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El-Mansi S, Robinson CL, Kostelnik KB, McCormack JJ, Mitchell TP, Lobato-Márquez D, Rajeeve V, Cutillas P, Cutler DF, Mostowy S, Nightingale TD. Proximity proteomics identifies septins and PAK2 as decisive regulators of actomyosin-mediated expulsion of von Willebrand factor. Blood 2023; 141:930-944. [PMID: 36564030 PMCID: PMC10023740 DOI: 10.1182/blood.2022017419] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 11/07/2022] [Accepted: 11/27/2022] [Indexed: 12/25/2022] Open
Abstract
In response to tissue injury, within seconds the ultra-large glycoprotein von Willebrand factor (VWF) is released from endothelial storage organelles (Weibel-Palade bodies) into the lumen of the blood vasculature, where it leads to the recruitment of platelets. The marked size of VWF multimers represents an unprecedented burden on the secretory machinery of endothelial cells (ECs). ECs have evolved mechanisms to overcome this, most notably an actomyosin ring that forms, contracts, and squeezes out its unwieldy cargo. Inhibiting the formation or function of these structures represents a novel therapeutic target for thrombotic pathologies, although characterizing proteins associated with such a dynamic process has been challenging. We have combined APEX2 proximity labeling with an innovative dual loss-of-function screen to identify proteins associated with actomyosin ring function. We show that p21 activated kinase 2 (PAK2) recruits septin hetero-oligomers, a molecular interaction that forms a ring around exocytic sites. This cascade of events controls actomyosin ring function, aiding efficient exocytic release. Genetic or pharmacological inhibition of PAK2 or septins led to inefficient release of VWF and a failure to form platelet-catching strings. This new molecular mechanism offers additional therapeutic targets for the control of thrombotic disease and is highly relevant to other secretory systems that employ exocytic actomyosin machinery.
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Affiliation(s)
- Sammy El-Mansi
- Centre for Microvascular Research, William Harvey Research Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Christopher L. Robinson
- Centre for Microvascular Research, William Harvey Research Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Katja B. Kostelnik
- Centre for Microvascular Research, William Harvey Research Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Jessica J. McCormack
- MRC Laboratory of Molecular Cell Biology, University College London, London, United Kingdom
| | - Tom P. Mitchell
- Centre for Microvascular Research, William Harvey Research Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Damián Lobato-Márquez
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Vinothini Rajeeve
- Cell Signalling & Proteomics Group, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
| | - Pedro Cutillas
- Cell Signalling & Proteomics Group, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
| | - Daniel F. Cutler
- MRC Laboratory of Molecular Cell Biology, University College London, London, United Kingdom
| | - Serge Mostowy
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Thomas D. Nightingale
- Centre for Microvascular Research, William Harvey Research Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
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2
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Rojas J, Hinostroza F, Vergara S, Pinto-Borguero I, Aguilera F, Fuentes R, Carvacho I. Knockin' on Egg's Door: Maternal Control of Egg Activation That Influences Cortical Granule Exocytosis in Animal Species. Front Cell Dev Biol 2021; 9:704867. [PMID: 34540828 PMCID: PMC8446563 DOI: 10.3389/fcell.2021.704867] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/16/2021] [Indexed: 12/23/2022] Open
Abstract
Fertilization by multiple sperm leads to lethal chromosomal number abnormalities, failed embryo development, and miscarriage. In some vertebrate and invertebrate eggs, the so-called cortical reaction contributes to their activation and prevents polyspermy during fertilization. This process involves biogenesis, redistribution, and subsequent accumulation of cortical granules (CGs) at the female gamete cortex during oogenesis. CGs are oocyte- and egg-specific secretory vesicles whose content is discharged during fertilization to block polyspermy. Here, we summarize the molecular mechanisms controlling critical aspects of CG biology prior to and after the gametes interaction. This allows to block polyspermy and provide protection to the developing embryo. We also examine how CGs form and are spatially redistributed during oogenesis. During egg activation, CG exocytosis (CGE) and content release are triggered by increases in intracellular calcium and relies on the function of maternally-loaded proteins. We also discuss how mutations in these factors impact CG dynamics, providing unprecedented models to investigate the genetic program executing fertilization. We further explore the phylogenetic distribution of maternal proteins and signaling pathways contributing to CGE and egg activation. We conclude that many important biological questions and genotype–phenotype relationships during fertilization remain unresolved, and therefore, novel molecular players of CG biology need to be discovered. Future functional and image-based studies are expected to elucidate the identity of genetic candidates and components of the molecular machinery involved in the egg activation. This, will open new therapeutic avenues for treating infertility in humans.
