251
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Wu S, Majeed SR, Evans TM, Camus MD, Wong NML, Schollmeier Y, Park M, Muppidi JR, Reboldi A, Parham P, Cyster JG, Brodsky FM. Clathrin light chains' role in selective endocytosis influences antibody isotype switching. Proc Natl Acad Sci U S A 2016; 113:9816-21. [PMID: 27540116 PMCID: PMC5024586 DOI: 10.1073/pnas.1611189113] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Clathrin, a cytosolic protein composed of heavy and light chain subunits, assembles into a vesicle coat, controlling receptor-mediated endocytosis. To establish clathrin light chain (CLC) function in vivo, we engineered mice lacking CLCa, the major CLC isoform in B lymphocytes, generating animals with CLC-deficient B cells. In CLCa-null mice, the germinal centers have fewer B cells, and they are enriched for IgA-producing cells. This enhanced switch to IgA production in the absence of CLCa was attributable to increased transforming growth factor β receptor 2 (TGFβR2) signaling resulting from defective endocytosis. Internalization of C-X-C chemokine receptor 4 (CXCR4), but not CXCR5, was affected in CLCa-null B cells, and CLC depletion from cell lines affected endocytosis of the δ-opioid receptor, but not the β2-adrenergic receptor, defining a role for CLCs in the uptake of a subset of signaling receptors. This instance of clathrin subunit deletion in vertebrates demonstrates that CLCs contribute to clathrin's role in vivo by influencing cargo selectivity, a function previously assigned exclusively to adaptor molecules.
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MESH Headings
- Animals
- B-Lymphocytes/immunology
- B-Lymphocytes/pathology
- Cerebral Cortex/cytology
- Cerebral Cortex/immunology
- Clathrin Light Chains/genetics
- Clathrin Light Chains/immunology
- Endocytosis/immunology
- Gene Deletion
- Gene Expression Regulation
- Humans
- Immunoglobulin A/biosynthesis
- Immunoglobulin A/genetics
- Immunoglobulin Class Switching
- Liver/cytology
- Liver/immunology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Myocardium/cytology
- Myocardium/immunology
- Organ Specificity
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/immunology
- Receptor, Transforming Growth Factor-beta Type II
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/immunology
- Receptors, CXCR4/genetics
- Receptors, CXCR4/immunology
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, delta/immunology
- Receptors, Transforming Growth Factor beta/agonists
- Receptors, Transforming Growth Factor beta/genetics
- Receptors, Transforming Growth Factor beta/immunology
- Spleen/cytology
- Spleen/immunology
- T-Lymphocytes/cytology
- T-Lymphocytes/immunology
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Affiliation(s)
- Shuang Wu
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143; Department of Microbiology and Immunology, University of California, San Francisco, CA 94143; The G. W. Hooper Foundation, University of California, San Francisco, CA 94143
| | - Sophia R Majeed
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143; Department of Microbiology and Immunology, University of California, San Francisco, CA 94143; The G. W. Hooper Foundation, University of California, San Francisco, CA 94143
| | - Timothy M Evans
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143; Department of Microbiology and Immunology, University of California, San Francisco, CA 94143; The G. W. Hooper Foundation, University of California, San Francisco, CA 94143
| | - Marine D Camus
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143; Department of Microbiology and Immunology, University of California, San Francisco, CA 94143; The G. W. Hooper Foundation, University of California, San Francisco, CA 94143; Division of Biosciences, University College London, London WC1E 6BT, United Kingdom
| | - Nicole M L Wong
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143; Department of Microbiology and Immunology, University of California, San Francisco, CA 94143; The G. W. Hooper Foundation, University of California, San Francisco, CA 94143
| | - Yvette Schollmeier
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143; Department of Microbiology and Immunology, University of California, San Francisco, CA 94143; The G. W. Hooper Foundation, University of California, San Francisco, CA 94143
| | - Minjong Park
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143; Department of Microbiology and Immunology, University of California, San Francisco, CA 94143; The G. W. Hooper Foundation, University of California, San Francisco, CA 94143
| | - Jagan R Muppidi
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143
| | - Andrea Reboldi
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143
| | - Peter Parham
- Department of Structural Biology, Stanford University, Stanford, CA 94305; Department of Microbiology and Immunology, Stanford University, Stanford, CA 94305
| | - Jason G Cyster
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143;
| | - Frances M Brodsky
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143; Department of Microbiology and Immunology, University of California, San Francisco, CA 94143; The G. W. Hooper Foundation, University of California, San Francisco, CA 94143; Division of Biosciences, University College London, London WC1E 6BT, United Kingdom;
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252
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Liu Z, Ning G, Xu R, Cao Y, Meng A, Wang Q. Fscn1 is required for the trafficking of TGF-β family type I receptors during endoderm formation. Nat Commun 2016; 7:12603. [PMID: 27545838 PMCID: PMC4996939 DOI: 10.1038/ncomms12603] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 07/15/2016] [Indexed: 01/01/2023] Open
Abstract
Microtubules function in TGF-β signalling by facilitating the cytoplasmic trafficking of internalized receptors and the nucleocytoplasmic shuttling of Smads. However, nothing is known about whether actin filaments are required for these processes. Here we report that zebrafish actin-bundling protein fscn1a is highly expressed in mesendodermal precursors and its expression is directly regulated by the TGF-β superfamily member Nodal. Knockdown or knockout of fscn1a leads to a reduction of Nodal signal transduction and endoderm formation in zebrafish embryos. Fscn1 specifically interacts with TGF-β family type I receptors, and its depletion disrupts the association between receptors and actin filaments and sequesters the internalized receptors into clathrin-coated vesicles. Therefore, Fscn1 acts as a molecular linker between TGF-β family type I receptors and the actin filaments to promote the trafficking of internalized receptors from clathrin-coated vesicles to early endosomes during zebrafish endoderm formation. It is unclear how the cytoskeleton acts to assist in TGF-β signalling downstream of the receptor. Here, in zebrafish, the authors show that the actin-bundling protein FSCN1 interacts with TGF-β type I receptors ALK 4 and 5, enabling actin filament mediated vesicle trafficking and endoderm formation.
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Affiliation(s)
- Zhaoting Liu
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Guozhu Ning
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Ranran Xu
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yu Cao
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Anming Meng
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qiang Wang
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
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253
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Aguet F, Upadhyayula S, Gaudin R, Chou YY, Cocucci E, He K, Chen BC, Mosaliganti K, Pasham M, Skillern W, Legant WR, Liu TL, Findlay G, Marino E, Danuser G, Megason S, Betzig E, Kirchhausen T. Membrane dynamics of dividing cells imaged by lattice light-sheet microscopy. Mol Biol Cell 2016; 27:3418-3435. [PMID: 27535432 PMCID: PMC5221578 DOI: 10.1091/mbc.e16-03-0164] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 08/03/2016] [Indexed: 12/02/2022] Open
Abstract
Lattice light-sheet microscopy is used to examine two problems in membrane dynamics—molecular events in clathrin-coated pit formation and changes in cell shape during cell division. This methodology sets a new standard for imaging membrane dynamics in single cells and multicellular assemblies. Membrane remodeling is an essential part of transferring components to and from the cell surface and membrane-bound organelles and for changes in cell shape, which are particularly critical during cell division. Earlier analyses, based on classical optical live-cell imaging and mostly restricted by technical necessity to the attached bottom surface, showed persistent formation of endocytic clathrin pits and vesicles during mitosis. Taking advantage of the resolution, speed, and noninvasive illumination of the newly developed lattice light-sheet fluorescence microscope, we reexamined their assembly dynamics over the entire cell surface and found that clathrin pits form at a lower rate during late mitosis. Full-cell imaging measurements of cell surface area and volume throughout the cell cycle of single cells in culture and in zebrafish embryos showed that the total surface increased rapidly during the transition from telophase to cytokinesis, whereas cell volume increased slightly in metaphase and was relatively constant during cytokinesis. These applications demonstrate the advantage of lattice light-sheet microscopy and enable a new standard for imaging membrane dynamics in single cells and multicellular assemblies.
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Affiliation(s)
- François Aguet
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Srigokul Upadhyayula
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Raphaël Gaudin
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Yi-Ying Chou
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Emanuele Cocucci
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Kangmin He
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Bi-Chang Chen
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147
| | | | - Mithun Pasham
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Wesley Skillern
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Wesley R Legant
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147
| | - Tsung-Li Liu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147
| | - Greg Findlay
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Eric Marino
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Gaudenz Danuser
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX 75390
| | - Sean Megason
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115
| | - Eric Betzig
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147
| | - Tom Kirchhausen
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115 .,Departments of Cell Biology and Pediatrics, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
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254
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Jarsch IK, Daste F, Gallop JL. Membrane curvature in cell biology: An integration of molecular mechanisms. J Cell Biol 2016; 214:375-87. [PMID: 27528656 PMCID: PMC4987295 DOI: 10.1083/jcb.201604003] [Citation(s) in RCA: 215] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 07/29/2016] [Indexed: 01/03/2023] Open
Abstract
Curving biological membranes establishes the complex architecture of the cell and mediates membrane traffic to control flux through subcellular compartments. Common molecular mechanisms for bending membranes are evident in different cell biological contexts across eukaryotic phyla. These mechanisms can be intrinsic to the membrane bilayer (either the lipid or protein components) or can be brought about by extrinsic factors, including the cytoskeleton. Here, we review examples of membrane curvature generation in animals, fungi, and plants. We showcase the molecular mechanisms involved and how they collaborate and go on to highlight contexts of curvature that are exciting areas of future research. Lessons from how membranes are bent in yeast and mammals give hints as to the molecular mechanisms we expect to see used by plants and protists.
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Affiliation(s)
- Iris K Jarsch
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, England, UK
| | - Frederic Daste
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, England, UK
| | - Jennifer L Gallop
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, England, UK
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255
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Simunovic M, Prévost C, Callan-Jones A, Bassereau P. Physical basis of some membrane shaping mechanisms. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2016; 374:rsta.2016.0034. [PMID: 27298443 PMCID: PMC4920286 DOI: 10.1098/rsta.2016.0034] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/07/2016] [Indexed: 05/24/2023]
Abstract
In vesicular transport pathways, membrane proteins and lipids are internalized, externalized or transported within cells, not by bulk diffusion of single molecules, but embedded in the membrane of small vesicles or thin tubules. The formation of these 'transport carriers' follows sequential events: membrane bending, fission from the donor compartment, transport and eventually fusion with the acceptor membrane. A similar sequence is involved during the internalization of drug or gene carriers inside cells. These membrane-shaping events are generally mediated by proteins binding to membranes. The mechanisms behind these biological processes are actively studied both in the context of cell biology and biophysics. Bin/amphiphysin/Rvs (BAR) domain proteins are ideally suited for illustrating how simple soft matter principles can account for membrane deformation by proteins. We review here some experimental methods and corresponding theoretical models to measure how these proteins affect the mechanics and the shape of membranes. In more detail, we show how an experimental method employing optical tweezers to pull a tube from a giant vesicle may give important quantitative insights into the mechanism by which proteins sense and generate membrane curvature and the mechanism of membrane scission.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'.
