach
- Transplantation & Clinical Virology, Department Biomedicine (Haus Petersplatz), University of Basel, Petersplatz 10, CH-4009 Basel, Switzerland
| | - Fabrice E Graf
- Transplantation & Clinical Virology, Department Biomedicine (Haus Petersplatz), University of Basel, Petersplatz 10, CH-4009 Basel, Switzerland
| | - Gunhild Unterstab
- Transplantation & Clinical Virology, Department Biomedicine (Haus Petersplatz), University of Basel, Petersplatz 10, CH-4009 Basel, Switzerland
| | - Marion Wernli
- Transplantation & Clinical Virology, Department Biomedicine (Haus Petersplatz), University of Basel, Petersplatz 10, CH-4009 Basel, Switzerland
| | - Helmut Hopfer
- Institute for Pathology, University Hospital Basel, Basel, Switzerland
| | - Cinthia B Drachenberg
- Departments of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Christine Hanssen Rinaldo
- Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway; Metabolic and Renal Research Group, UiT The Arctic University of Norway, Tromsø, Norway
| | - Hans H Hirsch
- Transplantation & Clinical Virology, Department Biomedicine (Haus Petersplatz), University of Basel, Petersplatz 10, CH-4009 Basel, Switzerland; Clinical Virology, Laboratory Medicine, University Hospital Basel, Basel, Switzerland; Infectious Diseases & Hospital Epidemiology, University Hospital Basel, Basel, Switzerland.
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12
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Vidyadhara DJ, Lee JE, Chandra SS. Role of the endolysosomal system in Parkinson's disease. J Neurochem 2019; 150:487-506. [PMID: 31287913 PMCID: PMC6707858 DOI: 10.1111/jnc.14820] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/01/2019] [Accepted: 07/03/2019] [Indexed: 12/13/2022]
Abstract
Parkinson's disease (PD) is one of the most common neurodegenerative disorders, affecting 1-1.5% of the total population. While progress has been made in understanding the neurodegenerative mechanisms that lead to cell death in late stages of PD, mechanisms for early, causal pathogenic events are still elusive. Recent developments in PD genetics increasingly point at endolysosomal (E-L) system dysfunction as the early pathomechanism and key pathway affected in PD. Clathrin-mediated synaptic endocytosis, an integral part of the neuronal E-L system, is probably the main early target as evident in auxilin, RME-8, and synaptojanin-1 mutations that cause PD. Autophagy, another important pathway in the E-L system, is crucial in maintaining proteostasis and a healthy mitochondrial pool, especially in neurons considering their inability to divide and requirement to function an entire life-time. PINK1 and Parkin mutations severely perturb autophagy of dysfunctional mitochondria (mitophagy), both in the cell body and synaptic terminals of dopaminergic neurons, leading to PD. Endolysosomal sorting and trafficking is also crucial, which is complex in multi-compartmentalized neurons. VPS35 and VPS13C mutations noted in PD target these mechanisms. Mutations in GBA comprise the most common risk factor for PD and initiate pathology by compromising lysosomal function. This is also the case for ATP13A2 mutations. Interestingly, α-synuclein and LRRK2, key proteins involved in PD, function in different steps of the E-L pathway and target their components to induce disease pathogenesis. In this review, we discuss these E-L system genes that are linked to PD and how their dysfunction results in PD pathogenesis. This article is part of the Special Issue "Synuclein".
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Affiliation(s)
- D J Vidyadhara
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, USA
| | - John E Lee
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sreeganga S Chandra
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, USA
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13
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Liang H, Mu H, Jean-Francois F, Lakshman B, Sarkar-Banerjee S, Zhuang Y, Zeng Y, Gao W, Zaske AM, Nissley DV, Gorfe AA, Zhao W, Zhou Y. Membrane curvature sensing of the lipid-anchored K-Ras small GTPase. Life Sci Alliance 2019; 2:e201900343. [PMID: 31296567 PMCID: PMC6625090 DOI: 10.26508/lsa.201900343] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 07/01/2019] [Accepted: 07/02/2019] [Indexed: 12/26/2022] Open
Abstract
Plasma membrane (PM) curvature defines cell shape and intracellular organelle morphologies and is a fundamental cell property. Growth/proliferation is more stimulated in flatter cells than the same cells in elongated shapes. PM-anchored K-Ras small GTPase regulates cell growth/proliferation and plays key roles in cancer. The lipid-anchored K-Ras form nanoclusters selectively enriched with specific phospholipids, such as phosphatidylserine (PS), for efficient effector recruitment and activation. K-Ras function may, thus, be sensitive to changing lipid distribution at membranes with different curvatures. Here, we used complementary methods to manipulate membrane curvature of intact/live cells, native PM blebs, and synthetic liposomes. We show that the spatiotemporal organization and signaling of an oncogenic mutant K-Ras G12V favor flatter membranes with low curvature. Our findings are consistent with the more stimulated growth/proliferation in flatter cells. Depletion of endogenous PS abolishes K-Ras G12V PM curvature sensing. In cells and synthetic bilayers, only mixed-chain PS species, but not other PS species tested, mediate K-Ras G12V membrane curvature sensing. Thus, K-Ras nanoclusters act as relay stations to convert mechanical perturbations to mitogenic signaling.
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Affiliation(s)
- Hong Liang
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Huanwen Mu
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
| | - Frantz Jean-Francois
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Bindu Lakshman
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | | | - Yinyin Zhuang
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
| | - Yongpeng Zeng
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
| | - Weibo Gao
- School of Physics and Mathematical Science, Nanyang Technological University, Singapore
| | - Ana Maria Zaske
- Internal Medicine, Cardiology Division, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Dwight V Nissley
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Alemayehu A Gorfe
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Wenting Zhao
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
| | - Yong Zhou
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, USA
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14
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Kumar MN, Bau YC, Longkumer T, Verslues PE. Low Water Potential and At14a-Like1 (AFL1) Effects on Endocytosis and Actin Filament Organization. PLANT PHYSIOLOGY 2019; 179:1594-1607. [PMID: 30728274 PMCID: PMC6446769 DOI: 10.1104/pp.18.01314] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 01/31/2019] [Indexed: 05/20/2023]
Abstract
At14a-Like1 (AFL1) is a stress-induced protein of unknown function that promotes growth during low water potential stress and drought. Previous analysis indicated that AFL1 may have functions related to endocytosis and regulation of actin filament organization, processes for which the effects of low water potential are little known. We found that low water potential led to a decrease in endocytosis, as measured by uptake of the membrane-impermeable dye FM4-64. Ectopic expression of AFL1 reversed the decrease in FM4-64 uptake seen in wild type, while reduced AFL1 expression led to further inhibition of FM4-64 uptake. Increased AFL1 also made FM4-64 uptake less sensitive to the actin filament disruptor Latrunculin B (LatB). LatB decreased AFL1-Clathrin Light Chain colocalization, further indicating that effects of AFL1 on endocytosis may be related to actin filament organization or stability. Consistent with this hypothesis, ectopic AFL1 expression made actin filaments less sensitive to disruption by LatB or Cytochalasin D and led to increased actin filament skewness and decreased occupancy, indicative of more bundled actin filaments. This latter effect could be partially mimicked by the actin filament stabilizer Jasplakinolide (JASP). However, AFL1 did not substantially inhibit actin filament dynamics, indicating that AFL1 acts via a different mechanism than JASP-induced stabilization. AFL1 partially colocalized with actin filaments but not with microtubules, further indicating actin-filament-related function of AFL1. These data provide insight into endocytosis and actin filament responses to low water potential stress and demonstrate an involvement of AFL1 in these key cellular processes.
