1
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Kvalvaag A, Dustin ML. Clathrin controls bidirectional communication between T cells and antigen presenting cells. Bioessays 2024; 46:e2300230. [PMID: 38412391 DOI: 10.1002/bies.202300230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 02/05/2024] [Accepted: 02/06/2024] [Indexed: 02/29/2024]
Abstract
In circulation, T cells are spherical with selectin enriched dynamic microvilli protruding from the surface. Following extravasation, these microvilli serve another role, continuously surveying their environment for antigen in the form of peptide-MHC (pMHC) expressed on the surface of antigen presenting cells (APCs). Upon recognition of their cognate pMHC, the microvilli are initially stabilized and then flatten into F-actin dependent microclusters as the T cell spreads over the APC. Within 1-5 min, clathrin is recruited by the ESCRT-0 component Hrs to mediate release of T cell receptor (TCR) loaded vesicles directly from the plasma membrane by clathrin and ESCRT-mediated ectocytosis (CEME). After 5-10 min, Hrs is displaced by the endocytic clathrin adaptor epsin-1 to induce clathrin-mediated trans-endocytosis (CMTE) of TCR-pMHC conjugates. Here we discuss some of the functional properties of the clathrin machinery which enables it to control these topologically opposite modes of membrane transfer at the immunological synapse, and how this might be regulated during T cell activation.
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Affiliation(s)
- Audun Kvalvaag
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Michael L Dustin
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK
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2
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Anny CA, Nouaille S, Fauré R, Schulz C, Spriet C, Huvent I, Biot C, Lefebvre T. A Step-by-Step Guide for the Production of Recombinant Fluorescent TAT-HA-Tagged Proteins and their Transduction into Mammalian Cells. Curr Protoc 2024; 4:e1016. [PMID: 38511507 DOI: 10.1002/cpz1.1016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
Investigating the function of target proteins for functional prospection or therapeutic applications typically requires the production and purification of recombinant proteins. The fusion of these proteins with tag peptides and fluorescently derived proteins allows the monitoring of candidate proteins using SDS-PAGE coupled with western blotting and fluorescent microscopy, respectively. However, protein engineering poses a significant challenge for many researchers. In this protocol, we describe step-by-step the engineering of a recombinant protein with various tags: TAT-HA (trans-activator of transduction-hemagglutinin), 6×His and EGFP (enhanced green fluorescent protein) or mCherry. Fusion proteins are produced in E. coli BL21(DE3) cells and purified by immobilized metal affinity chromatography (IMAC) using a Ni-nitrilotriacetic acid (NTA) column. Then, tagged recombinant proteins are introduced into cultured animal cells by using the penetrating peptide TAT-HA. Here, we present a thorough protocol providing a detailed guide encompassing every critical step from plasmid DNA molecular assembly to protein expression and subsequent purification and outlines the conditions necessary for protein transduction technology into animal cells in a comprehensive manner. We believe that this protocol will be a valuable resource for researchers seeking an exhaustive, step-by-step guide for the successful production and purification of recombinant proteins and their entry by transduction within living cells. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: DNA cloning, molecular assembly strategies, and protein production Basic Protocol 2: Protein purification Basic Protocol 3: Protein transduction in mammalian cells.
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Affiliation(s)
| | | | - Régis Fauré
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - Céline Schulz
- Université de Lille, CNRS, UMR 8576 - UGSF, Lille, France
| | - Corentin Spriet
- Université de Lille, CNRS, UMR 8576 - UGSF, Lille, France
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, US 41 - UAR 2014 - PLBS, F-59000, Lille, France
| | | | | | - Tony Lefebvre
- Université de Lille, CNRS, UMR 8576 - UGSF, Lille, France
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3
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Ashby G, Keng KE, Hayden CC, Gollapudi S, Houser JR, Jamal S, Stachowiak JC. Selective Endocytic Uptake of Targeted Liposomes Occurs within a Narrow Range of Liposome Diameters. ACS APPLIED MATERIALS & INTERFACES 2023; 15:49988-50001. [PMID: 37862704 PMCID: PMC11165932 DOI: 10.1021/acsami.3c09399] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2023]
Abstract
Cell surface receptors facilitate signaling and nutrient uptake. These processes are dynamic, requiring receptors to be actively recycled by endocytosis. Due to their differential expression in disease states, receptors are often the target of drug-carrier particles, which are adorned with ligands that bind specifically to receptors. These targeted particles are taken into the cell by multiple routes of internalization, where the best-characterized pathway is clathrin-mediated endocytosis. Most studies of particle uptake have utilized bulk assays rather than observing individual endocytic events. As a result, the detailed mechanisms of particle uptake remain obscure. To address this gap, we employed a live-cell imaging approach to study the uptake of individual liposomes as they interact with clathrin-coated structures. By tracking individual internalization events, we find that the size of liposomes rather than the density of the ligands on their surfaces primarily determines their probability of uptake. Interestingly, targeting has the greatest impact on endocytosis of liposomes of intermediate diameters, with the smallest and largest liposomes being internalized or excluded, respectively, regardless of whether they are targeted. These findings, which highlight a previously unexplored limitation of targeted delivery, can be used to design more effective drug carriers.
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Affiliation(s)
- Grant Ashby
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
| | - Kayla E. Keng
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
| | - Carl C. Hayden
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
| | - Sadhana Gollapudi
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
| | - Justin R. Houser
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
| | - Sabah Jamal
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
| | - Jeanne C. Stachowiak
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
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4
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Pan T, Liu Y, Hu X, Li P, Lin C, Tang Y, Tang W, Liu Y, Guo L, Kim C, Fang J, Lin H, Wu Z, Blumwald E, Wang S. Stress-induced endocytosis from chloroplast inner envelope membrane is mediated by CHLOROPLAST VESICULATION but inhibited by GAPC. Cell Rep 2023; 42:113208. [PMID: 37792531 DOI: 10.1016/j.celrep.2023.113208] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 06/16/2023] [Accepted: 09/18/2023] [Indexed: 10/06/2023] Open
Abstract
Clathrin-mediated vesicular formation and trafficking are responsible for molecular cargo transport and signal transduction among organelles. Our previous study shows that CHLOROPLAST VESICULATION (CV)-containing vesicles (CVVs) are generated from chloroplasts for chloroplast degradation under abiotic stress. Here, we show that CV interacts with the clathrin heavy chain (CHC) and induces vesicle budding toward the cytosol from the chloroplast inner envelope membrane. In the defective mutants of CHC2 and the dynamin-encoding DRP1A, CVV budding and releasing from chloroplast are impeded. The mutations of CHC2 inhibit CV-induced chloroplast degradation and hypersensitivity to water stress. Moreover, CV-CHC2 interaction is impaired by the oxidized GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE (GAPC). GAPC1 overexpression suppresses CV-mediated chloroplast degradation and hypersensitivity to water stress, while CV silencing alleviates the hypersensitivity of the gapc1gapc2 plant to water stress. Together, our work identifies a pathway of clathrin-assisted CVV budding outward from chloroplast, which is involved in chloroplast degradation and stress response.
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Affiliation(s)
- Ting Pan
- Anhui Province Key Laboratory of Horticultural Crop Quality Biology, School of Horticulture, Anhui Agricultural University, Hefei 230036, China; Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yangxuan Liu
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
| | - Xufan Hu
- Anhui Province Key Laboratory of Horticultural Crop Quality Biology, School of Horticulture, Anhui Agricultural University, Hefei 230036, China
| | - Pengwei Li
- Anhui Province Key Laboratory of Horticultural Crop Quality Biology, School of Horticulture, Anhui Agricultural University, Hefei 230036, China
| | - Chengcheng Lin
- Anhui Province Key Laboratory of Horticultural Crop Quality Biology, School of Horticulture, Anhui Agricultural University, Hefei 230036, China
| | - Yuying Tang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
| | - Wei Tang
- Anhui Province Key Laboratory of Horticultural Crop Quality Biology, School of Horticulture, Anhui Agricultural University, Hefei 230036, China
| | - Yongsheng Liu
- Anhui Province Key Laboratory of Horticultural Crop Quality Biology, School of Horticulture, Anhui Agricultural University, Hefei 230036, China
| | - Liang Guo
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Chanhong Kim
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jun Fang
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Honghui Lin
- Ministry of Education, Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China
| | - Zhihua Wu
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Eduardo Blumwald
- Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
| | - Songhu Wang
- Anhui Province Key Laboratory of Horticultural Crop Quality Biology, School of Horticulture, Anhui Agricultural University, Hefei 230036, China; Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China.
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5
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Choi JT, Choi Y, Lee Y, Lee SH, Kang S, Lee KT, Bahn YS. The hybrid RAVE complex plays V-ATPase-dependent and -independent pathobiological roles in Cryptococcus neoformans. PLoS Pathog 2023; 19:e1011721. [PMID: 37812645 PMCID: PMC10586682 DOI: 10.1371/journal.ppat.1011721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 10/19/2023] [Accepted: 09/29/2023] [Indexed: 10/11/2023] Open
Abstract
V-ATPase, which comprises 13-14 subunits, is essential for pH homeostasis in all eukaryotes, but its proper function requires a regulator to assemble its subunits. While RAVE (regulator of H+-ATPase of vacuolar and endosomal membranes) and Raboconnectin-3 complexes assemble V-ATPase subunits in Saccharomyces cerevisiae and humans, respectively, the function of the RAVE complex in fungal pathogens remains largely unknown. In this study, we identified two RAVE complex components, Rav1 and Wdr1, in the fungal meningitis pathogen Cryptococcus neoformans, and analyzed their roles. Rav1 and Wdr1 are orthologous to yeast RAVE and human Rabconnectin-3 counterparts, respectively, forming the hybrid RAVE (hRAVE) complex. Deletion of RAV1 caused severe defects in growth, cell cycle control, morphogenesis, sexual development, stress responses, and virulence factor production, while the deletion of WDR1 resulted in similar but modest changes, suggesting that Rav1 and Wdr1 play central and accessary roles, respectively. Proteomics analysis confirmed that Wdr1 was one of the Rav1-interacting proteins. Although the hRAVE complex generally has V-ATPase-dependent functions, it also has some V-ATPase-independent roles, suggesting a unique role beyond conventional intracellular pH regulation in C. neoformans. The hRAVE complex played a critical role in the pathogenicity of C. neoformans, and RAV1 deletion attenuated virulence and impaired blood-brain barrier crossing ability. This study provides comprehensive insights into the pathobiological roles of the fungal RAVE complex and suggests a novel therapeutic strategy for controlling cryptococcosis.