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Affiliation(s)
- Mijo Simunovic
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Coline Prévost
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France Sorbonne Universités, UPMC Univ Paris 06, 75005 Paris, France
| | - Andrew Callan-Jones
- Laboratoire Matière et Systèmes Complexes, CNRS, UMR 7057, 75205 Paris Cedex 13, France
| | - Patricia Bassereau
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France Sorbonne Universités, UPMC Univ Paris 06, 75005 Paris, France
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256
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Gleisner M, Kroppen B, Fricke C, Teske N, Kliesch TT, Janshoff A, Meinecke M, Steinem C. Epsin N-terminal Homology Domain (ENTH) Activity as a Function of Membrane Tension. J Biol Chem 2016; 291:19953-61. [PMID: 27466364 DOI: 10.1074/jbc.m116.731612] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Indexed: 12/18/2022] Open
Abstract
The epsin N-terminal homology domain (ENTH) is a major player in clathrin-mediated endocytosis. To investigate the influence of initial membrane tension on ENTH binding and activity, we established a bilayer system based on adhered giant unilamellar vesicles (GUVs) to be able to control and adjust the membrane tension σ covering a broad regime. The shape of each individual adhered GUV as well as its adhesion area was monitored by spinning disc confocal laser microscopy. Control of σ in a range of 0.08-1.02 mN/m was achieved by altering the Mg(2+) concentration in solution, which changes the surface adhesion energy per unit area of the GUVs. Specific binding of ENTH to phosphatidylinositol 4,5-bisphosphate leads to a substantial increase in adhesion area of the sessile GUV. At low tension (<0.1 mN/m) binding of ENTH can induce tubular structures, whereas at higher membrane tension the ENTH interaction deflates the sessile GUV and thereby increases the adhesion area. The increase in adhesion area is mainly attributed to a decrease in the area compressibility modulus KA We propose that the insertion of the ENTH helix-0 into the membrane is largely responsible for the observed decrease in KA, which is supported by the observation that the mutant ENTH L6E shows a reduced increase in adhesion area. These results demonstrate that even in the absence of tubule formation, the area compressibility modulus and, as such, the bending rigidity of the membrane is considerably reduced upon ENTH binding. This renders membrane bending and tubule formation energetically less costly.
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Affiliation(s)
- Martin Gleisner
- From the Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany
| | - Benjamin Kroppen
- Department of Cellular Biochemistry, University of Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Christian Fricke
- From the Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany
| | - Nelli Teske
- From the Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany
| | - Torben-Tobias Kliesch
- Institute of Physical Chemistry, University of Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany, and
| | - Andreas Janshoff
- Institute of Physical Chemistry, University of Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany, and Göttingen Center for Molecular Biosciences, 37077 Göttingen, Germany
| | - Michael Meinecke
- Department of Cellular Biochemistry, University of Göttingen, Humboldtallee 23, 37073 Göttingen, Germany, European Neuroscience Institute, 37073 Göttingen, Germany,
| | - Claudia Steinem
- From the Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany, Göttingen Center for Molecular Biosciences, 37077 Göttingen, Germany
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257
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Dimitriadi M, Derdowski A, Kalloo G, Maginnis MS, O'Hern P, Bliska B, Sorkaç A, Nguyen KCQ, Cook SJ, Poulogiannis G, Atwood WJ, Hall DH, Hart AC. Decreased function of survival motor neuron protein impairs endocytic pathways. Proc Natl Acad Sci U S A 2016; 113:E4377-86. [PMID: 27402754 PMCID: PMC4968725 DOI: 10.1073/pnas.1600015113] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by depletion of the ubiquitously expressed survival motor neuron (SMN) protein, with 1 in 40 Caucasians being heterozygous for a disease allele. SMN is critical for the assembly of numerous ribonucleoprotein complexes, yet it is still unclear how reduced SMN levels affect motor neuron function. Here, we examined the impact of SMN depletion in Caenorhabditis elegans and found that decreased function of the SMN ortholog SMN-1 perturbed endocytic pathways at motor neuron synapses and in other tissues. Diminished SMN-1 levels caused defects in C. elegans neuromuscular function, and smn-1 genetic interactions were consistent with an endocytic defect. Changes were observed in synaptic endocytic proteins when SMN-1 levels decreased. At the ultrastructural level, defects were observed in endosomal compartments, including significantly fewer docked synaptic vesicles. Finally, endocytosis-dependent infection by JC polyomavirus (JCPyV) was reduced in human cells with decreased SMN levels. Collectively, these results demonstrate for the first time, to our knowledge, that SMN depletion causes defects in endosomal trafficking that impair synaptic function, even in the absence of motor neuron cell death.
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Affiliation(s)
- Maria Dimitriadi
- Department of Neuroscience, Brown University, Providence, RI 02912; Department of Biological and Environmental Sciences, University of Hertfordshire, Hatfield AL10 9AB, United Kingdom
| | - Aaron Derdowski
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912
| | - Geetika Kalloo
- Department of Neuroscience, Brown University, Providence, RI 02912
| | - Melissa S Maginnis
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912; Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469
| | - Patrick O'Hern
- Department of Neuroscience, Brown University, Providence, RI 02912
| | - Bryn Bliska
- Department of Neuroscience, Brown University, Providence, RI 02912
| | - Altar Sorkaç
- Department of Neuroscience, Brown University, Providence, RI 02912
| | - Ken C Q Nguyen
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Steven J Cook
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461
| | - George Poulogiannis
- Chester Beatty Labs, The Institute of Cancer Research, London SW3 6JB, United Kingdom
| | - Walter J Atwood
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912
| | - David H Hall
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Anne C Hart
- Department of Neuroscience, Brown University, Providence, RI 02912;
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258
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Ferguson JP, Willy NM, Heidotting SP, Huber SD, Webber MJ, Kural C. Deciphering dynamics of clathrin-mediated endocytosis in a living organism. J Cell Biol 2016; 214:347-58. [PMID: 27458134 PMCID: PMC4970330 DOI: 10.1083/jcb.201604128] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 07/05/2016] [Indexed: 11/22/2022] Open
Abstract
Current understanding of clathrin-mediated endocytosis (CME) dynamics is based on detection and tracking of fluorescently tagged clathrin coat components within cultured cells. Because of technical limitations inherent to detection and tracking of single fluorescent particles, CME dynamics is not characterized in vivo, so the effects of mechanical cues generated during development of multicellular organisms on formation and dissolution of clathrin-coated structures (CCSs) have not been directly observed. Here, we use growth rates of fluorescence signals obtained from short CCS intensity trace fragments to assess CME dynamics. This methodology does not rely on determining the complete lifespan of individual endocytic assemblies. Therefore, it allows for real-time monitoring of spatiotemporal changes in CME dynamics and is less prone to errors associated with particle detection and tracking. We validate the applicability of this approach to in vivo systems by demonstrating the reduction of CME dynamics during dorsal closure of Drosophila melanogaster embryos.
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Affiliation(s)
- Joshua P Ferguson
- Department of Physics, The Ohio State University, Columbus, OH 43210
| | - Nathan M Willy
- Department of Physics, The Ohio State University, Columbus, OH 43210
| | | | - Scott D Huber
- Department of Physics, The Ohio State University, Columbus, OH 43210
| | - Matthew J Webber
- Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210
| | - Comert Kural
- Department of Physics, The Ohio State University, Columbus, OH 43210 Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210
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259
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Diz-Muñoz A, Thurley K, Chintamen S, Altschuler SJ, Wu LF, Fletcher DA, Weiner OD. Membrane Tension Acts Through PLD2 and mTORC2 to Limit Actin Network Assembly During Neutrophil Migration. PLoS Biol 2016; 14:e1002474. [PMID: 27280401 PMCID: PMC4900667 DOI: 10.1371/journal.pbio.1002474] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 05/04/2016] [Indexed: 11/18/2022] Open
Abstract
For efficient polarity and migration, cells need to regulate the magnitude and spatial distribution of actin assembly. This process is coordinated by reciprocal interactions between the actin cytoskeleton and mechanical forces. Actin polymerization-based protrusion increases tension in the plasma membrane, which in turn acts as a long-range inhibitor of actin assembly. These interactions form a negative feedback circuit that limits the magnitude of membrane tension in neutrophils and prevents expansion of the existing front and the formation of secondary fronts. It has been suggested that the plasma membrane directly inhibits actin assembly by serving as a physical barrier that opposes protrusion. Here we show that efficient control of actin polymerization-based protrusion requires an additional mechanosensory feedback cascade that indirectly links membrane tension with actin assembly. Specifically, elevated membrane tension acts through phospholipase D2 (PLD2) and the mammalian target of rapamycin complex 2 (mTORC2) to limit actin nucleation. In the absence of this pathway, neutrophils exhibit larger leading edges, higher membrane tension, and profoundly defective chemotaxis. Mathematical modeling suggests roles for both the direct (mechanical) and indirect (biochemical via PLD2 and mTORC2) feedback loops in organizing cell polarity and motility—the indirect loop is better suited to enable competition between fronts, whereas the direct loop helps spatially organize actin nucleation for efficient leading edge formation and cell movement. This circuit is essential for polarity, motility, and the control of membrane tension. A mechanosensory biochemical cascade involving phospholipase D2 and mTORC2 coordinates physical forces and cytoskeletal rearrangements to allow efficient polarization and migration of neutrophils. How cells regulate the size and number of their protrusions for efficient polarity and motility is a fundamental question in cell biology. We recently found that immune cells known as neutrophils use physical forces to regulate this process. Actin polymerization-based protrusion stretches the plasma membrane, and this increased membrane tension acts as a long-range inhibitor of actin-based protrusions elsewhere in the cell. Here we investigate how membrane tension limits protrusion. We demonstrate that the magnitude of actin network assembly in neutrophils is determined by a mechanosensory biochemical cascade that converts increases in membrane tension into decreases in protrusion. Specifically, we show that increasing plasma membrane tension acts through a pathway containing the phospholipase D2 (PLD2) and the mammalian target of rapamycin complex 2 (mTORC2) to limit actin network assembly. Without this negative feedback pathway, neutrophils exhibit larger leading edges, higher membrane tension, and profoundly defective chemotaxis. Mathematical modeling indicates that this feedback circuit is a favorable topology to enable competition between protrusions during neutrophil polarization. Our work shows how biochemical signals, physical forces, and the cytoskeleton can collaborate to generate large-scale cellular organization.