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Affiliation(s)
- M Nagaraj Kumar
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Taiwan
| | - Yu-Chiuan Bau
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Taiwan
| | | | - Paul E Verslues
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Taiwan
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15
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Tauroursodeoxycholic acid (TUDCA) inhibits influenza A viral infection by disrupting viral proton channel M2. Sci Bull (Beijing) 2019; 64:180-188. [PMID: 32288967 PMCID: PMC7104969 DOI: 10.1016/j.scib.2018.08.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/22/2018] [Accepted: 07/22/2018] [Indexed: 01/20/2023]
Abstract
Influenza is a persistent threat to human health and there is a continuing requirement for updating anti-influenza strategies. Initiated by observations of different endoplasmic reticulum (ER) responses of host to seasonal H1N1 and highly pathogenic avian influenza (HPAI) A H5N1 infections, we identified an alternative antiviral role of tauroursodeoxycholic acid (TUDCA), a clinically available ER stress inhibitor, both in vitro and in vivo. Rather than modulating ER stress in host cells, TUDCA abolished the proton conductivity of viral M2 by disrupting its oligomeric states, which induces inefficient viral infection. We also showed that M2 penetrated cells, whose intracellular uptake depended on its proton channel activity, an effect observed in both TUDCA and M2 inhibitor amantadine. The identification and application of TUDCA as an inhibitor of M2 proton channel will expand our understanding of IAV biology and complement current anti-IAV arsenals.
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16
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Huang M, Wang B, Li X, Fu C, Wang C, Kang X. α-Synuclein: A Multifunctional Player in Exocytosis, Endocytosis, and Vesicle Recycling. Front Neurosci 2019; 13:28. [PMID: 30745863 PMCID: PMC6360911 DOI: 10.3389/fnins.2019.00028] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 01/14/2019] [Indexed: 11/22/2022] Open
Abstract
α-synuclein (α-Syn) is a presynaptic enriched protein involved in the pathogenesis of Parkinson’s disease. However, the physiological roles of α-Syn remain poorly understood. Recent studies have indicated a critical role of α-Syn in the sensing and generation of membrane curvature during vesicular exocytosis and endocytosis. It has been known to modulate the assembly of SNARE complex during exocytosis including vesicle docking, priming and fusion steps. Growing evidence suggests that α-Syn also plays critical roles in the endocytosis of synaptic vesicles. It also modulates the availability of releasable vesicles by promoting synaptic vesicles clustering. Here, we provide an overview of recent progresses in understanding the function of α-Syn in the regulation of exocytosis, endocytosis, and vesicle recycling under physiological and pathological conditions.
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Affiliation(s)
- Mingzhu Huang
- School of Life Sciences, Liaocheng University, Liaocheng, China.,Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Bianbian Wang
- School of Life Sciences, Liaocheng University, Liaocheng, China.,Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Xiaopeng Li
- School of Life Sciences, Liaocheng University, Liaocheng, China.,Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Chongluo Fu
- School of Life Sciences, Liaocheng University, Liaocheng, China
| | - Changhe Wang
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Xinjiang Kang
- School of Life Sciences, Liaocheng University, Liaocheng, China.,Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
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17
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Shi Z, Graber ZT, Baumgart T, Stone HA, Cohen AE. Cell Membranes Resist Flow. Cell 2018; 175:1769-1779.e13. [PMID: 30392960 PMCID: PMC6541487 DOI: 10.1016/j.cell.2018.09.054] [Citation(s) in RCA: 203] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 07/16/2018] [Accepted: 09/26/2018] [Indexed: 02/06/2023]
Abstract
The fluid-mosaic model posits a liquid-like plasma membrane, which can flow in response to tension gradients. It is widely assumed that membrane flow transmits local changes in membrane tension across the cell in milliseconds, mediating long-range signaling. Here, we show that propagation of membrane tension occurs quickly in cell-attached blebs but is largely suppressed in intact cells. The failure of tension to propagate in cells is explained by a fluid dynamical model that incorporates the flow resistance from cytoskeleton-bound transmembrane proteins. Perturbations to tension propagate diffusively, with a diffusion coefficient Dσ ∼0.024 μm2/s in HeLa cells. In primary endothelial cells, local increases in membrane tension lead only to local activation of mechanosensitive ion channels and to local vesicle fusion. Thus, membrane tension is not a mediator of long-range intracellular signaling, but local variations in tension mediate distinct processes in sub-cellular domains.
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Affiliation(s)
- Zheng Shi
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute
| | - Zachary T Graber
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tobias Baumgart
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Adam E Cohen
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute.
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18
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Membrane re-modelling by BAR domain superfamily proteins via molecular and non-molecular factors. Biochem Soc Trans 2018. [PMID: 29540508 DOI: 10.1042/bst20170322] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Lipid membranes are structural components of cell surfaces and intracellular organelles. Alterations in lipid membrane shape are accompanied by numerous cellular functions, including endocytosis, intracellular transport, and cell migration. Proteins containing Bin-Amphiphysin-Rvs (BAR) domains (BAR proteins) are unique, because their structures correspond to the membrane curvature, that is, the shape of the lipid membrane. BAR proteins present at high concentration determine the shape of the membrane, because BAR domain oligomers function as scaffolds that mould the membrane. BAR proteins co-operate with various molecular and non-molecular factors. The molecular factors include cytoskeletal proteins such as the regulators of actin filaments and the membrane scission protein dynamin. Lipid composition, including saturated or unsaturated fatty acid tails of phospholipids, also affects the ability of BAR proteins to mould the membrane. Non-molecular factors include the external physical forces applied to the membrane, such as tension and friction. In this mini-review, we will discuss how the BAR proteins orchestrate membrane dynamics together with various molecular and non-molecular factors.
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19
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Enrique Gomez R, Joubès J, Valentin N, Batoko H, Satiat-Jeunemaître B, Bernard A. Lipids in membrane dynamics during autophagy in plants. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1287-1299. [PMID: 29140451 DOI: 10.1093/jxb/erx392] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 10/09/2017] [Indexed: 05/19/2023]
Abstract
Autophagy is a critical pathway for plant adaptation to stress. Macroautophagy relies on the biogenesis of a specialized membrane named the phagophore that maturates into a double membrane vesicle. Proteins and lipids act synergistically to promote membrane structure and functions, yet research on autophagy has mostly focused on autophagy-related proteins while knowledge of supporting lipids in the formation of autophagic membranes remains scarce. This review expands on studies in plants with examples from other organisms to present and discuss our current understanding of lipids in membrane dynamics associated with the autophagy pathway in plants.
