51
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Bag N, Holowka DA, Baird BA. Imaging FCS delineates subtle heterogeneity in plasma membranes of resting mast cells. Mol Biol Cell 2020; 31:709-723. [PMID: 31895009 PMCID: PMC7202073 DOI: 10.1091/mbc.e19-10-0559] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
A myriad of transient, nanoscopic lipid- and protein-based interactions confer a steady-state organization of the plasma membrane in resting cells that is poised to orchestrate assembly of key signaling components upon reception of an extracellular stimulus. Although difficult to observe directly in live cells, these subtle interactions can be discerned by their impact on the diffusion of membrane constituents. Here, we quantified the diffusion properties of a panel of structurally distinct lipid, lipid-anchored, and transmembrane (TM) probes in RBL mast cells by imaging fluorescence correlation spectroscopy (ImFCS). We developed a statistical analysis of data combined from many pixels over multiple cells to characterize differences in diffusion coefficients as small as 10%, which reflect differences in underlying interactions. We found that the distinctive diffusion properties of lipid probes can be explained by their dynamic partitioning into Lo-like proteolipid nanodomains, which encompass a major fraction of the membrane and whose physical properties are influenced by actin polymerization. Effects on diffusion of functional protein modules in both lipid-anchored and TM probes reflect additional complexity in steady state membrane organization. The contrast we observe between different probes diffusing through the same membrane milieu represents the dynamic resting steady state, which serves as a baseline for monitoring plasma membrane remodeling that occurs upon stimulation.
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Affiliation(s)
- Nirmalya Bag
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853
| | - David A Holowka
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853
| | - Barbara A Baird
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853
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52
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Petersen EN, Pavel MA, Wang H, Hansen SB. Disruption of palmitate-mediated localization; a shared pathway of force and anesthetic activation of TREK-1 channels. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2020; 1862:183091. [PMID: 31672538 PMCID: PMC6907892 DOI: 10.1016/j.bbamem.2019.183091] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 09/15/2019] [Accepted: 09/17/2019] [Indexed: 12/22/2022]
Abstract
TWIK related K+ channel (TREK-1) is a mechano- and anesthetic sensitive channel that when activated attenuates pain and causes anesthesia. Recently the enzyme phospholipase D2 (PLD2) was shown to bind to the channel and generate a local high concentration of phosphatidic acid (PA), an anionic signaling lipid that gates TREK-1. In a biological membrane, the cell harnesses lipid heterogeneity (lipid compartments) to control gating of TREK-1 using palmitate-mediated localization of PLD2. Here we discuss the ability of mechanical force and anesthetics to disrupt palmitate-mediated localization of PLD2 giving rise to TREK-1's mechano- and anesthetic-sensitive properties. The likely consequences of this indirect lipid-based mechanism of activation are discussed in terms of a putative model for excitatory and inhibitory mechano-effectors and anesthetic sensitive ion channels in a biological context. Lastly, we discuss the ability of locally generated PA to reach mM concentrations near TREK-1 and the biophysics of localized signaling. Palmitate-mediated localization of PLD2 emerges as a central control mechanism of TREK-1 responding to mechanical force and anesthetic action. This article is part of a Special Issue entitled: Molecular biophysics of membranes and membrane proteins.
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Affiliation(s)
- E Nicholas Petersen
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Mahmud Arif Pavel
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Hao Wang
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Scott B Hansen
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA.
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53
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Polanowski P, Sikorski A. Molecular transport in systems containing binding obstacles. SOFT MATTER 2019; 15:10045-10054. [PMID: 31769460 DOI: 10.1039/c9sm01876j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We studied the movement of particles in crowded environments by means of extensive Monte Carlo simulations. The dynamic lattice liquid model was employed for this purpose. It is based on the cooperative movement concept and allows the study of systems at high densities. The cooperative model of molecular transport is assumed: the motion of all moving particles is highly correlated. The model is supposed to mimic lateral motion in a membrane and therefore the system is two-dimensional with moving objects and traps placed on a triangular lattice. In our study the interaction (binding) of traps with moving particles was assumed. The conditions in which subdiffusive motion appeared in the system were analysed. The influence of the strength of binding on the dynamic percolation threshold was also shown. The differences in the dynamics compared to systems with impenetrable obstacles and with systems without correlation in motion were presented and discussed. It was shown that in the case of correlated motion the influence of deep traps is similar to that of impenetrable obstacles. If the traps are shallow a recovery to normal diffusion was observed for longer time periods.
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Affiliation(s)
- Piotr Polanowski
- Department of Molecular Physics, Łódź University of Technology, 90-924 Łódź, Poland
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54
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Basak S, Sengupta S, Chattopadhyay K. Understanding biochemical processes in the presence of sub-diffusive behavior of biomolecules in solution and living cells. Biophys Rev 2019; 11:851-872. [PMID: 31444739 PMCID: PMC6957588 DOI: 10.1007/s12551-019-00580-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 07/25/2019] [Indexed: 01/24/2023] Open
Abstract
In order to maintain cellular function, biomolecules like protein, DNA, and RNAs have to diffuse to the target spaces within the cell. Changes in the cytosolic microenvironment or in the nucleus during the fulfillment of these cellular processes affect their mobility, folding, and stability thereby impacting the transient or stable interactions with their adjacent neighbors in the organized and dynamic cellular interior. Using classical Brownian motion to elucidate the diffusion behavior of these biomolecules is hard considering their complex nature. The understanding of biomolecular diffusion inside cells still remains elusive due to the lack of a proper model that can be extrapolated to these cases. In this review, we have comprehensively addressed the progresses in this field, laying emphasis on the different aspects of anomalous diffusion in the different biochemical reactions in cell interior. These experiment-based models help to explain the diffusion behavior of biomolecules in the cytosolic and nuclear microenvironment. Moreover, since understanding of biochemical reactions within living cellular system is our main focus, we coupled the experimental observations with the concept of sub-diffusion from in vitro to in vivo condition. We believe that the pairing between the understanding of complex behavior and structure-function paradigm of biological molecules would take us forward by one step in order to solve the puzzle around diseases caused by cellular dysfunction.
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Affiliation(s)
- Sujit Basak
- Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA, 01605, USA.
| | - Sombuddha Sengupta
- Protein Folding and Dynamics Lab, Structural Biology and Bioinformatics, CSIR-Indian Institute of Chemical Biology (CSIR-IICB), 4 Raja S.C Mullick Road, Jadavpur, Kolkata, West Bengal, 700032, India
| | - Krishnananda Chattopadhyay
- Protein Folding and Dynamics Lab, Structural Biology and Bioinformatics, CSIR-Indian Institute of Chemical Biology (CSIR-IICB), 4 Raja S.C Mullick Road, Jadavpur, Kolkata, West Bengal, 700032, India
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55
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Amodeo R, Nifosì R, Giacomelli C, Ravelli C, La Rosa L, Callegari A, Trincavelli ML, Mitola S, Luin S, Marchetti L. Molecular insight on the altered membrane trafficking of TrkA kinase dead mutants. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1867:118614. [PMID: 31760089 DOI: 10.1016/j.bbamcr.2019.118614] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 11/11/2019] [Accepted: 11/18/2019] [Indexed: 12/18/2022]
Abstract
We address the contribution of kinase domain structure and catalytic activity to membrane trafficking of TrkA receptor tyrosine kinase. We conduct a systematic comparison between TrkA-wt, an ATP-binding defective mutant (TrkA-K544N) and other mutants displaying separate functional impairments of phosphorylation, ubiquitination, or recruitment of intracellular partners. We find that only K544N mutation endows TrkA with restricted membrane mobility and a substantial increase of cell surface pool already in the absence of ligand stimulation. This mutation is predicted to drive a structural destabilization of the αC helix in the N-lobe by molecular dynamics simulations, and enhances interactions with elements of the actin cytoskeleton. On the other hand, a different TrkA membrane immobilization is selectively observed after NGF stimulation, requires both phosphorylation and ubiquitination to occur, and is most probably related to the signaling abilities displayed by the wt but not mutated receptors. In conclusion, our results allow to distinguish two different TrkA membrane immobilization modes and demonstrate that not all kinase-inactive mutants display identical membrane trafficking.
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Affiliation(s)
- Rosy Amodeo
- NEST, Scuola Normale Superiore, Pisa, Italy; Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa, Italy.
| | - Riccardo Nifosì
- NEST, Scuola Normale Superiore, Pisa, Italy; NEST, Istituto Nanoscienze-CNR, Pisa, Italy
| | | | - Cosetta Ravelli
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | | | | | | | - Stefania Mitola
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Stefano Luin
- NEST, Scuola Normale Superiore, Pisa, Italy; NEST, Istituto Nanoscienze-CNR, Pisa, Italy
| | - Laura Marchetti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa, Italy; Department of Pharmacy, University of Pisa, Pisa, Italy.
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56
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Fooladi H, Moradi P, Sharifi-Zarchi A, Hosein Khalaj B. Enhanced Waddington landscape model with cell-cell communication can explain molecular mechanisms of self-organization. Bioinformatics 2019; 35:4081-4088. [PMID: 30903147 DOI: 10.1093/bioinformatics/btz201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Revised: 02/09/2019] [Accepted: 03/20/2019] [Indexed: 11/14/2022] Open
Abstract
MOTIVATION The molecular mechanisms of self-organization that orchestrate embryonic cells to create astonishing patterns have been among major questions of developmental biology. It is recently shown that embryonic stem cells (ESCs), when cultured in particular micropatterns, can self-organize and mimic the early steps of pre-implantation embryogenesis. A systems-biology model to address this observation from a dynamical systems perspective is essential and can enhance understanding of the phenomenon. RESULTS Here, we propose a multicellular mathematical model for pattern formation during in vitro gastrulation of human ESCs. This model enhances the basic principles of Waddington epigenetic landscape with cell-cell communication, in order to enable pattern and tissue formation. We have shown the sufficiency of a simple mechanism by using a minimal number of parameters in the model, in order to address a variety of experimental observations such as the formation of three germ layers and trophectoderm, responses to altered culture conditions and micropattern diameters and unexpected spotted forms of the germ layers under certain conditions. Moreover, we have tested different boundary conditions as well as various shapes, observing that the pattern is initiated from the boundary and gradually spreads towards the center. This model provides a basis for in-silico modeling of self-organization. AVAILABILITY AND IMPLEMENTATION https://github.com/HFooladi/Self_Organization. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Hosein Fooladi
- Department of Electrical Engineering, Sharif University of Technology, Tehran, Iran
| | - Parsa Moradi
- Department of Electrical Engineering, Sharif University of Technology, Tehran, Iran
| | - Ali Sharifi-Zarchi
- Department of Computer Engineering, Sharif University of Technology, Tehran, Iran.,Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Babak Hosein Khalaj
- Department of Electrical Engineering, Sharif University of Technology, Tehran, Iran
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57
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Kang M, Day CA, Kenworthy AK. A novel computational framework for D(t) from Fluorescence Recovery after Photobleaching data reveals various anomalous diffusion types in live cell membranes. Traffic 2019; 20:867-880. [PMID: 31452286 DOI: 10.1111/tra.12690] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 08/23/2019] [Accepted: 08/23/2019] [Indexed: 01/20/2023]
Abstract
Diffusion of proteins and lipids in lipid membranes plays a pivotal role in almost all aspects of cellular biology, including motility, exo-/endocytosis and signal transduction. For this reason, gaining a detailed understanding of membrane structure and function has long been a major area of cell biology research. To better elucidate this structure-function relationship, various tools have been developed for diffusion measurements, including Fluorescence Recovery After Photobleaching (FRAP). Because of the complexity of cellular microenvironments, biological diffusion is often correlated over time and described by a time-dependent diffusion coefficient, D(t), although the underlying mechanisms are not fully understood. Since D(t) provides important information regarding cellular structures, such as the existence of subresolution barriers to diffusion, many efforts have been made to quantify D(t) by FRAP assuming a single power law, D(t) = Γt α - 1 where Γ and α are transport coefficient and anomalous exponent. However, straightforward approaches to quantify a general form of D(t) are lacking. In this study, we develop a novel mathematical and computational framework to compute the mean square displacement of diffusing molecules and diffusion coefficient D(t) from each individual time point of confocal FRAP data without the single power law assumption. Additionally, we developed an auxiliary equation for D(t) which can readily distinguish normal diffusion or single power law anomalous diffusion from other types of anomalous diffusion directly from FRAP data. Importantly, by applying this approach to FRAP data from a variety of membrane markers, we demonstrate the single power law anomalous diffusion assumption is not sufficient to describe various types of D(t) of membrane proteins. Lastly, we discuss how our new approaches can be applied to other fluorescence microscopy tools such as Fluorescence Correlation Spectroscopy (FCS) and Single Particle Tracking (SPT).