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Affiliation(s)
- Alba Diz-Muñoz
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
- Bioengineering Department and Biophysics Program, University of California Berkeley, Berkeley, California, United States of America
| | - Kevin Thurley
- Dept. of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Sana Chintamen
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
| | - Steven J. Altschuler
- Dept. of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Lani F. Wu
- Dept. of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Daniel A. Fletcher
- Bioengineering Department and Biophysics Program, University of California Berkeley, Berkeley, California, United States of America
- * E-mail: (DAF); (ODW)
| | - Orion D. Weiner
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
- * E-mail: (DAF); (ODW)
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260
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López-Ortega O, Ovalle-García E, Ortega-Blake I, Antillón A, Chávez-Munguía B, Patiño-López G, Fragoso-Soriano R, Santos-Argumedo L. Myo1g is an active player in maintaining cell stiffness in B-lymphocytes. Cytoskeleton (Hoboken) 2016; 73:258-68. [DOI: 10.1002/cm.21299] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 04/11/2016] [Accepted: 04/13/2016] [Indexed: 12/11/2022]
Affiliation(s)
- O. López-Ortega
- Departamento De Biomedicina Molecular; Centro De Investigación Y De Estudios Avanzados Del Instituto Politécnico Nacional; Ciudad De México C. P. 07360 México
- Facultad De Medicina, Universidad Nacional Autónoma De México; Ciudad De México C. P. 04510 México
| | - E. Ovalle-García
- Universidad Autónoma De Nuevo León, UANL. Facultad De Ingeniería Mecánica Y Eléctrica, Av. Universidad S/N, Ciudad Universitaria, San Nicolás De Los Garza; Nuevo León C. P. 66451 México
| | - I. Ortega-Blake
- Instituto De Ciencias Físicas, UNAM; Cuernavaca Morelos C. P. 62210 México
| | - A. Antillón
- Instituto De Ciencias Físicas, UNAM; Cuernavaca Morelos C. P. 62210 México
| | - B. Chávez-Munguía
- Departamento De Infectómica Y Patogénesis Molecular; Centro De Investigación Y De Estudios Avanzados Del Instituto Politécnico Nacional; Ciudad De México C. P. 07360 México
| | - G. Patiño-López
- Laboratorio De Investigación En Inmunología Y Proteómica, Hospital Infantil De México, “Federico Gómez”; Ciudad De México C. P. 06720 México
| | - R. Fragoso-Soriano
- Departamento De Física; Centro De Investigación Y De Estudios Avanzados Del Instituto Politécnico Nacional; Ciudad De México C. P. 07360 México
| | - L. Santos-Argumedo
- Departamento De Biomedicina Molecular; Centro De Investigación Y De Estudios Avanzados Del Instituto Politécnico Nacional; Ciudad De México C. P. 07360 México
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261
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Abstract
I-BAR proteins are well-known actin-cytoskeleton adaptors and have been observed to be involved in the formation of plasma membrane protrusions (filopodia). I-BAR proteins contain an all-helical, crescent-shaped IRSp53-MIM domain (IMD) dimer that is believed to be able to couple with a membrane shape. This coupling could involve the sensing and even the generation of negative plasma membrane curvature. Indeed, the in vitro studies have shown that IMDs can induce inward tubulation of liposomes. While N-BAR domains, which generate positive membrane curvature, have received a considerable amount of attention from both theory and experiments, the mechanisms of curvature coupling through IMDs are comparatively less studied and understood. Here we used a membrane-shape stability assay developed recently in our lab to quantitatively characterize IMD-induced membrane-shape transitions. We determined a membrane-shape stability diagram for IMDs that reveals how membrane tension and protein density can comodulate the generation of IMD-induced membrane protrusions. From comparison to analytical theory, we determine three key parameters that characterize the curvature coupling of IMD. We find that the curvature generation capacity of IMDs is significantly stronger compared to that of endophilin, an N-BAR protein known to be involved in plasma membrane shape transitions. Contrary to N-BAR domains, where amphipathic helix insertion is known to promote its membrane curvature generation, for IMDs we find that amphipathic helices inhibit membrane shape transitions, consistent with the inverse curvature that IMDs generate. Importantly, in both of these types of BAR domains, electrostatic interactions affect membrane-binding capacity, but do not appear to affect the curvature generation capacity of the protein. These two types of BAR domain proteins show qualitatively similar membrane shape stability diagrams, suggesting an underlying ubiquitous mechanism by which peripheral proteins regulate membrane curvature.
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262
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Barbieri E, Di Fiore PP, Sigismund S. Endocytic control of signaling at the plasma membrane. Curr Opin Cell Biol 2016; 39:21-7. [DOI: 10.1016/j.ceb.2016.01.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 01/18/2016] [Accepted: 01/23/2016] [Indexed: 01/26/2023]
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263
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Beletkaia E, Fenz SF, Pomp W, Snaar-Jagalska BE, Hogendoorn PW, Schmidt T. CXCR4 signaling is controlled by immobilization at the plasma membrane. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:607-16. [DOI: 10.1016/j.bbamcr.2015.12.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 12/23/2015] [Accepted: 12/29/2015] [Indexed: 12/14/2022]
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264
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Abstract
PURPOSE OF REVIEW The proximal tubule plays a critical role in the reabsorption of ions, solutes and low molecular weight proteins from the glomerular filtrate. Although the proximal tubule has long been known to acutely modulate ion reabsorption in response to changes in flow rates of the glomerular filtrate, it has only recently been discovered that proximal tubule cells can similarly adjust endocytic capacity in response to flow. This review synthesizes our current understanding of mechanosensitive regulation of endocytic capacity in proximal tubule epithelia and highlights areas of opportunity for future investigations. RECENT FINDINGS Recent studies have reported that the endocytic capacity of proximal tubule cells is dramatically increased upon exposure to flow and the accompanying fluid shear stress. Modulation of this pathway is dependent on increases in intracellular calcium initiated by bending of the primary cilium, and also requires purinergic receptor activation that is mediated by release of extracellular ATP. This article summarizes what is currently known about the signaling cascade that transduces changes in flow into alterations in endocytosis. We discuss the implications of this newly described regulatory pathway with respect to our understanding of protein retrieval by the kidney under normal conditions, and in diseases that present with low molecular weight proteinuria. SUMMARY Primary cilia act as mechanotransducers that modulate apical endocytic capacity in proximal tubule cells in response to changes in fluid shear stress.
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265
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Hutchison JB, Karunanayake Mudiyanselage APKK, Weis RM, Dinsmore AD. Osmotically-induced tension and the binding of N-BAR protein to lipid vesicles. SOFT MATTER 2016; 12:2465-2472. [PMID: 26822233 DOI: 10.1039/c5sm02496j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The binding affinity of a curvature-sensing protein domain (N-BAR) is measured as a function of applied osmotic stress while the membrane curvature is nearly constant. Varying the osmotic stress allows us to control membrane tension, which provides a probe of the mechanism of binding. We study the N-BAR domain of the Drosophila amphiphysin and monitor its binding on 50 nm-radius vesicles composed of 90 mol% DOPC and 10 mol% PIP. We find that the bound fraction of N-BAR is enhanced by a factor of approximately 6.5 when the tension increases from zero to 2.6 mN m(-1). This tension-induced response can be explained by the hydrophobic insertion mechanism. From the data we extract a hydrophobic domain area that is consistent with known structure. These results indicate that membrane stress and strain could play a major role in the previously reported curvature-affinity of N-BAR.
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Affiliation(s)
- Jaime B Hutchison
- Department of Physics, University of Massachusetts Amherst, Hasbrouck Lab 411, 666 North Pleasant Street, Amherst, MA 01003, USA.
| | | | - Robert M Weis
- Department of Chemistry, University of Massachusetts Amherst, USA
| | - Anthony D Dinsmore
- Department of Physics, University of Massachusetts Amherst, Hasbrouck Lab 411, 666 North Pleasant Street, Amherst, MA 01003, USA.
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266
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Lewellyn EB, Pedersen RTA, Hong J, Lu R, Morrison HM, Drubin DG. An Engineered Minimal WASP-Myosin Fusion Protein Reveals Essential Functions for Endocytosis. Dev Cell 2016; 35:281-94. [PMID: 26555049 DOI: 10.1016/j.devcel.2015.10.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 09/21/2015] [Accepted: 10/09/2015] [Indexed: 11/28/2022]
Abstract
Actin polymerization powers membrane deformation during many processes, including clathrin-mediated endocytosis (CME). During CME in yeast, actin polymerization is triggered and coordinated by a six-protein WASP/Myosin complex that includes WASP, class I myosins (Myo3 and Myo5), WIP (Vrp1), and two other proteins. We show that a single engineered protein can replace this entire complex while still supporting CME. This engineered protein reveals that the WASP/Myosin complex has four essential activities: recruitment to endocytic sites, anchorage to the plasma membrane, Arp2/3 activation, and transient actin filament binding by the motor domain. The requirement for both membrane and F-actin binding reveals that myosin-mediated coupling between actin filaments and the base of endocytic sites is essential for allowing actin polymerization to drive membrane invagination.
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Affiliation(s)
- Eric B Lewellyn
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Biology, Lawrence University, Appleton, WI 54911, USA
| | - Ross T A Pedersen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Jessica Hong
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Rebecca Lu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Huntly M Morrison
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - David G Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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267
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Li D, Shao L, Chen BC, Zhang X, Zhang M, Moses B, Milkie DE, Beach JR, Hammer JA, Pasham M, Kirchhausen T, Baird MA, Davidson MW, Xu P, Betzig E. ADVANCED IMAGING. Extended-resolution structured illumination imaging of endocytic and cytoskeletal dynamics. Science 2016; 349:aab3500. [PMID: 26315442 DOI: 10.1126/science.aab3500] [Citation(s) in RCA: 402] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Super-resolution fluorescence microscopy is distinct among nanoscale imaging tools in its ability to image protein dynamics in living cells. Structured illumination microscopy (SIM) stands out in this regard because of its high speed and low illumination intensities, but typically offers only a twofold resolution gain. We extended the resolution of live-cell SIM through two approaches: ultrahigh numerical aperture SIM at 84-nanometer lateral resolution for more than 100 multicolor frames, and nonlinear SIM with patterned activation at 45- to 62-nanometer resolution for approximately 20 to 40 frames. We applied these approaches to image dynamics near the plasma membrane of spatially resolved assemblies of clathrin and caveolin, Rab5a in early endosomes, and α-actinin, often in relationship to cortical actin. In addition, we examined mitochondria, actin, and the Golgi apparatus dynamics in three dimensions.