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Affiliation(s)
- Rodrigo Enrique Gomez
- CNRS, Laboratoire de Biogenèse Membranaire, UMR5200, Bordeaux, France
- Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR5200, Bordeaux, France
| | - Jérôme Joubès
- CNRS, Laboratoire de Biogenèse Membranaire, UMR5200, Bordeaux, France
- Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR5200, Bordeaux, France
| | - Nicolas Valentin
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Paris-Sud University, Avenue de la Terrasse, Gif-sur-Yvette, France
| | - Henri Batoko
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, Louvain-la-Neuve, Belgium
| | - Béatrice Satiat-Jeunemaître
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Paris-Sud University, Avenue de la Terrasse, Gif-sur-Yvette, France
| | - Amélie Bernard
- CNRS, Laboratoire de Biogenèse Membranaire, UMR5200, Bordeaux, France
- Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR5200, Bordeaux, France
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20
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Influenza A Virus M2 Protein: Roles from Ingress to Egress. Int J Mol Sci 2017; 18:ijms18122649. [PMID: 29215568 PMCID: PMC5751251 DOI: 10.3390/ijms18122649] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 11/17/2022] Open
Abstract
Influenza A virus (IAV) matrix protein 2 (M2) is among the smallest bona fide, hence extensively studied, ion channel proteins. The M2 ion channel activity is not only essential for virus replication, but also involved in modulation of cellular homeostasis in a variety of ways. It is also the target for ion channel inhibitors, i.e., anti-influenza drugs. Thus far, several studies have been conducted to elucidate its biophysical characteristics, structure-function relationships of the ion channel, and the M2-host interactome. In this review, we discuss M2 protein synthesis and assembly into an ion channel, its roles in IAV replication, and the pathophysiological impact on the host cell.
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21
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Ma L, Cai Y, Li Y, Jiao J, Wu Z, O'Shaughnessy B, De Camilli P, Karatekin E, Zhang Y. Single-molecule force spectroscopy of protein-membrane interactions. eLife 2017; 6:30493. [PMID: 29083305 PMCID: PMC5690283 DOI: 10.7554/elife.30493] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/29/2017] [Indexed: 12/17/2022] Open
Abstract
Many biological processes rely on protein–membrane interactions in the presence of mechanical forces, yet high resolution methods to quantify such interactions are lacking. Here, we describe a single-molecule force spectroscopy approach to quantify membrane binding of C2 domains in Synaptotagmin-1 (Syt1) and Extended Synaptotagmin-2 (E-Syt2). Syts and E-Syts bind the plasma membrane via multiple C2 domains, bridging the plasma membrane with synaptic vesicles or endoplasmic reticulum to regulate membrane fusion or lipid exchange, respectively. In our approach, single proteins attached to membranes supported on silica beads are pulled by optical tweezers, allowing membrane binding and unbinding transitions to be measured with unprecedented spatiotemporal resolution. C2 domains from either protein resisted unbinding forces of 2–7 pN and had binding energies of 4–14 kBT per C2 domain. Regulation by bilayer composition or Ca2+ recapitulated known properties of both proteins. The method can be widely applied to study protein–membrane interactions.
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Affiliation(s)
- Lu Ma
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States.,CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.,Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Yiying Cai
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States.,Department of Neuroscience, Yale University School of Medicine, New Haven, United States.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, United States
| | - Yanghui Li
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States.,College of Optical and Electronic Technology, China Jiliang University, Hangzhou, China
| | - Junyi Jiao
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States.,Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, United States
| | - Zhenyong Wu
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, United States.,Nanobiology Institute, Yale University, West Haven, United States
| | - Ben O'Shaughnessy
- Department of Chemical Engineering, Columbia University, New York, United States
| | - Pietro De Camilli
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States.,Department of Neuroscience, Yale University School of Medicine, New Haven, United States.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, United States.,Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, United States
| | - Erdem Karatekin
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, United States.,Nanobiology Institute, Yale University, West Haven, United States.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States.,Laboratoire de Neurophotonique, Faculté des Sciences Fondamentales et Biomédicales, Centre National de la Recherche Scientifique (CNRS) UMR 8250, Université Paris Descartes, Paris, France
| | - Yongli Zhang
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States
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22
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Lautenschläger J, Kaminski CF, Kaminski Schierle GS. α-Synuclein – Regulator of Exocytosis, Endocytosis, or Both? Trends Cell Biol 2017; 27:468-479. [DOI: 10.1016/j.tcb.2017.02.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 02/01/2017] [Accepted: 02/02/2017] [Indexed: 10/20/2022]
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23
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Huber N, Bieniossek C, Wagner KM, Elsässer HP, Suter U, Berger I, Niemann A. Glutathione-conjugating and membrane-remodeling activity of GDAP1 relies on amphipathic C-terminal domain. Sci Rep 2016; 6:36930. [PMID: 27841286 PMCID: PMC5107993 DOI: 10.1038/srep36930] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 10/21/2016] [Indexed: 11/09/2022] Open
Abstract
Mutations in the ganglioside-induced differentiation associated protein 1 (GDAP1) cause severe peripheral motor and sensory neuropathies called Charcot-Marie-Tooth disease. GDAP1 expression induces fission of mitochondria and peroxisomes by a currently elusive mechanism, while disease causing mutations in GDAP1 impede the protein's role in mitochondrial dynamics. In silico analysis reveals sequence similarities of GDAP1 to glutathione S-transferases (GSTs). However, a proof of GST activity and its possible impact on membrane dynamics are lacking to date. Using recombinant protein, we demonstrate for the first time theta-class-like GST activity for GDAP1, and it's activity being regulated by the C-terminal hydrophobic domain 1 (HD1) of GDAP1 in an autoinhibitory manner. Moreover, we show that the HD1 amphipathic pattern is required to induce membrane dynamics by GDAP1. As both, fission and GST activities of GDAP1, are critically dependent on HD1, we propose that GDAP1 undergoes a molecular switch, turning from a pro-fission active to an auto-inhibited inactive conformation.