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Affiliation(s)
- Japhet Rojas
- Laboratorio Fisiología de la Reproducción, Departamento de Biología y Química, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Chile.,Escuela de Ingeniería en Biotecnología, Facultad de Ciencias Agrarias y Forestales, Universidad Católica del Maule, Talca, Chile
| | - Fernando Hinostroza
- Laboratorio Fisiología de la Reproducción, Departamento de Biología y Química, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Chile.,Centro de Investigación de Estudios Avanzados del Maule (CIEAM), Vicerrectoría de Investigación y Postgrado, Universidad Católica del Maule, Talca, Chile.,Centro de Investigación en Neuropsicología y Neurociencias Cognitivas, Facultad de Ciencias de la Salud, Universidad Católica del Maule, Talca, Chile
| | - Sebastián Vergara
- Laboratorio Fisiología de la Reproducción, Departamento de Biología y Química, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Chile.,Escuela de Ingeniería en Biotecnología, Facultad de Ciencias Agrarias y Forestales, Universidad Católica del Maule, Talca, Chile
| | - Ingrid Pinto-Borguero
- Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Felipe Aguilera
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Ricardo Fuentes
- Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Ingrid Carvacho
- Laboratorio Fisiología de la Reproducción, Departamento de Biología y Química, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Chile
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3
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Pernier J, Morchain A, Caorsi V, Bertin A, Bousquet H, Bassereau P, Coudrier E. Myosin 1b flattens and prunes branched actin filaments. J Cell Sci 2020; 133:jcs247403. [PMID: 32895245 PMCID: PMC7522023 DOI: 10.1242/jcs.247403] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 08/18/2020] [Indexed: 01/29/2023] Open
Abstract
Motile and morphological cellular processes require a spatially and temporally coordinated branched actin network that is controlled by the activity of various regulatory proteins, including the Arp2/3 complex, profilin, cofilin and tropomyosin. We have previously reported that myosin 1b regulates the density of the actin network in the growth cone. Here, by performing in vitro F-actin gliding assays and total internal reflection fluorescence (TIRF) microscopy, we show that this molecular motor flattens (reduces the branch angle) in the Arp2/3-dependent actin branches, resulting in them breaking, and reduces the probability of new branches forming. This experiment reveals that myosin 1b can produce force sufficient enough to break up the Arp2/3-mediated actin junction. Together with the former in vivo studies, this work emphasizes the essential role played by myosins in the architecture and dynamics of actin networks in different cellular regions.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Julien Pernier
- Laboratoire Physico-Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Laboratory Cell Biology and Cancer, Institut Curie, PSL Research University, C.N.R.S. UMR 144, 26 rue d'Ulm, Paris, France
| | - Antoine Morchain
- Laboratoire Physico-Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
| | | | - Aurélie Bertin
- Laboratoire Physico-Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
| | - Hugo Bousquet
- Sorbonne Université, 75005 Paris, France
- Laboratory Cell Biology and Cancer, Institut Curie, PSL Research University, C.N.R.S. UMR 144, 26 rue d'Ulm, Paris, France
| | - Patricia Bassereau
- Laboratoire Physico-Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