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Affiliation(s)
- Jin-Tae Choi
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Yeseul Choi
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Yujin Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Seung-Heon Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Seun Kang
- Korea Zoonosis Research Institute, Jeonbuk National University, Jeonbuk, Republic of Korea
| | - Kyung-Tae Lee
- Korea Zoonosis Research Institute, Jeonbuk National University, Jeonbuk, Republic of Korea
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
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6
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Richards CJ, Burgers TCQ, Vlijm R, Roos WH, Åberg C. Rapid Internalization of Nanoparticles by Human Cells at the Single Particle Level. ACS NANO 2023; 17:16517-16529. [PMID: 37642490 PMCID: PMC10510712 DOI: 10.1021/acsnano.3c01124] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 08/17/2023] [Indexed: 08/31/2023]
Abstract
Nanoparticle uptake by cells has been studied for applications both in nanomedicine and in nanosafety. While the majority of studies have focused on the biological mechanisms underlying particle internalization, less attention has been given to questions of a more quantitative nature, such as how many nanoparticles enter cells and how rapidly they do so. To address this, we exposed human embryonic kidney cells to 40-200 nm carboxylated polystyrene nanoparticles and the particles were observed by live-cell confocal and super-resolution stimulated emission depletion fluorescence microscopy. How long a particle remained at the cell membrane after adsorbing onto it was monitored, distinguishing whether the particle ultimately desorbed again or was internalized by the cell. We found that the majority of particles desorb, but interestingly, most of the particles that are internalized do so within seconds, independently of particle size. As this is faster than typical endocytic mechanisms, we interpret this observation as the particles entering via an endocytic event that is already taking place (as opposed to directly triggering their own uptake) or possibly via an as yet uncharacterized endocytic route. Aside from the rapidly internalizing particles, a minority of particles remain at the membrane for tens of seconds to minutes before desorbing or being internalized. We also followed particles after cell internalization, observing particles that appeared to exit the cell, sometimes as rapidly as within tens of seconds. Overall, our results provide quantitative information about nanoparticle cell internalization times and early trafficking.
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Affiliation(s)
- Ceri J. Richards
- Pharmaceutical
Analysis, Groningen Research Institute of Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands
- Molecular
Biophysics, Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Thomas C. Q. Burgers
- Molecular
Biophysics, Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Rifka Vlijm
- Molecular
Biophysics, Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Wouter H. Roos
- Molecular
Biophysics, Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Christoffer Åberg
- Pharmaceutical
Analysis, Groningen Research Institute of Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands
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7
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Ashby G, Keng KE, Hayden CC, Gollapudi S, Houser JR, Jamal S, Stachowiak JC. Selective endocytic uptake of targeted liposomes occurs within a narrow range of liposome diameter. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.06.548000. [PMID: 37461728 PMCID: PMC10350051 DOI: 10.1101/2023.07.06.548000] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/27/2023]
Abstract
Cell surface receptors facilitate signaling and nutrient uptake. These processes are dynamic, requiring receptors to be actively recycled by endocytosis. Due to their differential expression in disease states, receptors are often the target of drug-carrier particles, which are adorned with ligands that bind specifically to receptors. These targeted particles are taken into the cell by multiple routes of internalization, where the best-characterized pathway is clathrin-mediated endocytosis. Most studies of particle uptake have utilized bulk assays, rather than observing individual endocytic events. As a result, the detailed mechanisms of particle uptake remain obscure. To address this gap, we have employed a live-cell imaging approach to study the uptake of individual liposomes as they interact with clathrin-coated structures. By tracking individual internalization events, we find that the size of liposomes, rather than the density of the ligands on their surfaces, primarily determines their probability of uptake. Interestingly, targeting has the greatest impact on endocytosis of liposomes of intermediate diameters, with the smallest and largest liposomes being internalized or excluded, respectively, regardless of whether they are targeted. These findings, which highlight a previously unexplored limitation of targeted delivery, can be used to design more effective drug carriers.
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Affiliation(s)
- Grant Ashby
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Kayla E Keng
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Carl C Hayden
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Sadhana Gollapudi
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Justin R Houser
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Sabah Jamal
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Jeanne C Stachowiak
- Department of Biomedical Engineering, The University of Texas at Austin
- Department of Chemical Engineering, The University of Texas at Austin
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8
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Krishnan S, Klingauf J. The readily retrievable pool of synaptic vesicles. Biol Chem 2023; 404:385-397. [PMID: 36867726 DOI: 10.1515/hsz-2022-0298] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 02/16/2023] [Indexed: 03/05/2023]
Abstract
In the CNS communication between neurons occurs at synapses by secretion of neurotransmitter via exocytosis of synaptic vesicles (SVs) at the active zone. Given the limited number of SVs in presynaptic boutons a fast and efficient recycling of exocytosed membrane and proteins by triggered compensatory endocytosis is required to maintain neurotransmission. Thus, pre-synapses feature a unique tight coupling of exo- and endocytosis in time and space resulting in the reformation of SVs with uniform morphology and well-defined molecular composition. This rapid response requires early stages of endocytosis at the peri-active zone to be well choreographed to ensure reformation of SVs with high fidelity. The pre-synapse can address this challenge by a specialized membrane microcompartment, where a pre-sorted and pre-assembled readily retrievable pool (RRetP) of endocytic membrane patches is formed, consisting of the vesicle cargo, presumably bound within a nucleated Clathrin and adaptor complex. This review considers evidence for the RRetP microcompartment to be the primary organizer of presynaptic triggered compensatory endocytosis.
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Affiliation(s)
- Sai Krishnan
- Institute of Medical Physics and Biophysics, University of Münster, Robert-Koch Strasse 31, D-48149, Münster, Germany
| | - Jürgen Klingauf
- Institute of Medical Physics and Biophysics, University of Münster, Robert-Koch Strasse 31, D-48149, Münster, Germany.,Center for Soft Nanoscience, Busso-Peus Strasse 10, D-48149, Münster, Germany
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9
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Nawara TJ, Mattheyses AL. Imaging nanoscale axial dynamics at the basal plasma membrane. Int J Biochem Cell Biol 2023; 156:106349. [PMID: 36566777 PMCID: PMC10634635 DOI: 10.1016/j.biocel.2022.106349] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/16/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022]
Abstract
Understanding of how energetically unfavorable plasma membrane shapes form, especially in the context of dynamic processes in living cells or tissues like clathrin-mediated endocytosis is in its infancy. Even though cutting-edge microscopy techniques that bridge this gap exist, they remain underused in biomedical sciences. Here, we demystify the perceived complexity of these advanced microscopy approaches and demonstrate their power in resolving nanometer axial dynamics in living cells. Total internal reflection fluorescence microscopy based approaches are the main focus of this review. We present clathrin-mediated endocytosis as a model system when describing the principles, data acquisition requirements, data interpretation strategies, and limitations of the described techniques. We hope this standardized description will bring the approaches for measuring nanoscale axial dynamics closer to the potential users and help in choosing the right approach to the right question.
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Affiliation(s)
- Tomasz J Nawara
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Alexa L Mattheyses
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA.
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10
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Gallusser B, Maltese G, Di Caprio G, Vadakkan TJ, Sanyal A, Somerville E, Sahasrabudhe M, O’Connor J, Weigert M, Kirchhausen T. Deep neural network automated segmentation of cellular structures in volume electron microscopy. J Cell Biol 2023; 222:e202208005. [PMID: 36469001 PMCID: PMC9728137 DOI: 10.1083/jcb.202208005] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/03/2022] [Accepted: 11/14/2022] [Indexed: 12/12/2022] Open
Abstract
Volume electron microscopy is an important imaging modality in contemporary cell biology. Identification of intracellular structures is a laborious process limiting the effective use of this potentially powerful tool. We resolved this bottleneck with automated segmentation of intracellular substructures in electron microscopy (ASEM), a new pipeline to train a convolutional neural network to detect structures of a wide range in size and complexity. We obtained dedicated models for each structure based on a small number of sparsely annotated ground truth images from only one or two cells. Model generalization was improved with a rapid, computationally effective strategy to refine a trained model by including a few additional annotations. We identified mitochondria, Golgi apparatus, endoplasmic reticulum, nuclear pore complexes, caveolae, clathrin-coated pits, and vesicles imaged by focused ion beam scanning electron microscopy. We uncovered a wide range of membrane-nuclear pore diameters within a single cell and derived morphological metrics from clathrin-coated pits and vesicles, consistent with the classical constant-growth assembly model.
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Affiliation(s)
- Benjamin Gallusser
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Giorgio Maltese
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA
| | - Giuseppe Di Caprio
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA
- Department of Pediatrics, Harvard Medical School, Boston, MA
| | - Tegy John Vadakkan
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA
| | - Anwesha Sanyal
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA
- Department of Cell Biology, Harvard Medical School, Boston, MA
| | - Elliott Somerville
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA
| | - Mihir Sahasrabudhe
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA
- Université Paris-Saclay, CentraleSupélec, Mathématiques et Informatique pour la Complexité et les Systèmes, Gif-sur-Yvette, France
| | - Justin O’Connor
- Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, Boston, MA
| | - Martin Weigert
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Tom Kirchhausen
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA
- Department of Pediatrics, Harvard Medical School, Boston, MA
- Department of Cell Biology, Harvard Medical School, Boston, MA
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11
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Zimmer O, Goepferich A. How clathrin-coated pits control nanoparticle avidity for cells. NANOSCALE HORIZONS 2023; 8:256-269. [PMID: 36594629 DOI: 10.1039/d2nh00543c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The paramount relevance of clathrin-coated pits (CCPs) to receptor-mediated endocytosis of nanoparticles, extracellular vesicles, and viruses has made them the focus of many studies; however, the role of CCP geometry in the ligand-receptor interactions between multivalent nanoparticles and cells has not been investigated. We hypothesized the general dependence of nanoparticle binding energy on local membrane curvature to be expandable to the specific case of ligand-functionalized nanoparticles binding cell membranes, in the sense that membrane structures whose curvature matches that of the particle (e.g., CCPs) signficantly contribute to binding avidity. We investigated this hypothesis with nanoparticles that bind multivalently to angiotensin II receptor type 1, which is subject to clathrin-mediated endocytosis. When we used cholesterol extraction to prevent the action of CCPs, we found a 67 to 100-fold loss in avidity. We created a theoretical model that predicts this decrease based on the loss of ligand-receptor interactions when CCPs, which perfectly match nanoparticle geometry, are absent. Our findings shed new light on how cells "see" nanoparticles. The presence or absence of CPPs is so influential on how cells interact with nanoparticles that the number of particles required to be visible to cells changes by two orders of magnitude depending on CCP presence.
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Affiliation(s)
- Oliver Zimmer
- Department for Pharmaceutical Technology, University of Regensburg, Regensburg, 93050, Germany.
| | - Achim Goepferich
- Department for Pharmaceutical Technology, University of Regensburg, Regensburg, 93050, Germany.
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12
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Kozlov MM, Taraska JW. Generation of nanoscopic membrane curvature for membrane trafficking. Nat Rev Mol Cell Biol 2023; 24:63-78. [PMID: 35918535 DOI: 10.1038/s41580-022-00511-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2022] [Indexed: 11/09/2022]
Abstract
Curved membranes are key features of intracellular organelles, and their generation involves dynamic protein complexes. Here we describe the fundamental mechanisms such as the hydrophobic insertion, scaffolding and crowding mechanisms these proteins use to produce membrane curvatures and complex shapes required to form intracellular organelles and vesicular structures involved in endocytosis and secretion. For each mechanism, we discuss its cellular functions as well as the underlying physical principles and the specific membrane properties required for the mechanism to be feasible. We propose that the integration of individual mechanisms into a highly controlled, robust process of curvature generation often relies on the assembly of proteins into coats. How cells unify and organize the curvature-generating factors at the nanoscale is presented for three ubiquitous coats central for membrane trafficking in eukaryotes: clathrin-coated pits, caveolae, and COPI and COPII coats. The emerging theme is that these coats arrange and coordinate curvature-generating factors in time and space to dynamically shape membranes to accomplish membrane trafficking within cells.