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Affiliation(s)
- Minchul Kang
- Department of Mathematics, Texas A&M University-Commerce, Commerce, Texas
| | - Charles A Day
- The Hormel Institute, University of Minnesota, Austin, Minnesota
| | - Anne K Kenworthy
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee.,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee.,Chemical and Physical Biology Program, Vanderbilt University School of Medicine, Nashville, Tennessee
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58
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Nicovich PR, Kwiatek JM, Ma Y, Benda A, Gaus K. FSCS Reveals the Complexity of Lipid Domain Dynamics in the Plasma Membrane of Live Cells. Biophys J 2019; 114:2855-2864. [PMID: 29925022 PMCID: PMC6026469 DOI: 10.1016/j.bpj.2018.04.050] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 02/14/2018] [Accepted: 04/10/2018] [Indexed: 12/14/2022] Open
Abstract
The coexistence of lipid domains with different degrees of lipid packing in the plasma membrane of mammalian cells has been postulated, but direct evidence has so far been challenging to obtain because of the small size and short lifetime of these domains in live cells. Here, we use fluorescence spectral correlation spectroscopy in conjunction with a probe sensitive to the membrane environment to quantify spectral fluctuations associated with dynamics of membrane domains in live cells. With this method, we show that membrane domains are present in live COS-7 cells and have a lifetime lower bound of 5.90 and 14.69 ms for the ordered and disordered phases, respectively. Comparisons to simulations indicate that the underlying mechanism of these fluctuations is complex but qualitatively described by a combination of dye diffusion between membrane domains as well as the motion of domains within the membrane.
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Affiliation(s)
- Philip R Nicovich
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, Sydney, New South Wales, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, New South Wales, Australia; Allen Institute for Brain Science, Seattle, Washington.
| | - Joanna M Kwiatek
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, Sydney, New South Wales, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, New South Wales, Australia
| | - Yuanqing Ma
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, Sydney, New South Wales, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, New South Wales, Australia
| | - Aleš Benda
- Imaging Methods Core Facility at BIOCEV, Faculty of Sciences, Charles University, Vestec, Czech Republic
| | - Katharina Gaus
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, Sydney, New South Wales, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, New South Wales, Australia
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59
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Kumari A, Pineau J, Sáez PJ, Maurin M, Lankar D, San Roman M, Hennig K, Boura VF, Voituriez R, Karlsson MCI, Balland M, Lennon Dumenil AM, Pierobon P. Actomyosin-driven force patterning controls endocytosis at the immune synapse. Nat Commun 2019; 10:2870. [PMID: 31253773 PMCID: PMC6599028 DOI: 10.1038/s41467-019-10751-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 05/30/2019] [Indexed: 11/30/2022] Open
Abstract
An important channel of cell-to-cell communication is direct contact. The immune synapse is a paradigmatic example of such type of interaction: it forms upon engagement of antigen receptors in lymphocytes by antigen-presenting cells and allows the local exchange of molecules and information. Although mechanics has been shown to play an important role in this process, how forces organize and impact on synapse function is unknown. We find that mechanical forces are spatio-temporally patterned at the immune synapse: global pulsatile myosin II-driven tangential forces are observed at the synapse periphery while localised forces generated by invadosome-like F-actin protrusions are detected at its centre. Noticeably, we observe that these force-producing actin protrusions constitute the main site of antigen extraction and endocytosis and require myosin II contractility to form. The interplay between global and local forces dictated by the organization of the actomyosin cytoskeleton therefore controls endocytosis at the immune synapse. The immune synapse promotes cellular information exchange but the role of biophysical forces in synapse function is unclear. Here, the authors show that B cells exert two types of forces, a centripetal myosin II-driven force and a central actin protrusive force at the site of antigen extraction.
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Affiliation(s)
- Anita Kumari
- Institut Curie, PSL Research University, INSERM U932, 26 rue d'Ulm, 75248, Paris, Cedex 05, France.,Université Paris Descartes, Paris, 75006, France
| | - Judith Pineau
- Institut Curie, PSL Research University, INSERM U932, 26 rue d'Ulm, 75248, Paris, Cedex 05, France.,Université Paris Descartes, Paris, 75006, France
| | - Pablo J Sáez
- Institut Curie, PSL Research University, INSERM U932, 26 rue d'Ulm, 75248, Paris, Cedex 05, France
| | - Mathieu Maurin
- Institut Curie, PSL Research University, INSERM U932, 26 rue d'Ulm, 75248, Paris, Cedex 05, France
| | - Danielle Lankar
- Institut Curie, PSL Research University, INSERM U932, 26 rue d'Ulm, 75248, Paris, Cedex 05, France
| | - Mabel San Roman
- Institut Curie, PSL Research University, INSERM U932, 26 rue d'Ulm, 75248, Paris, Cedex 05, France
| | - Katharina Hennig
- Laboratoire Interdisciplinaire de Physique, Université Joseph Fourier (Grenoble 1), 38402, Saint, Martin d'Hères Cedex 9, France
| | - Vanessa F Boura
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, 17177, Sweden
| | - Raphael Voituriez
- Laboratoire de Physique Théorique de la Matière Condensée, UMR 7600 CNRS /UPMC and Laboratoire Jean Perrin, UMR 8237 CNRS /UPMC, 4 Place Jussieu, 75255, Paris, Cedex 05, France
| | - Mikael C I Karlsson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, 17177, Sweden
| | - Martial Balland
- Laboratoire Interdisciplinaire de Physique, Université Joseph Fourier (Grenoble 1), 38402, Saint, Martin d'Hères Cedex 9, France
| | - Ana-Maria Lennon Dumenil
- Institut Curie, PSL Research University, INSERM U932, 26 rue d'Ulm, 75248, Paris, Cedex 05, France.
| | - Paolo Pierobon
- Institut Curie, PSL Research University, INSERM U932, 26 rue d'Ulm, 75248, Paris, Cedex 05, France.
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60
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Abstract
Rods and cones are retinal photoreceptor neurons required for our visual sensation. Because of their highly polarized structures and well-characterized processes of G protein-coupled receptor-mediated phototransduction signaling, these photoreceptors have been excellent models for studying the compartmentalization and sorting of proteins. Rods and cones have a modified ciliary compartment called the outer segment (OS) as well as non-OS compartments. The distinct membrane protein compositions between OS and non-OS compartments suggest that the OS is separated from the rest of the cellular compartments by multiple barriers or gates that are selectively permissive to specific cargoes. This review discusses the mechanisms of protein sorting and compartmentalization in photoreceptor neurons. Proper sorting and compartmentalization of membrane proteins are required for signal transduction and transmission. This review also discusses the roles of compartmentalized signaling, which is compromised in various retinal ciliopathies.
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Affiliation(s)
- Yoshikazu Imanishi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, USA;
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61
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Aaron J, Wait E, DeSantis M, Chew TL. Practical Considerations in Particle and Object Tracking and Analysis. ACTA ACUST UNITED AC 2019; 83:e88. [PMID: 31050869 DOI: 10.1002/cpcb.88] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The rapid advancement of live-cell imaging technologies has enabled biologists to generate high-dimensional data to follow biological movement at the microscopic level. Yet, the "perceived" ease of use of modern microscopes has led to challenges whereby sub-optimal data are commonly generated that cannot support quantitative tracking and analysis as a result of various ill-advised decisions made during image acquisition. Even optimally acquired images often require further optimization through digital processing before they can be analyzed. In writing this article, we presume our target audience to be biologists with a foundational understanding of digital image acquisition and processing, who are seeking to understand the essential steps for particle/object tracking experiments. It is with this targeted readership in mind that we review the basic principles of image-processing techniques as well as analysis strategies commonly used for tracking experiments. We conclude this technical survey with a discussion of how movement behavior can be mathematically modeled and described. © 2019 by John Wiley & Sons, Inc.
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Affiliation(s)
- Jesse Aaron
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia
| | - Eric Wait
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia
| | - Michael DeSantis
- Light Microscopy Facility, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia
| | - Teng-Leong Chew
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia.,Light Microscopy Facility, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia
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62
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Gmachowski L. Biomolecule displacement by Brownian step. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2019.02.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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63
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Distinct segregation patterns of yeast cell-peripheral proteins uncovered by a method for protein segregatome analysis. Proc Natl Acad Sci U S A 2019; 116:8909-8918. [PMID: 30975753 DOI: 10.1073/pnas.1819715116] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Protein segregation contributes to various cellular processes such as polarization, differentiation, and aging. However, the difficulty in global determination of protein segregation hampers our understanding of its mechanisms and physiological roles. Here, by developing a quantitative proteomics technique, we globally monitored segregation of preexisting and newly synthesized proteins during cell division of budding yeast, and identified crucial domains that determine the segregation of cell-peripheral proteins. Remarkably, the proteomic and subsequent microscopic analyses demonstrated that the flow through the bud neck of the proteins that harbor both endoplasmic reticulum (ER) membrane-spanning and plasma membrane (PM)-binding domains is not restricted by the previously suggested ER membrane or PM diffusion barriers but by septin-mediated partitioning of the PM-associated ER (pmaER). Furthermore, the proteomic analysis revealed that although the PM-spanning t-SNARE Sso2 was retained in mother cells, its paralog Sso1 unexpectedly showed symmetric localization. We found that the transport of Sso1 to buds was required for enhancement of polarized cell growth and resistance to cell-wall stress. Taken together, these data resolve long-standing questions about septin-mediated compartmentalization of the cell periphery, and provide new mechanistic insights into the segregation of cell-periphery proteins and their cellular functions.