| | - Evelyne Coudrier
- Sorbonne Université, 75005 Paris, France
- Laboratory Cell Biology and Cancer, Institut Curie, PSL Research University, C.N.R.S. UMR 144, 26 rue d'Ulm, Paris, France
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4
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Gundersen CB. Cysteine string proteins. Prog Neurobiol 2020; 188:101758. [DOI: 10.1016/j.pneurobio.2020.101758] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 01/06/2020] [Accepted: 01/13/2020] [Indexed: 12/17/2022]
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5
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Barger SR, Reilly NS, Shutova MS, Li Q, Maiuri P, Heddleston JM, Mooseker MS, Flavell RA, Svitkina T, Oakes PW, Krendel M, Gauthier NC. Membrane-cytoskeletal crosstalk mediated by myosin-I regulates adhesion turnover during phagocytosis. Nat Commun 2019; 10:1249. [PMID: 30890704 PMCID: PMC6425032 DOI: 10.1038/s41467-019-09104-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 02/21/2019] [Indexed: 11/09/2022] Open
Abstract
Phagocytosis of invading pathogens or cellular debris requires a dramatic change in cell shape driven by actin polymerization. For antibody-covered targets, phagocytosis is thought to proceed through the sequential engagement of Fc-receptors on the phagocyte with antibodies on the target surface, leading to the extension and closure of the phagocytic cup around the target. We find that two actin-dependent molecular motors, class 1 myosins myosin 1e and myosin 1f, are specifically localized to Fc-receptor adhesions and required for efficient phagocytosis of antibody-opsonized targets. Using primary macrophages lacking both myosin 1e and myosin 1f, we find that without the actin-membrane linkage mediated by these myosins, the organization of individual adhesions is compromised, leading to excessive actin polymerization, slower adhesion turnover, and deficient phagocytic internalization. This work identifies a role for class 1 myosins in coordinated adhesion turnover during phagocytosis and supports a mechanism involving membrane-cytoskeletal crosstalk for phagocytic cup closure.
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Affiliation(s)
- Sarah R Barger
- Cell and Developmental Biology Department, State University of New York Upstate Medical University, Syracuse, 13210, NY, USA
| | - Nicholas S Reilly
- Department of Physics, University of Rochester, Rochester, 14627, NY, USA
| | - Maria S Shutova
- Department of Biology, University of Pennsylvania, Philadelphia, 19104, PA, USA
| | - Qingsen Li
- IFOM, FIRC Institute of Molecular Oncology, Milan, 20139, Italy
| | - Paolo Maiuri
- IFOM, FIRC Institute of Molecular Oncology, Milan, 20139, Italy
| | - John M Heddleston
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, 20147, VA, USA
| | - Mark S Mooseker
- Molecular, Cellular and Developmental Biology, Yale University, New Haven, 06520, CT, USA
| | - Richard A Flavell
- Department of Immunobiology, Yale University School of Medicine, New Haven, 06519, CT, USA
- Howard Hughes Medical Institute, Yale University, New Haven, 06519, CT, USA
| | - Tatyana Svitkina
- Department of Biology, University of Pennsylvania, Philadelphia, 19104, PA, USA
| | - Patrick W Oakes
- Department of Physics, University of Rochester, Rochester, 14627, NY, USA
- Department of Biology, University of Rochester, Rochester, 14627, NY, USA
| | - Mira Krendel
- Cell and Developmental Biology Department, State University of New York Upstate Medical University, Syracuse, 13210, NY, USA.
| | - Nils C Gauthier
- IFOM, FIRC Institute of Molecular Oncology, Milan, 20139, Italy.