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Affiliation(s)
- Nina Huber
- Institute of Molecular Health Sciences, Department of Biology, ETH Zürich, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Christoph Bieniossek
- European Molecular Biology Laboratory, Grenoble Outstation, 38042 Grenoble, France
- Roche Pharma Research and Early Development, Infectious Diseases Discovery, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Konstanze Marion Wagner
- Institute of Molecular Health Sciences, Department of Biology, ETH Zürich, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Hans-Peter Elsässer
- Department of Cytobiology and Cytopathobiology, Philipps University of Marburg, 35033 Marburg, Germany
| | - Ueli Suter
- Institute of Molecular Health Sciences, Department of Biology, ETH Zürich, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Imre Berger
- European Molecular Biology Laboratory, Grenoble Outstation, 38042 Grenoble, France
- School of Biochemistry, Bristol University, Bristol BS8 1TD, United Kingdom
| | - Axel Niemann
- Institute of Molecular Health Sciences, Department of Biology, ETH Zürich, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
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24
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Breeze E, Dzimitrowicz N, Kriechbaumer V, Brooks R, Botchway SW, Brady JP, Hawes C, Dixon AM, Schnell JR, Fricker MD, Frigerio L. A C-terminal amphipathic helix is necessary for the in vivo tubule-shaping function of a plant reticulon. Proc Natl Acad Sci U S A 2016; 113:10902-7. [PMID: 27621477 PMCID: PMC5047209 DOI: 10.1073/pnas.1605434113] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Reticulons (RTNs) are a class of endoplasmic reticulum (ER) membrane proteins that are capable of maintaining high membrane curvature, thus helping shape the ER membrane into tubules. The mechanism of action of RTNs is hypothesized to be a combination of wedging, resulting from the transmembrane topology of their conserved reticulon homology domain, and scaffolding, arising from the ability of RTNs to form low-mobility homo-oligomers within the membrane. We studied the plant RTN isoform RTN13, which has previously been shown to locate to ER tubules and the edges of ER cisternae and to induce constrictions in ER tubules when overexpressed, and identified a region in the C terminus containing a putative amphipathic helix (APH). Here we show that deletion of this region or disruption of the hydrophobic face of the predicted helix abolishes the ability of RTN13 to induce constrictions of ER tubules in vivo. These mutants, however, still retain their ability to interact and form low-mobility oligomers in the ER membrane. Hence, our evidence indicates that the conserved APH is a key structural feature for RTN13 function in vivo, and we propose that RTN, like other membrane morphogens, rely on APHs for their function.
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Affiliation(s)
- Emily Breeze
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Natasha Dzimitrowicz
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Verena Kriechbaumer
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
| | - Rhiannon Brooks
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Stanley W Botchway
- Central Laser Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0QX, United Kingdom
| | - Jacob P Brady
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Chris Hawes
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
| | - Ann M Dixon
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Jason R Schnell
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Mark D Fricker
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - Lorenzo Frigerio
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom;
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25
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Thiam AR, Forêt L. The physics of lipid droplet nucleation, growth and budding. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:715-22. [PMID: 27131867 DOI: 10.1016/j.bbalip.2016.04.018] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 04/05/2016] [Accepted: 04/22/2016] [Indexed: 11/25/2022]
Abstract
Lipid droplets (LDs) are intracellular oil-in-water emulsion droplets, covered by a phospholipid monolayer and mainly present in the cytosol. Despite their important role in cellular metabolism and growing number of newly identified functions, LD formation mechanism from the endoplasmic reticulum remains poorly understood. To form a LD, the oil molecules synthesized in the ER accumulate between the monolayer leaflets and induce deformation of the membrane. This formation process works through three steps: nucleation, growth and budding, exactly as in phase separation and dewetting phenomena. These steps involve sequential biophysical membrane remodeling mechanisms for which we present basic tools of statistical physics, membrane biophysics, and soft matter science underlying them. We aim to highlight relevant factors that could control LD formation size, site and number through this physics description. An emphasis will be given to a currently underestimated contribution of the molecular interactions between lipids to favor an energetically costless mechanism of LD formation.
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Affiliation(s)
- Abdou Rachid Thiam
- Laboratoire de Physique Statistique, École Normale Supérieure, PSL Research University, Université Paris Diderot Sorbonne Paris-Cité, Sorbonne Universités UPMC Univ Paris 06, CNRS, 24 rue Lhomond, 75005 Paris, France.
| | - Lionel Forêt
- Laboratoire de Physique Statistique, École Normale Supérieure, PSL Research University, Université Paris Diderot Sorbonne Paris-Cité, Sorbonne Universités UPMC Univ Paris 06, CNRS, 24 rue Lhomond, 75005 Paris, France
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26
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Lowengrub J, Allard J, Aland S. Numerical simulation of endocytosis: Viscous flow driven by membranes with non-uniformly distributed curvature-inducing molecules. JOURNAL OF COMPUTATIONAL PHYSICS 2016; 309:112-128. [PMID: 26869729 PMCID: PMC4746022 DOI: 10.1016/j.jcp.2015.12.055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The formation of membrane vesicles from a larger membrane that occurs during endocytosis and other cell processes are typically orchestrated by curvature-inducing molecules attached to the membrane. Recent reports demonstrate that vesicles can form de novo in a few milliseconds. Membrane dynamics at these scales are strongly influenced by hydrodynamic interactions. To study this problem, we develop new diffuse interface models for the dynamics of inextensible vesicles in a viscous fluid with stiff, curvature-inducing molecules. The model couples the Navier-Stokes equations with membrane-induced bending forces that incorporate concentration-dependent bending stiffness coefficients and spontaneous curvatures, with equations for molecule transport and for a Lagrange multiplier to enforce local inextensibility. Two forms of surface transport equations are considered: Fickian surface diffusion and Cahn-Hilliard surface dynamics, with the former being more appropriate for small molecules and the latter being better for large molecules. The system is solved using adaptive finite element methods in 3D axisymmetric geometries. The results demonstrate that hydrodynamics can indeed enable the rapid formation of a small vesicle attached to the membrane by a narrow neck. When the Fickian model is used, this is a transient state with the steady state being a flat membrane with a uniformly distributed molecule concentration due to diffusion. When the Cahn-Hilliard model is used, molecule concentration gradients are sustained, the neck stabilizes and the system evolves to a steady-state with a small, compact vesicle attached to the membrane. By varying the membrane coverage of molecules in the Cahn-Hilliard model, we find that there is a critical (smallest) neck radius and a critical (fastest) budding time. These critical points are associated with changes in the vesicle morphology from spherical to mushroom-like as the molecule coverage on the membrane is increased.
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Affiliation(s)
- John Lowengrub
- Department of Mathematics, UC Irvine, Irvine, CA 92697, USA
- Center for Complex Biological Systems, UC Irvine, CA 92697, USA
- Department of Biomedical Engineering, UC Irvine, Irvine, CA 92697, USA
| | - Jun Allard
- Department of Mathematics, UC Irvine, Irvine, CA 92697, USA
- Center for Complex Biological Systems, UC Irvine, CA 92697, USA
- Department of Physics and Astronomy, UC Irvine, Irvine, CA 92697, USA
| | - Sebastian Aland
- Institut für wissenschaftliches Rechnen, TU Dresden, 01062 Dresden, Germany
- Department of Mathematics, UC Irvine, Irvine, CA 92697, USA
- Center for Complex Biological Systems, UC Irvine, CA 92697, USA
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Kim SS, Upshur MA, Saotome K, Sahu ID, McCarrick RM, Feix JB, Lorigan GA, Howard KP. Cholesterol-Dependent Conformational Exchange of the C-Terminal Domain of the Influenza A M2 Protein. Biochemistry 2015; 54:7157-67. [PMID: 26569023 PMCID: PMC4734095 DOI: 10.1021/acs.biochem.5b01065] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The C-terminal amphipathic helix of the influenza A M2 protein plays a critical cholesterol-dependent role in viral budding. To provide atomic-level detail on the impact cholesterol has on the conformation of M2 protein, we spin-labeled sites right before and within the C-terminal amphipathic helix of the M2 protein. We studied the spin-labeled M2 proteins in membranes both with and without cholesterol. We used a multipronged site-directed spin-label electron paramagnetic resonance (SDSL-EPR) approach and collected data on line shapes, relaxation rates, accessibility of sites to the membrane, and distances between symmetry-related sites within the tetrameric protein. We demonstrate that the C-terminal amphipathic helix of M2 populates at least two conformations in POPC/POPG 4:1 bilayers. Furthermore, we show that the conformational state that becomes more populated in the presence of cholesterol is less dynamic, less membrane buried, and more tightly packed than the other state. Cholesterol-dependent changes in M2 could be attributed to the changes cholesterol induces in bilayer properties and/or direct binding of cholesterol to the protein. We propose a model consistent with all of our experimental data that suggests that the predominant conformation we observe in the presence of cholesterol is relevant for the understanding of viral budding.