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64
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Pereira PM, Albrecht D, Culley S, Jacobs C, Marsh M, Mercer J, Henriques R. Fix Your Membrane Receptor Imaging: Actin Cytoskeleton and CD4 Membrane Organization Disruption by Chemical Fixation. Front Immunol 2019; 10:675. [PMID: 31024536 PMCID: PMC6460894 DOI: 10.3389/fimmu.2019.00675] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 03/12/2019] [Indexed: 12/25/2022] Open
Abstract
Single-molecule localization microscopy (SMLM) techniques allow near molecular scale resolution (~ 20 nm) as well as precise and robust analysis of protein organization at different scales. SMLM hardware, analytics and probes have been the focus of a variety of studies and are now commonly used in laboratories across the world. Protocol reliability and artifact identification are increasingly seen as important aspects of super-resolution microscopy. The reliability of these approaches thus requires in-depth evaluation so that biological findings are based on solid foundations. Here we explore how different fixation approaches that disrupt or preserve the actin cytoskeleton affect membrane protein organization. Using CD4 as a model, we show that fixation-mediated disruption of the actin cytoskeleton correlates with changes in CD4 membrane organization. We highlight how these artifacts are easy to overlook and how careful sample preparation is essential for extracting meaningful results from super-resolution microscopy.
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Affiliation(s)
- Pedro M. Pereira
- MRC-Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
- The Francis Crick Institute, London, United Kingdom
| | - David Albrecht
- MRC-Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Siân Culley
- MRC-Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
- The Francis Crick Institute, London, United Kingdom
- Institute for the Physics of Living Systems, University College London, London, United Kingdom
| | - Caron Jacobs
- MRC-Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Mark Marsh
- MRC-Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Jason Mercer
- MRC-Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Ricardo Henriques
- MRC-Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
- The Francis Crick Institute, London, United Kingdom
- Institute for the Physics of Living Systems, University College London, London, United Kingdom
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
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65
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Rajagopal N, Irudayanathan FJ, Nangia S. Palmitoylation of Claudin-5 Proteins Influences Their Lipid Domain Affinity and Tight Junction Assembly at the Blood–Brain Barrier Interface. J Phys Chem B 2019; 123:983-993. [DOI: 10.1021/acs.jpcb.8b09535] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Nandhini Rajagopal
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse 13244, United States
| | | | - Shikha Nangia
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse 13244, United States
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66
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Understanding phosphoinositides: rare, dynamic, and essential membrane phospholipids. Biochem J 2019; 476:1-23. [PMID: 30617162 DOI: 10.1042/bcj20180022] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 12/03/2018] [Accepted: 12/07/2018] [Indexed: 12/15/2022]
Abstract
Polyphosphoinositides (PPIs) are essential phospholipids located in the cytoplasmic leaflet of eukaryotic cell membranes. Despite contributing only a small fraction to the bulk of cellular phospholipids, they make remarkable contributions to practically all aspects of a cell's life and death. They do so by recruiting cytoplasmic proteins/effectors or by interacting with cytoplasmic domains of membrane proteins at the membrane-cytoplasm interface to organize and mold organelle identity. The present study summarizes aspects of our current understanding concerning the metabolism, manipulation, measurement, and intimate roles these lipids play in regulating membrane homeostasis and vital cell signaling reactions in health and disease.
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67
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Rothen-Rutishauser B, Bourquin J, Petri-Fink A. Nanoparticle-Cell Interactions: Overview of Uptake, Intracellular Fate and Induction of Cell Responses. BIOLOGICAL RESPONSES TO NANOSCALE PARTICLES 2019. [DOI: 10.1007/978-3-030-12461-8_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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68
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Freeman SA, Vega A, Riedl M, Collins RF, Ostrowski PP, Woods EC, Bertozzi CR, Tammi MI, Lidke DS, Johnson P, Mayor S, Jaqaman K, Grinstein S. Transmembrane Pickets Connect Cyto- and Pericellular Skeletons Forming Barriers to Receptor Engagement. Cell 2018; 172:305-317.e10. [PMID: 29328918 DOI: 10.1016/j.cell.2017.12.023] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 08/03/2017] [Accepted: 12/18/2017] [Indexed: 01/17/2023]
Abstract
Phagocytic receptors must diffuse laterally to become activated upon clustering by multivalent targets. Receptor diffusion, however, can be obstructed by transmembrane proteins ("pickets") that are immobilized by interacting with the cortical cytoskeleton. The molecular identity of these pickets and their role in phagocytosis have not been defined. We used single-molecule tracking to study the interaction between Fcγ receptors and CD44, an abundant transmembrane protein capable of indirect association with F-actin, hence likely to serve as a picket. CD44 tethers reversibly to formin-induced actin filaments, curtailing receptor diffusion. Such linear filaments predominate in the trailing end of polarized macrophages, where receptor mobility was minimal. Conversely, receptors were most mobile at the leading edge, where Arp2/3-driven actin branching predominates. CD44 binds hyaluronan, anchoring a pericellular coat that also limits receptor displacement and obstructs access to phagocytic targets. Force must be applied to traverse the pericellular barrier, enabling receptors to engage their targets.
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Affiliation(s)
- Spencer A Freeman
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Anthony Vega
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Magdalena Riedl
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Richard F Collins
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Phillip P Ostrowski
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Elliot C Woods
- Departments of Chemistry and Molecular Biology and Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Carolyn R Bertozzi
- Departments of Chemistry and Molecular Biology and Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Markku I Tammi
- Institute of Biomedicine, University of Eastern Finland, Kuopio 70210, Finland
| | - Diane S Lidke
- Department of Pathology, Cancer Research Facility, School of Medicine, University of New Mexico, Albuquerque, NM 87131, USA
| | - Pauline Johnson
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Satyajit Mayor
- Cellular Organization and Signaling, National Centre for Biological Science, Tata Institute for Fundamental Research, Bangalore 560 065, India
| | - Khuloud Jaqaman
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sergio Grinstein
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON M5C 1N8, Canada.
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69
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Shireen Z, Babu SB. Cage dynamics leads to double relaxation of the intermediate scattering function in a binary colloidal system. SOFT MATTER 2018; 14:9271-9281. [PMID: 30403250 DOI: 10.1039/c8sm01474d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A system of binary colloids where one fraction of particles is aggregating by forming irreversible bonds and the other fraction of particles only interacts as hard spheres, is simulated using Brownian cluster dynamics. These aggregating species always formed percolating clusters for the case of diffusing hard spheres while for the static case, formation of percolating clusters depended on the fraction of static hard spheres in the system. The dynamics of the hard spheres inside the percolating clusters was studied by restarting the simulation after the kinetics of aggregation was arrested. Two cases were studied, one where the percolated particles moved within the bonds or cage dynamics was allowed and another where the movement within the bonds was not allowed or the cages were static. The hard spheres showed anomalous diffusion in both cases. The mean square displacement showed that for the case of dynamic cages we always had diffusive hard spheres irrespective of the fraction of hard spheres for volume fractions below 0.49. Static cages, depending on the fraction of hard spheres, showed either diffusive or arrested behavior of hard spheres. The intermediate scattering function of only the hard sphere particles showed double relaxation similar to the colloidal glass system for low volume fraction, where the fraction of hard sphere particles was small. For higher fractions we observed only a single stretched exponential. We could differentiate between slow and fast particles for both static and dynamic cages. For the case of static cages the hard spheres were permanently stuck inside the cages while for the case of dynamic cages almost all the hard spheres were moving in and out of the cages.
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Affiliation(s)
- Zakiya Shireen
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
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70
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Belardi B, Son S, Vahey MD, Wang J, Hou J, Fletcher DA. Claudin-4 reconstituted in unilamellar vesicles is sufficient to form tight interfaces that partition membrane proteins. J Cell Sci 2018; 132:jcs.221556. [PMID: 30209136 DOI: 10.1242/jcs.221556] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 09/01/2018] [Indexed: 01/05/2023] Open
Abstract
Tight junctions have been hypothesized to act as molecular fences in the plasma membrane of epithelial cells, helping to form differentiated apical and basolateral domains. While this fence function is believed to arise from the interaction of four-pass transmembrane claudins, the complexity of tight junctions has made direct evidence of their role as a putative diffusion barrier difficult to obtain. Here, we address this challenge by reconstituting claudin-4 into giant unilamellar vesicles using microfluidic jetting. We find that reconstituted claudin-4 alone can form adhesive membrane interfaces without the accessory proteins that are present in vivo By controlling the molecular composition of the inner and outer leaflets of jetted vesicle membranes, we show that claudin-4-mediated interfaces can drive partitioning of extracellular membrane proteins with ectodomains as small as 5 nm but not of inner or outer leaflet lipids. Our findings indicate that homotypic interactions of claudins and their small size can contribute to the polarization of epithelial cells.
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Affiliation(s)
- Brian Belardi
- Department of Bioengineering and Biophysics Program, University of California, Berkeley, CA 94720, USA
| | - Sungmin Son
- Department of Bioengineering and Biophysics Program, University of California, Berkeley, CA 94720, USA
| | - Michael D Vahey
- Department of Bioengineering and Biophysics Program, University of California, Berkeley, CA 94720, USA
| | - Jinzhi Wang
- Department of Internal Medicine & Center for Investigation of Membrane Excitability Disease, Washington University Medical School, St. Louis, MO 63110, USA
| | - Jianghui Hou
- Department of Internal Medicine & Center for Investigation of Membrane Excitability Disease, Washington University Medical School, St. Louis, MO 63110, USA
| | - Daniel A Fletcher
- Department of Bioengineering and Biophysics Program, University of California, Berkeley, CA 94720, USA .,Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
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71
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Mu L, Tu Z, Miao L, Ruan H, Kang N, Hei Y, Chen J, Wei W, Gong F, Wang B, Du Y, Ma G, Amerein MW, Xia T, Shi Y. A phosphatidylinositol 4,5-bisphosphate redistribution-based sensing mechanism initiates a phagocytosis programing. Nat Commun 2018; 9:4259. [PMID: 30323235 PMCID: PMC6189171 DOI: 10.1038/s41467-018-06744-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 09/20/2018] [Indexed: 12/30/2022] Open
Abstract
Phagocytosis is one of the earliest cellular functions, developing approximately 2 billion years ago. Although FcR-based phagocytic signaling is well-studied, how it originated from ancient phagocytosis is unknown. Lipid redistribution upregulates a phagocytic program recapitulating FcR-based phagocytosis with complete dependence on Src family kinases, Syk, and phosphoinositide 3-kinases (PI3K). Here we show that in phagocytes, an atypical ITAM sequence in the ancient membrane anchor protein Moesin transduces signal without receptor activation. Plasma membrane deformation created by solid structure binding generates phosphatidylinositol 4,5-bisphosphate (PIP2) accumulation at the contact site, which binds the Moesin FERM domain and relocalizes Syk to the membrane via the ITAM motif. Phylogenic analysis traces this signaling using PI3K and Syk to 0.8 billion years ago, earlier than immune receptor signaling. The proposed general model of solid structure phagocytosis implies a preexisting lipid redistribution-based activation platform collecting intracellular signaling components for the emergence of immune receptors.