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Affiliation(s)
- Dong Li
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Lin Shao
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Bi-Chang Chen
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Xi Zhang
- Key Laboratory of RNA Biology and Beijing Key Laboratory of Noncoding RNA, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China. College of Life Sciences, Central China Normal University, Wuhan 430079, Hubei, China
| | - Mingshu Zhang
- Key Laboratory of RNA Biology and Beijing Key Laboratory of Noncoding RNA, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Brian Moses
- Coleman Technologies, 5131 West Chester Pike, Newtown Square, PA 19073, USA
| | - Daniel E Milkie
- Coleman Technologies, 5131 West Chester Pike, Newtown Square, PA 19073, USA
| | - Jordan R Beach
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - John A Hammer
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mithun Pasham
- Department of Cell Biology and Pediatrics, Harvard Medical School and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Tomas Kirchhausen
- Department of Cell Biology and Pediatrics, Harvard Medical School and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Michelle A Baird
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA. National High Magnetic Field Laboratory and Department of Biological Science, Florida State University, Tallahassee, FL 32310, USA
| | - Michael W Davidson
- National High Magnetic Field Laboratory and Department of Biological Science, Florida State University, Tallahassee, FL 32310, USA
| | - Pingyong Xu
- Key Laboratory of RNA Biology and Beijing Key Laboratory of Noncoding RNA, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Eric Betzig
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
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268
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Suetsugu S. Higher-order assemblies of BAR domain proteins for shaping membranes. Microscopy (Oxf) 2016; 65:201-10. [DOI: 10.1093/jmicro/dfw002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 01/09/2016] [Indexed: 02/07/2023] Open
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269
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CPG2 Recruits Endophilin B2 to the Cytoskeleton for Activity-Dependent Endocytosis of Synaptic Glutamate Receptors. Curr Biol 2016; 26:296-308. [PMID: 26776730 DOI: 10.1016/j.cub.2015.11.071] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 09/21/2015] [Accepted: 11/30/2015] [Indexed: 11/23/2022]
Abstract
Internalization of glutamate receptors at the postsynaptic membrane via clathrin-mediated endocytosis (CME) is a key mechanism for regulating synaptic strength. A role for the F-actin cytoskeleton in CME is well established, and recently, PKA-dependent association of candidate plasticity gene 2 (CPG2) with the spine-cytoskeleton has been shown to mediate synaptic glutamate receptor internalization. Yet, how the endocytic machinery is physically coupled to the actin cytoskeleton to facilitate glutamate receptor internalization has not been demonstrated. Moreover, there has been no distinction of endocytic-machinery components that are specific to activity-dependent versus constitutive glutamate receptor internalization. Here, we show that CPG2, through a direct physical interaction, recruits endophilin B2 (EndoB2) to F-actin, thus anchoring the endocytic machinery to the spine cytoskeleton and facilitating glutamate receptor internalization. Regulation of CPG2 binding to the actin cytoskeleton by protein kinase A directly impacts recruitment of EndoB2 and clathrin. Specific disruption of EndoB2 or the CPG2-EndoB2 interaction impairs activity-dependent, but not constitutive, internalization of both NMDA- and AMPA-type glutamate receptors. These results demonstrate that, through direct interactions with F-actin and EndoB2, CPG2 physically bridges the spine cytoskeleton and the endocytic machinery, and this tripartite association is critical specifically for activity-dependent CME of synaptic glutamate receptors.
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270
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Skau CT, Waterman CM. Specification of Architecture and Function of Actin Structures by Actin Nucleation Factors. Annu Rev Biophys 2016; 44:285-310. [PMID: 26098516 DOI: 10.1146/annurev-biophys-060414-034308] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The actin cytoskeleton is essential for diverse processes in mammalian cells; these processes range from establishing cell polarity to powering cell migration to driving cytokinesis to positioning intracellular organelles. How these many functions are carried out in a spatiotemporally regulated manner in a single cytoplasm has been the subject of much study in the cytoskeleton field. Recent work has identified a host of actin nucleation factors that can build architecturally diverse actin structures. The biochemical properties of these factors, coupled with their cellular location, likely define the functional properties of actin structures. In this article, we describe how recent advances in cell biology and biochemistry have begun to elucidate the role of individual actin nucleation factors in generating distinct cellular structures. We also consider how the localization and orientation of actin nucleation factors, in addition to their kinetic properties, are critical to their ability to build a functional actin cytoskeleton.
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Affiliation(s)
- Colleen T Skau
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892; ,
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271
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Lieber AD, Schweitzer Y, Kozlov MM, Keren K. Front-to-rear membrane tension gradient in rapidly moving cells. Biophys J 2016; 108:1599-1603. [PMID: 25863051 DOI: 10.1016/j.bpj.2015.02.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 01/29/2015] [Accepted: 02/03/2015] [Indexed: 11/27/2022] Open
Abstract
Membrane tension is becoming recognized as an important mechanical regulator of motile cell behavior. Although membrane-tension measurements have been performed in various cell types, the tension distribution along the plasma membrane of motile cells has been largely unexplored. Here, we present an experimental study of the distribution of tension in the plasma membrane of rapidly moving fish epithelial keratocytes. We find that during steady movement the apparent membrane tension is ∼30% higher at the leading edge than at the trailing edge. Similar tension differences between the front and the rear of the cell are found in keratocyte fragments that lack a cell body. This front-to-rear tension variation likely reflects a tension gradient developed in the plasma membrane along the direction of movement due to viscous friction between the membrane and the cytoskeleton-attached protein anchors embedded in the membrane matrix. Theoretical modeling allows us to estimate the area density of these membrane anchors. Overall, our results indicate that even though membrane tension equilibrates rapidly and mechanically couples local boundary dynamics over cellular scales, steady-state variations in tension can exist in the plasma membranes of moving cells.
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Affiliation(s)
- Arnon D Lieber
- Department of Physics, Technion- Israel Institute of Technology, Haifa, Israel; Russell Berrie Nanotechnology Institute, Technion- Israel Institute of Technology, Haifa, Israel
| | - Yonatan Schweitzer
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Michael M Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Kinneret Keren
- Department of Physics, Technion- Israel Institute of Technology, Haifa, Israel; Russell Berrie Nanotechnology Institute, Technion- Israel Institute of Technology, Haifa, Israel; Network Biology Research Laboratories, Technion-Israel Institute of Technology, Haifa, Israel.
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272
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Lee SJ, Seo BR, Koh JY. Metallothionein-3 modulates the amyloid β endocytosis of astrocytes through its effects on actin polymerization. Mol Brain 2015; 8:84. [PMID: 26637294 PMCID: PMC4670512 DOI: 10.1186/s13041-015-0173-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 11/30/2015] [Indexed: 12/30/2022] Open
Abstract
Background Astrocytes may play important roles in the pathogenesis of Alzheimer’s disease (AD) by clearing extracellular amyloid beta (Aβ) through endocytosis and degradation. We recently showed that metallothionein 3 (Mt3), a zinc-binding metallothionein that is enriched in the central nervous system, contributes to actin polymerization in astrocytes. Because actin is likely involved in the endocytosis of Aβ, we investigated the possible role of Mt3 in Aβ endocytosis by cortical astrocytes in this study. Results To assess the route of Aβ uptake, we exposed cultured astrocytes to fluorescently labeled Aβ1–40 or Aβ1–42 together with chloropromazine (CP) or methyl-beta-cyclodextrin (MβCD), inhibitors of clathrin- and caveolin-dependent endocytosis, respectively. CP treatment almost completely blocked Aβ1–40 and Aβ1–42 endocytosis, whereas exposure to MβCD had no significant effect. Actin disruption with cytochalasin D (CytD) or latrunculin B also completely blocked Aβ1–40 and Aβ1–42 endocytosis. Because the absence of Mt3 also results in actin disruption, we examined Aβ1–40 and Aβ1–42 uptake and expression in Mt3−/− astrocytes. Compared with wild-type (WT) cells, Mt3−/− cells exhibited markedly reduced Aβ1–40 and Aβ1–42 endocytosis and expression of Aβ1-42 monomers and oligomers. A similar reduction was observed in CytD-treated WT cells. Finally, actin disruption and Mt3 knockout each increased the overall levels of clathrin and the associated protein phosphatidylinositol-binding clathrin assembly protein (PICALM) in astrocytes. Conclusions Our results suggest that the absence of Mt3 reduces Aβ uptake in astrocytes through an abnormality in actin polymerization. In light of evidence that Mt3 is downregulated in AD, our findings indicate that this mechanism may contribute to the extracellular accumulation of Aβ in this disease.
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Affiliation(s)
- Sook-Jeong Lee
- Neural Injury Research Center, Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, South Korea. .,Present address: Department of New Drug Discovery and Development, Chungnam National University, 99 Daehak-ro, Yuseong, Daejeon, 34134, South Korea.
| | - Bo-Ra Seo
- Neural Injury Research Center, Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, South Korea.
| | - Jae-Young Koh
- Neural Injury Research Center, Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, South Korea. .,Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-Gil, Songpa-Gu, Seoul, 05505, South Korea.
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273
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Preferential Budding of Vesicular Stomatitis Virus from the Basolateral Surface of Polarized Epithelial Cells Is Not Solely Directed by Matrix Protein or Glycoprotein. J Virol 2015; 89:11718-22. [PMID: 26339064 PMCID: PMC4645653 DOI: 10.1128/jvi.01658-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 08/28/2015] [Indexed: 11/20/2022] Open
Abstract
Vesicular stomatitis virus has been shown to bud basolaterally, and the matrix protein, but not glycoprotein, was proposed to mediate this asymmetry. Using polarized T84 monolayers, we demonstrate that no single viral protein is sufficient for polarized budding. Particles are released from the apical and basolateral surfaces and are indistinguishable, indicating that there is no apical assembly defect. We propose that aspects of host cell polarity create a more efficient budding process at the basolateral surface.
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274
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Tan X, Heureaux J, Liu AP. Cell spreading area regulates clathrin-coated pit dynamics on micropatterned substrate. Integr Biol (Camb) 2015; 7:1033-43. [PMID: 26205141 PMCID: PMC4558397 DOI: 10.1039/c5ib00111k] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Clathrin-mediated endocytosis (CME) is the most characterized pathway for the endocytic entry of proteins and lipids at the plasma membrane of eukaryotic cells. Numerous studies have probed the roles of different endocytic accessory proteins in regulating the dynamics of clathrin-coated pit (CCP) assembly. However, it is not completely clear how physical cues regulate CCP dynamics. Here we employ microcontact printing to control cell shape and examine CCP dynamics as a function of cell spreading area for three differently sized cells. Cells with a large spreading area had more short-lived CCPs but a higher CCP initiation rate. Interestingly, we found that fluorescence intensity of CCPs decreased with increasing cell spreading area in a manner that was dependent on the cortical actin network. Our results point to another facet of the regulation of CCP dynamics, suggesting that CME may be modulated while cells change their mechanical state and remodel their actin cytoskeleton during various processes.
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Affiliation(s)
- Xinyu Tan
- Department of Mechanical Engineering, University of Michigan, 2350 Hayward Street, Ann Arbor, Michigan MI 48105, USA.
