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Miner MV, Rauch I. Why put yourself on a pedestal? The pathogenic role of the A/E pedestal. Infect Immun 2024:e0048923. [PMID: 38591884 DOI: 10.1128/iai.00489-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024] Open
Abstract
Certain Escherichia coli (E. coli) strains are attaching and effacing (A/E) lesion pathogens that primarily infect intestinal epithelial cells. They cause actin restructuring and polymerization within the host cell to create an actin-rich protrusion below the site of adherence, termed the pedestal. Although there is clarity on the pathways initiating pedestal formation, the underlying purpose(s) of the pedestal remains ambiguous. The conservation of pedestal-forming activity across multiple pathogens and redundancy in formation pathways indicate a pathogenic advantage. However, few decisive conclusions have been drawn, given that the results vary between model systems. Some research argues that the pedestal increases the colonization capability of the bacterium. These studies utilize A/E pathogens specifically deficient in pedestal formation to evaluate adhesion and intestinal colonization following infection. There have been many proposed mechanisms for the colonization benefit conferred by the pedestal. One suggested benefit is that the pedestal allows for direct cytosolic anchoring through incorporation of the established host cortical actin, causing a stable link between the pathogen and cell structure. The pedestal may confer enhanced motility, as enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) are better able to migrate on the surface of host cells and infect neighboring cells in the presence of the pedestal. Additionally, some research suggests that the pedestal improves effector delivery. This review will investigate the purpose of pedestal formation using evidence from recent literature and will critically evaluate the methodology and model systems. Most importantly, we will contextualize the proposed functions to reconcile potential synergistic effects.
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Affiliation(s)
- M V Miner
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
| | - I Rauch
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
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Bacterial Quorum-Sensing Regulation Induces Morphological Change in a Key Host Tissue during the Euprymna scolopes-Vibrio fischeri Symbiosis. mBio 2021; 12:e0240221. [PMID: 34579565 PMCID: PMC8546586 DOI: 10.1128/mbio.02402-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Microbes colonize the apical surfaces of polarized epithelia in nearly all animal taxa. In one example, the luminous bacterium Vibrio fischeri enters, grows to a dense population within, and persists for months inside, the light-emitting organ of the squid Euprymna scolopes. Crucial to the symbiont's success after entry is the ability to trigger the constriction of a host tissue region (the "bottleneck") at the entrance to the colonization site. Bottleneck constriction begins at about the same time as bioluminescence, which is induced in V. fischeri through an autoinduction process called quorum sensing. Here, we asked the following questions: (i) Are the quorum signals that induce symbiont bioluminescence also involved in triggering the constriction? (ii) Does improper signaling of constriction affect the normal maintenance of the symbiont population? We manipulated the presence of three factors, the two V. fischeri quorum signal synthases, AinS and LuxI, the transcriptional regulator LuxR, and light emission itself, and found that the major factor triggering and maintaining bottleneck constriction is an as yet unknown effector(s) regulated by LuxIR. Treating the animal with chemical inhibitors of actin polymerization reopened the bottlenecks, recapitulating the host's response to quorum-sensing defective symbionts, as well as suggesting that actin polymerization is the primary mechanism underlying constriction. Finally, we found that these host responses to the presence of symbionts changed as a function of tissue maturation. Taken together, this work broadens our concept of how quorum sensing can regulate host development, thereby allowing bacteria to maintain long-term tissue associations. IMPORTANCE Interbacterial signaling within a host-associated population can have profound effects on the behavior of the bacteria, for instance, in their production of virulence/colonization factors; in addition, such signaling can dictate the nature of the outcome for the host, in both pathogenic and beneficial associations. Using the monospecific squid-vibrio model of symbiosis, we examined how quorum-sensing regulation by the Vibrio fischeri population induces a biogeographic tissue phenotype that promotes the retention of this extracellular symbiont within the light organ of its host, Euprymna scolopes. Understanding the influence of bacterial symbionts on key sites of tissue architecture has implications for all horizontally transmitted symbioses, especially those that colonize an epithelial surface within the host.