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Affiliation(s)
- Sangwoo S. Kim
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA 19081
| | - Mary Alice Upshur
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA 19081
| | - Kei Saotome
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA 19081
| | - Indra D. Sahu
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056
| | - Robert M. McCarrick
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056
| | - Jimmy B. Feix
- Department of Biophysics, National Biomedical EPR Center, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Gary A. Lorigan
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056
| | - Kathleen P. Howard
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA 19081
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28
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Fu R, Gill RL, Kim EY, Briley NE, Tyndall ER, Xu J, Li C, Ramamurthi KS, Flanagan JM, Tian F. Spherical nanoparticle supported lipid bilayers for the structural study of membrane geometry-sensitive molecules. J Am Chem Soc 2015; 137:14031-14034. [PMID: 26488086 DOI: 10.1021/jacs.5b08303] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many essential cellular processes including endocytosis and vesicle trafficking require alteration of membrane geometry. These changes are usually mediated by proteins that can sense and/or induce membrane curvature. Using spherical nanoparticle supported lipid bilayers (SSLBs), we characterize how SpoVM, a bacterial development factor, interacts with differently curved membranes by magic angle spinning solid-state NMR. Our results demonstrate that SSLBs are an effective system for structural and topological studies of membrane geometry-sensitive molecules.
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Affiliation(s)
- Riqiang Fu
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Richard L Gill
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, Hershey, Pennsylvania 17033, United States
| | - Edward Y Kim
- Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Nicole E Briley
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, Hershey, Pennsylvania 17033, United States
| | - Erin R Tyndall
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, Hershey, Pennsylvania 17033, United States
| | - Jie Xu
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, Hershey, Pennsylvania 17033, United States
| | - Conggang Li
- National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| | - Kumaran S Ramamurthi
- Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - John M Flanagan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, Hershey, Pennsylvania 17033, United States
| | - Fang Tian
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, Hershey, Pennsylvania 17033, United States
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29
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Plattner H. Signalling in ciliates: long- and short-range signals and molecular determinants for cellular dynamics. Biol Rev Camb Philos Soc 2015; 92:60-107. [PMID: 26487631 DOI: 10.1111/brv.12218] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 07/28/2015] [Accepted: 08/21/2015] [Indexed: 12/30/2022]
Abstract
In ciliates, unicellular representatives of the bikont branch of evolution, inter- and intracellular signalling pathways have been analysed mainly in Paramecium tetraurelia, Paramecium multimicronucleatum and Tetrahymena thermophila and in part also in Euplotes raikovi. Electrophysiology of ciliary activity in Paramecium spp. is a most successful example. Established signalling mechanisms include plasmalemmal ion channels, recently established intracellular Ca2+ -release channels, as well as signalling by cyclic nucleotides and Ca2+ . Ca2+ -binding proteins (calmodulin, centrin) and Ca2+ -activated enzymes (kinases, phosphatases) are involved. Many organelles are endowed with specific molecules cooperating in signalling for intracellular transport and targeted delivery. Among them are recently specified soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs), monomeric GTPases, H+ -ATPase/pump, actin, etc. Little specification is available for some key signal transducers including mechanosensitive Ca2+ -channels, exocyst complexes and Ca2+ -sensor proteins for vesicle-vesicle/membrane interactions. The existence of heterotrimeric G-proteins and of G-protein-coupled receptors is still under considerable debate. Serine/threonine kinases dominate by far over tyrosine kinases (some predicted by phosphoproteomic analyses). Besides short-range signalling, long-range signalling also exists, e.g. as firmly installed microtubular transport rails within epigenetically determined patterns, thus facilitating targeted vesicle delivery. By envisaging widely different phenomena of signalling and subcellular dynamics, it will be shown (i) that important pathways of signalling and cellular dynamics are established already in ciliates, (ii) that some mechanisms diverge from higher eukaryotes and (iii) that considerable uncertainties still exist about some essential aspects of signalling.
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Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz, PO Box M625, 78457, Konstanz, Germany
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Diacylglycerol Guides the Hopping of Clathrin-Coated Pits along Microtubules for Exo-Endocytosis Coupling. Dev Cell 2015; 35:120-30. [PMID: 26439397 DOI: 10.1016/j.devcel.2015.09.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 08/05/2015] [Accepted: 09/10/2015] [Indexed: 01/01/2023]
Abstract
Many receptor-mediated endocytic processes are mediated by constitutive budding of clathrin-coated pits (CCPs) at spatially randomized sites before slowly pinching off from the plasma membrane (60-100 s). In contrast, clathrin-mediated endocytosis (CME) coupled with regulated exocytosis in excitable cells occurs at peri-exocytic sites shortly after vesicle fusion (∼10 s). The molecular mechanism underlying this spatiotemporal coupling remains elusive. We show that coupled endocytosis makes use of pre-formed CCPs, which hop to nascent fusion sites nearby following vesicle exocytosis. A dynamic cortical microtubular network, anchored at the cell surface by the cytoplasmic linker-associated protein on microtubules and the LL5β/ELKS complex on the plasma membrane, provides the track for CCP hopping. Local diacylglycerol gradients generated upon exocytosis guide the direction of hopping. Overall, the CCP-cytoskeleton-lipid interaction demonstrated here mediates exocytosis-coupled fast recycling of both plasma membrane and vesicular proteins, and it is required for the sustained exocytosis during repetitive stimulations.