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275
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Urbanek AN, Allwood EG, Smith AP, Booth WI, Ayscough KR. Distinct Actin and Lipid Binding Sites in Ysc84 Are Required during Early Stages of Yeast Endocytosis. PLoS One 2015; 10:e0136732. [PMID: 26312755 PMCID: PMC4552428 DOI: 10.1371/journal.pone.0136732] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/08/2015] [Indexed: 11/18/2022] Open
Abstract
During endocytosis in S. cerevisiae, actin polymerization is proposed to provide the driving force for invagination against the effects of turgor pressure. In previous studies, Ysc84 was demonstrated to bind actin through a conserved N-terminal domain. However, full length Ysc84 could only bind actin when its C-terminal SH3 domain also bound to the yeast WASP homologue Las17. Live cell-imaging has revealed that Ysc84 localizes to endocytic sites after Las17/WASP but before other known actin binding proteins, suggesting it is likely to function at an early stage of membrane invagination. While there are homologues of Ysc84 in other organisms, including its human homologue SH3yl-1, little is known of its mode of interaction with actin or how this interaction affects actin filament dynamics. Here we identify key residues involved both in Ysc84 actin and lipid binding, and demonstrate that its actin binding activity is negatively regulated by PI(4,5)P2. Ysc84 mutants defective in their lipid or actin-binding interaction were characterized in vivo. The abilities of Ysc84 to bind Las17 through its C-terminal SH3 domain, or to actin and lipid through the N-terminal domain were all shown to be essential in order to rescue temperature sensitive growth in a strain requiring YSC84 expression. Live cell imaging in strains with fluorescently tagged endocytic reporter proteins revealed distinct phenotypes for the mutants indicating the importance of these interactions for regulating key stages of endocytosis.
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Affiliation(s)
- Agnieszka N. Urbanek
- Department of Biomedical Science, Firth Court, University of Sheffield, Sheffield, United Kingdom
| | - Ellen G. Allwood
- Department of Biomedical Science, Firth Court, University of Sheffield, Sheffield, United Kingdom
| | - Adam P. Smith
- Department of Biomedical Science, Firth Court, University of Sheffield, Sheffield, United Kingdom
| | - Wesley I. Booth
- Department of Biomedical Science, Firth Court, University of Sheffield, Sheffield, United Kingdom
| | - Kathryn R. Ayscough
- Department of Biomedical Science, Firth Court, University of Sheffield, Sheffield, United Kingdom
- * E-mail:
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276
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Sauvanet C, Garbett D, Bretscher A. The function and dynamics of the apical scaffolding protein E3KARP are regulated by cell-cycle phosphorylation. Mol Biol Cell 2015; 26:3615-27. [PMID: 26310448 PMCID: PMC4603932 DOI: 10.1091/mbc.e15-07-0498] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 08/18/2015] [Indexed: 11/11/2022] Open
Abstract
We examine the dynamics and function of the apical scaffolding protein E3KARP/NHERF2, which consists of two PDZ domains and a tail containing an ezrin-binding domain. The exchange rate of E3KARP is greatly enhanced during mitosis due to phosphorylation at Ser-303 in its tail region. Whereas E3KARP can substitute for the function of the closely related scaffolding protein EBP50/NHERF1 in the formation of interphase microvilli, E3KARP S303D cannot. Moreover, the S303D mutation enhances the in vivo dynamics of the E3KARP tail alone, whereas in vitro the interaction of E3KARP with active ezrin is unaffected by S303D, implicating another factor regulating dynamics in vivo. A-Raf is found to be required for S303 phosphorylation in mitotic cells. Regulation of the dynamics of EBP50 is known to be dependent on its tail region but modulated by PDZ domain occupancy, which is not the case for E3KARP. Of interest, in both cases, the mechanisms regulating dynamics involve the tails, which are the most diverged region of the paralogues and probably evolved independently after a gene duplication event that occurred early in vertebrate evolution.
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Affiliation(s)
- Cécile Sauvanet
- Department of Molecular Biology and Genetics, Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, NY 14853
| | - Damien Garbett
- Department of Molecular Biology and Genetics, Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, NY 14853
| | - Anthony Bretscher
- Department of Molecular Biology and Genetics, Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, NY 14853
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277
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Membrane tension and membrane fusion. Curr Opin Struct Biol 2015; 33:61-7. [PMID: 26282924 DOI: 10.1016/j.sbi.2015.07.010] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Revised: 07/19/2015] [Accepted: 07/24/2015] [Indexed: 12/29/2022]
Abstract
Diverse cell biological processes that involve shaping and remodeling of cell membranes are regulated by membrane lateral tension. Here we focus on the role of tension in driving membrane fusion. We discuss the physics of membrane tension, forces that can generate the tension in plasma membrane of a cell, and the hypothesis that tension powers expansion of membrane fusion pores in late stages of cell-to-cell and exocytotic fusion. We propose that fusion pore expansion can require unusually large membrane tensions or, alternatively, low line tensions of the pore resulting from accumulation in the pore rim of membrane-bending proteins. Increase of the inter-membrane distance facilitates the reaction.
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278
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Basquin C, Trichet M, Vihinen H, Malardé V, Lagache T, Ripoll L, Jokitalo E, Olivo-Marin JC, Gautreau A, Sauvonnet N. Membrane protrusion powers clathrin-independent endocytosis of interleukin-2 receptor. EMBO J 2015; 34:2147-61. [PMID: 26124312 PMCID: PMC4557667 DOI: 10.15252/embj.201490788] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 05/27/2015] [Accepted: 05/27/2015] [Indexed: 11/09/2022] Open
Abstract
Endocytosis controls many functions including nutrient uptake, cell division, migration and signal transduction. A clathrin- and caveolin-independent endocytosis pathway is used by important physiological cargos, including interleukin-2 receptors (IL-2R). However, this process lacks morphological and dynamic data. Our electron microscopy (EM) and tomography studies reveal that IL-2R-pits and vesicles are initiated at the base of protrusions. We identify the WAVE complex as a specific endocytic actor. The WAVE complex interacts with IL-2R, via a WAVE-interacting receptor sequence (WIRS) present in the receptor polypeptide, and allows for receptor clustering close to membrane protrusions. In addition, using total internal reflection fluorescent microscopy (TIRF) and automated analysis we demonstrate that two timely distinct bursts of actin polymerization are required during IL-2R uptake, promoted first by the WAVE complex and then by N-WASP. Finally, our data reveal that dynamin acts as a transition controller for the recruitment of Arp2/3 activators required for IL-2R endocytosis. Altogether, our work identifies the spatio-temporal specific role of factors initiating clathrin-independent endocytosis by a unique mechanism that does not depend on the deformation of a flat membrane, but rather on that of membrane protrusions.
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Affiliation(s)
- Cyril Basquin
- Unité de Biologie des Interactions Cellulaires, Institut Pasteur, Paris, France CNRS UMR3691, Paris, France
| | - Michaël Trichet
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut de Biologie Paris-Seine (IBPS), FR3631, Electron Microscopy Facility, Paris, France
| | - Helena Vihinen
- Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Valérie Malardé
- Unité de Biologie des Interactions Cellulaires, Institut Pasteur, Paris, France CNRS UMR3691, Paris, France
| | - Thibault Lagache
- CNRS UMR3691, Paris, France Unité d'Analyse d'Images Biologiques, Institut Pasteur, Paris, France
| | - Léa Ripoll
- Unité de Biologie des Interactions Cellulaires, Institut Pasteur, Paris, France CNRS UMR3691, Paris, France
| | - Eija Jokitalo
- Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | | | - Alexis Gautreau
- Laboratoire de Biochimie, Unité Mixte de Recherche 7654 Ecole Polytechnique Centre, National de la Recherche Scientifique, Palaiseau, France
| | - Nathalie Sauvonnet
- Unité de Biologie des Interactions Cellulaires, Institut Pasteur, Paris, France CNRS UMR3691, Paris, France
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279
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Thelen S, Abouhamed M, Ciarimboli G, Edemir B, Bähler M. Rho GAP myosin IXa is a regulator of kidney tubule function. Am J Physiol Renal Physiol 2015; 309:F501-13. [PMID: 26136556 DOI: 10.1152/ajprenal.00220.2014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 06/29/2015] [Indexed: 11/22/2022] Open
Abstract
Mammalian class IX myosin Myo9a is a single-headed, actin-dependent motor protein with Rho GTPase-activating protein activity that negatively regulates Rho GTPase signaling. Myo9a is abundantly expressed in ciliated epithelial cells of several organs. In mice, genetic deletion of Myo9a leads to the formation of hydrocephalus. Whether Myo9a also has essential functions in the epithelia of other organs of the body has not been explored. In the present study, we report that Myo9a-deficient mice develop bilateral renal disease, characterized by dilation of proximal tubules, calyceal dilation, and thinning of the parenchyma and fibrosis. These structural changes are accompanied by polyuria (with normal vasopressin levels) and low-molecular-weight proteinuria. Immunohistochemistry revealed that Myo9a is localized to the circumferential F-actin belt of proximal tubule cells. In kidneys lacking Myo9a, the multiligand binding receptor megalin and its ligand albumin accumulated at the luminal surface of Myo9a-deficient proximal tubular cells, suggesting that endocytosis is dysregulated. In addition, we found, surprisingly, that levels of murine diaphanous-related formin-1, a Rho effector, were decreased in Myo9a-deficient kidneys as well as in Myo9a knockdown LLC-PK1 cells. In summary, deletion of the Rho GTPase-activating protein Myo9a in mice causes proximal tubular dilation and fibrosis, and we speculate that downregulation of murine diaphanous-related formin-1 and impaired protein reabsorption contribute to the pathophysiology.
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Affiliation(s)
- Sabine Thelen
- Institute of Molecular Cell Biology, Westfalian Wilhelms University, Münster, Germany; and
| | - Marouan Abouhamed
- Institute of Molecular Cell Biology, Westfalian Wilhelms University, Münster, Germany; and
| | - Giuliano Ciarimboli
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Münster, Münster, Germany
| | - Bayram Edemir
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Münster, Münster, Germany
| | - Martin Bähler
- Institute of Molecular Cell Biology, Westfalian Wilhelms University, Münster, Germany; and
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280
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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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281
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Boulant S, Stanifer M, Lozach PY. Dynamics of virus-receptor interactions in virus binding, signaling, and endocytosis. Viruses 2015; 7:2794-815. [PMID: 26043381 PMCID: PMC4488714 DOI: 10.3390/v7062747] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 05/21/2015] [Accepted: 05/27/2015] [Indexed: 02/06/2023] Open
Abstract
During viral infection the first challenge that viruses have to overcome is gaining access to the intracellular compartment. The infection process starts when the virus contacts the surface of the host cell. A complex series of events ensues, including diffusion at the host cell membrane surface, binding to receptors, signaling, internalization, and delivery of the genetic information. The focus of this review is on the very initial steps of virus entry, from receptor binding to particle uptake into the host cell. We will discuss how viruses find their receptor, move to sub-membranous regions permissive for entry, and how they hijack the receptor-mediated signaling pathway to promote their internalization.