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Affiliation(s)
- Michael M Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Justin W Taraska
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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13
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Richards CJ, Ahmadi M, Stuart MCA, Kooi BJ, Åberg C, Roos WH. The effect of biomolecular corona on adsorption onto and desorption from a model lipid membrane. NANOSCALE 2022; 15:248-258. [PMID: 36472238 DOI: 10.1039/d2nr05296b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The current lack of insight into nanoparticle-cell membrane interactions hampers smart design strategies and thereby the development of effective nanodrugs. Quantitative and methodical approaches utilizing cell membrane models offer an opportunity to unravel particle-membrane interactions in a detailed manner under well controlled conditions. Here we use total internal reflection microscopy for real-time studies of the non-specific interactions between nanoparticles and a model cell membrane at 50 ms temporal resolution over a time course of several minutes. Maintaining a simple lipid bilayer system across conditions, adsorption and desorption were quantified as a function of biomolecular corona, particle size and fluid flow. The presence of a biomolecular corona reduced both the particle adsorption rate onto the membrane and the duration of adhesion, compared to pristine particle conditions. Particle size, on the other hand, was only observed to affect the adsorption rate. The introduction of flow reduced the number of adsorption events, but increased the residence time. Lastly, altering the composition of the membrane itself resulted in a decreased number of adsorption events onto negatively charged bilayers compared to neutral bilayers. Overall, a model membrane system offers a facile platform for real-time imaging of individual adsorption-desorption processes, revealing complex adsorption kinetics, governed by particle surface energy, size dependent interaction forces, flow and membrane composition.
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Affiliation(s)
- Ceri J Richards
- Molecular Biophysics, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, 9747 AG Groningen, Netherlands.
- Pharmaceutical Analysis, Groningen Research Institute of Pharmacy, Rijksuniversiteit Groningen, 9713 AV Groningen, Netherlands.
| | - Majid Ahmadi
- Nanostructure Materials and Interfaces, Zernike Institute for Advanced Materials, Rijksuniversiteit 9747 AG Groningen, Netherlands
| | - Marc C A Stuart
- Department of Electron Microscopy, Groningen Biomolecular Sciences and Biotechnology Institute, Rijksuniversiteit Groningen, 9747 AG Groningen, Netherlands
| | - Bart J Kooi
- Nanostructure Materials and Interfaces, Zernike Institute for Advanced Materials, Rijksuniversiteit 9747 AG Groningen, Netherlands
| | - Christoffer Åberg
- Pharmaceutical Analysis, Groningen Research Institute of Pharmacy, Rijksuniversiteit Groningen, 9713 AV Groningen, Netherlands.
| | - Wouter H Roos
- Molecular Biophysics, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, 9747 AG Groningen, Netherlands.
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14
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Yang C, Colosi P, Hugelier S, Zabezhinsky D, Lakadamyali M, Svitkina T. Actin polymerization promotes invagination of flat clathrin-coated lattices in mammalian cells by pushing at lattice edges. Nat Commun 2022; 13:6127. [PMID: 36253374 PMCID: PMC9576739 DOI: 10.1038/s41467-022-33852-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 10/05/2022] [Indexed: 12/24/2022] Open
Abstract
Clathrin-mediated endocytosis (CME) requires energy input from actin polymerization in mechanically challenging conditions. The roles of actin in CME are poorly understood due to inadequate knowledge of actin organization at clathrin-coated structures (CCSs). Using platinum replica electron microscopy of mammalian cells, we show that Arp2/3 complex-dependent branched actin networks, which often emerge from microtubule tips, assemble along the CCS perimeter, lack interaction with the apical clathrin lattice, and have barbed ends oriented toward the CCS. This structure is hardly compatible with the widely held "apical pulling" model describing actin functions in CME. Arp2/3 complex inhibition or epsin knockout produce large flat non-dynamic CCSs, which split into invaginating subdomains upon recovery from Arp2/3 inhibition. Moreover, epsin localization to CCSs depends on Arp2/3 activity. We propose an "edge pushing" model for CME, wherein branched actin polymerization promotes severing and invagination of flat CCSs in an epsin-dependent manner by pushing at the CCS boundary, thus releasing forces opposing the intrinsic curvature of clathrin lattices.
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Affiliation(s)
- Changsong Yang
- grid.25879.310000 0004 1936 8972Department of Biology, University of Pennsylvania, Philadelphia, PA USA
| | - Patricia Colosi
- grid.25879.310000 0004 1936 8972Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Siewert Hugelier
- grid.25879.310000 0004 1936 8972Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Daniel Zabezhinsky
- grid.25879.310000 0004 1936 8972Department of Biology, University of Pennsylvania, Philadelphia, PA USA
| | - Melike Lakadamyali
- grid.25879.310000 0004 1936 8972Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Tatyana Svitkina
- grid.25879.310000 0004 1936 8972Department of Biology, University of Pennsylvania, Philadelphia, PA USA
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15
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Ghosh A, Kar PK, Gautam A, Gupta R, Singh R, Chakravarti R, Ravichandiran V, Ghosh Dastidar S, Ghosh D, Roy S. An insight into SARS-CoV-2 structure, pathogenesis, target hunting for drug development and vaccine initiatives. RSC Med Chem 2022; 13:647-675. [PMID: 35814927 PMCID: PMC9215161 DOI: 10.1039/d2md00009a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 01/20/2022] [Indexed: 01/27/2023] Open
Abstract
SARS-CoV-2, the virus responsible for the COVID-19 pandemic, has been confirmed to be a new coronavirus having 79% and 50% similarity with SARS-CoV and MERS-CoV, respectively. For a better understanding of the features of the new virus SARS-CoV-2, we have discussed a possible correlation between some unique features of the genome of SARS-CoV-2 in relation to pathogenesis. We have also reviewed structural druggable viral and host targets for possible clinical application if any, as cases of reinfection and compromised protection have been noticed due to the emergence of new variants with increased infectivity even after vaccination. We have also discussed the types of vaccines that are being developed against SARS-CoV-2. In this review, we have tried to give a brief overview of the fundamental factors of COVID-19 research like basic virology, virus variants and the newly emerging techniques that can be applied to develop advanced treatment strategies for the management of COVID-19 disease.
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Affiliation(s)
- Arijit Ghosh
- Department of Natural Products, National Institute of Pharmaceutical Education and Research Kolkata India
- Department of Chemistry, University of Calcutta Kolkata India
- Netaji Subhas Chandra Bose Cancer Research institute 3081, Nayabad Kolkata-700094 India
| | - Paritosh K Kar
- Foundation on Tropical Diseases & Health Research Development, A Mission on Charitable Health Care Unit Balichak CT, Paschim Medinipur West Bengal 721 124 India
| | - Anupam Gautam
- Institute for Bioinformatics and Medical Informatics, University of Tübingen Sand 14 72076 Tübingen Germany
- International Max Planck Research School "From Molecules to Organisms", Max Planck Institute for Biology Tübingen Max-Planck-Ring 5 72076 Tübingen Germany
| | - Rahul Gupta
- Infectious Diseases and Immunology Division, CSIR-Indian Institute of Chemical Biology Kolkata India
| | - Rajveer Singh
- Department of Natural Products, National Institute of Pharmaceutical Education and Research Kolkata India
| | - Rudra Chakravarti
- Department of Natural Products, National Institute of Pharmaceutical Education and Research Kolkata India
| | - Velayutham Ravichandiran
- Department of Natural Products, National Institute of Pharmaceutical Education and Research Kolkata India
| | | | - Dipanjan Ghosh
- Department of Natural Products, National Institute of Pharmaceutical Education and Research Kolkata India
| | - Syamal Roy
- Infectious Diseases and Immunology Division, CSIR-Indian Institute of Chemical Biology Kolkata India
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16
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Szabó I, Yousef M, Soltész D, Bató C, Mező G, Bánóczi Z. Redesigning of Cell-Penetrating Peptides to Improve Their Efficacy as a Drug Delivery System. Pharmaceutics 2022; 14:pharmaceutics14050907. [PMID: 35631493 PMCID: PMC9146218 DOI: 10.3390/pharmaceutics14050907] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/11/2022] [Accepted: 04/13/2022] [Indexed: 12/29/2022] Open
Abstract
Cell-penetrating peptides (CPP) are promising tools for the transport of a broad range of compounds into cells. Since the discovery of the first members of this peptide family, many other peptides have been identified; nowadays, dozens of these peptides are known. These peptides sometimes have very different chemical–physical properties, but they have similar drawbacks; e.g., non-specific internalization, fast elimination from the body, intracellular/vesicular entrapment. Although our knowledge regarding the mechanism and structure–activity relationship of internalization is growing, the prediction and design of the cell-penetrating properties are challenging. In this review, we focus on the different modifications of well-known CPPs to avoid their drawbacks, as well as how these modifications may increase their internalization and/or change the mechanism of penetration.
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Affiliation(s)
- Ildikó Szabó
- MTA-ELTE Research Group of Peptide Chemistry, Eötvös Loránd Research Network (ELKH), Eötvös Loránd University, 1117 Budapest, Hungary;
- Correspondence: (I.S.); (Z.B.)
| | - Mo’ath Yousef
- Department of Organic Chemistry, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary; (M.Y.); (D.S.); (C.B.)
| | - Dóra Soltész
- Department of Organic Chemistry, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary; (M.Y.); (D.S.); (C.B.)
| | - Csaba Bató
- Department of Organic Chemistry, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary; (M.Y.); (D.S.); (C.B.)
| | - Gábor Mező
- MTA-ELTE Research Group of Peptide Chemistry, Eötvös Loránd Research Network (ELKH), Eötvös Loránd University, 1117 Budapest, Hungary;
- Department of Organic Chemistry, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary; (M.Y.); (D.S.); (C.B.)
| | - Zoltán Bánóczi
- Department of Organic Chemistry, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary; (M.Y.); (D.S.); (C.B.)
- Correspondence: (I.S.); (Z.B.)
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17
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Nawara TJ, Williams YD, Rao TC, Hu Y, Sztul E, Salaita K, Mattheyses AL. Imaging vesicle formation dynamics supports the flexible model of clathrin-mediated endocytosis. Nat Commun 2022; 13:1732. [PMID: 35365614 PMCID: PMC8976038 DOI: 10.1038/s41467-022-29317-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 02/24/2022] [Indexed: 12/11/2022] Open
Abstract
Clathrin polymerization and changes in plasma membrane architecture are necessary steps in forming vesicles to internalize cargo during clathrin-mediated endocytosis (CME). Simultaneous analysis of clathrin dynamics and membrane structure is challenging due to the limited axial resolution of fluorescence microscopes and the heterogeneity of CME. This has fueled conflicting models of vesicle assembly and obscured the roles of flat clathrin assemblies. Here, using Simultaneous Two-wavelength Axial Ratiometry (STAR) microscopy, we bridge this critical knowledge gap by quantifying the nanoscale dynamics of clathrin-coat shape change during vesicle assembly. We find that de novo clathrin accumulations generate both flat and curved structures. High-throughput analysis reveals that the initiation of vesicle curvature does not directly correlate with clathrin accumulation. We show clathrin accumulation is preferentially simultaneous with curvature formation at shorter-lived clathrin-coated vesicles (CCVs), but favors a flat-to-curved transition at longer-lived CCVs. The broad spectrum of curvature initiation dynamics revealed by STAR microscopy supports multiple productive mechanisms of vesicle formation and advocates for the flexible model of CME. Despite decades of research, the dynamics of clathrin-coated vesicle formation is ambiguous. Here, authors use STAR microscopy to quantify the nanoscale dynamics of vesicle formation, supporting the flexible model of clathrin-mediated endocytosis.
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Affiliation(s)
- Tomasz J Nawara
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Yancey D Williams
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Tejeshwar C Rao
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Yuesong Hu
- Department of Chemistry, Emory University, Atlanta, GA, USA
| | - Elizabeth Sztul
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Khalid Salaita
- Department of Chemistry, Emory University, Atlanta, GA, USA
| | - Alexa L Mattheyses
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA.