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31
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At14a-Like1 participates in membrane-associated mechanisms promoting growth during drought in Arabidopsis thaliana. Proc Natl Acad Sci U S A 2015; 112:10545-50. [PMID: 26240315 DOI: 10.1073/pnas.1510140112] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Limited knowledge of how plants regulate their growth and metabolism in response to drought and reduced soil water potential has impeded efforts to improve stress tolerance. Increased expression of the membrane-associated protein At14a-like1 (AFL1) led to increased growth and accumulation of the osmoprotective solute proline without negative effects on unstressed plants. Conversely, inducible RNA-interference suppression of AFL1 decreased growth and proline accumulation during low water potential while having no effect on unstressed plants. AFL1 overexpression lines had reduced expression of many stress-responsive genes, suggesting AFL1 may promote growth in part by suppression of negative regulatory genes. AFL1 interacted with the endomembrane proteins protein disulfide isomerase 5 (PDI5) and NAI2, with the PDI5 interaction being particularly increased by stress. PDI5 and NAI2 are negative regulatory factors, as pdi5, nai2, and pdi5-2nai2-3 mutants had increased growth and proline accumulation at low water potential. AFL1 also interacted with Adaptor protein2-2A (AP2-2A), which is part of a complex that recruits cargo proteins and promotes assembly of clathrin-coated vesicles. AFL1 colocalization with clathrin light chain along the plasma membrane, together with predictions of AFL1 structure, were consistent with a role in vesicle formation or trafficking. Fractionation experiments indicated that AFL1 is a peripheral membrane protein associated with both plasma membrane and endomembranes. These data identify classes of proteins (AFL1, PDI5, and NAI2) not previously known to be involved in drought signaling. AFL1-predicted structure, protein interactions, and localization all indicate its involvement in previously uncharacterized membrane-associated drought sensing or signaling mechanisms.
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32
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Kosmalska AJ, Casares L, Elosegui-Artola A, Thottacherry JJ, Moreno-Vicente R, González-Tarragó V, Del Pozo MÁ, Mayor S, Arroyo M, Navajas D, Trepat X, Gauthier NC, Roca-Cusachs P. Physical principles of membrane remodelling during cell mechanoadaptation. Nat Commun 2015; 6:7292. [PMID: 26073653 PMCID: PMC4490354 DOI: 10.1038/ncomms8292] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 04/24/2015] [Indexed: 01/14/2023] Open
Abstract
Biological processes in any physiological environment involve changes in cell shape, which must be accommodated by their physical envelope—the bilayer membrane. However, the fundamental biophysical principles by which the cell membrane allows for and responds to shape changes remain unclear. Here we show that the 3D remodelling of the membrane in response to a broad diversity of physiological perturbations can be explained by a purely mechanical process. This process is passive, local, almost instantaneous, before any active remodelling and generates different types of membrane invaginations that can repeatedly store and release large fractions of the cell membrane. We further demonstrate that the shape of those invaginations is determined by the minimum elastic and adhesive energy required to store both membrane area and liquid volume at the cell–substrate interface. Once formed, cells reabsorb the invaginations through an active process with duration of the order of minutes. Variations in cell shape must be accommodated by the cell membrane, but how the membrane adjusts to changes in area and volume is not known. Here the authors show that the membrane responds in a nearly instantaneous, purely physical manner involving the flattening or generation of membrane invaginations.
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Affiliation(s)
- Anita Joanna Kosmalska
- Institute for Bioengineering of Catalonia (IBEC), Barcelona 08028, Spain.,Department of Physiological Sciences I, University of Barcelona, Barcelona 08036, Spain
| | - Laura Casares
- Institute for Bioengineering of Catalonia (IBEC), Barcelona 08028, Spain.,Department of Physiological Sciences I, University of Barcelona, Barcelona 08036, Spain
| | | | | | | | - Víctor González-Tarragó
- Institute for Bioengineering of Catalonia (IBEC), Barcelona 08028, Spain.,Department of Physiological Sciences I, University of Barcelona, Barcelona 08036, Spain
| | | | - Satyajit Mayor
- National Centre for Biological Sciences (TIFR), Bangalore 560065, India
| | - Marino Arroyo
- LaCàN, Universitat Politècnica de Catalunya-BarcelonaTech, Barcelona 08034, Spain
| | - Daniel Navajas
- Institute for Bioengineering of Catalonia (IBEC), Barcelona 08028, Spain.,Department of Physiological Sciences I, University of Barcelona, Barcelona 08036, Spain.,Ciber Enfermedades Respiratorias, Madrid 28029, Spain
| | - Xavier Trepat
- Institute for Bioengineering of Catalonia (IBEC), Barcelona 08028, Spain.,Department of Physiological Sciences I, University of Barcelona, Barcelona 08036, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona 08010, Spain
| | - Nils C Gauthier
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
| | - Pere Roca-Cusachs
- Institute for Bioengineering of Catalonia (IBEC), Barcelona 08028, Spain.,Department of Physiological Sciences I, University of Barcelona, Barcelona 08036, Spain
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33
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Hawes C, Kiviniemi P, Kriechbaumer V. The endoplasmic reticulum: a dynamic and well-connected organelle. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2015; 57:50-62. [PMID: 25319240 DOI: 10.1111/jipb.12297] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 10/09/2014] [Indexed: 06/04/2023]
Abstract
The endoplasmic reticulum forms the first compartment in a series of organelles which comprise the secretory pathway. It takes the form of an extremely dynamic and pleomorphic membrane-bounded network of tubules and cisternae which have numerous different cellular functions. In this review, we discuss the nature of endoplasmic reticulum structure and dynamics, its relationship with closely associated organelles, and its possible function as a highway for the distribution and delivery of a diverse range of structures from metabolic complexes to viral particles.
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Affiliation(s)
- Chris Hawes
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
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34
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Suetsugu S, Kurisu S, Takenawa T. Dynamic shaping of cellular membranes by phospholipids and membrane-deforming proteins. Physiol Rev 2014; 94:1219-48. [PMID: 25287863 DOI: 10.1152/physrev.00040.2013] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
All cellular compartments are separated from the external environment by a membrane, which consists of a lipid bilayer. Subcellular structures, including clathrin-coated pits, caveolae, filopodia, lamellipodia, podosomes, and other intracellular membrane systems, are molded into their specific submicron-scale shapes through various mechanisms. Cells construct their micro-structures on plasma membrane and execute vital functions for life, such as cell migration, cell division, endocytosis, exocytosis, and cytoskeletal regulation. The plasma membrane, rich in anionic phospholipids, utilizes the electrostatic nature of the lipids, specifically the phosphoinositides, to form interactions with cytosolic proteins. These cytosolic proteins have three modes of interaction: 1) electrostatic interaction through unstructured polycationic regions, 2) through structured phosphoinositide-specific binding domains, and 3) through structured domains that bind the membrane without specificity for particular phospholipid. Among the structured domains, there are several that have membrane-deforming activity, which is essential for the formation of concave or convex membrane curvature. These domains include the amphipathic helix, which deforms the membrane by hemi-insertion of the helix with both hydrophobic and electrostatic interactions, and/or the BAR domain superfamily, known to use their positively charged, curved structural surface to deform membranes. Below the membrane, actin filaments support the micro-structures through interactions with several BAR proteins as well as other scaffold proteins, resulting in outward and inward membrane micro-structure formation. Here, we describe the characteristics of phospholipids, and the mechanisms utilized by phosphoinositides to regulate cellular events. We then summarize the precise mechanisms underlying the construction of membrane micro-structures and their involvements in physiological and pathological processes.