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Affiliation(s)
- Steeve Boulant
- CellNetworks-Cluster of Excellence and Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany.
- Schaller research group at CellNetworks and DKFZ (German cancer research center), 69120 Heidelberg, Germany.
| | - Megan Stanifer
- CellNetworks-Cluster of Excellence and Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany.
- Schaller research group at CellNetworks and DKFZ (German cancer research center), 69120 Heidelberg, Germany.
| | - Pierre-Yves Lozach
- CellNetworks-Cluster of Excellence and Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany.
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282
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Membrane tension controls the assembly of curvature-generating proteins. Nat Commun 2015; 6:7219. [PMID: 26008710 PMCID: PMC4455092 DOI: 10.1038/ncomms8219] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 04/18/2015] [Indexed: 12/16/2022] Open
Abstract
Proteins containing a Bin/Amphiphysin/Rvs (BAR) domain regulate membrane curvature in the cell. Recent simulations have revealed that BAR proteins assemble into linear aggregates, strongly affecting membrane curvature and its in-plane stress profile. Here, we explore the opposite question: do mechanical properties of the membrane impact protein association? By using coarse-grained molecular dynamics simulations, we show that increased surface tension significantly impacts the dynamics of protein assembly. While tensionless membranes promote a rapid formation of long-living linear aggregates of N-BAR proteins, increase in tension alters the geometry of protein association. At high tension, protein interactions are strongly inhibited. Increasing surface density of proteins leads to a wider range of protein association geometries, promoting the formation of meshes, which can be broken apart with membrane tension. Our work indicates that surface tension may play a key role in recruiting proteins to membrane-remodelling sites in the cell. BAR domain proteins are known to reshape cell membranes. Using coarse-grained molecular dynamics simulations, Simunovic and Voth demonstrate that membrane tension strongly affects the association of BAR proteins, in turn controlling their recruitment to membrane-remodelling sites.
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283
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Gonzalez-Rodriguez D, Barakat AI. Dynamics of receptor-mediated nanoparticle internalization into endothelial cells. PLoS One 2015; 10:e0122097. [PMID: 25901833 PMCID: PMC4406860 DOI: 10.1371/journal.pone.0122097] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 02/19/2015] [Indexed: 12/17/2022] Open
Abstract
Nanoparticles offer a promising medical tool for targeted drug delivery, for example to treat inflamed endothelial cells during the development of atherosclerosis. To inform the design of such therapeutic strategies, we develop a computational model of nanoparticle internalization into endothelial cells, where internalization is driven by receptor-ligand binding and limited by the deformation of the cell membrane and cytoplasm. We specifically consider the case of nanoparticles targeted against ICAM-1 receptors, of relevance for treating atherosclerosis. The model computes the kinetics of the internalization process, the dynamics of binding, and the distribution of stresses exerted between the nanoparticle and the cell membrane. The model predicts the existence of an optimal nanoparticle size for fastest internalization, consistent with experimental observations, as well as the role of bond characteristics, local cell mechanical properties, and external forces in the nanoparticle internalization process.
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Affiliation(s)
- David Gonzalez-Rodriguez
- Laboratoire d’Hydrodynamique (LadHyX), École Polytechnique, CNRS UMR 7646, Palaiseau, France
- * E-mail: (DGR), (AIB)
| | - Abdul I. Barakat
- Laboratoire d’Hydrodynamique (LadHyX), École Polytechnique, CNRS UMR 7646, Palaiseau, France
- * E-mail: (DGR), (AIB)
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284
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Abstract
New findings report a mechanical role for actin in Golgi organization and vesicular trafficking. An elegant study uses optical tweezers and live-cell imaging to demonstrate the effects of a mechanical constraint on the dynamics of secretory membrane trafficking, combining physical experimental approaches with in cellulo studies of endomembranes.
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285
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Chanet S, Martin AC. Mechanical force sensing in tissues. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 126:317-52. [PMID: 25081624 DOI: 10.1016/b978-0-12-394624-9.00013-0] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Tissue size, shape, and organization reflect individual cell behaviors such as proliferation, shape change, and movement. Evidence suggests that mechanical signals operate in tandem with biochemical cues to properly coordinate cell behavior and pattern tissues. The objective of this chapter is to present recent evidence demonstrating that forces transmitted between cells act as signals that coordinate cell behavior across tissues. We first briefly summarize molecular and cellular mechanisms by which forces are sensed by cells with an emphasis on forces generated and transmitted by cytoskeletal networks. We then discuss evidence for these mechanisms operating in multicellular contexts to coordinate complex cell and tissue behaviors that occur during embryonic development: specifically growth and morphogenesis.
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Affiliation(s)
- Soline Chanet
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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286
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Skruzny M, Desfosses A, Prinz S, Dodonova S, Gieras A, Uetrecht C, Jakobi A, Abella M, Hagen W, Schulz J, Meijers R, Rybin V, Briggs J, Sachse C, Kaksonen M. An Organized Co-assembly of Clathrin Adaptors Is Essential for Endocytosis. Dev Cell 2015; 33:150-62. [DOI: 10.1016/j.devcel.2015.02.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 11/29/2014] [Accepted: 02/25/2015] [Indexed: 10/23/2022]
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287
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Palmer SE, Smaczynska-de Rooij II, Marklew CJ, Allwood EG, Mishra R, Johnson S, Goldberg MW, Ayscough KR. A dynamin-actin interaction is required for vesicle scission during endocytosis in yeast. Curr Biol 2015; 25:868-78. [PMID: 25772449 PMCID: PMC4386032 DOI: 10.1016/j.cub.2015.01.061] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 11/23/2014] [Accepted: 01/23/2015] [Indexed: 12/29/2022]
Abstract
Actin is critical for endocytosis in yeast cells, and also in mammalian cells under tension. However, questions remain as to how force generated through actin polymerization is transmitted to the plasma membrane to drive invagination and scission. Here, we reveal that the yeast dynamin Vps1 binds and bundles filamentous actin. Mutational analysis of Vps1 in a helix of the stalk domain identifies a mutant RR457-458EE that binds actin more weakly. In vivo analysis of Vps1 function demonstrates that the mutation disrupts endocytosis but not other functions of Vps1 such as vacuolar trafficking or peroxisome fission. The mutant Vps1 is stably expressed in cells and co-localizes with the endocytic reporters Abp1 and the amphiphysin Rvs167. Detailed analysis of individual endocytic patch behavior indicates that the mutation causes aberrant movements in later stages of endocytosis, consistent with a scission defect. Ultrastructural analysis of yeast cells using electron microscopy reveals a significant increase in invagination depth, further supporting a role for the Vps1-actin interaction during scission. In vitro analysis of the mutant protein demonstrates that--like wild-type Vps1--it is able to form oligomeric rings, but, critically, it has lost its ability to bundle actin filaments into higher-order structures. A model is proposed in which actin filaments bind Vps1 during invagination, and this interaction is important to transduce the force of actin polymerization to the membrane to drive successful scission.
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Affiliation(s)
- Sarah E Palmer
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | | | | | - Ellen G Allwood
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - Ritu Mishra
- Department of Biological Science, Durham University, Durham DH1 3LE, UK
| | - Simeon Johnson
- Department of Biological Science, Durham University, Durham DH1 3LE, UK
| | - Martin W Goldberg
- Department of Biological Science, Durham University, Durham DH1 3LE, UK
| | - Kathryn R Ayscough
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK.
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288
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Kellner M, Rohrmoser M, Forné I, Voss K, Burger K, Mühl B, Gruber-Eber A, Kremmer E, Imhof A, Eick D. DEAD-box helicase DDX27 regulates 3' end formation of ribosomal 47S RNA and stably associates with the PeBoW-complex. Exp Cell Res 2015; 334:146-59. [PMID: 25825154 DOI: 10.1016/j.yexcr.2015.03.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 03/18/2015] [Accepted: 03/19/2015] [Indexed: 02/07/2023]
Abstract
PeBoW, a trimeric complex consisting of pescadillo (Pes1), block of proliferation (Bop1), and the WD repeat protein 12 (WDR12), is essential for processing and maturation of mammalian 5.8S and 28S ribosomal RNAs. Applying a mass spectrometric analysis, we identified the DEAD-box helicase DDX27 as stably associated factor of the PeBoW-complex. DDX27 interacts with the PeBoW-complex via an evolutionary conserved F×F motif in the N-terminal domain and is recruited to the nucleolus via its basic C-terminal domain. This recruitment is RNA-dependent and occurs independently of the PeBoW-complex. Interestingly, knockdown of DDX27, but not of Pes1, induces the accumulation of an extended form of the primary 47S rRNA. We conclude that DDX27 can interact specifically with the Pes1 and Bop1 but fulfils critical function(s) for proper 3' end formation of 47S rRNA independently of the PeBoW-complex.
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Affiliation(s)
- Markus Kellner
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377, Germany
| | - Michaela Rohrmoser
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377, Germany
| | - Ignasi Forné
- Adolf Butenandt Institute, Ludwig Maximilians University of Munich, Center for Integrated Protein Science Munich (CIPSM), Schillerstr. 44, Munich 80336, Germany
| | - Kirsten Voss
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377, Germany
| | - Kaspar Burger
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377, Germany
| | - Bastian Mühl
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377, Germany
| | - Anita Gruber-Eber
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377, Germany
| | - Elisabeth Kremmer
- Institute of Molecular Immunology, Helmholtz Center Munich, Marchioninistr. 25, Munich 81377, Germany
| | - Axel Imhof
- Adolf Butenandt Institute, Ludwig Maximilians University of Munich, Center for Integrated Protein Science Munich (CIPSM), Schillerstr. 44, Munich 80336, Germany
| | - Dirk Eick
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377, Germany.
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289
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Endocytic proteins drive vesicle growth via instability in high membrane tension environment. Proc Natl Acad Sci U S A 2015; 112:E1423-32. [PMID: 25775509 DOI: 10.1073/pnas.1418491112] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Clathrin-mediated endocytosis (CME) is a key pathway for transporting cargo into cells via membrane vesicles; it plays an integral role in nutrient import, signal transduction, neurotransmission, and cellular entry of pathogens and drug-carrying nanoparticles. Because CME entails substantial local remodeling of the plasma membrane, the presence of membrane tension offers resistance to bending and hence, vesicle formation. Experiments show that in such high-tension conditions, actin dynamics is required to carry out CME successfully. In this study, we build on these pioneering experimental studies to provide fundamental mechanistic insights into the roles of two key endocytic proteins-namely, actin and BAR proteins-in driving vesicle formation in high membrane tension environment. Our study reveals an actin force-induced "snap-through instability" that triggers a rapid shape transition from a shallow invagination to a highly invaginated tubular structure. We show that the association of BAR proteins stabilizes vesicles and induces a milder instability. In addition, we present a rather counterintuitive role of BAR depolymerization in regulating the shape evolution of vesicles. We show that the dissociation of BAR proteins, supported by actin-BAR synergy, leads to considerable elongation and squeezing of vesicles. Going beyond the membrane geometry, we put forth a stress-based perspective for the onset of vesicle scission and predict the shapes and composition of detached vesicles. We present the snap-through transition and the high in-plane stress as possible explanations for the intriguing direct transformation of broad and shallow invaginations into detached vesicles in BAR mutant yeast cells.