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Affiliation(s)
- Libing Mu
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Institute for Immunology and Department of Basic Medical Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Medicine; Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Zhongyuan Tu
- Department of Microbiology, Immunology & Infectious Diseases and Snyder Institute, University of Calgary, Calgary, T2N 4N1, AB, Canada
| | - Lin Miao
- Institute for Immunology and Department of Basic Medical Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Medicine; Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China
- School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Hefei Ruan
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Institute for Immunology and Department of Basic Medical Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Medicine; Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Ning Kang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Institute for Immunology and Department of Basic Medical Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Medicine; Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yongzhen Hei
- Institute for Immunology and Department of Basic Medical Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Medicine; Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jiahuan Chen
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Institute for Immunology and Department of Basic Medical Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Medicine; Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Wei Wei
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China
| | - Fangling Gong
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China
| | - Bingjie Wang
- Department of Biomedical Engineering, School of Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Tsinghua University, Beijing, 100084, China
| | - Yanan Du
- Department of Biomedical Engineering, School of Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Tsinghua University, Beijing, 100084, China
| | - Guanghui Ma
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China
| | - Matthias W Amerein
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, T2N 4N1, AB, Canada
- Snyder Institute of Chronic Diseases, University of Calgary, Calgary, T2N 4N1, AB, Canada
| | - Tie Xia
- School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Institute for Immunology and Department of Basic Medical Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Medicine; Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China.
| | - Yan Shi
- School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Institute for Immunology and Department of Basic Medical Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Medicine; Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China.
- Department of Microbiology, Immunology & Infectious Diseases and Snyder Institute, University of Calgary, Calgary, T2N 4N1, AB, Canada.
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72
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Abstract
The pulmonary endothelial cell forms a critical semi-permeable barrier between the vascular and interstitial space. As part of the blood-gas barrier in the lung, the endothelium plays a key role in normal physiologic function and pathologic disease. Changes in endothelial cell shape, defined by its plasma membrane, determine barrier integrity. A number of key cytoskeletal regulatory and effector proteins including non-muscle myosin light chain kinase, cortactin, and Arp 2/3 mediate actin rearrangements to form cortical and membrane associated structures in response to barrier enhancing stimuli. These actin formations support and interact with junctional complexes and exert forces to protrude the lipid membrane to and close gaps between individual cells. The current knowledge of these cytoskeletal processes and regulatory proteins are the subject of this review. In addition, we explore novel advancements in cellular imaging that are poised to shed light on the complex nature of pulmonary endothelial permeability.
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73
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Georgi J, Metere R, Jäger C, Morawski M, Möller HE. Influence of the extracellular matrix on water mobility in subcortical gray matter. Magn Reson Med 2018; 81:1265-1279. [PMID: 30276849 DOI: 10.1002/mrm.27459] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/12/2018] [Accepted: 06/29/2018] [Indexed: 11/12/2022]
Abstract
PURPOSE Water mobility in tissues is related to the microstructure that modulates diffusion and spin relaxation. Previous work has shown that the extracellular matrix (ECM) impacts water diffusion in cartilage. To investigate if similar contributions to image contrast exist for brain, which is characterized by a substantially lower ECM content, diffusion and relaxation were studied in fixed samples from goat and human thalamus before and after enzymatic digestion of ECM compounds. Selected experiments in human corpus callosum were included for comparing subcortical gray matter and white matter. METHODS Digestion of matrix components was achieved by treatment with hyaluronidase. Nonlocalized pulsed field gradient measurements were performed with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>b</mml:mi></mml:math> values between 0.6 and 18,000 s/mm2 at 3T and temperatures between 0°C and 20°C, in addition to T1 and T2 relaxation measurements. The data were fitted to multiexponential models to account for different water compartments. After the measurements, the samples were sliced and stained for ECM-sensitive markers to verify efficient digestion. RESULTS Microstructural alterations associated with hyaluronan digestion did not lead to measurable effects on water diffusion or <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>T</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:math> . However, T1 of the main relaxographic component, attributed to intra-/extracellular water, decreased by 7%. CONCLUSION Investigations with very strong gradients did not reveal a detectable effect on water diffusion or <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>T</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:math> after hyaluronan removal, indicating that the brain ECM content is too low to produce a detectable effect. The subtle alteration of T1 upon hyaluronidase treatment might reflect a modulation of intercompartmental water exchange properties.
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Affiliation(s)
- Jakob Georgi
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Riccardo Metere
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Carsten Jäger
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Paul Flechsig Institute of Brain Research, University of Leipzig, Germany
| | - Markus Morawski
- Paul Flechsig Institute of Brain Research, University of Leipzig, Germany
| | - Harald E Möller
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Felix Bloch Institute for Solid State Physics, University of Leipzig, Germany
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74
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Gronnier J, Gerbeau-Pissot P, Germain V, Mongrand S, Simon-Plas F. Divide and Rule: Plant Plasma Membrane Organization. TRENDS IN PLANT SCIENCE 2018; 23:899-917. [PMID: 30174194 DOI: 10.1016/j.tplants.2018.07.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 07/09/2018] [Accepted: 07/13/2018] [Indexed: 05/24/2023]
Abstract
Since the publication of the fluid mosaic as a relevant model for biological membranes, accumulating evidence has revealed the outstanding complexity of the composition and organization of the plant plasma membrane (PM). Powerful new methodologies have uncovered the remarkable multiscale and multicomponent heterogeneity of PM subcompartmentalization, and this is emerging as a general trait with different features and properties. It is now evident that the dynamics of such a complex organization are intrinsically related to signaling pathways that regulate key physiological processes. Listing and linking recent progress in precisely qualifying these heterogeneities will help to draw an integrated picture of the plant PM. Understanding the key principles governing such a complex dynamic organization will contribute to deciphering the crucial role of the PM in cell physiology.
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Affiliation(s)
- Julien Gronnier
- Laboratoire de Biogenèse Membranaire (LBM), Unité Mixte de Recherche (UMR) 5200, Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, Bordeaux, France; Present address: Laboratory of Cyril Zipfel, Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland
| | - Patricia Gerbeau-Pissot
- Agroécologie, Institut National Supérieur des Sciences Agronomiques, de l'Alimentation, et de l'Environnement (AgroSup) Dijon, CNRS, Institut National de la Recherche Agronomique (INRA), Université Bourgogne Franche-Comté, Dijon, France
| | - Véronique Germain
- Laboratoire de Biogenèse Membranaire (LBM), Unité Mixte de Recherche (UMR) 5200, Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, Bordeaux, France
| | - Sébastien Mongrand
- Laboratoire de Biogenèse Membranaire (LBM), Unité Mixte de Recherche (UMR) 5200, Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, Bordeaux, France; These authors contributed equally to this work
| | - Françoise Simon-Plas
- Agroécologie, Institut National Supérieur des Sciences Agronomiques, de l'Alimentation, et de l'Environnement (AgroSup) Dijon, CNRS, Institut National de la Recherche Agronomique (INRA), Université Bourgogne Franche-Comté, Dijon, France; These authors contributed equally to this work.
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75
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Gawden-Bone CM, Frazer GL, Richard AC, Ma CY, Strege K, Griffiths GM. PIP5 Kinases Regulate Membrane Phosphoinositide and Actin Composition for Targeted Granule Secretion by Cytotoxic Lymphocytes. Immunity 2018; 49:427-437.e4. [PMID: 30217409 PMCID: PMC6162341 DOI: 10.1016/j.immuni.2018.08.017] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 06/22/2018] [Accepted: 08/21/2018] [Indexed: 01/19/2023]
Abstract
How cytotoxic T lymphocytes (CTLs) sense T cell receptor (TCR) signaling in order to specialize an area of plasma membrane for granule secretion is not understood. Here, we demonstrate that immune synapse formation led to rapid localized changes in the phosphoinositide composition of the plasma membrane, both reducing phosphoinositide-4-phosphate (PI(4)P), PI(4,5)P2, and PI(3,4,5)P3 and increasing diacylglycerol (DAG) and PI(3,4)P2 within the first 2 min of synapse formation. These changes reduced negative charge across the synapse, triggering the release of electrostatically bound PIP5 kinases that are required to replenish PI(4,5)P2. As PI(4,5)P2 decreased, actin was depleted from the membrane, allowing secretion. Forced localization of PIP5Kβ across the synapse prevented actin depletion, blocking both centrosome docking and secretion. Thus, PIP5Ks act as molecular sensors of TCR activation, controlling actin recruitment across the synapse, ensuring exquisite co-ordination between TCR signaling and CTL secretion. Immune synapse formation triggers rapid changes in the membrane composition and charge PIP5K is a molecular sensor of TCR activation and is rapidly depleted at the synapse PIP5K distribution controls actin recruitment across the immune synapse Membrane specialization controls accessibility for centrosome docking and secretion
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Affiliation(s)
- Christian M Gawden-Bone
- Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Gordon L Frazer
- Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Arianne C Richard
- Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK; Cancer Research UK Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0RE, UK
| | - Claire Y Ma
- Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Katharina Strege
- Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Gillian M Griffiths
- Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK.
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76
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Ma Y, Benda A, Kwiatek J, Owen DM, Gaus K. Time-Resolved Laurdan Fluorescence Reveals Insights into Membrane Viscosity and Hydration Levels. Biophys J 2018; 115:1498-1508. [PMID: 30269886 PMCID: PMC6257870 DOI: 10.1016/j.bpj.2018.08.041] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 06/27/2018] [Accepted: 08/27/2018] [Indexed: 11/24/2022] Open
Abstract
Membrane viscosity and hydration levels characterize the biophysical properties of biological membranes and are reflected in the rate and extent of solvent relaxation, respectively, of environmentally sensitive fluorophores such as Laurdan. Here, we first developed a method for a time-resolved general polarization (GP) analysis with fluorescence-lifetime imaging microscopy that captures both the extent and rate of Laurdan solvent relaxation. We then conducted time-resolved GP measurements with Laurdan-stained model membranes and cell membranes. These measurements revealed that cholesterol levels in lipid vesicles altered membrane hydration and viscosity, whereas curvature had little effect on either parameter. We also applied the method to the plasma membrane of live cells using a supercritical angle fluorescence objective, to our knowledge the first time fluorescence-lifetime imaging microscopy images were generated with supercritical angle fluorescence. Here, we found that local variations in membrane cholesterol most likely account for the heterogeneity of Laurdan lifetime in plasma membrane. In conclusion, time-resolved GP measurements provide additional insights into the biophysical properties of membranes.