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6
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Zhang P, Jiang W, Luo N, Zhu W, Fan L. IQ motif containing D (IQCD), a new acrosomal protein involved in the acrosome reaction and fertilisation. Reprod Fertil Dev 2019; 31:898-914. [DOI: 10.1071/rd18416] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 12/07/2018] [Indexed: 11/23/2022] Open
Abstract
The acrosome is single, large, dense-core secretory granule overlying the nucleus of most mammalian spermatozoa. Its exocytosis, the acrosome reaction, is a crucial event during fertilisation. In this study we identified a new acrosome-associated gene, namely IQ motif containing D (IQCD), expressed nearly in multiple tissues with highest expression levels in the testis. In mouse testis, Iqcd transcript accumulated from Postnatal Day (PND) 1 to adulthood. However, expression of IQCD protein at the testicular development stage started primarily from PND 18 and increased in an age-dependent manner until plateauing in adulthood. IQCD was primarily accumulated in the acrosome area of round and elongating spermatids within seminiferous tubules of the testes during the late stage of spermiogenesis; this immunolocalisation pattern is similar in mice and humans. IQCD levels in spermatozoa were significantly lower in IVF patients with total fertilisation failure or a low fertilisation rate than in healthy men. Anti-IQCD antibody significantly inhibited the acrosome reaction and slightly reduced protein tyrosine phosphorylation levels in human spermatozoa, but specifically blocked murine IVF. IQCD interacted with mammalian homolog of C. elegans uncoordinated gene 13 (Munc13) in spermatozoa and may participate in acrosome exocytosis. In conclusion, this study identified a new acrosomal protein, namely IQCD, which is involved in fertilisation and the acrosome reaction.
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7
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Abstract
Myosin-I molecular motors are proposed to play various cellular roles related to membrane dynamics and trafficking. In this Cell Science at a Glance article and the accompanying poster, we review and illustrate the proposed cellular functions of metazoan myosin-I molecular motors by examining the structural, biochemical, mechanical and cell biological evidence for their proposed molecular roles. We highlight evidence for the roles of myosin-I isoforms in regulating membrane tension and actin architecture, powering plasma membrane and organelle deformation, participating in membrane trafficking, and functioning as a tension-sensitive dock or tether. Collectively, myosin-I motors have been implicated in increasingly complex cellular phenomena, yet how a single isoform accomplishes multiple types of molecular functions is still an active area of investigation. To fully understand the underlying physiology, it is now essential to piece together different approaches of biological investigation. This article will appeal to investigators who study immunology, metabolic diseases, endosomal trafficking, cell motility, cancer and kidney disease, and to those who are interested in how cellular membranes are coupled to the underlying actin cytoskeleton in a variety of different applications.
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Affiliation(s)
- Betsy B McIntosh
- Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA
| | - E Michael Ostap
- Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA
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8
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Wenzel J, Ouderkirk JL, Krendel M, Lang R. Class I myosin Myo1e regulates TLR4-triggered macrophage spreading, chemokine release, and antigen presentation via MHC class II. Eur J Immunol 2014; 45:225-37. [PMID: 25263281 DOI: 10.1002/eji.201444698] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 08/26/2014] [Accepted: 09/24/2014] [Indexed: 12/25/2022]
Abstract
TLR-mediated recognition of microbial danger induces substantial changes in macrophage migration, adherence, and phagocytosis. Recently, we described the LPS-regulated phosphorylation of many cytoskeleton-associated proteins by phosphoproteomics. The functional role of these cytoskeletal and motor proteins in innate immune cell responses is largely unexplored. Here, we first identified both long-tailed class I myosins Myo1e and Myo1f as important contributors to LPS-triggered macrophage spreading. Mouse bone marrow-derived macrophages and DCs deficient in Myo1e selectively secreted increased amounts of the chemokine CCL2. In addition, the cell surface expression of MHC class II (MHC-II) on both cell types was reduced in the absence of Myo1e. However, transcriptional changes in CCL2 and MHC-II were not observed in the absence of Myo1e, indicating that Myo1e regulates specific intracellular transport processes. The capacity of macrophages and DCs lacking Myo1e to stimulate antigen-specific CD4(+) T-cell proliferation was impaired, consistent with the reduced MHC-II surface protein levels. Surprisingly, in Myo1e-deficient DCs, the proteolytic cleavage of endocytosed antigen was also increased. Together, our results provide evidence for a non-redundant function of the motor protein Myo1e in the regulation of TLR4-controlled, cytoskeleton-associated functional properties of macrophages and DCs, and in induction of a full MHC-II-restricted adaptive immune response.