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18
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Prichard KL, O'Brien NS, Murcia SR, Baker JR, McCluskey A. Role of Clathrin and Dynamin in Clathrin Mediated Endocytosis/Synaptic Vesicle Recycling and Implications in Neurological Diseases. Front Cell Neurosci 2022; 15:754110. [PMID: 35115907 PMCID: PMC8805674 DOI: 10.3389/fncel.2021.754110] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 12/10/2021] [Indexed: 12/17/2022] Open
Abstract
Endocytosis is a process essential to the health and well-being of cell. It is required for the internalisation and sorting of “cargo”—the macromolecules, proteins, receptors and lipids of cell signalling. Clathrin mediated endocytosis (CME) is one of the key processes required for cellular well-being and signalling pathway activation. CME is key role to the recycling of synaptic vesicles [synaptic vesicle recycling (SVR)] in the brain, it is pivotal to signalling across synapses enabling intracellular communication in the sensory and nervous systems. In this review we provide an overview of the general process of CME with a particular focus on two key proteins: clathrin and dynamin that have a central role to play in ensuing successful completion of CME. We examine these two proteins as they are the two endocytotic proteins for which small molecule inhibitors, often of known mechanism of action, have been identified. Inhibition of CME offers the potential to develop therapeutic interventions into conditions involving defects in CME. This review will discuss the roles and the current scope of inhibitors of clathrin and dynamin, providing an insight into how further developments could affect neurological disease treatments.
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19
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Moulay G, Bitoun M, Furling D, Vassilopoulos S. [How alternative splicing contributes to clathrin's structural plasticity]. Med Sci (Paris) 2021; 37:1186-1188. [PMID: 34928228 DOI: 10.1051/medsci/2021178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Gilles Moulay
- Sorbonne Université, Inserm, Association Institut de myologie, Centre de recherche en myologie, UMRS 974, 47 boulevard de l'Hôpital, 75013 Paris, France
| | - Marc Bitoun
- Sorbonne Université, Inserm, Association Institut de myologie, Centre de recherche en myologie, UMRS 974, 47 boulevard de l'Hôpital, 75013 Paris, France
| | - Denis Furling
- Sorbonne Université, Inserm, Association Institut de myologie, Centre de recherche en myologie, UMRS 974, 47 boulevard de l'Hôpital, 75013 Paris, France
| | - Stéphane Vassilopoulos
- Sorbonne Université, Inserm, Association Institut de myologie, Centre de recherche en myologie, UMRS 974, 47 boulevard de l'Hôpital, 75013 Paris, France
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20
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Willy NM, Ferguson JP, Akatay A, Huber S, Djakbarova U, Silahli S, Cakez C, Hasan F, Chang HC, Travesset A, Li S, Zandi R, Li D, Betzig E, Cocucci E, Kural C. De novo endocytic clathrin coats develop curvature at early stages of their formation. Dev Cell 2021; 56:3146-3159.e5. [PMID: 34774130 DOI: 10.1016/j.devcel.2021.10.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/14/2021] [Accepted: 10/22/2021] [Indexed: 01/09/2023]
Abstract
Sculpting a flat patch of membrane into an endocytic vesicle requires curvature generation on the cell surface, which is the primary function of the endocytosis machinery. Using super-resolved live cell fluorescence imaging, we demonstrate that curvature generation by individual clathrin-coated pits can be detected in real time within cultured cells and tissues of developing organisms. Our analyses demonstrate that the footprint of clathrin coats increases monotonically during the formation of pits at different levels of plasma membrane tension. These findings are only compatible with models that predict curvature generation at the early stages of endocytic clathrin pit formation. We also found that CALM adaptors associated with clathrin plaques form clusters, whereas AP2 distribution is more homogenous. Considering the curvature sensing and driving roles of CALM, we propose that CALM clusters may increase the strain on clathrin lattices locally, eventually giving rise to rupture and subsequent pit completion at the edges of plaques.
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Affiliation(s)
- Nathan M Willy
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Joshua P Ferguson
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Ata Akatay
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Scott Huber
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | | | - Salih Silahli
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Cemal Cakez
- Department of Nuclear Engineering, University of New Mexico, Albuquerque, NM 87131, USA
| | - Farah Hasan
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Henry C Chang
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Alex Travesset
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA; Ames Laboratory, Iowa State University, Ames, IA 50011, USA
| | - Siyu Li
- Department of Physics and Astronomy, University of California, Riverside, Riverside, CA 92521, USA
| | - Roya Zandi
- Department of Physics and Astronomy, University of California, Riverside, Riverside, CA 92521, USA
| | - Dong Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Eric Betzig
- Departments of Physics and Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Emanuele Cocucci
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA.
| | - Comert Kural
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA; Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA.
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21
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Tagiltsev G, Haselwandter CA, Scheuring S. Nanodissected elastically loaded clathrin lattices relax to increased curvature. SCIENCE ADVANCES 2021; 7:7/33/eabg9934. [PMID: 34389539 PMCID: PMC8363152 DOI: 10.1126/sciadv.abg9934] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
Clathrin-mediated endocytosis (CME) is the major endocytosis pathway for the specific internalization of large compounds, growth factors, and receptors. Formation of internalized vesicles from the flat plasma membrane is accompanied by maturation of cytoplasmic clathrin coats. How clathrin coats mature and the mechanistic role of clathrin coats are still largely unknown. Maturation models proposed clathrin coats to mature at constant radius or constant area, driven by molecular actions or elastic energy. Here, combining high-speed atomic force microscopy (HS-AFM) imaging, HS-AFM nanodissection, and elasticity theory, we show that clathrin lattices deviating from the intrinsic curvature of clathrin form elastically loaded assemblies. Upon nanodissection of the clathrin network, the stored elastic energy in these lattices drives lattice relaxation to accommodate an ideal area-curvature ratio toward the formation of closed clathrin-coated vesicles. Our work supports that the release of elastic energy stored in curvature-frustrated clathrin lattices could play a major role in CME.
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Affiliation(s)
- Grigory Tagiltsev
- Department of Anesthesiology, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA
- Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA
| | - Christoph A Haselwandter
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Simon Scheuring
- Department of Anesthesiology, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA.
- Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA
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22
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Kadir SR, Lilja A, Gunn N, Strong C, Hughes RT, Bailey BJ, Rae J, Parton RG, McGhee J. Nanoscape, a data-driven 3D real-time interactive virtual cell environment. eLife 2021; 10:64047. [PMID: 34191720 PMCID: PMC8245131 DOI: 10.7554/elife.64047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 06/04/2021] [Indexed: 12/15/2022] Open
Abstract
Our understanding of cellular and structural biology has reached unprecedented levels of detail, and computer visualisation techniques can be used to create three-dimensional (3D) representations of cells and their environment that are useful in both teaching and research. However, extracting and integrating the relevant scientific data, and then presenting them in an effective way, can pose substantial computational and aesthetic challenges. Here we report how computer artists, experts in computer graphics and cell biologists have collaborated to produce a tool called Nanoscape that allows users to explore and interact with 3D representations of cells and their environment that are both scientifically accurate and visually appealing. We believe that using Nanoscape as an immersive learning application will lead to an improved understanding of the complexities of cellular scales, densities and interactions compared with traditional learning modalities.
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Affiliation(s)
- Shereen R Kadir
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Andrew Lilja
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Nick Gunn
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Campbell Strong
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Rowan T Hughes
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Benjamin J Bailey
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - James Rae
- Institute for Molecular Bioscience, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Australia
| | - John McGhee
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
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23
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Djakbarova U, Madraki Y, Chan ET, Kural C. Dynamic interplay between cell membrane tension and clathrin-mediated endocytosis. Biol Cell 2021; 113:344-373. [PMID: 33788963 DOI: 10.1111/boc.202000110] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 03/08/2021] [Accepted: 03/19/2021] [Indexed: 12/26/2022]
Abstract
Deformability of the plasma membrane, the outermost surface of metazoan cells, allows cells to be dynamic, mobile and flexible. Factors that affect this deformability, such as tension on the membrane, can regulate a myriad of cellular functions, including membrane resealing, cell motility, polarisation, shape maintenance, membrane area control and endocytic vesicle trafficking. This review focuses on mechanoregulation of clathrin-mediated endocytosis (CME). We first delineate the origins of cell membrane tension and the factors that yield to its spatial and temporal fluctuations within cells. We then review the recent literature demonstrating that tension on the membrane is a fast-acting and reversible regulator of CME. Finally, we discuss tension-based regulation of endocytic clathrin coat formation during physiological processes.
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Affiliation(s)
| | - Yasaman Madraki
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA
| | - Emily T Chan
- Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH, 43210, USA.,Molecular Biophysics Training Program, The Ohio State University, Columbus, OH, 43210, USA
| | - Cömert Kural
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA.,Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH, 43210, USA
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24
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Camblor-Perujo S, Kononenko NL. Brain-specific functions of the endocytic machinery. FEBS J 2021; 289:2219-2246. [PMID: 33896112 DOI: 10.1111/febs.15897] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 03/29/2021] [Indexed: 12/12/2022]
Abstract
Endocytosis is an essential cellular process required for multiple physiological functions, including communication with the extracellular environment, nutrient uptake, and signaling by the cell surface receptors. In a broad sense, endocytosis is accomplished through either constitutive or ligand-induced invagination of the plasma membrane, which results in the formation of the plasma membrane-retrieved endocytic vesicles, which can either be sent for degradation to the lysosomes or recycled back to the PM. This additional function of endocytosis in membrane retrieval has been adopted by excitable cells, such as neurons, for membrane equilibrium maintenance at synapses. The last two decades were especially productive with respect to the identification of brain-specific functions of the endocytic machinery, which additionally include but not limited to regulation of neuronal differentiation and migration, maintenance of neuron morphology and synaptic plasticity, and prevention of neurotoxic aggregates spreading. In this review, we highlight the current knowledge of brain-specific functions of endocytic machinery with a specific focus on three brain cell types, neuronal progenitor cells, neurons, and glial cells.
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Affiliation(s)
| | - Natalia L Kononenko
- CECAD Cluster of Excellence, University of Cologne, Germany.,Center for Physiology & Pathophysiology, Medical Faculty, University of Cologne, Germany
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25
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Wu M, Wu X. A kinetic view of clathrin assembly and endocytic cargo sorting. Curr Opin Cell Biol 2021; 71:130-138. [PMID: 33865229 DOI: 10.1016/j.ceb.2021.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 02/10/2021] [Accepted: 02/12/2021] [Indexed: 01/30/2023]
Abstract
Specificity and sensitivity in biochemical reactions can be achieved through regulation of equilibrium binding affinity or through proofreading mechanisms that allow for the dissociation of unwanted intermediates. In this essay, we aim to provide our perspectives on how the concept of kinetic proofreading might apply in the context of cargo sorting in clathrin-mediated endocytosis.