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Affiliation(s)
- Yuanqing Ma
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, New South Wales, Australia
| | - Aleš Benda
- Biomedical Imaging Facility, Lowy Cancer Research Centre, University of New South Wales, Sydney, New South Wales, Australia
| | - Joanna Kwiatek
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, New South Wales, Australia
| | - Dylan M Owen
- Department of Physics and Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Katharina Gaus
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, New South Wales, Australia.
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77
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Ikenouchi J. Roles of membrane lipids in the organization of epithelial cells: Old and new problems. Tissue Barriers 2018; 6:1-8. [PMID: 30156967 DOI: 10.1080/21688370.2018.1502531] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Epithelial cells have characteristic membrane domains. Identification of membrane proteins playing an important role in these membrane domains has progressed and numerous studies have been performed on the functional analysis of these membrane proteins. On the other hand, the precise roles of membrane lipids in the organization of these membrane domains are largely unknown. Historically, the concept of lipid raft arose from the analysis of lipid composition of the apical membrane, and it can be said that epithelial cells are an optimal experimental model for elucidating the functions of lipids. In this review, I discuss the role of lipids in the formation of epithelial polarity and in the formation of cell membrane structures of epithelial cells such as microvilli in the apical domain, cell-cell adhesion apparatus in the lateral domain and cell-matrix adhesion in the basal domain.
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Affiliation(s)
- Junichi Ikenouchi
- a Department of Biology, Faculty of Sciences , Kyushu University , Fukuoka , Nishi-ku , Japan.,b AMED-PRIME, Japan Agency for Medical Research and Development , Tokyo , Japan
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78
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Lyssenko NN, Haider N, Picataggi A, Cipollari E, Jiao W, Phillips MC, Rader DJ, Chavali VRM. Directional ABCA1-mediated cholesterol efflux and apoB-lipoprotein secretion in the retinal pigment epithelium. J Lipid Res 2018; 59:1927-1939. [PMID: 30076206 DOI: 10.1194/jlr.m087361] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 06/21/2018] [Indexed: 12/15/2022] Open
Abstract
Cholesterol-containing soft drusen and subretinal drusenoid deposits (SDDs) occur at the basolateral and apical side of the retinal pigment epithelium (RPE), respectively, in the chorioretina and are independent risk factors for late age-related macular degeneration (AMD). Cholesterol in these deposits could originate from the RPE as nascent HDL or apoB-lipoprotein. We characterized cholesterol efflux and apoB-lipoprotein secretion in RPE cells. Human RPE cells, ARPE-19, formed nascent HDL that was similar in physicochemical properties to nascent HDL formed by other cell types. In highly polarized primary human fetal RPE (phfRPE) monolayers grown in low-lipid conditions, cholesterol efflux to HDL was moderately directional to the apical side and much stronger than ABCA1-mediated efflux to apoA-I at both sides; ABCA1-mediated efflux was weak and equivalent between the two sides. Feeding phfRPE monolayers with oxidized or acetylated LDL increased intracellular levels of free and esterified cholesterol and substantially raised ABCA1-mediated cholesterol efflux at the apical side. phfRPE monolayers secreted apoB-lipoprotein preferentially to the apical side in low-lipid and oxidized LDL-feeding conditions. These findings together with evidence from human genetics and AMD pathology suggest that RPE-generated HDL may contribute lipid to SDDs.
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Affiliation(s)
- Nicholas N Lyssenko
- Division of Translational Medicine and Human Genetics, Department of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Naqi Haider
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA
| | - Antonino Picataggi
- Division of Translational Medicine and Human Genetics, Department of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Eleonora Cipollari
- Division of Translational Medicine and Human Genetics, Department of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Wanzhen Jiao
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA
| | - Michael C Phillips
- Division of Translational Medicine and Human Genetics, Department of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Daniel J Rader
- Division of Translational Medicine and Human Genetics, Department of Medicine, University of Pennsylvania, Philadelphia, PA.,Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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79
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De Franceschi N, Alqabandi M, Miguet N, Caillat C, Mangenot S, Weissenhorn W, Bassereau P. The ESCRT protein CHMP2B acts as a diffusion barrier on reconstituted membrane necks. J Cell Sci 2018; 132:jcs.217968. [PMID: 29967034 DOI: 10.1242/jcs.217968] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 06/25/2018] [Indexed: 01/23/2023] Open
Abstract
Endosomal sorting complexes required for transport (ESCRT)-III family proteins catalyze membrane remodeling processes that stabilize and constrict membrane structures. It has been proposed that stable ESCRT-III complexes containing CHMP2B could establish diffusion barriers at the post-synaptic spine neck. In order to better understand this process, we developed a novel method based on fusion of giant unilamellar vesicles to reconstitute ESCRT-III proteins inside GUVs, from which membrane nanotubes are pulled. The new assay ensures that ESCRT-III proteins polymerize only when they become exposed to physiologically relevant membrane topology mimicking the complex geometry of post-synaptic spines. We establish that CHMP2B, both full-length and with a C-terminal deletion (ΔC), preferentially binds to membranes containing phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. Moreover, we show that CHMP2B preferentially accumulates at the neck of membrane nanotubes, and provide evidence that CHMP2B-ΔC prevents the diffusion of PI(4,5)P2 lipids and membrane-bound proteins across the tube neck. This indicates that CHMP2B polymers formed at a membrane neck may function as a diffusion barrier, highlighting a potential important function of CHMP2B in maintaining synaptic spine structures.
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Affiliation(s)
- Nicola De Franceschi
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France.,Sorbonne Université, 75005, Paris, France
| | - Maryam Alqabandi
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France.,Sorbonne Université, 75005, Paris, France
| | - Nolwenn Miguet
- Institut de Biologie Structurale (IBS), Univ. Grenoble Alpes, CEA, CNRS, 71, avenue des Martyrs, 38000 Grenoble, France
| | - Christophe Caillat
- Institut de Biologie Structurale (IBS), Univ. Grenoble Alpes, CEA, CNRS, 71, avenue des Martyrs, 38000 Grenoble, France
| | - Stephanie Mangenot
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France.,Sorbonne Université, 75005, Paris, France
| | - Winfried Weissenhorn
- Institut de Biologie Structurale (IBS), Univ. Grenoble Alpes, CEA, CNRS, 71, avenue des Martyrs, 38000 Grenoble, France
| | - Patricia Bassereau
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France .,Sorbonne Université, 75005, Paris, France
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80
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Ye F, Nager AR, Nachury MV. BBSome trains remove activated GPCRs from cilia by enabling passage through the transition zone. J Cell Biol 2018; 217:1847-1868. [PMID: 29483145 PMCID: PMC5940304 DOI: 10.1083/jcb.201709041] [Citation(s) in RCA: 167] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 12/27/2017] [Accepted: 01/29/2018] [Indexed: 02/08/2023] Open
Abstract
A diffusion barrier at the transition zone enables the compartmentalization of signaling molecules by cilia. The BBSome and the small guanosine triphosphatase Arl6, which triggers BBSome coat polymerization, are required for the exit of activated signaling receptors from cilia, but how diffusion barriers are crossed when membrane proteins exit cilia remains to be determined. In this study, we found that activation of the ciliary G protein-coupled receptors (GPCRs) Smoothened and SSTR3 drove the Arl6-dependent assembly of large, highly processive, and cargo-laden retrograde BBSome trains. Single-molecule imaging revealed that the assembly of BBSome trains enables the lateral transport of ciliary GPCRs across the transition zone. However, the removal of activated GPCRs from cilia was inefficient because a second periciliary diffusion barrier was infrequently crossed. We conclude that exit from cilia is a two-step process in which BBSome/Arl6 trains first move activated GPCRs through the transition zone before a periciliary barrier can be crossed.
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Affiliation(s)
- Fan Ye
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA
| | - Andrew R Nager
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA
| | - Maxence V Nachury
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA
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81
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Curto MÁ, Moro S, Yanguas F, Gutiérrez-González C, Valdivieso MH. The ancient claudin Dni2 facilitates yeast cell fusion by compartmentalizing Dni1 into a membrane subdomain. Cell Mol Life Sci 2018; 75:1687-1706. [PMID: 29134248 PMCID: PMC11105288 DOI: 10.1007/s00018-017-2709-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 10/10/2017] [Accepted: 11/03/2017] [Indexed: 12/20/2022]
Abstract
Dni1 and Dni2 facilitate cell fusion during mating. Here, we show that these proteins are interdependent for their localization in a plasma membrane subdomain, which we have termed the mating fusion domain. Dni1 compartmentation in the domain is required for cell fusion. The contribution of actin, sterol-dependent membrane organization, and Dni2 to this compartmentation was analysed, and the results showed that Dni2 plays the most relevant role in the process. In turn, the Dni2 exit from the endoplasmic reticulum depends on Dni1. These proteins share the presence of a cysteine motif in their first extracellular loop related to the claudin GLWxxC(8-10 aa)C signature motif. Structure-function analyses show that mutating each Dni1 conserved cysteine has mild effects, and that only simultaneous elimination of several cysteines leads to a mating defect. On the contrary, eliminating each single cysteine and the C-terminal tail in Dni2 abrogates Dni1 compartmentation and cell fusion. Sequence alignments show that claudin trans-membrane helixes bear small-XXX-small motifs at conserved positions. The fourth Dni2 trans-membrane helix tends to form homo-oligomers in Escherichia plasma membrane, and two concatenated small-XXX-small motifs are required for efficient oligomerization and for Dni2 export from the yeast endoplasmic reticulum. Together, our results strongly suggest that Dni2 is an ancient claudin that blocks Dni1 diffusion from the intercellular region where two plasma membranes are in close proximity, and that this function is required for Dni1 to facilitate cell fusion.
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Affiliation(s)
- M-Ángeles Curto
- Departamento de Microbiología y Genética, Universidad de Salamanca, Calle Zacarías González 2, Lab P1.1, Edificio IBFG, 37007, Salamanca, Spain
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), Calle Zacarías González 2, 37007, Salamanca, Spain
| | - Sandra Moro
- Departamento de Microbiología y Genética, Universidad de Salamanca, Calle Zacarías González 2, Lab P1.1, Edificio IBFG, 37007, Salamanca, Spain
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), Calle Zacarías González 2, 37007, Salamanca, Spain
| | - Francisco Yanguas
- Departamento de Microbiología y Genética, Universidad de Salamanca, Calle Zacarías González 2, Lab P1.1, Edificio IBFG, 37007, Salamanca, Spain
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), Calle Zacarías González 2, 37007, Salamanca, Spain
| | - Carmen Gutiérrez-González
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), Calle Zacarías González 2, 37007, Salamanca, Spain
| | - M-Henar Valdivieso
- Departamento de Microbiología y Genética, Universidad de Salamanca, Calle Zacarías González 2, Lab P1.1, Edificio IBFG, 37007, Salamanca, Spain.