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Affiliation(s)
- Jens Wenzel
- Institute of Clinical Microbiology, Immunology and Hygiene, University Hospital Erlangen, Friedrich Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
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9
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Papadopulos A, Tomatis VM, Kasula R, Meunier FA. The cortical acto-Myosin network: from diffusion barrier to functional gateway in the transport of neurosecretory vesicles to the plasma membrane. Front Endocrinol (Lausanne) 2013; 4:153. [PMID: 24155741 PMCID: PMC3800816 DOI: 10.3389/fendo.2013.00153] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 10/05/2013] [Indexed: 01/14/2023] Open
Abstract
Dysregulation of regulated exocytosis is linked to an array of pathological conditions, including neurodegenerative disorders, asthma, and diabetes. Understanding the molecular mechanisms underpinning neuroexocytosis including the processes that allow neurosecretory vesicles to access and fuse with the plasma membrane and to recycle post-fusion, is therefore critical to the design of future therapeutic drugs that will efficiently tackle these diseases. Despite considerable efforts to determine the principles of vesicular fusion, the mechanisms controlling the approach of vesicles to the plasma membrane in order to undergo tethering, docking, priming, and fusion remain poorly understood. All these steps involve the cortical actin network, a dense mesh of actin filaments localized beneath the plasma membrane. Recent work overturned the long-held belief that the cortical actin network only plays a passive constraining role in neuroexocytosis functioning as a physical barrier that partly breaks down upon entry of Ca(2+) to allow secretory vesicles to reach the plasma membrane. A multitude of new roles for the cortical actin network in regulated exocytosis have now emerged and point to highly dynamic novel functions of key myosin molecular motors. Myosins are not only believed to help bring about dynamic changes in the actin cytoskeleton, tethering and guiding vesicles to their fusion sites, but they also regulate the size and duration of the fusion pore, thereby directly contributing to the release of neurotransmitters and hormones. Here we discuss the functions of the cortical actin network, myosins, and their effectors in controlling the processes that lead to tethering, directed transport, docking, and fusion of exocytotic vesicles in regulated exocytosis.
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Affiliation(s)
- Andreas Papadopulos
- Queensland Brain Institute, The University of Queensland, St Lucia Campus, Brisbane, QLD, Australia
| | - Vanesa M. Tomatis
- Queensland Brain Institute, The University of Queensland, St Lucia Campus, Brisbane, QLD, Australia
| | - Ravikiran Kasula
- Queensland Brain Institute, The University of Queensland, St Lucia Campus, Brisbane, QLD, Australia
| | - Frederic A. Meunier
- Queensland Brain Institute, The University of Queensland, St Lucia Campus, Brisbane, QLD, Australia
- *Correspondence: Frederic A. Meunier, Queensland Brain Institute, The University of Queensland, St Lucia Campus, QBI Building #79, St Lucia, QLD 4072, Australia e-mail:
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10
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Nightingale TD, Cutler DF, Cramer LP. Actin coats and rings promote regulated exocytosis. Trends Cell Biol 2012; 22:329-37. [DOI: 10.1016/j.tcb.2012.03.003] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Revised: 03/21/2012] [Accepted: 03/22/2012] [Indexed: 11/16/2022]
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11
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Bond LM, Brandstaetter H, Sellers JR, Kendrick-Jones J, Buss F. Myosin motor proteins are involved in the final stages of the secretory pathways. Biochem Soc Trans 2011; 39:1115-9. [PMID: 21936774 PMCID: PMC3403808 DOI: 10.1042/bst0391115] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In eukaryotes, the final steps in both the regulated and constitutive secretory pathways can be divided into four distinct stages: (i) the 'approach' of secretory vesicles/granules to the PM (plasma membrane), (ii) the 'docking' of these vesicles/granules at the membrane itself, (iii) the 'priming' of the secretory vesicles/granules for the fusion process, and, finally, (iv) the 'fusion' of vesicular/granular membranes with the PM to permit content release from the cell. Recent work indicates that non-muscle myosin II and the unconventional myosin motor proteins in classes 1c/1e, Va and VI are specifically involved in these final stages of secretion. In the present review, we examine the roles of these myosins in these stages of the secretory pathway and the implications of their roles for an enhanced understanding of secretion in general.