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Affiliation(s)
- Min Wu
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520-8002, USA.
| | - Xudong Wu
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA, 02115, USA
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26
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Moulay G, Lainé J, Lemaître M, Nakamori M, Nishino I, Caillol G, Mamchaoui K, Julien L, Dingli F, Loew D, Bitoun M, Leterrier C, Furling D, Vassilopoulos S. Alternative splicing of clathrin heavy chain contributes to the switch from coated pits to plaques. J Cell Biol 2021; 219:151930. [PMID: 32642759 PMCID: PMC7480091 DOI: 10.1083/jcb.201912061] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 04/14/2020] [Accepted: 05/15/2020] [Indexed: 12/18/2022] Open
Abstract
Clathrin function directly derives from its coat structure, and while endocytosis is mediated by clathrin-coated pits, large plaques contribute to cell adhesion. Here, we show that the alternative splicing of a single exon of the clathrin heavy chain gene (CLTC exon 31) helps determine the clathrin coat organization. Direct genetic control was demonstrated by forced CLTC exon 31 skipping in muscle cells that reverses the plasma membrane content from clathrin plaques to pits and by promoting exon inclusion that stimulated flat plaque assembly. Interestingly, mis-splicing of CLTC exon 31 found in the severe congenital form of myotonic dystrophy was associated with reduced plaques in patient myotubes. Moreover, forced exclusion of this exon in WT mice muscle induced structural disorganization and reduced force, highlighting the contribution of this splicing event for the maintenance of tissue homeostasis. This genetic control on clathrin assembly should influence the way we consider how plasticity in clathrin-coated structures is involved in muscle development and maintenance.
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Affiliation(s)
- Gilles Moulay
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS 974, Paris, France
| | - Jeanne Lainé
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS 974, Paris, France.,Sorbonne Université, Department of Physiology, Pitié-Salpêtrière Hospital, Paris, France
| | - Mégane Lemaître
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Phénotypage du petit animal - UMS 28, Paris, France
| | - Masayuki Nakamori
- Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Ichizo Nishino
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Ghislaine Caillol
- Aix Marseille Université, Centre National de la Recherche Scientifique, NeuroCyto, Marseille, France
| | - Kamel Mamchaoui
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS 974, Paris, France
| | - Laura Julien
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS 974, Paris, France
| | - Florent Dingli
- Institut Curie, PSL Research University, Centre de Recherche, Laboratoire de Spectrométrie de Masse Protéomique, Paris, France
| | - Damarys Loew
- Institut Curie, PSL Research University, Centre de Recherche, Laboratoire de Spectrométrie de Masse Protéomique, Paris, France
| | - Marc Bitoun
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS 974, Paris, France
| | - Christophe Leterrier
- Aix Marseille Université, Centre National de la Recherche Scientifique, NeuroCyto, Marseille, France
| | - Denis Furling
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS 974, Paris, France
| | - Stéphane Vassilopoulos
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS 974, Paris, France
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27
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Clathrin senses membrane curvature. Biophys J 2021; 120:818-828. [PMID: 33524373 DOI: 10.1016/j.bpj.2020.12.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/23/2020] [Accepted: 12/07/2020] [Indexed: 11/21/2022] Open
Abstract
The ability of proteins to assemble at sites of high membrane curvature is essential to diverse membrane remodeling processes, including clathrin-mediated endocytosis. Multiple adaptor proteins within the clathrin pathway have been shown to sense regions of high membrane curvature, leading to local recruitment of the clathrin coat. Because clathrin triskelia do not bind to the membrane directly, it has remained unclear whether the clathrin coat plays an active role in sensing membrane curvature or is passively recruited by adaptor proteins. Using a synthetic tag to assemble clathrin directly on membrane surfaces, here we show that clathrin is a strong sensor of membrane curvature, comparable with previously studied adaptor proteins. Interestingly, this sensitivity arises from clathrin assembly rather than from the properties of unassembled triskelia, suggesting that triskelia have preferred angles of interaction, as predicted by earlier structural data. Furthermore, when clathrin is recruited by adaptors, its curvature sensitivity is amplified by 2- to 10-fold, such that the resulting protein complex is up to 100 times more likely to assemble on a highly curved surface compared with a flatter one. This exquisite sensitivity points to a synergistic relationship between the coat and its adaptor proteins, which enables clathrin to pinpoint sites of high membrane curvature, an essential step in ensuring robust membrane traffic. More broadly, these findings suggest that protein networks, rather than individual protein domains, are likely the most potent drivers of membrane curvature sensing.
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28
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Akisaka T, Yoshida A. Surface distribution of heterogenous clathrin assemblies in resorbing osteoclasts. Exp Cell Res 2020; 399:112433. [PMID: 33359468 DOI: 10.1016/j.yexcr.2020.112433] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/06/2020] [Accepted: 12/12/2020] [Indexed: 01/04/2023]
Abstract
Osteoclasts seeded on either glass coverslips or apatite pellets have at least two morphologically distinct substrate adhesion sites: actin-based adhesion structures including podosome belts and sealing zones, and adjacent clathrin sheets. Clathrin-coated structures are exclusively localized at the podosome belts and sealing zone, in both of which the plasma membrane forms a tight attachment to the substrate surface. When cultured on apatite osteoclasts can degrade the apatite leading to the formation of resorption lacunae. The sealing zone divides the ventral membrane into different domains, outside and inside of the sealing zones. The former facing the smooth-surfaced intact apatite contains relatively solitary or networks of larger flat clathrin structures; and the latter, facing the rough-surfaced degraded apatite in the resorption lacunae contain clathrin in various shapes and sizes. Clathrin assemblies on the membrane domain facing not only a resorption lacuna, or trails but also intact apatite indeed were observed to be heterogeneous in size and intensity, suggesting that they appeared to follow variations in the surface topography of the apatite surface. These results provide a detailed insight into the flat clathrin sheets that have been suggested to be the sites of adhesion and mechanosensing in co-operation with podosomes.
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Affiliation(s)
- Toshitaka Akisaka
- Department of Oral Anatomy and Neurobiology, Graduate School of Dentistry, Osaka University, Japan.
| | - Atsushi Yoshida
- Department of Oral Anatomy and Neurobiology, Graduate School of Dentistry, Osaka University, Japan.
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29
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Complementary mesoscale dynamics of spectrin and acto-myosin shape membrane territories during mechanoresponse. Nat Commun 2020; 11:5108. [PMID: 33037189 PMCID: PMC7547731 DOI: 10.1038/s41467-020-18825-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 09/11/2020] [Indexed: 11/08/2022] Open
Abstract
The spectrin-based membrane skeleton is a major component of the cell cortex. While expressed by all metazoans, its dynamic interactions with the other cortex components, including the plasma membrane or the acto-myosin cytoskeleton, are poorly understood. Here, we investigate how spectrin re-organizes spatially and dynamically under the membrane during changes in cell mechanics. We find spectrin and acto-myosin to be spatially distinct but cooperating during mechanical challenges, such as cell adhesion and contraction, or compression, stretch and osmolarity fluctuations, creating a cohesive cortex supporting the plasma membrane. Actin territories control protrusions and contractile structures while spectrin territories concentrate in retractile zones and low-actin density/inter-contractile regions, acting as a fence that organize membrane trafficking events. We unveil here the existence of a dynamic interplay between acto-myosin and spectrin necessary to support a mesoscale organization of the lipid bilayer into spatially-confined cortical territories during cell mechanoresponse.
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30
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Chen Z, Schmid SL. Evolving models for assembling and shaping clathrin-coated pits. J Cell Biol 2020; 219:e202005126. [PMID: 32770195 PMCID: PMC7480099 DOI: 10.1083/jcb.202005126] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/13/2020] [Accepted: 07/13/2020] [Indexed: 01/01/2023] Open
Abstract
Clathrin-mediated endocytosis occurs via the assembly of clathrin-coated pits (CCPs) that invaginate and pinch off to form clathrin-coated vesicles (CCVs). It is well known that adaptor protein 2 (AP2) complexes trigger clathrin assembly on the plasma membrane, and biochemical and structural studies have revealed the nature of these interactions. Numerous endocytic accessory proteins collaborate with clathrin and AP2 to drive CCV formation. However, many questions remain as to the molecular events involved in CCP initiation, stabilization, and curvature generation. Indeed, a plethora of recent evidence derived from cell perturbation, correlative light and EM tomography, live-cell imaging, modeling, and high-resolution structural analyses has revealed more complexity and promiscuity in the protein interactions driving CCP maturation than anticipated. After briefly reviewing the evidence supporting prevailing models, we integrate these new lines of evidence to develop a more dynamic and flexible model for how redundant, dynamic, and competing protein interactions can drive endocytic CCV formation and suggest new approaches to test emerging models.
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Affiliation(s)
| | - Sandra L. Schmid
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
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31
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Sposini S, Rosendale M, Claverie L, Van TNN, Jullié D, Perrais D. Imaging endocytic vesicle formation at high spatial and temporal resolutions with the pulsed-pH protocol. Nat Protoc 2020; 15:3088-3104. [PMID: 32807908 DOI: 10.1038/s41596-020-0371-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 06/04/2020] [Indexed: 11/09/2022]
Abstract
Endocytosis is a fundamental process occurring in all eukaryotic cells. Live cell imaging of endocytosis has helped to decipher many of its mechanisms and regulations. With the pulsed-pH (ppH) protocol, one can detect the formation of individual endocytic vesicles (EVs) with an unmatched temporal resolution of 2 s. The ppH protocol makes use of cargo protein (e.g., the transferrin receptor) coupled to a pH-sensitive fluorescent protein, such as superecliptic pHluorin (SEP), which is brightly fluorescent at pH 7.4 but not fluorescent at pH <6.0. If the SEP moiety is at the surface, its fluorescence will decrease when cells are exposed to a low pH (5.5) buffer. If the SEP moiety has been internalized, SEP will remain fluorescent even during application of the low pH buffer. Fast perfusion enables the complete exchange of low and high pH extracellular solutions every 2 s, defining the temporal resolution of the technique. Unlike other imaging-based endocytosis assays, the ppH protocol detects EVs without a priori hypotheses on the dynamics of vesicle formation. Here, we explain how the ppH protocol quantifies the endocytic activity of living cells and the recruitment of associated proteins in real time. We provide a step-by-step procedure for expression of the reporter proteins with transient transfection, live cell image acquisition with synchronized pH changes and automated analysis. The whole protocol can be performed in 2 d to provide quantitative information on the endocytic process being studied.
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Affiliation(s)
- Silvia Sposini
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France.,CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France
| | - Morgane Rosendale
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France.,CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France.,CNRS, Institut des Sciences Moléculaires, UMR 5255, Talence, France
| | - Léa Claverie
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France.,CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France.,Euroquality, Bordeaux, France
| | - Thi Nhu Ngoc Van
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France.,CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France.,Sys2diag, Montpellier, France
| | - Damien Jullié
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France.,CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France.,University of California, San Francisco, San Francisco, CA, USA
| | - David Perrais
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France. .,CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France.
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32
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Brod J, Hellwig A, Wieland FT. Epsin but not AP-2 supports reconstitution of endocytic clathrin-coated vesicles. FEBS Lett 2020; 594:2227-2239. [PMID: 32337703 DOI: 10.1002/1873-3468.13801] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 04/05/2020] [Accepted: 04/10/2020] [Indexed: 12/12/2022]
Abstract
Formation of clathrin-coated vesicles (CCVs) in receptor-mediated endocytosis is a mechanistically well-established process, in which clathrin, the adaptor protein complex AP-2, and the large GTPase dynamin play crucial roles. In order to obtain more mechanistic insight into this process, here we established a giant unilamellar vesicle (GUV)-based in vitro CCV reconstitution system with chemically defined components and the full-length recombinant proteins clathrin, AP-2, epsin-1, and dynamin-2. Our results support the predominant model in which hydrolysis of GTP by dynamin is a prerequisite to generate CCVs. Strikingly, in this system at near physiological concentrations of reagents, epsin-1 alone does not have the propensity for scission but is required for bud formation, whereas AP-2 and clathrin are not sufficient. Thus, our study reveals that epsin-1 is an important factor for the maturation of clathrin coated buds, a prerequisite for vesicle generation.