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Correlative light and scanning electron microscopy (CLSEM) for analysis of bacterial infection of polarized epithelial cells. Sci Rep 2019; 9:17079. [PMID: 31745114 PMCID: PMC6863815 DOI: 10.1038/s41598-019-53085-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/16/2019] [Indexed: 12/11/2022] Open
Abstract
Infection of mammalian host cells by bacterial pathogens is a highly dynamic process and microscopy is instrumental to reveal the cellular and molecular details of host-pathogen interactions. Correlative light and electron microscopy (CLEM) combines the advantages of three-dimensional live cell imaging with ultrastructural analysis. The analyses of adhesion to, and invasion of polarized epithelial cells by pathogens often deploys scanning electron microscopy (SEM), since surface structures of the apical brush border can be analyzed in detail. Most available CLEM approaches focus on relocalization of separated single cells in different imaging modalities, but are not readily applicable to polarized epithelial cell monolayers, since orientation marks on substrate are overgrown during differentiation. To address this problem, we developed a simple and convenient workflow for correlative light and scanning electron microscopy (CLSEM), using gold mesh grids as carrier for growth of epithelial cell monolayers, and for imaging infection. The approach allows fast live cell imaging of bacterial infection of polarized cells with subsequent analyses by SEM. As examples for CLSEM applications, we investigated trigger invasion by Salmonella enterica, zipper invasion by Listeria monocytogenes, and the enterocyte attachment and effacement phenotype of enteropathogenic Escherichia coli. Our study demonstrates the versatile use of gold mesh grids for CLSEM of the interaction of bacterial pathogens with the apical side of polarized epithelial cells.
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Abstract
The entry of pathogens into nonphagocytic host cells has received much attention in the past three decades, revealing a vast array of strategies employed by bacteria and viruses. A method of internalization that has been extensively studied in the context of viral infections is the use of the clathrin-mediated pathway. More recently, a role for clathrin in the entry of some intracellular bacterial pathogens was discovered. Classically, clathrin-mediated endocytosis was thought to accommodate internalization only of particles smaller than 150 nm; however, this was challenged upon the discovery that Listeria monocytogenes requires clathrin to enter eukaryotic cells. Now, with discoveries that clathrin is required during other stages of some bacterial infections, another paradigm shift is occurring. There is a more diverse impact of clathrin during infection than previously thought. Much of the recent data describing clathrin utilization in processes such as bacterial attachment, cell-to-cell spread and intracellular growth may be due to newly discovered divergent roles of clathrin in the cell. Not only does clathrin act to facilitate endocytosis from the plasma membrane, but it also participates in budding from endosomes and the Golgi apparatus and in mitosis. Here, the manipulation of clathrin processes by bacterial pathogens, including its traditional role during invasion and alternative ways in which clathrin supports bacterial infection, is discussed. Researching clathrin in the context of bacterial infections will reveal new insights that inform our understanding of host-pathogen interactions and allow researchers to fully appreciate the diverse roles of clathrin in the eukaryotic cell.
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Affiliation(s)
- Eleanor A Latomanski
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Hayley J Newton
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
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Chua MD, Walker BD, Jin JP, Guttman JA. Calponins Are Recruited to Actin-Rich Structures Generated by Pathogenic Escherichia coli, Listeria, and Salmonella. Anat Rec (Hoboken) 2018; 301:2103-2111. [PMID: 30312538 DOI: 10.1002/ar.23956] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 07/10/2018] [Accepted: 07/12/2018] [Indexed: 01/12/2023]
Abstract
The ingestion of enteropathogenic Escherichia coli (EPEC), Listeria monocytogenes, or Salmonella enterica serovar Typhimurium leads to their colonization of the intestinal lumen, which ultimately causes an array of ailments ranging from diarrhea to bacteremia. Once in the intestines, these microbes generate various actin-rich structures to attach, invade, or move within the host intestinal epithelial cells. Although an assortment of actin-associated proteins has been identified to varying degrees at these structures, the localization of many actin stabilizing proteins have yet to be analyzed. Here, we examined the recruitment of the actin-associated proteins, calponin 1 and 2 at EPEC pedestals, L. monocytogenes actin clouds, comet tails and listeriopods, and S. Typhimurium membrane ruffles. In other systems, calponins are known to bind to and stabilize actin filaments. In EPEC pedestals, calponin 1 was recruited uniformly throughout the structures while calponin 2 was enriched at the apical tip. During L. monocytogenes infections, calponin 1 was found through all the actin-rich structures generated by the bacteria, while calponin 2 was only present within actin-rich structures formed by L. monocytogenes near the host cell membrane. Finally, both calponins were found within S. Typhimurium-generated membrane ruffles. Taken together, we have shown that although calponin 1 is recruited to actin-rich structures formed by the three bacteria, calponin 2 is specifically recruited to only membrane-bound actin-rich structures formed by the bacteria. Thus, our findings suggest that calponin 2 is a novel marker for membrane-bound actin structures formed by pathogenic bacteria. Anat Rec, 301:2103-2111, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Michael Dominic Chua