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Affiliation(s)
- Shiro Suetsugu
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan; Biosignal Research Center, Kobe University, Kobe, Hyogo, Japan; and Graduate School of Medicine, Kobe University, Kobe, Hyogo, Japan
| | - Shusaku Kurisu
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan; Biosignal Research Center, Kobe University, Kobe, Hyogo, Japan; and Graduate School of Medicine, Kobe University, Kobe, Hyogo, Japan
| | - Tadaomi Takenawa
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan; Biosignal Research Center, Kobe University, Kobe, Hyogo, Japan; and Graduate School of Medicine, Kobe University, Kobe, Hyogo, Japan
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35
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Merrifield CJ, Kaksonen M. Endocytic accessory factors and regulation of clathrin-mediated endocytosis. Cold Spring Harb Perspect Biol 2014; 6:a016733. [PMID: 25280766 DOI: 10.1101/cshperspect.a016733] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Up to 60 different proteins are recruited to the site of clathrin-mediated endocytosis in an ordered sequence. These accessory proteins have roles during all the different stages of clathrin-mediated endocytosis. First, they participate in the initiation of the endocytic event, thereby determining when and where endocytic vesicles are made; later they are involved in the maturation of the clathrin coat, recruitment of specific cargo molecules, bending of the membrane, and finally in scission and uncoating of the nascent vesicle. In addition, many of the accessory components are involved in regulating and coupling the actin cytoskeleton to the endocytic membrane. We will discuss the different accessory components and their various roles. Most of the data comes from studies performed with cultured mammalian cells or yeast cells. The process of endocytosis is well conserved between these different organisms, but there are also many interesting differences that may shed light on the mechanistic principles of endocytosis.
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Affiliation(s)
- Christien J Merrifield
- Laboratoire d'Enzymologie et Biochimie Structurales, Centre National de la Recherche Scientifique UPR3082, 91198 Gif-sur-Yvette, France
| | - Marko Kaksonen
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
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36
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Shen H, Giordano F, Wu Y, Chan J, Zhu C, Milosevic I, Wu X, Yao K, Chen B, Baumgart T, Sieburth D, De Camilli P. Coupling between endocytosis and sphingosine kinase 1 recruitment. Nat Cell Biol 2014; 16:652-62. [PMID: 24929359 PMCID: PMC4230894 DOI: 10.1038/ncb2987] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 05/09/2014] [Indexed: 12/13/2022]
Abstract
Genetic studies have suggested a functional link between cholesterol/sphingolipid metabolism and endocytic membrane traffic. Here we show that perturbing the cholesterol/sphingomyelin balance in the plasma membrane results in the massive formation of clusters of narrow endocytic tubular invaginations positive for N-BAR proteins. These tubules are intensely positive for sphingosine kinase 1 (SPHK1). SPHK1 is also targeted to physiologically occurring early endocytic intermediates, and is highly enriched in nerve terminals, which are cellular compartments specialized for exo/endocytosis. Membrane recruitment of SPHK1 involves a direct, curvature-sensitive interaction with the lipid bilayer mediated by a hydrophobic patch on the enzyme's surface. The knockdown of SPHKs results in endocytic recycling defects, and a mutation that disrupts the hydrophobic patch of Caenorhabditis elegans SPHK fails to rescue the neurotransmission defects in loss-of-function mutants of this enzyme. Our studies support a role for sphingosine phosphorylation in endocytic membrane trafficking beyond the established function of sphingosine-1-phosphate in intercellular signalling.
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Affiliation(s)
- Hongying Shen
- 1] Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA [2] Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA [3]
| | - Francesca Giordano
- 1] Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA [2] Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA [3]
| | - Yumei Wu
- 1] Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA [2] Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Jason Chan
- 1] Zilkha Neurogenetic Institute, Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA [2]
| | - Chen Zhu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Ira Milosevic
- 1] Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA [2] Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Xudong Wu
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Kai Yao
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Bo Chen
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Tobias Baumgart
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Derek Sieburth
- Zilkha Neurogenetic Institute, Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Pietro De Camilli
- 1] Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA [2] Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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37
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Hissa B, Pontes B, Roma PMS, Alves AP, Rocha CD, Valverde TM, Aguiar PHN, Almeida FP, Guimarães AJ, Guatimosim C, Silva AM, Fernandes MC, Andrews NW, Viana NB, Mesquita ON, Agero U, Andrade LO. Membrane cholesterol removal changes mechanical properties of cells and induces secretion of a specific pool of lysosomes. PLoS One 2013; 8:e82988. [PMID: 24376622 PMCID: PMC3869752 DOI: 10.1371/journal.pone.0082988] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 10/29/2013] [Indexed: 11/18/2022] Open
Abstract
In a previous study we had shown that membrane cholesterol removal induced unregulated lysosomal exocytosis events leading to the depletion of lysosomes located at cell periphery. However, the mechanism by which cholesterol triggered these exocytic events had not been uncovered. In this study we investigated the importance of cholesterol in controlling mechanical properties of cells and its connection with lysosomal exocytosis. Tether extraction with optical tweezers and defocusing microscopy were used to assess cell dynamics in mouse fibroblasts. These assays showed that bending modulus and surface tension increased when cholesterol was extracted from fibroblasts plasma membrane upon incubation with MβCD, and that the membrane-cytoskeleton relaxation time increased at the beginning of MβCD treatment and decreased at the end. We also showed for the first time that the amplitude of membrane-cytoskeleton fluctuation decreased during cholesterol sequestration, showing that these cells become stiffer. These changes in membrane dynamics involved not only rearrangement of the actin cytoskeleton, but also de novo actin polymerization and stress fiber formation through Rho activation. We found that these mechanical changes observed after cholesterol sequestration were involved in triggering lysosomal exocytosis. Exocytosis occurred even in the absence of the lysosomal calcium sensor synaptotagmin VII, and was associated with actin polymerization induced by MβCD. Notably, exocytosis triggered by cholesterol removal led to the secretion of a unique population of lysosomes, different from the pool mobilized by actin depolymerizing drugs such as Latrunculin-A. These data support the existence of at least two different pools of lysosomes with different exocytosis dynamics, one of which is directly mobilized for plasma membrane fusion after cholesterol removal.