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Affiliation(s)
- Lisa M. Bond
- Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
- Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, 20892, USA
| | - Hemma Brandstaetter
- Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - James R. Sellers
- Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | | | - Folma Buss
- Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
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12
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Nightingale TD, White IJ, Doyle EL, Turmaine M, Harrison-Lavoie KJ, Webb KF, Cramer LP, Cutler DF. Actomyosin II contractility expels von Willebrand factor from Weibel-Palade bodies during exocytosis. ACTA ACUST UNITED AC 2011; 194:613-29. [PMID: 21844207 PMCID: PMC3160584 DOI: 10.1083/jcb.201011119] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
High-resolution microscopy reveals how discrete actin cytoskeletal functions inhibit or promote specific exocytic steps during regulated secretion. The study of actin in regulated exocytosis has a long history with many different results in numerous systems. A major limitation on identifying precise mechanisms has been the paucity of experimental systems in which actin function has been directly assessed alongside granule content release at distinct steps of exocytosis of a single secretory organelle with sufficient spatiotemporal resolution. Using dual-color confocal microscopy and correlative electron microscopy in human endothelial cells, we visually distinguished two sequential steps of secretagogue-stimulated exocytosis: fusion of individual secretory granules (Weibel–Palade bodies [WPBs]) and subsequent expulsion of von Willebrand factor (VWF) content. Based on our observations, we conclude that for fusion, WPBs are released from cellular sites of actin anchorage. However, once fused, a dynamic ring of actin filaments and myosin II forms around the granule, and actomyosin II contractility squeezes VWF content out into the extracellular environment. This study therefore demonstrates how discrete actin cytoskeleton functions within a single cellular system explain actin filament–based prevention and promotion of specific exocytic steps during regulated secretion.
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Affiliation(s)
- Thomas D Nightingale
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, England, UK
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13
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Paul P, van den Hoorn T, Jongsma MLM, Bakker MJ, Hengeveld R, Janssen L, Cresswell P, Egan DA, van Ham M, Ten Brinke A, Ovaa H, Beijersbergen RL, Kuijl C, Neefjes J. A Genome-wide multidimensional RNAi screen reveals pathways controlling MHC class II antigen presentation. Cell 2011; 145:268-83. [PMID: 21458045 DOI: 10.1016/j.cell.2011.03.023] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 10/27/2010] [Accepted: 03/06/2011] [Indexed: 12/31/2022]
Abstract
MHC class II molecules (MHC-II) present peptides to T helper cells to facilitate immune responses and are strongly linked to autoimmune diseases. To unravel processes controlling MHC-II antigen presentation, we performed a genome-wide flow cytometry-based RNAi screen detecting MHC-II expression and peptide loading followed by additional high-throughput assays. All data sets were integrated to answer two fundamental questions: what regulates tissue-specific MHC-II transcription, and what controls MHC-II transport in dendritic cells? MHC-II transcription was controlled by nine regulators acting in feedback networks with higher-order control by signaling pathways, including TGFβ. MHC-II transport was controlled by the GTPase ARL14/ARF7, which recruits the motor myosin 1E via an effector protein ARF7EP. This complex controls movement of MHC-II vesicles along the actin cytoskeleton in human dendritic cells (DCs). These genome-wide systems analyses have thus identified factors and pathways controlling MHC-II transcription and transport, defining targets for manipulation of MHC-II antigen presentation in infection and autoimmunity.