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Affiliation(s)
- Jan Brod
- Heidelberg University Biochemistry Center (BZH), University of Heidelberg, Germany
| | - Andrea Hellwig
- Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, Germany
| | - Felix T Wieland
- Heidelberg University Biochemistry Center (BZH), University of Heidelberg, Germany
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33
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Chen Y, Yong J, Martínez-Sánchez A, Yang Y, Wu Y, De Camilli P, Fernández-Busnadiego R, Wu M. Dynamic instability of clathrin assembly provides proofreading control for endocytosis. J Cell Biol 2019; 218:3200-3211. [PMID: 31451612 PMCID: PMC6781453 DOI: 10.1083/jcb.201804136] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 06/03/2019] [Accepted: 08/01/2019] [Indexed: 12/18/2022] Open
Abstract
Chen et al. reconstitute endocytosis in a cell-free system and show that cargo sorting requires the dynamic dissociation of clathrin during the growth phase of the clathrin-coated pit formation. Clathrin-mediated endocytosis depends on the formation of functional clathrin-coated pits that recruit cargos and mediate the uptake of those cargos into the cell. However, it remains unclear whether the cargos in the growing clathrin-coated pits are actively monitored by the coat assembly machinery. Using a cell-free reconstitution system, we report that clathrin coat formation and cargo sorting can be uncoupled, indicating that a checkpoint is required for functional cargo incorporation. We demonstrate that the ATPase Hsc70 and a dynamic exchange of clathrin during assembly are required for this checkpoint. In the absence of Hsc70 function, clathrin assembles into pits but fails to enrich cargo. Using single-molecule imaging, we further show that uncoating takes place throughout the lifetime of the growing clathrin-coated pits. Our results suggest that the dynamic exchange of clathrin, at the cost of the reduced overall assembly rates, primarily serves as a proofreading mechanism for quality control of endocytosis.
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Affiliation(s)
- Yan Chen
- Centre for Bioimaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore
| | - Jeffery Yong
- Centre for Bioimaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore
| | | | - Yang Yang
- Centre for Bioimaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore
| | - Yumei Wu
- Howard Hughes Medical Institute, Department of Cell Biology and Department of Neuroscience, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Pietro De Camilli
- Howard Hughes Medical Institute, Department of Cell Biology and Department of Neuroscience, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Rubén Fernández-Busnadiego
- Max Planck Institute for Biochemistry, Martinsried, Germany.,Department of Neuropathology, University Medical Center, Georg-August University Göttingen, Göttingen, Germany
| | - Min Wu
- Centre for Bioimaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore .,Mechanobiology Institute, National University of Singapore, Singapore
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34
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Shi X, Duan F, Lin L, Xu Q, Xu T, Zhang R. WIP-1 and DBN-1 promote scission of endocytic vesicles by bridging actin and Dynamin-1 in the C. elegans intestine. J Cell Sci 2019; 132:jcs.228023. [PMID: 31118234 DOI: 10.1242/jcs.228023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 05/13/2019] [Indexed: 01/13/2023] Open
Abstract
There has been a consensus that actin plays an important role in scission of the clathrin-coated pits (CCPs) together with large GTPases of the dynamin family in metazoan cells. However, the recruitment, regulation and functional interdependence of actin and dynamin during this process remain inadequately understood. Here, based on small-scale screening and in vivo live-imaging techniques, we identified a novel set of molecules underlying CCP scission in the multicellular organism Caenorhabditis elegans We found that loss of Wiskott-Aldrich syndrome protein (WASP)-interacting protein (WIP-1) impaired CCP scission in a manner that is independent of the C. elegans homolog of WASP/N-WASP (WSP-1) and is mediated by direct binding to G-actin. Moreover, the cortactin-binding domain of WIP-1 serves as the binding interface for DBN-1 (also known in other organisms as Abp1), another actin-binding protein. We demonstrate that the interaction between DBN-1 and F-actin is essential for Dynamin-1 (DYN-1) recruitment at endocytic sites. In addition, the recycling regulator RME-1, a homolog of mammalian Eps15 homology (EH) domain-containing proteins, is increasingly recruited at the arrested endocytic intermediates induced by F-actin loss or DYN-1 inactivation, which further stabilizes the tubular endocytic intermediates. Our study provides new insights into the molecular network underlying F-actin participation in the scission of CCPs.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Xuemeng Shi
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Fengyun Duan
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Long Lin
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Qifeng Xu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Tao Xu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China .,National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Rongying Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
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35
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Rees P, Wills JW, Brown MR, Barnes CM, Summers HD. The origin of heterogeneous nanoparticle uptake by cells. Nat Commun 2019; 10:2341. [PMID: 31138801 PMCID: PMC6538724 DOI: 10.1038/s41467-019-10112-4] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 04/18/2019] [Indexed: 12/16/2022] Open
Abstract
Understanding nanoparticle uptake by biological cells is fundamentally important to wide-ranging fields from nanotoxicology to drug delivery. It is now accepted that the arrival of nanoparticles at the cell is an extremely complicated process, shaped by many factors including unique nanoparticle physico-chemical characteristics, protein-particle interactions and subsequent agglomeration, diffusion and sedimentation. Sequentially, the nanoparticle internalisation process itself is also complex, and controlled by multiple aspects of a cell's state. Despite this multitude of factors, here we demonstrate that the statistical distribution of the nanoparticle dose per endosome is independent of the initial administered dose and exposure duration. Rather, it is the number of nanoparticle containing endosomes that are dependent on these initial dosing conditions. These observations explain the heterogeneity of nanoparticle delivery at the cellular level and allow the derivation of simple, yet powerful probabilistic distributions that accurately predict the nanoparticle dose delivered to individual cells across a population.
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Affiliation(s)
- Paul Rees
- Centre for Nanohealth, Swansea University College of Engineering, Fabian Way, Crymlyn Burrows, Swansea, SA1 8EN, UK. .,Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA, 02142, USA.
| | - John W Wills
- Biominerals Research, Cambridge University Department of Veterinary Medicine, School of Biological Sciences, Madingley Road, Cambridge, CB3 0ES, UK.
| | - M Rowan Brown
- Centre for Nanohealth, Swansea University College of Engineering, Fabian Way, Crymlyn Burrows, Swansea, SA1 8EN, UK
| | - Claire M Barnes
- Centre for Nanohealth, Swansea University College of Engineering, Fabian Way, Crymlyn Burrows, Swansea, SA1 8EN, UK
| | - Huw D Summers
- Centre for Nanohealth, Swansea University College of Engineering, Fabian Way, Crymlyn Burrows, Swansea, SA1 8EN, UK
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36
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Temporal dependence of shifts in mu opioid receptor mobility at the cell surface after agonist binding observed by single-particle tracking. Sci Rep 2019; 9:7297. [PMID: 31086197 PMCID: PMC6514008 DOI: 10.1038/s41598-019-43657-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 04/24/2019] [Indexed: 01/13/2023] Open
Abstract
Agonist binding to the mu opioid receptor (MOR) results in conformational changes that allow recruitment of G-proteins, activation of downstream effectors and eventual desensitization and internalization, all of which could affect receptor mobility. The present study employed single particle tracking (SPT) of quantum dot labeled FLAG-tagged MORs to examine shifts in MOR mobility after agonist binding. FLAG-MORs on the plasma membrane were in both mobile and immobile states under basal conditions. Activation of FLAG-MORs with DAMGO caused an acute increase in the fraction of mobile MORs, and free portions of mobile tracks were partially dependent on interactions with G-proteins. In contrast, 10-minute exposure to DAMGO or morphine increased the fraction of immobile FLAG-MORs. While the decrease in mobility with prolonged DAMGO exposure corresponded to an increase in colocalization with clathrin, the increase in colocalization was present in both mobile and immobile FLAG-MORs. Thus, no single mobility state of the receptor accounted for colocalization with clathrin. These findings demonstrate that SPT can be used to track agonist-dependent changes in MOR mobility over time, but that the mobility states observed likely arise from a diverse set of interactions and will be most informative when examined in concert with particular downstream effectors.
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37
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Xu D, Zhang X, Zhang B, Zeng X, Mao H, Xu H, Jiang L, Li F. The lipid flippase subunit Cdc50 is required for antifungal drug resistance, endocytosis, hyphal development and virulence in Candida albicans. FEMS Yeast Res 2019; 19:5475645. [PMID: 31004489 DOI: 10.1093/femsyr/foz033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 04/18/2019] [Indexed: 12/22/2022] Open
Abstract
Cdc50 is the non-catalytic subunit of the flippase that establishes phospholipid asymmetry in membranes and functions in vesicle-mediated trafficking in Saccharomyces cerevisiae. Here, we have identified the homologous gene CaCDC50 that encodes a protein of 396 amino acids with two conserved transmembrane domains in Candidaalbicans. Deletion of CaCDC50 results in C. albicans cells becoming sensitive to the antifungal drugs azoles, terbinafine and caspofungin, as well as to the membrane-perturbing agent sodium dodecyl sulfate. We also show that CaCDC50 is involved in both endocytosis and vacuolar function. CaCDC50 confers tolerance to high concentrations of cations, although it is not required for osmolar response. Moreover, deletion of CaCDC50 leads to severe defects in hyphal development of C. albicans cells and highly attenuated virulence in the mouse model of systemic infection. Therefore, CaCDC50 regulates cellular responses to antifungal drugs, cell membrane stress, endocytosis, filamentation and virulence in the human fungal pathogen C. albicans.
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Affiliation(s)
- Dayong Xu
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, Anhui, China
| | - Xing Zhang
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, Anhui, China
| | - Biao Zhang
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, Anhui, China
| | - Xin Zeng
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, Anhui, China
| | - Hongchen Mao
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, Anhui, China
| | - Haitao Xu
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, Anhui, China
| | - Linghuo Jiang
- Laboratory for Yeast Molecular and Cell Biology, The Research Center of Fermentation Technology, School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255000, Shandong, China
| | - Feng Li
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, Anhui, China
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38
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Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
![]()
Biological
membranes are tricky to investigate. They are complex
in terms of molecular composition and structure, functional
over a wide range of time scales, and characterized
by nonequilibrium conditions. Because of all of these
features, simulations are a great technique to study biomembrane
behavior. A significant part of the functional processes
in biological membranes takes place at the molecular
level; thus computer simulations are the method of
choice to explore how their properties emerge from specific
molecular features and how the interplay among the numerous
molecules gives rise to function over spatial and
time scales larger than the molecular ones. In this
review, we focus on this broad theme. We discuss the current
state-of-the-art of biomembrane simulations that, until
now, have largely focused on a rather narrow picture
of the complexity of the membranes. Given this, we
also discuss the challenges that we should unravel in the
foreseeable future. Numerous features such as the actin-cytoskeleton
network, the glycocalyx network, and nonequilibrium
transport under ATP-driven conditions have so far
received very little attention; however, the potential
of simulations to solve them would be exceptionally high. A
major milestone for this research would be that one day
we could say that computer simulations genuinely research
biological membranes, not just lipid bilayers.