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), Calle Zacarías González 2, 37007, Salamanca, Spain.
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82
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Sartorel E, Ünlü C, Jose M, Massoni-Laporte A, Meca J, Sibarita JB, McCusker D. Phosphatidylserine and GTPase activation control Cdc42 nanoclustering to counter dissipative diffusion. Mol Biol Cell 2018; 29:1299-1310. [PMID: 29668348 PMCID: PMC5994902 DOI: 10.1091/mbc.e18-01-0051] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The anisotropic organization of plasma membrane constituents is indicative of mechanisms that drive the membrane away from equilibrium. However, defining these mechanisms is challenging due to the short spatiotemporal scales at which diffusion operates. Here, we use high-density single protein tracking combined with photoactivation localization microscopy (sptPALM) to monitor Cdc42 in budding yeast, a system in which Cdc42 exhibits anisotropic organization. Cdc42 exhibited reduced mobility at the cell pole, where it was organized in nanoclusters. The Cdc42 nanoclusters were larger at the cell pole than those observed elsewhere in the cell. These features were exacerbated in cells expressing Cdc42-GTP, and were dependent on the scaffold Bem1, which contributed to the range of mobility and nanocluster size exhibited by Cdc42. The lipid environment, in particular phosphatidylserine levels, also played a role in regulating Cdc42 nanoclustering. These studies reveal how the mobility of a Rho GTPase is controlled to counter the depletive effects of diffusion, thus stabilizing Cdc42 on the plasma membrane and sustaining cell polarity.
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Affiliation(s)
- Elodie Sartorel
- Université Bordeaux, CNRS, UMR 5095, European Institute of Chemistry and Biology, Pessac 33607, France
| | - Caner Ünlü
- Université Bordeaux, CNRS, UMR 5095, European Institute of Chemistry and Biology, Pessac 33607, France
| | - Mini Jose
- Université Bordeaux, CNRS, UMR 5095, European Institute of Chemistry and Biology, Pessac 33607, France
| | - Aurélie Massoni-Laporte
- Université Bordeaux, CNRS, UMR 5095, European Institute of Chemistry and Biology, Pessac 33607, France
| | - Julien Meca
- Université Bordeaux, CNRS, UMR 5095, European Institute of Chemistry and Biology, Pessac 33607, France
| | - Jean-Baptiste Sibarita
- Université Bordeaux, Institut Interdisciplinaire de Neurosciences, Bordeaux 33077, France.,CNRS UMR 5297, Institut Interdisciplinaire de Neurosciences, Bordeaux 33077, France
| | - Derek McCusker
- Université Bordeaux, CNRS, UMR 5095, European Institute of Chemistry and Biology, Pessac 33607, France
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83
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Nachury MV. The molecular machines that traffic signaling receptors into and out of cilia. Curr Opin Cell Biol 2018; 51:124-131. [PMID: 29579578 PMCID: PMC5949257 DOI: 10.1016/j.ceb.2018.03.004] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/06/2018] [Accepted: 03/08/2018] [Indexed: 12/12/2022]
Abstract
Cilia are surface-exposed organelles that dynamically concentrate signaling molecules to organize sensory, developmental and homeostatic pathways. Entry and exit of signaling receptors is germane to the processing of signals and the molecular machines for entry and exit have started to emerge. The IFT-A complex and its membrane recruitment factor Tulp3 complex promotes the entry of signaling receptors into cilia while the BBSome and its membrane recruitment factor Arl6GTP ferry activated signaling receptors out of cilia. Ciliary exit is a surprisingly complex process entailing passage through a first diffusion barrier at the transition zone, diffusion inside an intermediate compartment and crossing of a periciliary diffusion barrier. The two barriers may organize a privileged compartment where activated signaling receptors transiently reside.
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Affiliation(s)
- Maxence V Nachury
- UCSF School of Medicine, Department of Ophthalmology, United States.
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84
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Lu SM, Fairn GD. Mesoscale organization of domains in the plasma membrane - beyond the lipid raft. Crit Rev Biochem Mol Biol 2018; 53:192-207. [PMID: 29457544 DOI: 10.1080/10409238.2018.1436515] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The plasma membrane is compartmentalized into several distinct regions or domains, which show a broad diversity in both size and lifetime. The segregation of lipids and membrane proteins is thought to be driven by the lipid composition itself, lipid-protein interactions and diffusional barriers. With regards to the lipid composition, the immiscibility of certain classes of lipids underlies the "lipid raft" concept of plasmalemmal compartmentalization. Historically, lipid rafts have been described as cholesterol and (glyco)sphingolipid-rich regions of the plasma membrane that exist as a liquid-ordered phase that are resistant to extraction with non-ionic detergents. Over the years the interest in lipid rafts grew as did the challenges with studying these nanodomains. The term lipid raft has fallen out of favor with many scientists and instead the terms "membrane raft" or "membrane nanodomain" are preferred as they connote the heterogeneity and dynamic nature of the lipid-protein assemblies. In this article, we will discuss the classical lipid raft hypothesis and its limitations. This review will also discuss alternative models of lipid-protein interactions, annular lipid shells, and larger membrane clusters. We will also discuss the mesoscale organization of plasmalemmal domains including visible structures such as clathrin-coated pits and caveolae.
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Affiliation(s)
- Stella M Lu
- a Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto , Canada.,b Department of Biochemistry , University of Toronto , Toronto , Canada
| | - Gregory D Fairn
- a Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto , Canada.,b Department of Biochemistry , University of Toronto , Toronto , Canada.,c Department of Surgery , University of Toronto , Toronto , Canada
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85
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Expanding the Repertoire of Dielectric Fractional Models: A Comprehensive Development and Functional Applications to Predict Metabolic Alterations in Experimentally-Inaccessible Cells or Tissues. FLUIDS 2018. [DOI: 10.3390/fluids3010009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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86
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Barredo WI, Bernido CC, Carpio-Bernido MV, Bornales JB. Modelling non-Markovian fluctuations in intracellular biomolecular transport. Math Biosci 2018; 297:27-31. [PMID: 29337131 DOI: 10.1016/j.mbs.2018.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 04/02/2017] [Accepted: 01/08/2018] [Indexed: 11/25/2022]
Abstract
To model non-Markovian fluctuations arising in biomolecular transport, we introduce a stochastic process with memory where Brownian motion is modulated sinusoidally. The probability density function and moments of this non-Markovian process are evaluated analytically as Hida stochastic functional integrals. Comparison of graphs of computed variance vis-á-vis empirical data for protein diffusion coefficients closely match with both exhibiting emergent superdiffusive then subdiffusive behavior for longer proteins.
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Affiliation(s)
- Wilson I Barredo
- Physics Department, MSU-Iligan Institute of Technology, Tibanga, Iligan City, 9200, Philippines; Physics Department, Mindanao State University, Marawi City, 9700, Philippines
| | - Christopher C Bernido
- Physics Department, MSU-Iligan Institute of Technology, Tibanga, Iligan City, 9200, Philippines; Research Center for Theoretical Physics, Central Visayan Institute Foundation, Jagna, Bohol, 6308, Philippines; Physics Department, University of San Carlos, Cebu City, 6000, Philippines.
| | - M Victoria Carpio-Bernido
- Physics Department, MSU-Iligan Institute of Technology, Tibanga, Iligan City, 9200, Philippines; Research Center for Theoretical Physics, Central Visayan Institute Foundation, Jagna, Bohol, 6308, Philippines; Physics Department, University of San Carlos, Cebu City, 6000, Philippines
| | - Jinky B Bornales
- Physics Department, MSU-Iligan Institute of Technology, Tibanga, Iligan City, 9200, Philippines
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87
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Phosphorylation of Pnut in the Early Stages of Drosophila Embryo Development Affects Association of the Septin Complex with the Membrane and Is Important for Viability. G3-GENES GENOMES GENETICS 2018; 8:27-38. [PMID: 29079679 PMCID: PMC5765355 DOI: 10.1534/g3.117.300186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Septin proteins are polymerizing GTPases that are found in most eukaryotic species. Septins are important for cytokinesis and participate in many processes involving spatial modifications of the cell cortex. In Drosophila, septin proteins Pnut, Sep1, and Sep2 form a hexameric septin complex. Here, we found that septin protein Pnut is phosphorylated during the first 2 hr of Drosophila embryo development. To study the effect of Pnut phosphorylation in a live organism, we created a new Drosophila pnut null mutant that allows for the analysis of Pnut mutations during embryogenesis. To understand the functional significance of Pnut phosphorylation, Drosophila strains carrying nonphosphorylatable and phospho-mimetic mutant pnut transgenes were established. The expression of the nonphosphorylatable Pnut protein resulted in semilethality and abnormal protein localization, whereas the expression of the phospho-mimetic mutant form of Pnut disrupted the assembly of a functional septin complex and septin filament formation in vitro. Overall, our findings indicate that the controlled phosphorylation of Pnut plays an important role in regulating septin complex functions during organism development.
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88
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89
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Naegeli KM, Hastie E, Garde A, Wang Z, Keeley DP, Gordon KL, Pani AM, Kelley LC, Morrissey MA, Chi Q, Goldstein B, Sherwood DR. Cell Invasion In Vivo via Rapid Exocytosis of a Transient Lysosome-Derived Membrane Domain. Dev Cell 2017; 43:403-417.e10. [PMID: 29161591 DOI: 10.1016/j.devcel.2017.10.024] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 09/19/2017] [Accepted: 10/22/2017] [Indexed: 11/27/2022]
Abstract
Invasive cells use small invadopodia to breach basement membrane (BM), a dense matrix that encases tissues. Following the breach, a large protrusion forms to clear a path for tissue entry by poorly understood mechanisms. Using RNAi screening for defects in Caenorhabditis elegans anchor cell (AC) invasion, we found that UNC-6(netrin)/UNC-40(DCC) signaling at the BM breach site directs exocytosis of lysosomes using the exocyst and SNARE SNAP-29 to form a large protrusion that invades vulval tissue. Live-cell imaging revealed that the protrusion is enriched in the matrix metalloprotease ZMP-1 and transiently expands AC volume by more than 20%, displacing surrounding BM and vulval epithelium. Photobleaching and genetic perturbations showed that the BM receptor dystroglycan forms a membrane diffusion barrier at the neck of the protrusion, which enables protrusion growth. Together these studies define a netrin-dependent pathway that builds an invasive protrusion, an isolated lysosome-derived membrane structure specialized to breach tissue barriers.