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Affiliation(s)
- Petra Paul
- Division of Cell Biology and Centre for Biomedical Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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14
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McConnell RE, Tyska MJ. Leveraging the membrane - cytoskeleton interface with myosin-1. Trends Cell Biol 2010; 20:418-26. [PMID: 20471271 DOI: 10.1016/j.tcb.2010.04.004] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 04/15/2010] [Accepted: 04/16/2010] [Indexed: 12/19/2022]
Abstract
Class 1 myosins are small motor proteins with the ability to simultaneously bind to actin filaments and cellular membranes. Given their ability to generate mechanical force, and their high prevalence in many cell types, these molecules are well positioned to carry out several important biological functions at the interface of membrane and the actin cytoskeleton. Indeed, recent studies implicate these motors in endocytosis, exocytosis, release of extracellular vesicles, and the regulation of tension between membrane and the cytoskeleton. Many class 1 myosins also exhibit a load-dependent mechano-chemical cycle that enables them to maintain tension for long periods of time without hydrolyzing ATP. These properties put myosins-1 in a unique position to regulate dynamic membrane-cytoskeleton interactions and respond to physical forces during these events.
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Affiliation(s)
- Russell E McConnell
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37205, USA
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15
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Abstract
All cell functions that involve membrane deformation or a change in cell shape (e.g., endocytosis, exocytosis, cell motility, and cytokinesis) are regulated by membrane tension. While molecular contacts between the plasma membrane and the underlying actin cytoskeleton are known to make significant contributions to membrane tension, little is known about the molecules that mediate these interactions. We used an optical trap to directly probe the molecular determinants of membrane tension in isolated organelles and in living cells. Here, we show that class I myosins, a family of membrane-binding, actin-based motor proteins, mediate membrane/cytoskeleton adhesion and thus, make major contributions to membrane tension. These studies show that class I myosins directly control the mechanical properties of the cell membrane; they also position these motor proteins as master regulators of cellular events involving membrane deformation.
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Woolner S, Bement WM. Unconventional myosins acting unconventionally. Trends Cell Biol 2009; 19:245-52. [PMID: 19406643 DOI: 10.1016/j.tcb.2009.03.003] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Revised: 03/26/2009] [Accepted: 03/27/2009] [Indexed: 11/26/2022]
Abstract
Unconventional myosins are proteins that bind actin filaments in an ATP-regulated manner. Because of their association with membranes, they have traditionally been viewed as motors that function primarily to transport membranous organelles along actin filaments. Recently, however, a wealth of roles for myosins that are not obviously related to organelle transport have been uncovered, including organization of F-actin, mitotic spindle regulation and gene transcription. Furthermore, it has also become apparent that the motor domains of different myosins vary strikingly in their biophysical attributes. We suggest that the assumption that most unconventional myosins function primarily as organelle transporters might be misguided.
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Affiliation(s)
- Sarah Woolner
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, UK.
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Yu HYE, Bement WM. Multiple myosins are required to coordinate actin assembly with coat compression during compensatory endocytosis. Mol Biol Cell 2007; 18:4096-105. [PMID: 17699600 PMCID: PMC1995739 DOI: 10.1091/mbc.e06-11-0993] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Actin is involved in endocytosis in organisms ranging from yeast to mammals. In activated Xenopus eggs, exocytosing cortical granules (CGs) are surrounded by actin "coats," which compress the exocytosing compartments, resulting in compensatory endocytosis. Here, we examined the roles of two myosins in actin coat compression. Myosin-2 is recruited to exocytosing CGs late in coat compression. Inhibition of myosin-2 slows coat compression without affecting actin assembly. This differs from phenotype induced by inhibition of actin assembly, where exocytosing CGs are trapped at the plasma membrane (PM) completely. Thus, coat compression is likely driven in part by actin assembly itself, but it requires myosin-2 for efficient completion. In contrast to myosin-2, the long-tailed myosin-1e is recruited to exocytosing CGs immediately after egg activation. Perturbation of myosin-1e results in partial actin coat assembly and induces CG collapse into the PM. Intriguingly, simultaneous inhibition of actin assembly and myosin-1e prevents CG collapse. Together, the results show that myosin-1e and myosin-2 are part of an intricate machinery that coordinates coat compression at exocytosing CGs.
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Affiliation(s)
- Hoi-Ying E Yu
- Program in Cellular and Molecular Biology and Department of Zoology, University of Wisconsin-Madison, Madison, WI 53706, USA.
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