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | | | - Jian-Ping Jin
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Julian A Guttman
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
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Chua MD, Hipolito KJ, Singerr OB, Solway J, Guttman JA. SM22 is required for the maintenance of actin-rich structures generated during bacterial infections. Exp Cell Res 2018; 369:139-146. [PMID: 29778753 DOI: 10.1016/j.yexcr.2018.05.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 11/19/2022]
Abstract
The host actin cytoskeleton is utilized by an assortment of pathogenic bacteria to colonize and cause disease in their hosts. Two prominently studied actin-hijacking bacteria are enteropathogenic Escherichia coli (EPEC) and Listeria monocytogenes. EPEC form actin-rich pedestals atop its host cells to move across the intestinal epithelia, while Listeria monocytogenes generate branched actin networks arranged as actin clouds around the bacteria and as comet tails for propulsion within and amongst their host cells. Previous mass spectrometry analysis revealed that a member of the calponin family of actin-bundling proteins, transgelin/SM22 was enriched in EPEC pedestals. To validate that finding and examine the role of SM22 during infections, we initially immunolocalized SM22 in EPEC and L. monocytogenes infected cells, used siRNA to deplete SM22 and EGFP-SM22 to overexpress SM22, then quantified the alterations to the bacterially generated actin structures. SM22 concentrated at all bacterially-generated actin structures. Depletion of SM22 resulted in fewer pedestals and comet tails and caused comet tails to shorten. The decrease in comet tail abundance caused a proportional increase in actin clouds whereas overexpression of SM22 reversed the actin cloud to comet tail proportions and increased comet tail length, while not influencing EPEC pedestal abundance. Thus, we demonstrate that SM22 plays a role in regulating the transitions and morphological appearance of bacterially generated actin-rich structures during infections.
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Affiliation(s)
- Michael Dominic Chua
- Department of Biological Sciences, Simon Fraser University, 8888 University Dr Shrum Science Centre Rm B7239, Burnaby, BC, Canada V5A1S6
| | - Kevin Jay Hipolito
- Department of Biological Sciences, Simon Fraser University, 8888 University Dr Shrum Science Centre Rm B7239, Burnaby, BC, Canada V5A1S6
| | - Onisokumen Benny Singerr
- Department of Biological Sciences, Simon Fraser University, 8888 University Dr Shrum Science Centre Rm B7239, Burnaby, BC, Canada V5A1S6
| | - Julian Solway
- Department of Medicine, University of Chicago, 5841 S. Maryland Ave, MC6026, Rm BH-M644, Chicago, IL 60637, USA
| | - Julian Andrew Guttman
- Department of Biological Sciences, Simon Fraser University, 8888 University Dr Shrum Science Centre Rm B7239, Burnaby, BC, Canada V5A1S6.
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Lee PP, Lobato-Márquez D, Pramanik N, Sirianni A, Daza-Cajigal V, Rivers E, Cavazza A, Bouma G, Moulding D, Hultenby K, Westerberg LS, Hollinshead M, Lau YL, Burns SO, Mostowy S, Bajaj-Elliott M, Thrasher AJ. Wiskott-Aldrich syndrome protein regulates autophagy and inflammasome activity in innate immune cells. Nat Commun 2017; 8:1576. [PMID: 29146903 PMCID: PMC5691069 DOI: 10.1038/s41467-017-01676-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 10/09/2017] [Indexed: 12/11/2022] Open
Abstract
Dysregulation of autophagy and inflammasome activity contributes to the development of auto-inflammatory diseases. Emerging evidence highlights the importance of the actin cytoskeleton in modulating inflammatory responses. Here we show that deficiency of Wiskott-Aldrich syndrome protein (WASp), which signals to the actin cytoskeleton, modulates autophagy and inflammasome function. In a model of sterile inflammation utilizing TLR4 ligation followed by ATP or nigericin treatment, inflammasome activation is enhanced in monocytes from WAS patients and in WAS-knockout mouse dendritic cells. In ex vivo models of enteropathogenic Escherichia coli and Shigella flexneri infection, WASp deficiency causes defective bacterial clearance, excessive inflammasome activation and host cell death that are associated with dysregulated septin cage-like formation, impaired autophagic p62/LC3 recruitment and defective formation of canonical autophagosomes. Taken together, we propose that dysregulation of autophagy and inflammasome activities contribute to the autoinflammatory manifestations of WAS, thereby identifying potential targets for therapeutic intervention.