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Affiliation(s)
- Barbara Hissa
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Bruno Pontes
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Paula Magda S. Roma
- Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ana Paula Alves
- Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Carolina D. Rocha
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Thalita M. Valverde
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Pedro Henrique N. Aguiar
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Fernando P. Almeida
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Allan J. Guimarães
- Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Rio de Janeiro, RJ, Brazil
| | - Cristina Guatimosim
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Aristóbolo M. Silva
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Maria C. Fernandes
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
| | - Norma W. Andrews
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
| | - Nathan B. Viana
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Oscar N. Mesquita
- Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ubirajara Agero
- Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Luciana O. Andrade
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
- * E-mail:
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Plattner H. The contractile vacuole complex of protists--new cues to function and biogenesis. Crit Rev Microbiol 2013; 41:218-27. [PMID: 23919298 DOI: 10.3109/1040841x.2013.821650] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The contractile vacuole complex (CVC) of freshwater protists sequesters the excess of water and ions (Ca(2+)) for exocytosis cycles at the pore. Sequestration is based on a chemiosmotic proton gradient produced by a V-type H(+)-ATPase. So far, many pieces of information available have not been combined to a comprehensive view on CVC biogenesis and function. One main function now appears as follows. Ca(2+)-release channels, type inositol 1,4,5-trisphosphate receptors (InsP3R), may serve for fine-tuning of local cytosolic Ca(2+) concentration and mediate numerous membrane-to-membrane interactions within the tubular spongiome meshwork. Such activity is suggested by the occurrence of organelle-specific soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) and Ras-related in brain (Rab) proteins, which may regulate functional requirements. For tubulation, F-Bin-amphiphysin-Rvs (F-BAR) proteins are available. In addition, there is indirect evidence for the occurrence of H(+)/Ca(2+) exchangers (to sequester Ca(2+)) and mechanosensitive Ca(2+)-channels (for signaling the filling sate). The periodic activity of the CVC may be regulated by the mechanosensitive Ca(2+)-channels. Such channels are known to colocalize with and to be functionally supported by stomatins, which were recently detected in the CVC. A Kif18-related kinesin motor protein might control the length of radial arms. Two additional InsP3-related channels and several SNAREs are associated with the pore. De novo organelle biogenesis occurs under epigenetic control during mitotic activity and may involve the assembly of γ-tubulin, centrin, calmodulin and a never in mitosis A-type (NIMA) kinase - components also engaged in mitotic processes.
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Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz , Konstanz , Germany
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The amphipathic helix of influenza A virus M2 protein is required for filamentous bud formation and scission of filamentous and spherical particles. J Virol 2013; 87:9973-82. [PMID: 23843641 DOI: 10.1128/jvi.01363-13] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Influenza virus assembles and buds at the infected-cell plasma membrane. This involves extrusion of the plasma membrane followed by scission of the bud, resulting in severing the nascent virion from its former host. The influenza virus M2 ion channel protein contains in its cytoplasmic tail a membrane-proximal amphipathic helix that facilitates the scission process and is also required for filamentous particle formation. Mutation of five conserved hydrophobic residues to alanines within the amphipathic helix (M2 five-point mutant, or 5PM) reduced scission and also filament formation, whereas single mutations had no apparent phenotype. Here, we show that any two of these five residues mutated together to alanines result in virus debilitated for growth and filament formation in a manner similar to 5PM. Growth kinetics of the M2 mutants are approximately 2 logs lower than the wild-type level, and plaque diameter was significantly reduced. When the 5PM and a representative double mutant (I51A-Y52A) were introduced into A/WSN/33 M2, a strain that produces spherical particles, similar debilitation in viral growth occurred. Electron microscopy showed that with the 5PM and the I51A-Y52A A/Udorn/72 and WSN viruses, scission failed, and emerging virus particles exhibited a "beads-on-a-string" morphology. The major spike glycoprotein hemagglutinin is localized within lipid rafts in virus-infected cells, whereas M2 is associated at the periphery of rafts. Mutant M2s were more widely dispersed, and their abundance at the raft periphery was reduced, suggesting that the M2 amphipathic helix is required for proper localization in the host membrane and that this has implications for budding and scission.
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Pontes B, Ayala Y, Fonseca ACC, Romão LF, Amaral RF, Salgado LT, Lima FR, Farina M, Viana NB, Moura-Neto V, Nussenzveig HM. Membrane elastic properties and cell function. PLoS One 2013; 8:e67708. [PMID: 23844071 PMCID: PMC3701085 DOI: 10.1371/journal.pone.0067708] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 05/22/2013] [Indexed: 12/18/2022] Open
Abstract
Recent studies indicate that the cell membrane, interacting with its attached cytoskeleton, is an important regulator of cell function, exerting and responding to forces. We investigate this relationship by looking for connections between cell membrane elastic properties, especially surface tension and bending modulus, and cell function. Those properties are measured by pulling tethers from the cell membrane with optical tweezers. Their values are determined for all major cell types of the central nervous system, as well as for macrophage. Astrocytes and glioblastoma cells, which are considerably more dynamic than neurons, have substantially larger surface tensions. Resting microglia, which continually scan their environment through motility and protrusions, have the highest elastic constants, with values similar to those for resting macrophage. For both microglia and macrophage, we find a sharp softening of bending modulus between their resting and activated forms, which is very advantageous for their acquisition of phagocytic functions upon activation. We also determine the elastic constants of pure cell membrane, with no attached cytoskeleton. For all cell types, the presence of F-actin within tethers, contrary to conventional wisdom, is confirmed. Our findings suggest the existence of a close connection between membrane elastic constants and cell function.
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Affiliation(s)
- Bruno Pontes
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Yareni Ayala
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Anna Carolina C. Fonseca
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luciana F. Romão
- Universidade Federal do Rio de Janeiro/Macaé, Macaé, Rio de Janeiro, Brazil
| | - Racκele F. Amaral
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Leonardo T. Salgado
- Diretoria de Pesquisas, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Flavia R. Lima
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcos Farina
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nathan B. Viana
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Vivaldo Moura-Neto
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - H. Moysés Nussenzveig
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
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Phosphorylation of the Bin, Amphiphysin, and RSV161/167 (BAR) domain of ACAP4 regulates membrane tubulation. Proc Natl Acad Sci U S A 2013; 110:11023-8. [PMID: 23776207 DOI: 10.1073/pnas.1217727110] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
ArfGAP With Coiled-Coil, Ankyrin Repeat And PH Domains 4 (ACAP4) is an ADP-ribosylation factor 6 (ARF6) GTPase-activating protein essential for EGF-elicited cell migration. However, how ACAP4 regulates membrane dynamics and curvature in response to EGF stimulation is unknown. Here, we show that phosphorylation of the N-terminal region of ACAP4, named the Bin, Amphiphysin, and RSV161/167 (BAR) domain, at Tyr34 is necessary for EGF-elicited membrane remodeling. Domain structure analysis demonstrates that the BAR domain regulates membrane curvature. EGF stimulation of cells causes phosphorylation of ACAP4 at Tyr34, which subsequently promotes ACAP4 homodimer curvature. The phospho-mimicking mutant of ACAP4 demonstrates lipid-binding activity and tubulation in vitro, and ARF6 enrichment at the membrane is associated with ruffles of EGF-stimulated cells. Expression of the phospho-mimicking ACAP4 mutant promotes ARF6-dependent cell migration. Thus, the results present a previously undefined mechanism by which EGF-elicited phosphorylation of the BAR domain controls ACAP4 molecular plasticity and plasma membrane dynamics during cell migration.
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Poring over pores: nuclear pore complex insertion into the nuclear envelope. Trends Biochem Sci 2013; 38:292-301. [DOI: 10.1016/j.tibs.2013.04.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Revised: 03/29/2013] [Accepted: 04/02/2013] [Indexed: 11/18/2022]
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Contractile Vacuole Complex—Its Expanding Protein Inventory. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 306:371-416. [DOI: 10.1016/b978-0-12-407694-5.00009-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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