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290
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Feliciano D, Tolsma TO, Farrell KB, Aradi A, Di Pietro SM. A second Las17 monomeric actin-binding motif functions in Arp2/3-dependent actin polymerization during endocytosis. Traffic 2015; 16:379-97. [PMID: 25615019 DOI: 10.1111/tra.12259] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 01/03/2015] [Accepted: 01/05/2015] [Indexed: 12/16/2022]
Abstract
During clathrin-mediated endocytosis (CME), actin assembly provides force to drive vesicle internalization. Members of the Wiskott-Aldrich syndrome protein (WASP) family play a fundamental role stimulating actin assembly. WASP family proteins contain a WH2 motif that binds globular actin (G-actin) and a central-acidic motif that binds the Arp2/3 complex, thus promoting the formation of branched actin filaments. Yeast WASP (Las17) is the strongest of five factors promoting Arp2/3-dependent actin polymerization during CME. It was suggested that this strong activity may be caused by a putative second G-actin-binding motif in Las17. Here, we describe the in vitro and in vivo characterization of such Las17 G-actin-binding motif (LGM) and its dependence on a group of conserved arginine residues. Using the yeast two-hybrid system, GST-pulldown, fluorescence polarization and pyrene-actin polymerization assays, we show that LGM binds G-actin and is necessary for normal Arp2/3-mediated actin polymerization in vitro. Live-cell fluorescence microscopy experiments demonstrate that LGM is required for normal dynamics of actin polymerization during CME. Further, LGM is necessary for normal dynamics of endocytic machinery components that are recruited at early, intermediate and late stages of endocytosis, as well as for optimal endocytosis of native CME cargo. Both in vitro and in vivo experiments show that LGM has relatively lower potency compared to the previously known Las17 G-actin-binding motif, WH2. These results establish a second G-actin-binding motif in Las17 and advance our knowledge on the mechanism of actin assembly during CME.
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Affiliation(s)
- Daniel Feliciano
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
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Chapnick DA, Bunker E, Liu X. A biosensor for the activity of the "sheddase" TACE (ADAM17) reveals novel and cell type-specific mechanisms of TACE activation. Sci Signal 2015; 8:rs1. [PMID: 25714465 DOI: 10.1126/scisignal.2005680] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Diverse environmental conditions stimulate protein "shedding" from the cell surface through proteolytic cleavage. The protease TACE [tumor necrosis factor-α (TNFα)--converting enzyme, encoded by ADAM17] mediates protein shedding, thereby regulating the maturation and release of various extracellular substrates, such as growth factors and cytokines, that induce diverse cellular responses. We developed a FRET (fluorescence resonance energy transfer)-based biosensor called TSen that quantitatively reports the kinetics of TACE activity in live cells. In combination with chemical biology approaches, we used TSen to probe the dependence of TACE activation on the induction of the kinases p38 and ERK (extracellular signal-regulated kinase) in various epithelial cell lines. Using TSen, we found that disruption of the actin cytoskeleton in keratinocytes induced rapid and robust TSen cleavage and the accumulation of TACE at the plasma membrane. Cytoskeletal disruption also increased the cleavage of endogenous TACE substrates, including transforming growth factor-α. Thus, TSen is a useful tool for unraveling the mechanisms underlying the spatiotemporal activation of TACE in live cells.
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Affiliation(s)
- Douglas A Chapnick
- Department of Chemistry and Biochemistry, 596 UCB, University of Colorado, Jennie Smoly Caruthers Biotechnology Building (JSCBB), 3415 Colorado Avenue, Boulder, CO 80303, USA
| | - Eric Bunker
- Department of Chemistry and Biochemistry, 596 UCB, University of Colorado, Jennie Smoly Caruthers Biotechnology Building (JSCBB), 3415 Colorado Avenue, Boulder, CO 80303, USA
| | - Xuedong Liu
- Department of Chemistry and Biochemistry, 596 UCB, University of Colorado, Jennie Smoly Caruthers Biotechnology Building (JSCBB), 3415 Colorado Avenue, Boulder, CO 80303, USA.
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292
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A balance between membrane elasticity and polymerization energy sets the shape of spherical clathrin coats. Nat Commun 2015; 6:6249. [PMID: 25695735 PMCID: PMC4346611 DOI: 10.1038/ncomms7249] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 01/09/2015] [Indexed: 01/22/2023] Open
Abstract
In endocytosis, scaffolding is one of the mechanisms to create membrane curvature by moulding the membrane into the spherical shape of the clathrin cage. However, the impact of membrane elastic parameters on the assembly and shape of clathrin lattices has never been experimentally evaluated. Here, we show that membrane tension opposes clathrin polymerization. We reconstitute clathrin budding in vitro with giant unilamellar vesicles (GUVs), purified adaptors and clathrin. By changing the osmotic conditions, we find that clathrin coats cause extensive budding of GUVs under low membrane tension while polymerizing into shallow pits under moderate tension. High tension fully inhibits polymerization. Theoretically, we predict the tension values for which transitions between different clathrin coat shapes occur. We measure the changes in membrane tension during clathrin polymerization, and use our theoretical framework to estimate the polymerization energy from these data. Our results show that membrane tension controls clathrin-mediated budding by varying the membrane budding energy. A relationship between membrane tension and clathrin polymerization during endocytosis has not been experimentally established. Here, the authors show using an in vitro reconstituted system and theoretical modelling that membrane tension regulates clathrin polymerization into spherical cages by varying the membrane budding energy.
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293
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Cortesio CL, Lewellyn EB, Drubin DG. Control of lipid organization and actin assembly during clathrin-mediated endocytosis by the cytoplasmic tail of the rhomboid protein Rbd2. Mol Biol Cell 2015; 26:1509-22. [PMID: 25694450 PMCID: PMC4395130 DOI: 10.1091/mbc.e14-11-1540] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/09/2015] [Indexed: 12/13/2022] Open
Abstract
Clathrin-mediated endocytosis (CME) requires precise regulation of the actin cytoskeleton. The yeast rhomboid protein Rbd2 controls the timing of actin polymerization during CME through its cytoplasmic tail and a PtdIns(4,5)P2-dependent mechanism. Clathrin-mediated endocytosis (CME) is facilitated by a precisely regulated burst of actin assembly. PtdIns(4,5)P2 is an important signaling lipid with conserved roles in CME and actin assembly regulation. Rhomboid family multipass transmembrane proteins regulate diverse cellular processes; however, rhomboid-mediated CME regulation has not been described. We report that yeast lacking the rhomboid protein Rbd2 exhibit accelerated endocytic-site dynamics and premature actin assembly during CME through a PtdIns(4,5)P2-dependent mechanism. Combined genetic and biochemical studies showed that the cytoplasmic tail of Rbd2 binds directly to PtdIns(4,5)P2 and is sufficient for Rbd2's role in actin regulation. Analysis of an Rbd2 mutant with diminished PtdIns(4,5)P2-binding capacity indicates that this interaction is necessary for the temporal regulation of actin assembly during CME. The cytoplasmic tail of Rbd2 appears to modulate PtdIns(4,5)P2 distribution on the cell cortex. The syndapin-like F-BAR protein Bzz1 functions in a pathway with Rbd2 to control the timing of type 1 myosin recruitment and actin polymerization onset during CME. This work reveals that the previously unstudied rhomboid protein Rbd2 functions in vivo at the nexus of three highly conserved processes: lipid regulation, endocytic regulation, and cytoskeletal function.
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Affiliation(s)
- Christa L Cortesio
- Department of Molecular- and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Eric B Lewellyn
- Department of Molecular- and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - David G Drubin
- Department of Molecular- and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
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294
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He K, Xing R, Yan X, Tian A, Zhang M, Yuan J, Lv Z, Fang X, Li Z, Zhang Y. Mammalian actin-binding protein 1/HIP-55 is essential for the scission of clathrin-coated pits by regulating dynamin-actin interaction. FASEB J 2015; 29:2495-503. [PMID: 25690657 DOI: 10.1096/fj.14-264259] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 02/03/2015] [Indexed: 02/03/2023]
Abstract
Actin and dynamin work cooperatively to drive the invagination and scission of clathrin-coated pits (CCPs). However, little is known about the mechanism that orchestrates the spatiotemporal recruitment of dynamin and actin. Here, we have identified the mammalian actin-binding protein 1 (mAbp1; also called HIP-55 or SH3P7), which could bind to clathrin, actin, as well as dynamin, as an adaptor that links the dynamic recruitment of dynamin and actin for the scission of CCPs. Live-cell imaging reveals that mAbp1 is specifically recruited at a late stage of the long-lived CCPs. mAbp1 knockdown impaired CCP scission by reducing dynamin recruitment at the plasma membrane. However, actin disruption remarkably eliminates mAbp1 recruitment and thus dynamin recruitment. These data suggest that by binding to both clathrin and F-actin, mAbp1 is specifically recruited at a late stage of CCP formation, which subsequently recruits dynamin to CCPs.