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Affiliation(s)
- Giray Enkavi
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland
| | - Matti Javanainen
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences , Flemingovo naḿesti 542/2 , 16610 Prague , Czech Republic.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland
| | - Waldemar Kulig
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland
| | - Tomasz Róg
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland
| | - Ilpo Vattulainen
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland.,MEMPHYS-Center for Biomembrane Physics
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Zhao P, Chen B, Li L, Wu H, Li Y, Shaneen B, Zhan X, Gu N. Missing-in-metastasis protein promotes internalization of magnetic nanoparticles via association with clathrin light chain and Rab7. Biochim Biophys Acta Gen Subj 2019; 1863:502-510. [PMID: 30528490 PMCID: PMC8218922 DOI: 10.1016/j.bbagen.2018.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 11/05/2018] [Accepted: 12/04/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Magnetic nanoparticles (MNPs) have been widely used in biomedical applications. Proper control of the duration of MNPs in circulation promises to improve further their applications, in particularly drug delivery. It is known that the uptake of tissue-associated MNPs is mainly carried out by macrophages. Yet, the molecular mechanism to control MNPs internalization in macrophages remains to be elusive. Missing-in-metastasis (MIM) is a scaffolding protein that is highly expressed in macrophages and regulates receptor-mediated endocytosis. We hypothesize that uptake of MNPs may also involve the function of MIM. METHODS We investigated the effect of MIM expression on the intracellular trafficking of MNPs by transmission electronic microscopy, flow cytometry, o-phenanthroline photometric analysis, Perl's staining, immunofluorescence microscopy and co-immunoprecipitation. To explore the molecular events in MIM-mediated MNPs uptake, we examined the effect of MNPs on the interaction of MIM with clathrin, Rab5 and Rab7. RESULTS Uptake of MNPs was significantly enhanced in cells overexpressing MIM. Upon exposure to MNPs, MIM was associated with clathrin light chain in endocytic vesicles and Rab7, a protein that regulates late endosomes. However, MNPs caused dissociation of MIM with Rab5, an early endosome-associated protein. CONCLUSIONS MIM regulates internalization of MNPs via promoting their trafficking from plasma membrane to late endosomes. GENERAL SIGNIFICANCE Our data unveiled a novel pathway which MNPs internalization and intracellular trafficking in macrophages. This new pathway may allow us to control the uptake of MNPs within cells by targeting MIM, thereby improving their medical applications.
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Affiliation(s)
- Peng Zhao
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, PR China; Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou 215123, PR China
| | - Bo Chen
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, PR China; Materials Science and Devices Institute, Suzhou University of Science and Technology, 1 Kerui Road, Suzhou, Jiangsu 215009, PR China
| | - Lushen Li
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Hao Wu
- School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing 210029, PR China
| | - Yan Li
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, PR China; Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou 215123, PR China
| | - Baxter Shaneen
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Xi Zhan
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Ning Gu
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, PR China; Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou 215123, PR China.
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40
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Extracting lipid vesicles from plasma membranes via self-assembly of clathrin-inspired scaffolding nanoparticles. Colloids Surf B Biointerfaces 2019; 176:239-248. [PMID: 30623811 DOI: 10.1016/j.colsurfb.2019.01.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/27/2018] [Accepted: 01/02/2019] [Indexed: 11/22/2022]
Abstract
Single-cell analysis is a new and rapidly expanding field, the goal of which is obtaining fresh information from individual cells to understand the regulatory mechanisms of cell development and diseases. Conventional approaches generally rely on the cell lysis which, however, is destructive to cells and against multiple sampling from the living cell. Here, we propose and design a scaffolding nanoparticle (NP) system that enables us to sample cytoplasmic contents without rupturing the cellular membrane, by mimicking the unusual features of clathrin. Our simulation results reveal the design principles, following which scaffolding NPs can extract lipid vesicles from plasma membranes, with both the pathway and the mechanism resembling the clathrin-mediated endocytosis, i.e. multiple NPs deposit at the membrane, assembling into cage-like structures to deform the membrane into a vesicle shape. As important design parameters, the interaction between different NPs should be properly stronger than that between each NP and the membrane to ensure the cage formation, and optimal NP concentration and the membrane surface tension are also requisite for extracting lipid vesicles. Our results provide useful guidelines for design of bio-inspired scaffolding NPs as an intelligent machine for practical use in but not limited to the single-cell analysis.
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41
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Bairwa G, Caza M, Horianopoulos L, Hu G, Kronstad J. Role of clathrin-mediated endocytosis in the use of heme and hemoglobin by the fungal pathogen Cryptococcus neoformans. Cell Microbiol 2018; 21:e12961. [PMID: 30291809 DOI: 10.1111/cmi.12961] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/23/2018] [Accepted: 09/17/2018] [Indexed: 12/29/2022]
Abstract
Heme is a major source of iron for pathogens of humans, and its use is critical in determining the outcome of infection and disease. Cryptococcus neoformans is an encapsulated fungal pathogen that causes life-threatening infections in immunocompromised individuals. C. neoformans effectively uses heme as an iron source, but the underlying mechanisms are poorly defined. Non-iron metalloporphyrins (MPPs) are toxic analogues of heme and are thought to enter microbial cells via endogenous heme acquisition systems. We therefore carried out a mutant screen for susceptibility against manganese MPP (MnMPP) to identify new components for heme uptake in C. neoformans. We identified several genes involved in signalling, DNA repair, sugar metabolism, and trafficking that play important roles in susceptibility to MnMPP and in the use of heme as an iron source. We focused on investigating the role of clathrin-mediated endocytosis (CME) and found that several components of CME including Chc1, Las17, Rvs161, and Rvs167 are required for growth on heme and hemoglobin and for endocytosis and intracellular trafficking of these molecules. We show that the hemoglobin uptake process in C. neoformans involves clathrin heavy chain, Chc1, which appears to colocalise with hemoglobin-containing vesicles and to potentially assist in proper delivery of hemoglobin to the vacuole. Additionally, C. neoformans strains lacking Chc1, Las17, Rvs161, or Rvs167 were defective in the elaboration of several key virulence factors, and a las17 mutant was avirulent in a mouse model of cryptococcosis. Overall, this study unveils crucial functions of CME in the use of heme iron by C. neoformans and reveals a role for CME in fungal pathogenesis.
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Affiliation(s)
- Gaurav Bairwa
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Mélissa Caza
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Linda Horianopoulos
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Guanggan Hu
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - James Kronstad
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
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42
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Fratini M, Wiegand T, Funaya C, Jiang Z, Shah PNM, Spatz JP, Cavalcanti-Adam EA, Boulant S. Surface Immobilization of Viruses and Nanoparticles Elucidates Early Events in Clathrin-Mediated Endocytosis. ACS Infect Dis 2018; 4:1585-1600. [PMID: 30200751 DOI: 10.1021/acsinfecdis.8b00134] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Clathrin-mediated endocytosis (CME) is an important entry pathway for viruses. Here, we applied click chemistry to covalently immobilize reovirus on surfaces to study CME during early host-pathogen interactions. To uncouple chemical and physical properties of viruses and determine their impact on CME initiation, we used the same strategy to covalently immobilize nanoparticles of different sizes. Using fluorescence live microscopy and electron microscopy, we confirmed that clathrin recruitment depends on particle size and discovered that the maturation into clathrin-coated vesicles (CCVs) is independent from cargo internalization. Surprisingly, we found that the final size of CCVs appears to be imprinted on the clathrin coat at early stages of cargo-cell interactions. Our approach has allowed us to unravel novel aspects of early interactions between viruses and the clathrin machinery that influence late stages of CME and CCVs formation. This method can be easily and broadly applied to the field of nanotechnology, endocytosis, and virology.
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Affiliation(s)
- Marta Fratini
- Heidelberg University, Department of Infectious Diseases, Virology and German Cancer Research Center, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
- Max Planck Institute for Medical Research, Department of Cellular Biophysics, Jahnstrasse 29, 69120 Heidelberg, Germany
- Heidelberg University, Institute of Physical Chemistry, Department of Biophysical Chemistry, Im Neuenheimer Feld 253, 69120, Heidelberg, Germany
| | - Tina Wiegand
- Max Planck Institute for Medical Research, Department of Cellular Biophysics, Jahnstrasse 29, 69120 Heidelberg, Germany
- Heidelberg University, Institute of Physical Chemistry, Department of Biophysical Chemistry, Im Neuenheimer Feld 253, 69120, Heidelberg, Germany
| | - Charlotta Funaya
- Heidelberg University, Electron Microscopy Core Facility, Im Neuenheimer Feld 345, 69120 Heidelberg, Germany
| | - Zhongxiang Jiang
- Leica Microsystems GmbH, Am Friedensplatz 3, 68165 Mannheim, Germany
| | - Pranav N. M. Shah
- Heidelberg University, Department of Infectious Diseases, Virology and German Cancer Research Center, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
| | - Joachim P. Spatz
- Max Planck Institute for Medical Research, Department of Cellular Biophysics, Jahnstrasse 29, 69120 Heidelberg, Germany
- Heidelberg University, Institute of Physical Chemistry, Department of Biophysical Chemistry, Im Neuenheimer Feld 253, 69120, Heidelberg, Germany
| | - Elisabetta Ada Cavalcanti-Adam
- Max Planck Institute for Medical Research, Department of Cellular Biophysics, Jahnstrasse 29, 69120 Heidelberg, Germany
- Heidelberg University, Institute of Physical Chemistry, Department of Biophysical Chemistry, Im Neuenheimer Feld 253, 69120, Heidelberg, Germany
| | - Steeve Boulant
- Heidelberg University, Department of Infectious Diseases, Virology and German Cancer Research Center, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
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43
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Haucke V, Kozlov MM. Membrane remodeling in clathrin-mediated endocytosis. J Cell Sci 2018; 131:131/17/jcs216812. [PMID: 30177505 DOI: 10.1242/jcs.216812] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Clathrin-mediated endocytosis is an essential cellular mechanism by which all eukaryotic cells regulate their plasma membrane composition to control processes ranging from cell signaling to adhesion, migration and morphogenesis. The formation of endocytic vesicles and tubules involves extensive protein-mediated remodeling of the plasma membrane that is organized in space and time by protein-protein and protein-phospholipid interactions. Recent studies combining high-resolution imaging with genetic manipulations of the endocytic machinery and with theoretical approaches have led to novel multifaceted phenomenological data of the temporal and spatial organization of the endocytic reaction. This gave rise to various - often conflicting - models as to how endocytic proteins and their association with lipids regulate the endocytic protein choreography to reshape the plasma membrane. In this Review, we discuss these findings in light of the hypothesis that endocytic membrane remodeling may be determined by an interplay between protein-protein interactions, the ability of proteins to generate and sense membrane curvature, and the ability of lipids to stabilize and reinforce the generated membrane shape through adopting their lateral distribution to the local membrane curvature.
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Affiliation(s)
- Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin, Germany .,Freie Universität Berlin, Department of Biology, Chemistry, Pharmacy, Takustrasse 3, 14195 Berlin, Germany
| | - Michael M Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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44
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Membrane Flow Drives an Adhesion-Independent Amoeboid Cell Migration Mode. Dev Cell 2018; 46:9-22.e4. [PMID: 29937389 DOI: 10.1016/j.devcel.2018.05.029] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 03/28/2018] [Accepted: 05/23/2018] [Indexed: 12/30/2022]
Abstract
Cells migrate by applying rearward forces against extracellular media. It is unclear how this is achieved in amoeboid migration, which lacks adhesions typical of lamellipodia-driven mesenchymal migration. To address this question, we developed optogenetically controlled models of lamellipodia-driven and amoeboid migration. On a two-dimensional surface, migration speeds in both modes were similar. However, when suspended in liquid, only amoeboid cells exhibited rapid migration accompanied by rearward membrane flow. These cells exhibited increased endocytosis at the back and membrane trafficking from back to front. Genetic or pharmacological perturbation of this polarized trafficking inhibited migration. The ratio of cell migration and membrane flow speeds matched the predicted value from a model where viscous forces tangential to the cell-liquid interface propel the cell forward. Since this mechanism does not require specific molecular interactions with the surrounding medium, it can facilitate amoeboid migration observed in diverse microenvironments during immune function and cancer metastasis.