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Affiliation(s)
- Pamela P Lee
- Infection, Immunity and Inflammation Program, Great Ormond Street Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK.,Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Damián Lobato-Márquez
- Section of Microbiology, MRC Centre of Molecular Bacteriology and Infection, Imperial College London, Armstrong Road, London, SW7 2AZ, UK
| | - Nayani Pramanik
- Infection, Immunity and Inflammation Program, Great Ormond Street Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK
| | - Andrea Sirianni
- Section of Microbiology, MRC Centre of Molecular Bacteriology and Infection, Imperial College London, Armstrong Road, London, SW7 2AZ, UK
| | - Vanessa Daza-Cajigal
- University College London Institute of Immunity and Transplantation, London, NW3 2PF, UK
| | - Elizabeth Rivers
- Infection, Immunity and Inflammation Program, Great Ormond Street Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK
| | - Alessia Cavazza
- Infection, Immunity and Inflammation Program, Great Ormond Street Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK
| | - Gerben Bouma
- Infection, Immunity and Inflammation Program, Great Ormond Street Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK
| | - Dale Moulding
- Infection, Immunity and Inflammation Program, Great Ormond Street Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK
| | - Kjell Hultenby
- Karolinska Institutet, Department of Laboratory Medicine, 14186, Stockholm, Sweden
| | - Lisa S Westerberg
- Karolinska Institutet, Department of Microbiology, Tumor and Cell Biology, 171 77, Stockholm, Sweden
| | - Michael Hollinshead
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1AP, UK
| | - Yu-Lung Lau
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China.,Shenzhen Primary Immunodeficiency Diagnostic and Therapeutic Laboratory, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Siobhan O Burns
- Infection, Immunity and Inflammation Program, Great Ormond Street Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK.,University College London Institute of Immunity and Transplantation, London, NW3 2PF, UK
| | - Serge Mostowy
- Section of Microbiology, MRC Centre of Molecular Bacteriology and Infection, Imperial College London, Armstrong Road, London, SW7 2AZ, UK
| | - Mona Bajaj-Elliott
- Infection, Immunity and Inflammation Program, Great Ormond Street Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK.
| | - Adrian J Thrasher
- Infection, Immunity and Inflammation Program, Great Ormond Street Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK. .,Great Ormond Street Hospital NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, UK.
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Fukuda K. Is it feasible to control pathogen infection by competitive binding of probiotics to the host? Virulence 2017; 8:1502-1505. [PMID: 28934003 DOI: 10.1080/21505594.2017.1382798] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
- Kenji Fukuda
- a Department of Animal and Food Hygiene , Obihiro University of Agriculture and Veterinary Medicine, Inada-cho , Obihiro , Hokkaido , Japan
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Velle KB, Campellone KG. Extracellular motility and cell-to-cell transmission of enterohemorrhagic E. coli is driven by EspFU-mediated actin assembly. PLoS Pathog 2017; 13:e1006501. [PMID: 28771584 PMCID: PMC5557606 DOI: 10.1371/journal.ppat.1006501] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 08/15/2017] [Accepted: 06/30/2017] [Indexed: 12/20/2022] Open
Abstract
Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) are closely-related pathogens that attach tightly to intestinal epithelial cells, efface microvilli, and promote cytoskeletal rearrangements into protrusions called actin pedestals. To trigger pedestal formation, EPEC employs the tyrosine phosphorylated transmembrane receptor Tir, while EHEC relies on the multivalent scaffolding protein EspFU. The ability to generate these structures correlates with bacterial colonization in several animal models, but the precise function of pedestals in infection remains unclear. To address this uncertainty, we characterized the colonization properties of EPEC and EHEC during infection of polarized epithelial cells. We found that EPEC and EHEC both formed distinct bacterial communities, or "macrocolonies," that encompassed multiple host cells. Tir and EspFU, as well as the host Arp2/3 complex, were all critical for the expansion of macrocolonies over time. Unexpectedly, EspFU accelerated the formation of larger macrocolonies compared to EPEC Tir, as EspFU-mediated actin assembly drove faster bacterial motility to cell junctions, where bacteria formed a secondary pedestal on a neighboring cell and divided, allowing one of the daughters to disengage and infect the second cell. Collectively, these data reveal that EspFU enhances epithelial colonization by increasing actin-based motility and promoting an efficient method of cell-to-cell transmission.