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Affiliation(s)
- Kaleb M Naegeli
- Department of Biology, Regeneration Next, Duke University, 130 Science Drive, Box 90338, Durham, NC 27708, USA; Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27708, USA
| | - Eric Hastie
- Department of Biology, Regeneration Next, Duke University, 130 Science Drive, Box 90338, Durham, NC 27708, USA
| | - Aastha Garde
- Department of Biology, Regeneration Next, Duke University, 130 Science Drive, Box 90338, Durham, NC 27708, USA
| | - Zheng Wang
- Research Center for Tissue Engineering and Regenerative Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China; Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China
| | - Daniel P Keeley
- Department of Biology, Regeneration Next, Duke University, 130 Science Drive, Box 90338, Durham, NC 27708, USA
| | - Kacy L Gordon
- Department of Biology, Regeneration Next, Duke University, 130 Science Drive, Box 90338, Durham, NC 27708, USA
| | - Ariel M Pani
- Biology Department and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Laura C Kelley
- Department of Biology, Regeneration Next, Duke University, 130 Science Drive, Box 90338, Durham, NC 27708, USA
| | - Meghan A Morrissey
- The Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Qiuyi Chi
- Department of Biology, Regeneration Next, Duke University, 130 Science Drive, Box 90338, Durham, NC 27708, USA
| | - Bob Goldstein
- Biology Department and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - David R Sherwood
- Department of Biology, Regeneration Next, Duke University, 130 Science Drive, Box 90338, Durham, NC 27708, USA; Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27708, USA; Regeneration Next, Duke University, Durham, NC 27710, USA.
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90
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Lippert A, Janeczek AA, Fürstenberg A, Ponjavic A, Moerner WE, Nusse R, Helms JA, Evans ND, Lee SF. Single-Molecule Imaging of Wnt3A Protein Diffusion on Living Cell Membranes. Biophys J 2017; 113:2762-2767. [PMID: 29262368 PMCID: PMC5925569 DOI: 10.1016/j.bpj.2017.08.060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/13/2017] [Accepted: 08/02/2017] [Indexed: 01/31/2023] Open
Abstract
Wnt proteins are secreted, hydrophobic, lipidated proteins found in all animals that play essential roles in development and disease. Lipid modification is thought to facilitate the interaction of the protein with its receptor, Frizzled, but may also regulate the transport of Wnt protein and its localization at the cell membrane. Here, by employing single-molecule fluorescence techniques, we show that Wnt proteins associate with and diffuse on the plasma membranes of living cells in the absence of any receptor binding. We find that labeled Wnt3A transiently and dynamically associates with the membranes of Drosophila Schneider 2 cells, diffuses with Brownian kinetics on flattened membranes and on cellular protrusions, and does not transfer between cells in close contact. In S2 receptor-plus (S2R+) cells, which express Frizzled receptors, membrane diffusion rate is reduced and membrane residency time is increased. These results provide direct evidence of Wnt3A interaction with living cell membranes, and represent, to our knowledge, a new system for investigating the dynamics of Wnt transport.
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Affiliation(s)
- Anna Lippert
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Agnieszka A Janeczek
- Centre for Human Development, Stem Cells and Regeneration, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Alexandre Fürstenberg
- Department of Chemistry, Stanford University, Palo Alto, California; Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, Genève, Switzerland
| | - Aleks Ponjavic
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - W E Moerner
- Department of Chemistry, Stanford University, Palo Alto, California
| | - Roel Nusse
- Department of Developmental Biology, Stanford University, Palo Alto, California
| | - Jill A Helms
- Division of Plastic and Reconstructive Surgery, Stanford University, Stanford, California
| | - Nicholas D Evans
- Centre for Human Development, Stem Cells and Regeneration, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom.
| | - Steven F Lee
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom; Department of Chemistry, Stanford University, Palo Alto, California.
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91
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Misonou H. Precise localizations of voltage-gated sodium and potassium channels in neurons. Dev Neurobiol 2017; 78:271-282. [PMID: 29218789 DOI: 10.1002/dneu.22565] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 12/01/2017] [Accepted: 12/06/2017] [Indexed: 11/08/2022]
Abstract
Neurons are extremely large and complex cells, and they regulate membrane potentials in multiple subcellular compartments using a variety of ion channels. Voltage-gated sodium (Nav) and potassium (Kv) channels are crucial in regulating neuronal membrane excitability owing to their diversity in subtypes, biophysical properties, and localizations. In particular, specific localizations of Nav and Kv channels in specific membrane compartments are essential to achieve a precise control of local membrane excitability. Recent advancement in super-resolution microscopy further substantiated nanoscale localizations of different ion channels in neuronal membranes. New questions arise from these new lines of evidence regarding how Nav and Kv channels are trafficked to a specific location and maintained against lateral diffusion. In this review, the aim is to summarize current information about ion channel localizations at nanoscopic levels and discuss what we can infer regarding the mechanisms. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 271-282, 2018.
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Affiliation(s)
- Hiroaki Misonou
- Graduate School of Brain Science, Doshisha University, Kyoto, Japan
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92
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Ribet D, Boscaini S, Cauvin C, Siguier M, Mostowy S, Echard A, Cossart P. SUMOylation of human septins is critical for septin filament bundling and cytokinesis. J Cell Biol 2017; 216:4041-4052. [PMID: 29051266 PMCID: PMC5716278 DOI: 10.1083/jcb.201703096] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 07/25/2017] [Accepted: 08/23/2017] [Indexed: 01/22/2023] Open
Abstract
Septins are cytoskeletal proteins that assemble into nonpolar filaments. They are critical in diverse cellular functions, acting as scaffolds for protein recruitment and as diffusion barriers for subcellular compartmentalization. Human septins are encoded by 13 different genes and are classified into four groups based on sequence homology (SEPT2, SEPT3, SEPT6, and SEPT7 groups). In yeast, septins were among the first proteins reported to be modified by SUMOylation, a ubiquitin-like posttranslational modification. However, whether human septins could be modified by small ubiquitin-like modifiers (SUMOs) and what roles this modification may have in septin function remains unknown. In this study, we first show that septins from all four human septin groups can be covalently modified by SUMOs. We show in particular that endogenous SEPT7 is constitutively SUMOylated during the cell cycle. We then map SUMOylation sites to the C-terminal domain of septins belonging to the SEPT6 and SEPT7 groups and to the N-terminal domain of septins from the SEPT3 group. We finally demonstrate that expression of non-SUMOylatable septin variants from the SEPT6 and SEPT7 groups leads to aberrant septin bundle formation and defects in cytokinesis after furrow ingression. Altogether, our results demonstrate a pivotal role for SUMOylation in septin filament bundling and cell division.
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Affiliation(s)
- David Ribet
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, Institut National de la Santé et de la Recherche Médicale, Institut National de la Recherche Agronomique, Paris, France
| | - Serena Boscaini
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, Institut National de la Santé et de la Recherche Médicale, Institut National de la Recherche Agronomique, Paris, France
| | - Clothilde Cauvin
- Unité de Trafic Membranaire et Division Cellulaire, Département de Biologie Cellulaire et Infection, Institut Pasteur, Paris, France
- Centre National de la Recherche Scientifique UMR3691, Paris, France
- Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 06, Institut de Formation Doctorale, Paris, France
| | - Martin Siguier
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, Institut National de la Santé et de la Recherche Médicale, Institut National de la Recherche Agronomique, Paris, France
| | - Serge Mostowy
- Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, England, UK
| | - Arnaud Echard
- Unité de Trafic Membranaire et Division Cellulaire, Département de Biologie Cellulaire et Infection, Institut Pasteur, Paris, France
- Centre National de la Recherche Scientifique UMR3691, Paris, France
- Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 06, Institut de Formation Doctorale, Paris, France
| | - Pascale Cossart
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, Institut National de la Santé et de la Recherche Médicale, Institut National de la Recherche Agronomique, Paris, France
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93
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Palanco ME, Skovgaard N, Hansen JS, Berg-Sørensen K, Hélix-Nielsen C. Tuning biomimetic membrane barrier properties by hydrocarbon, cholesterol and polymeric additives. BIOINSPIRATION & BIOMIMETICS 2017; 13:016005. [PMID: 29019793 DOI: 10.1088/1748-3190/aa92be] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The barrier properties of cellular membranes are increasingly attracting attention as a source of inspiration for designing biomimetic membranes. The broad range of potential technological applications makes the use of lipid and lately also polymeric materials a popular choice for constructing biomimetic membranes, where the barrier properties can be controlled by the composition of the membrane constituent elements. Here we investigate the membrane properties reported by the light-induced proton pumping activity of bacteriorhodopsin (bR) reconstituted in three vesicle systems of different membrane composition. Specifically we quantify how the resulting proton influx and efflux rates are influenced by the membrane composition using a variety of membrane modulators. We demonstrate that by adding hydrocarbons to vesicles with reconstituted bR formed from asolectin lipids the resulting transmembrane proton fluxes changes proportional to the carbon chain length when compared against control. We observe a similar proportionality in single-component 1,2-Dioleoyl-sn-glycero-3-phosphocholine model membranes when using cholesterol. Lastly we investigate the effects of adding the amphiphilic di-block co-polymer polybutadiene-polyethyleneoxide (PB12-PEO10) to phospholipid membranes formed from 1,2-Dioleoyl-sn-glycero-3-phosphocholine, 1,2-Dioleoyl-sn-glycero-3-phosphatidylethanolamine, and 1,2-Dioleoyl-sn-glycero-3-phosphatidylserine. The proton pumping activity of bR (measured as a change in extra-vesicular pH) in mixed lipid/PB12-PEO10 lipid systems is up to six-fold higher compared to that observed for bR containing vesicles made from PB12-PEO10 alone. Interestingly, bR inserts with apparent opposite orientation in pure PB12-PEO10 vesicles as compared to pure lipid vesicles. Addition of equimolar amounts of lipids to PB12-PEO10 results in bR orientation similar to that observed for pure lipids. In conclusion our results show how the barrier properties of the membranes can be controlled by the composition of the membrane. In particular the use of mixed lipid-polymer systems may pave the way for constructing biomimetic membranes tailored for optimal properties in various applications including drug delivery systems, biosensors and energy conservation technology.