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Affiliation(s)
- Kangmin He
- *Institute of Vascular Medicine, Peking University Third Hospital and Academy for Advanced Interdisciplinary Studies, Peking University, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, China; Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructures and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China; and State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Rui Xing
- *Institute of Vascular Medicine, Peking University Third Hospital and Academy for Advanced Interdisciplinary Studies, Peking University, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, China; Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructures and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China; and State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xiaohua Yan
- *Institute of Vascular Medicine, Peking University Third Hospital and Academy for Advanced Interdisciplinary Studies, Peking University, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, China; Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructures and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China; and State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Aiju Tian
- *Institute of Vascular Medicine, Peking University Third Hospital and Academy for Advanced Interdisciplinary Studies, Peking University, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, China; Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructures and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China; and State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Mingliang Zhang
- *Institute of Vascular Medicine, Peking University Third Hospital and Academy for Advanced Interdisciplinary Studies, Peking University, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, China; Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructures and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China; and State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jinghe Yuan
- *Institute of Vascular Medicine, Peking University Third Hospital and Academy for Advanced Interdisciplinary Studies, Peking University, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, China; Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructures and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China; and State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Zhizhen Lv
- *Institute of Vascular Medicine, Peking University Third Hospital and Academy for Advanced Interdisciplinary Studies, Peking University, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, China; Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructures and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China; and State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xiaohong Fang
- *Institute of Vascular Medicine, Peking University Third Hospital and Academy for Advanced Interdisciplinary Studies, Peking University, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, China; Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructures and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China; and State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Zijian Li
- *Institute of Vascular Medicine, Peking University Third Hospital and Academy for Advanced Interdisciplinary Studies, Peking University, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, China; Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructures and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China; and State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Youyi Zhang
- *Institute of Vascular Medicine, Peking University Third Hospital and Academy for Advanced Interdisciplinary Studies, Peking University, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, China; Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructures and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China; and State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
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295
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Picco A, Mund M, Ries J, Nédélec F, Kaksonen M. Visualizing the functional architecture of the endocytic machinery. eLife 2015; 4. [PMID: 25675087 PMCID: PMC4357291 DOI: 10.7554/elife.04535] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 02/10/2015] [Indexed: 01/08/2023] Open
Abstract
Clathrin-mediated endocytosis is an essential process that forms vesicles from the plasma membrane. Although most of the protein components of the endocytic protein machinery have been thoroughly characterized, their organization at the endocytic site is poorly understood. We developed a fluorescence microscopy method to track the average positions of yeast endocytic proteins in relation to each other with a time precision below 1 s and with a spatial precision of ∼10 nm. With these data, integrated with shapes of endocytic membrane intermediates and with superresolution imaging, we could visualize the dynamic architecture of the endocytic machinery. We showed how different coat proteins are distributed within the coat structure and how the assembly dynamics of N-BAR proteins relate to membrane shape changes. Moreover, we found that the region of actin polymerization is located at the base of the endocytic invagination, with the growing ends of filaments pointing toward the plasma membrane. DOI:http://dx.doi.org/10.7554/eLife.04535.001 Cells take up proteins and other useful material (called cargo) from their external environment through a process known as endocytosis. To start with, the cargo accumulates in a patch on the surface of the cell. On the inner side of the cell's membrane, a protein called clathrin gathers around the patch of cargo. Clathrin molecules and many other proteins bind together to make a lattice-like coat that causes the membrane to curve inwards and form a pocket that contains the cargo. This continues until the cargo is completely surrounded by membrane and eventually forms a bubble-like structure, or ‘vesicle’, that moves into the cell. More than 50 other proteins are involved in the endocytosis. These proteins arrive at the site of endocytosis in a particular order, complete their tasks and then move away to be used in further rounds of endocytosis. It is not clear how these proteins are organized to complete these steps because it is technically difficult to track the movements of many proteins at the same time. Here, Picco et al. developed a new fluorescence microscopy method that enabled them to track the positions of many of the proteins involved in endocytosis in yeast cells in real time. The experiments revealed when the proteins arrived at the site of endocytosis and how they assembled in relation to the membrane. For example, a group of proteins called N-BAR proteins formed an extended lattice covering the sides of the pocket that forms as the membrane curves inwards. To transform the flat membrane into a vesicle, a network of filaments made of a protein called actin needs to form at the site of endocytosis. The new method shows that the actin filaments grow in a small region at the base of the developing vesicle. By combining different types of microscopy data, Picco et al. were able to build a comprehensive model describing when the proteins involved in endocytosis move and assemble. The next challenge will be to understand the physics behind the molecular machine composed of these many proteins and the cell membrane. DOI:http://dx.doi.org/10.7554/eLife.04535.002
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Affiliation(s)
- Andrea Picco
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Markus Mund
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jonas Ries
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - François Nédélec
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Marko Kaksonen
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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296
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Madasu Y, Yang C, Boczkowska M, Bethoney KA, Zwolak A, Rebowski G, Svitkina T, Dominguez R. PICK1 is implicated in organelle motility in an Arp2/3 complex-independent manner. Mol Biol Cell 2015; 26:1308-22. [PMID: 25657323 PMCID: PMC4454178 DOI: 10.1091/mbc.e14-10-1448] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
A SAXS-based structural model is described for PICK1, a key player in AMPA receptor trafficking. It is shown that the acidic C-terminal tail of PICK1 is involved in autoinhibition and motility of PICK1-associated vesicle-like structures, but, contrary to previous reports, PICK1 neither binds nor inhibits Arp2/3 complex. PICK1 is a modular scaffold implicated in synaptic receptor trafficking. It features a PDZ domain, a BAR domain, and an acidic C-terminal tail (ACT). Analysis by small- angle x-ray scattering suggests a structural model that places the receptor-binding site of the PDZ domain and membrane-binding surfaces of the BAR and PDZ domains adjacent to each other on the concave side of the banana-shaped PICK1 dimer. In the model, the ACT of one subunit of the dimer interacts with the PDZ and BAR domains of the other subunit, possibly accounting for autoinhibition. Consistently, full-length PICK1 shows diffuse cytoplasmic localization, but it clusters on vesicle-like structures that colocalize with the trans-Golgi network marker TGN38 upon deletion of either the ACT or PDZ domain. This localization is driven by the BAR domain. Live-cell imaging further reveals that PICK1-associated vesicles undergo fast, nondirectional motility in an F-actin–dependent manner, but deleting the ACT dramatically reduces vesicle speed. Thus the ACT links PICK1-associated vesicles to a motility factor, likely myosin, but, contrary to previous reports, PICK1 neither binds nor inhibits Arp2/3 complex.
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Affiliation(s)
- Yadaiah Madasu
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Changsong Yang
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104
| | - Malgorzata Boczkowska
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Kelley A Bethoney
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Adam Zwolak
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Grzegorz Rebowski
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Tatyana Svitkina
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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297
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Simunovic M, Bassereau P. Reshaping biological membranes in endocytosis: crossing the configurational space of membrane-protein interactions. Biol Chem 2015; 395:275-83. [PMID: 24353142 DOI: 10.1515/hsz-2013-0242] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 12/16/2013] [Indexed: 11/15/2022]
Abstract
Lipid membranes are highly dynamic. Over several decades, physicists and biologists have uncovered a number of ways they can change the shape of membranes or alter their phase behavior. In cells, the intricate action of membrane proteins drives these processes. Considering the highly complex ways proteins interact with biological membranes, molecular mechanisms of membrane remodeling still remain unclear. When studying membrane remodeling phenomena, researchers often observe different results, leading them to disparate conclusions on the physiological course of such processes. Here we discuss how combining research methodologies and various experimental conditions contributes to the understanding of the entire phase space of membrane-protein interactions. Using the example of clathrin-mediated endocytosis we try to distinguish the question 'how can proteins remodel the membrane?' from 'how do proteins remodel the membrane in the cell?' In particular, we consider how altering physical parameters may affect the way membrane is remodeled. Uncovering the full range of physical conditions under which membrane phenomena take place is key in understanding the way cells take advantage of membrane properties in carrying out their vital tasks.
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298
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Rust MB, Maritzen T. Relevance of presynaptic actin dynamics for synapse function and mouse behavior. Exp Cell Res 2015; 335:165-71. [PMID: 25579398 DOI: 10.1016/j.yexcr.2014.12.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 12/26/2014] [Indexed: 01/26/2023]
Abstract
Actin is the most abundant cytoskeletal protein in presynaptic terminals as well as in postsynaptic dendritic spines of central excitatory synapses. While the relevance of actin dynamics for postsynaptic plasticity, for instance activity-induced changes in dendritic spine morphology and synaptic glutamate receptor mobility, is well-documented, only little is known about its function and regulatory mechanisms in presynaptic terminals. Moreover, studies on presynaptic actin dynamics have often been inconsistent, suggesting that actin has diverse presynaptic functions, varying likely between specific types of excitatory synapses and/or their activity states. In this review, we will summarize and discuss the function and upstream regulatory mechanisms of the actin cytoskeleton in presynaptic terminals, focusing on excitatory synapses of the mammalian central nervous system. Due to length restrictions we will mainly concentrate on new insights into actin's presynaptic function that have been gained by cell biological and mouse genetic approaches since the excellent 2008 review by Cingolani and Goda.
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Affiliation(s)
- Marco B Rust
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, Marburg, Germany.
| | - Tanja Maritzen
- Department of Molecular Physiology and Cell Biology, Leibniz-Institute for Molecular Pharmacology, Berlin, Germany.
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299
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Shi Z, Baumgart T. Membrane tension and peripheral protein density mediate membrane shape transitions. Nat Commun 2015; 6:5974. [PMID: 25569184 PMCID: PMC4353700 DOI: 10.1038/ncomms6974] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 11/28/2014] [Indexed: 01/21/2023] Open
Abstract
Endocytosis is a ubiquitous eukaryotic membrane budding, vesiculation and internalization process fulfilling numerous roles including compensation of membrane area increase after bursts of exocytosis. The mechanism of the coupling between these two processes to enable homeostasis is not well understood. Recently, an ultrafast endocytosis (UFE) pathway was revealed with a speed significantly exceeding classical clathrin-mediated endocytosis (CME). Membrane tension reduction is a potential mechanism by which endocytosis can be rapidly activated at remote sites. Here, we provide experimental evidence for a mechanism whereby membrane tension reduction initiates membrane budding and tubulation mediated by endocytic proteins, such as endophilin A1. We find that shape instabilities occur at well-defined membrane tensions and surface densities of endophilin. From our data, we obtain a membrane shape stability diagram that shows remarkable consistency with a quantitative model. This model applies to all laterally diffusive curvature-coupling proteins and therefore a wide range of endocytic proteins.
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Affiliation(s)
- Zheng Shi
- Department of Chemistry, University of Pennsylvania, 231 S. 34th St., Philadelphia, PA 19104, USA
| | - Tobias Baumgart
- Department of Chemistry, University of Pennsylvania, 231 S. 34th St., Philadelphia, PA 19104, USA
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300
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Hoogeboom R, Tolar P. Molecular Mechanisms of B Cell Antigen Gathering and Endocytosis. Curr Top Microbiol Immunol 2015; 393:45-63. [PMID: 26336965 DOI: 10.1007/82_2015_476] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Generation of high-affinity, protective antibodies requires B cell receptor (BCR) signaling, as well as antigen internalization and presentation to helper T cells. B cell antigen internalization is initiated by antigen capture, either from solution or from immune synapses formed on the surface of antigen-presenting cells, and proceeds via clathrin-dependent endocytosis and intracellular routing to late endosomes. Although the components of this pathway are still being discovered, it has become clear that antigen internalization is actively regulated by BCR signaling at multiple steps and, vice versa, that localization of the BCR along the endocytic pathway modulates signaling. Accordingly, defects in BCR internalization or trafficking contribute to enhanced B cell activation in models of autoimmune diseases and in B cell lymphomas. In this review, we discuss how BCR signaling complexes regulate each of the steps of this endocytic process and why defects along this pathway manifest as hyperactive B cell responses in vivo.
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Affiliation(s)
- Robbert Hoogeboom
- Division of Immune Cell Biology, National Institute for Medical Research, Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London, NW7 1AA, UK
| | - Pavel Tolar
- Division of Immune Cell Biology, National Institute for Medical Research, Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London, NW7 1AA, UK.
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