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Affiliation(s)
- Katrina B. Velle
- Department of Molecular and Cell Biology, Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut, United States of America
| | - Kenneth G. Campellone
- Department of Molecular and Cell Biology, Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut, United States of America
- * E-mail:
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Raval MH, Quintero OA, Weck ML, Unrath WC, Gallagher JW, Cui R, Kachar B, Tyska MJ, Yengo CM. Impact of the Motor and Tail Domains of Class III Myosins on Regulating the Formation and Elongation of Actin Protrusions. J Biol Chem 2016; 291:22781-22792. [PMID: 27582493 PMCID: PMC5077211 DOI: 10.1074/jbc.m116.733741] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 08/29/2016] [Indexed: 11/06/2022] Open
Abstract
Class III myosins (MYO3A and MYO3B) are proposed to function as transporters as well as length and ultrastructure regulators within stable actin-based protrusions such as stereocilia and calycal processes. MYO3A differs from MYO3B in that it contains an extended tail domain with an additional actin-binding motif. We examined how the properties of the motor and tail domains of human class III myosins impact their ability to enhance the formation and elongation of actin protrusions. Direct examination of the motor and enzymatic properties of human MYO3A and MYO3B revealed that MYO3A is a 2-fold faster motor with enhanced ATPase activity and actin affinity. A chimera in which the MYO3A tail was fused to the MYO3B motor demonstrated that motor activity correlates with formation and elongation of actin protrusions. We demonstrate that removal of individual exons (30-34) in the MYO3A tail does not prevent filopodia tip localization but abolishes the ability to enhance actin protrusion formation and elongation in COS7 cells. Interestingly, our results demonstrate that MYO3A slows filopodia dynamics and enhances filopodia lifetime in COS7 cells. We also demonstrate that MYO3A is more efficient than MYO3B at increasing formation and elongation of stable microvilli on the surface of cultured epithelial cells. We propose that the unique features of MYO3A, enhanced motor activity, and an extended tail with tail actin-binding motif, allow it to play an important role in stable actin protrusion length and ultrastructure maintenance.
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Affiliation(s)
- Manmeet H Raval
- From the Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania 17033
| | - Omar A Quintero
- the Department of Biology, University of Richmond, Richmond, Virginia 23173
| | - Meredith L Weck
- the Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - William C Unrath
- From the Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania 17033
| | - James W Gallagher
- the Department of Biology, Lincoln University, Philadelphia, Pennsylvania 19104, and
| | - Runjia Cui
- the Laboratory of Cell Structure and Dynamics, NIDCD, National Institutes of Health, Bethesda, Maryland 20892
| | - Bechara Kachar
- the Laboratory of Cell Structure and Dynamics, NIDCD, National Institutes of Health, Bethesda, Maryland 20892
| | - Matthew J Tyska
- the Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Christopher M Yengo
- From the Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania 17033,
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Abstract
The brush border on the apical surface of enterocytes is a highly specialized structure well-adapted for efficient digestion and nutrient transport, whilst at the same time providing a protective barrier for the intestinal mucosa. The brush border is constituted of a densely ordered array of microvilli, protrusions of the plasma membrane, which are supported by actin-based microfilaments and interacting proteins and anchored in an apical network of actomyosin and intermediate filaments, the so-called terminal web. The highly dynamic, specialized apical domain is both an essential partner for the gut microbiota and an efficient signalling platform that enables adaptation to physiological stimuli from the external and internal milieu. Nevertheless, genetic alterations or various pathological stresses, such as infection, inflammation, and mechanical or nutritional alterations, can jeopardize this equilibrium and compromise intestinal functions. Long-time neglected, the intestinal brush-border shall be enlightening again as the central actor of the complex but essential intestinal homeostasis. Here, we review the processes and components involved in brush border organization and discuss pathological mechanisms that can induce brush border defects and their physiological consequences.
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