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Affiliation(s)
- Marta Espina Palanco
- Department of Physics, Technical University of Denmark (DTU), 2800 Kgs. Lyngby, Denmark. These authors contributed equally to this work
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94
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Bohórquez-Hernández A, Gratton E, Pacheco J, Asanov A, Vaca L. Cholesterol modulates the cellular localization of Orai1 channels and its disposition among membrane domains. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1481-1490. [PMID: 28919480 PMCID: PMC5902182 DOI: 10.1016/j.bbalip.2017.09.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 09/04/2017] [Accepted: 09/10/2017] [Indexed: 02/08/2023]
Abstract
Store Operated Calcium Entry (SOCE) is one of the most important mechanisms for calcium mobilization in to the cell. Two main proteins sustain SOCE: STIM1 that acts as the calcium sensor in the endoplasmic reticulum (ER) and Orai1 responsible for calcium influx upon depletion of ER. There are many studies indicating that SOCE is modulated by the cholesterol content of the plasma membrane (PM). However, a myriad of questions remain unanswered concerning the precise molecular mechanism by which cholesterol modulates SOCE. In the present study we found that reducing PM cholesterol results in the internalization of Orai1 channels, which can be prevented by overexpressing caveolin 1 (Cav1). Furthermore, Cav1 and Orai1 associate upon SOCE activation as revealed by FRET and coimmunoprecipitation assays. The effects of reducing cholesterol were not limited to an increased rate of Orai1 internalization, but also, affects the lateral movement of Orai1, inducing movement in a linear pattern (unobstructed diffusion) opposite to basal cholesterol conditions were most of Orai1 channels moves in a confined space, as assessed by Fluorescence Correlation Spectroscopy, Cav1 overexpression inhibited these alterations maintaining Orai1 into a confined and partially confined movement. These results not only highlight the complex effect of cholesterol regulation on SOCE, but also indicate a direct regulatory effect on Orai1 localization and compartmentalization by this lipid.
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Affiliation(s)
- A Bohórquez-Hernández
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico
| | - Enrico Gratton
- Department of Biomedical Engineering, University of California, Irvine, 3210 Natural Sciences II, Irvine, CA 92697-2715, USA
| | - Jonathan Pacheco
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico
| | | | - Luis Vaca
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico.
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95
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The Unsolved Problem of How Cells Sense Micron-Scale Curvature. Trends Biochem Sci 2017; 42:961-976. [PMID: 29089160 DOI: 10.1016/j.tibs.2017.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 09/27/2017] [Accepted: 10/02/2017] [Indexed: 12/31/2022]
Abstract
Membrane curvature is a fundamental feature of cells and their organelles. Much of what we know about how cells sense curved surfaces comes from studies examining nanometer-sized molecules on nanometer-scale curvatures. We are only just beginning to understand how cells recognize curved topologies at the micron scale. In this review, we provide the reader with an overview of our current understanding of how cells sense and respond to micron-scale membrane curvature.
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96
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Dunsing V, Mayer M, Liebsch F, Multhaup G, Chiantia S. Direct evidence of amyloid precursor-like protein 1 trans interactions in cell-cell adhesion platforms investigated via fluorescence fluctuation spectroscopy. Mol Biol Cell 2017; 28:3609-3620. [PMID: 29021345 PMCID: PMC5706989 DOI: 10.1091/mbc.e17-07-0459] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/13/2017] [Accepted: 10/04/2017] [Indexed: 01/25/2023] Open
Abstract
The amyloid precursor–like protein 1 (APLP1) plays a role in synaptic adhesion and synaptogenesis. In this work, we use quantitative fluorescence microscopy to demonstrate the existence of APLP1–APLP1 trans interaction across cell–cell junctions and propose a model explaining the molecular mechanism driving APLP1 multimerization. The amyloid precursor–like protein 1 (APLP1) is a type I transmembrane protein that plays a role in synaptic adhesion and synaptogenesis. Past investigations indicated that APLP1 is involved in the formation of protein–protein complexes that bridge the junctions between neighboring cells. Nevertheless, APLP1–APLP1 trans interactions have never been directly observed in higher eukaryotic cells. Here, we investigated APLP1 interactions and dynamics directly in living human embryonic kidney cells using fluorescence fluctuation spectroscopy techniques, namely cross-correlation scanning fluorescence correlation spectroscopy and number and brightness analysis. Our results show that APLP1 forms homotypic trans complexes at cell–cell contacts. In the presence of zinc ions, the protein forms macroscopic clusters, exhibiting an even higher degree of trans binding and strongly reduced dynamics. Further evidence from giant plasma membrane vesicles suggests that the presence of an intact cortical cytoskeleton is required for zinc-induced cis multimerization. Subsequently, large adhesion platforms bridging interacting cells are formed through APLP1–APLP1 trans interactions. Taken together, our results provide direct evidence that APLP1 functions as a neuronal zinc-dependent adhesion protein and allow a more detailed understanding of the molecular mechanisms driving the formation of APLP1 adhesion platforms.
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Affiliation(s)
- Valentin Dunsing
- Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany
| | - Magnus Mayer
- Institute of Chemistry and Biochemistry, Free University of Berlin, 14195 Berlin, Germany
| | - Filip Liebsch
- Department of Pharmacology and Therapeutics/Integrated Program in Neuroscience, McGill University, Montreal, QC H3G 1Y63, Canada
| | - Gerhard Multhaup
- Department of Pharmacology and Therapeutics/Integrated Program in Neuroscience, McGill University, Montreal, QC H3G 1Y63, Canada
| | - Salvatore Chiantia
- Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany
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97
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Adkins MR, Zhou YC. Geodesic curvature driven surface microdomain formation. JOURNAL OF COMPUTATIONAL PHYSICS 2017; 345:260-274. [PMID: 28804159 PMCID: PMC5552095 DOI: 10.1016/j.jcp.2017.05.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Lipid bilayer membranes are not uniform and clusters of lipids in a more ordered state exist within the generally disorder lipid milieu of the membrane. These clusters of ordered lipids microdomains are now referred to as lipid rafts. Recent reports attribute the formation of these microdomains to the geometrical and molecular mechanical mismatch of lipids of different species on the boundary. Here we introduce the geodesic curvature to characterize the geometry of the domain boundary, and develop a geodesic curvature energy model to describe the formation of these microdomains as a result of energy minimization. Our model accepts the intrinsic geodesic curvature of any binary lipid mixture as an input, and will produce microdomains of the given geodesic curvature as demonstrated by three sets of numerical simulations. Our results are in contrast to the surface phase separation predicted by the classical surface Cahn-Hilliard equation, which tends to generate large domains as a result of the minimizing line tension. Our model provides a direct and quantified description of the structure inhomogeneity of lipid bilayer membrane, and can be coupled to the investigations of biological processes on membranes for which such inhomogeneity plays essential roles.
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Affiliation(s)
- Melissa R. Adkins
- Department of Mathematics, Colorado State University, Fort Collins, CO 80523-1874
| | - Y. C. Zhou
- Department of Mathematics, Colorado State University, Fort Collins, CO 80523-1874
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98
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Limitations of Qdot labelling compared to directly-conjugated probes for single particle tracking of B cell receptor mobility. Sci Rep 2017; 7:11379. [PMID: 28900238 PMCID: PMC5595841 DOI: 10.1038/s41598-017-11563-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/18/2017] [Indexed: 12/25/2022] Open
Abstract
Single-particle tracking (SPT) is a powerful method for exploring single-molecule dynamics in living cells with nanoscale spatiotemporal resolution. Photostability and bright fluorescence make quantum dots (Qdots) a popular choice for SPT. However, their large size could potentially alter the mobility of the molecule of interest. To test this, we labelled B cell receptors on the surface of B-lymphocytes with monovalent Fab fragments of antibodies that were either linked to Qdots via streptavidin or directly conjugated to the small organic fluorophore Cy3. Imaging of receptor mobility by total internal reflection fluorescence microscopy (TIRFM), followed by quantitative single-molecule diffusion and confinement analysis, definitively showed that Qdots sterically hinder lateral mobility regardless of the substrate to which the cells were adhered. Qdot labelling also drastically altered the frequency with which receptors transitioned between apparent slow- and fast-moving states and reduced the size of apparent confinement zones. Although we show that Qdot-labelled probes can detect large differences in receptor mobility, they fail to resolve subtle differences in lateral diffusion that are readily detectable using Cy3-labelled Fabs. Our findings highlight the utility and limitations of using Qdots for TIRFM and wide-field-based SPT, and have significant implications for interpreting SPT data.
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99
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Abstract
Regulated exocytosis can be split into a sequence of steps ending with the formation and the dilation of a fusion pore, a neck-like connection between the vesicle and the plasma membrane. Each of these steps is precisely controlled to achieve the optimal spatial and temporal profile of the release of signalling molecules. At the level of the fusion pore, tuning of the exocytosis can be achieved by preventing its formation, by stabilizing the unproductive narrow fusion pore, by altering the speed of fusion pore expansion and by completely closing the fusion pore. The molecular structure and dynamics of fusion pores have become a major focus of cell research, especially as a promising target for therapeutic strategies. Electrophysiological, optical and electrochemical methods have been used extensively to illuminate how cells regulate secretion at the level of a single fusion pore. Here, we describe recent advances in the structure and mechanisms of the initial fusion pore formation and the progress in therapeutic strategies with the focus on exocytosis.
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100
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Basset A, Bouthemy P, Boulanger J, Waharte F, Salamero J, Kervrann C. An extended model of vesicle fusion at the plasma membrane to estimate protein lateral diffusion from TIRF microscopy images. BMC Bioinformatics 2017; 18:352. [PMID: 28738814 PMCID: PMC5525284 DOI: 10.1186/s12859-017-1765-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 07/14/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Characterizing membrane dynamics is a key issue to understand cell exchanges with the extra-cellular medium. Total internal reflection fluorescence microscopy (TIRFM) is well suited to focus on the late steps of exocytosis at the plasma membrane. However, it is still a challenging task to quantify (lateral) diffusion and estimate local dynamics of proteins. RESULTS A new model was introduced to represent the behavior of cargo transmembrane proteins during the vesicle fusion to the plasma membrane at the end of the exocytosis process. Two biophysical parameters, the diffusion coefficient and the release rate parameter, are automatically estimated from TIRFM image sequences, to account for both the lateral diffusion of molecules at the membrane and the continuous release of the proteins from the vesicle to the plasma membrane. Quantitative evaluation on 300 realistic computer-generated image sequences demonstrated the efficiency and accuracy of the method. The application of our method on 16 real TIRFM image sequences additionally revealed differences in the dynamic behavior of Transferrin Receptor (TfR) and Langerin proteins. CONCLUSION An automated method has been designed to simultaneously estimate the diffusion coefficient and the release rate for each individual vesicle fusion event at the plasma membrane in TIRFM image sequences. It can be exploited for further deciphering cell membrane dynamics.
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Affiliation(s)
- Antoine Basset
- Inria, Campus de Beaulieu, Rennes, 35042 France
- CNES, 18 avenue Edouard Belin, Toulouse, 31401 France
| | | | - Jérôme Boulanger
- Institut Curie, PSL Research University, CNRS UMR 144 and PICT-Cell and Tissue Imaging Facility, 12 rue Lhomond, Paris, 75005 France
- MRC Laboratory of Molecular Biology, University of Cambridge, Francis Crick Avenue, CBC Cambridge Biomedical Campus, Cambridge, CB2 0QH UK
| | - François Waharte
- Institut Curie, PSL Research University, CNRS UMR 144 and PICT-Cell and Tissue Imaging Facility, 12 rue Lhomond, Paris, 75005 France
| | - Jean Salamero
- Institut Curie, PSL Research University, CNRS UMR 144 and PICT-Cell and Tissue Imaging Facility, 12 rue Lhomond, Paris, 75005 France
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