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45
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Yoshida A, Sakai N, Uekusa Y, Imaoka Y, Itagaki Y, Suzuki Y, Yoshimura SH. Morphological changes of plasma membrane and protein assembly during clathrin-mediated endocytosis. PLoS Biol 2018; 16:e2004786. [PMID: 29723197 PMCID: PMC5953504 DOI: 10.1371/journal.pbio.2004786] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 05/15/2018] [Accepted: 03/29/2018] [Indexed: 12/21/2022] Open
Abstract
Clathrin-mediated endocytosis (CME) proceeds through a series of morphological changes of the plasma membrane induced by a number of protein components. Although the spatiotemporal assembly of these proteins has been elucidated by fluorescence-based techniques, the protein-induced morphological changes of the plasma membrane have not been fully clarified in living cells. Here, we visualize membrane morphology together with protein localizations during CME by utilizing high-speed atomic force microscopy (HS-AFM) combined with a confocal laser scanning unit. The plasma membrane starts to invaginate approximately 30 s after clathrin starts to assemble, and the aperture diameter increases as clathrin accumulates. Actin rapidly accumulates around the pit and induces a small membrane swelling, which, within 30 s, rapidly covers the pit irreversibly. Inhibition of actin turnover abolishes the swelling and induces a reversible open–close motion of the pit, indicating that actin dynamics are necessary for efficient and irreversible pit closure at the end of CME. Cells communicate with their environments via the plasma membrane and various membrane proteins. Clathrin-mediated endocytosis (CME) plays a central role in such communication and proceeds with a series of multiprotein assembly, deformation of the plasma membrane, and production of a membrane vesicle that delivers extracellular signaling molecules into the cytoplasm. In this study, we utilized our home-built correlative imaging system comprising high-speed atomic force microscopy (HS-AFM) and confocal fluorescence microscopy to simultaneously image morphological changes of the plasma membrane and protein localization during CME in a living cell. The results revealed a tight correlation between the size of the pit and the amount of clathrin assembled. Actin dynamics play multiple roles in the assembly, maturation, and closing phases of the process, and affects membrane morphology, suggesting a close relationship between endocytosis and dynamic events at the cell cortex. Knock down of dynamin also affected the closing motion of the pit and showed functional correlation with actin.
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Affiliation(s)
- Aiko Yoshida
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | | | | | - Yuka Imaoka
- R&D Group, Olympus Corporation, Hachioji, Japan
| | | | - Yuki Suzuki
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
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46
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Bucher D, Frey F, Sochacki KA, Kummer S, Bergeest JP, Godinez WJ, Kräusslich HG, Rohr K, Taraska JW, Schwarz US, Boulant S. Clathrin-adaptor ratio and membrane tension regulate the flat-to-curved transition of the clathrin coat during endocytosis. Nat Commun 2018; 9:1109. [PMID: 29549258 PMCID: PMC5856840 DOI: 10.1038/s41467-018-03533-0] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 02/15/2018] [Indexed: 12/03/2022] Open
Abstract
Although essential for many cellular processes, the sequence of structural and molecular events during clathrin-mediated endocytosis remains elusive. While it was long believed that clathrin-coated pits grow with a constant curvature, it was recently suggested that clathrin first assembles to form flat structures that then bend while maintaining a constant surface area. Here, we combine correlative electron and light microscopy and mathematical growth laws to study the ultrastructural rearrangements of the clathrin coat during endocytosis in BSC-1 mammalian cells. We confirm that clathrin coats initially grow flat and demonstrate that curvature begins when around 70% of the final clathrin content is acquired. We find that this transition is marked by a change in the clathrin to clathrin-adaptor protein AP2 ratio and that membrane tension suppresses this transition. Our results support the notion that BSC-1 mammalian cells dynamically regulate the flat-to-curved transition in clathrin-mediated endocytosis by both biochemical and mechanical factors. The sequence of structural and molecular events during clathrin-mediated endocytosis is unclear. Here the authors combine correlative microscopy and simple mathematical growth laws to demonstrate that the flat patch starts to curve when around 70% of the final clathrin content is reached.
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Affiliation(s)
- Delia Bucher
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany.,German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120, Heidelberg, Germany
| | - Felix Frey
- BioQuant Center, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany.,Institute for Theoretical Physics, Heidelberg University, Philosophenweg 19, 69120, Heidelberg, Germany
| | - Kem A Sochacki
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Susann Kummer
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - Jan-Philip Bergeest
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120, Heidelberg, Germany.,BioQuant Center, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany.,Institute of Pharmacy and Molecular Biotechnology (IPMB), Department of Bioinformatics and Functional Genomics, Heidelberg University, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany
| | - William J Godinez
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120, Heidelberg, Germany.,BioQuant Center, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany.,Institute of Pharmacy and Molecular Biotechnology (IPMB), Department of Bioinformatics and Functional Genomics, Heidelberg University, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany
| | - Hans-Georg Kräusslich
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - Karl Rohr
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120, Heidelberg, Germany.,BioQuant Center, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany.,Institute of Pharmacy and Molecular Biotechnology (IPMB), Department of Bioinformatics and Functional Genomics, Heidelberg University, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany
| | - Justin W Taraska
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ulrich S Schwarz
- BioQuant Center, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany. .,Institute for Theoretical Physics, Heidelberg University, Philosophenweg 19, 69120, Heidelberg, Germany.
| | - Steeve Boulant
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany. .,German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120, Heidelberg, Germany.
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47
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Membrane bending occurs at all stages of clathrin-coat assembly and defines endocytic dynamics. Nat Commun 2018; 9:419. [PMID: 29379015 PMCID: PMC5789089 DOI: 10.1038/s41467-018-02818-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/02/2018] [Indexed: 01/01/2023] Open
Abstract
Clathrin-mediated endocytosis (CME) internalizes plasma membrane by reshaping small regions of the cell surface into spherical vesicles. The key mechanistic question of how coat assembly produces membrane curvature has been studied with molecular and cellular structural biology approaches, without direct visualization of the process in living cells; resulting in two competing models for membrane bending. Here we use polarized total internal reflection fluorescence microscopy (pol-TIRF) combined with electron, atomic force, and super-resolution optical microscopy to measure membrane curvature during CME. Surprisingly, coat assembly accommodates membrane bending concurrent with or after the assembly of the clathrin lattice. Once curvature began, CME proceeded to scission with robust timing. Four color pol-TIRF showed that CALM accumulated at high levels during membrane bending, implicating its auxiliary role in curvature generation. We conclude that clathrin-coat assembly is versatile and that multiple membrane-bending trajectories likely reflect the energetics of coat assembly relative to competing forces. Two distinct and opposing models for clathrin-mediated endocytosis have been inferred from EM and structural biology data. Here the authors develop an optical method to directly visualize membrane-bending dynamics and show that coat assembly accommodates membrane bending during or after the assembly of the clathrin lattice, which is not predicted by either model.
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48
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Santos AJM, Boucrot E. Probing Endocytosis During the Cell Cycle with Minimal Experimental Perturbation. Methods Mol Biol 2018; 1847:23-35. [PMID: 30129007 DOI: 10.1007/978-1-4939-8719-1_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Endocytosis mediates the cellular uptake of nutrients, modulates signaling by regulating levels of cell surface receptors, and is usurped by pathogens during infection. Endocytosis activity is known to vary during the cell cycle, in particular during mitosis. Importantly, different experimental conditions can lead to opposite results and conclusions, thereby emphasizing the need for a careful design of protocols. For example, experiments using serum-starvation, ice-cold steps or using mitotic arrest produced by chemicals widely used to synchronize cells (nocodazole, RO-3306, or S-trityl-L-cysteine) induce a blockage of clathrin-mediated endocytosis during mitosis not observed in unperturbed, dividing cells. In addition, perturbations produced by mRNA interference or dominant-negative mutant overexpression affect endocytosis long before cells are being assayed. Here, we describe simple experimental procedures to assay endocytosis along the cell cycle with minimal perturbations.
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Affiliation(s)
- António J M Santos
- Cell and Developmental Biology Program, Centre for Genomic Regulation (CRG), Barcelona, Spain
| | - Emmanuel Boucrot
- Institute of Structural and Molecular Biology, University College London and Birkbeck, London, UK.
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49
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Abstract
Nowadays, live fluorescent microscopes allow us to study the dynamics of cellular processes in living cells with high spatial and temporal resolution. Since the implementation of this methodology to the field of clathrin-mediated endocytosis (CME), this approach has revolutionized our molecular understanding of clathrin-driven cellular uptake. Conventional live cell microscopy approaches are used to determine the precise functions of specific proteins or lipids in orchestrating CME. Here, we will describe, in depth, the procedure to investigate the contribution of membrane tension in regulating clathrin-dependent endocytosis. We will explain two alternative methods to manipulate membrane tension while performing live fluorescence microscopy: cellular swelling through osmotic shock and cellular stretching of cells grown on stretchable silicon inserts.
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50
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Lorenz-Guertin JM, Wilcox MR, Zhang M, Larsen MB, Pilli J, Schmidt BF, Bruchez MP, Johnson JW, Waggoner AS, Watkins SC, Jacob TC. A versatile optical tool for studying synaptic GABA A receptor trafficking. J Cell Sci 2017; 130:3933-3945. [PMID: 29025969 DOI: 10.1242/jcs.205286] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 09/26/2017] [Indexed: 12/26/2022] Open
Abstract
Live-cell imaging methods can provide critical real-time receptor trafficking measurements. Here, we describe an optical tool to study synaptic γ-aminobutyric acid (GABA) type A receptor (GABAAR) dynamics through adaptable fluorescent-tracking capabilities. A fluorogen-activating peptide (FAP) was genetically inserted into a GABAAR γ2 subunit tagged with pH-sensitive green fluorescent protein (γ2pHFAP). The FAP selectively binds and activates Malachite Green (MG) dyes that are otherwise non-fluorescent in solution. γ2pHFAP GABAARs are expressed at the cell surface in transfected cortical neurons, form synaptic clusters and do not perturb neuronal development. Electrophysiological studies show γ2pHFAP GABAARs respond to GABA and exhibit positive modulation upon stimulation with the benzodiazepine diazepam. Imaging studies using γ2pHFAP-transfected neurons and MG dyes show time-dependent receptor accumulation into intracellular vesicles, revealing constitutive endosomal and lysosomal trafficking. Simultaneous analysis of synaptic, surface and lysosomal receptors using the γ2pHFAP-MG dye approach reveals enhanced GABAAR turnover following a bicucculine-induced seizure paradigm, a finding not detected by standard surface receptor measurements. To our knowledge, this is the first application of the FAP-MG dye system in neurons, demonstrating the versatility to study nearly all phases of GABAAR trafficking.
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Affiliation(s)
- Joshua M Lorenz-Guertin
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Madeleine R Wilcox
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Ming Zhang
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Mads B Larsen
- Department of Cell Biology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jyotsna Pilli
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Brigitte F Schmidt
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Marcel P Bruchez
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA.,Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Jon W Johnson
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Alan S Waggoner
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Simon C Watkins
- Department of Cell Biology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Tija C Jacob
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
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