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Kollmar M, Welz T, Ravi A, Kaufmann T, Alzahofi N, Hatje K, Alghamdi A, Kim J, Briggs DA, Samol-Wolf A, Pylypenko O, Hume AN, Burkhardt P, Faix J, Kerkhoff E. Actomyosin organelle functions of SPIRE actin nucleators precede animal evolution. Commun Biol 2024; 7:832. [PMID: 38977899 PMCID: PMC11231147 DOI: 10.1038/s42003-024-06458-1] [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: 08/25/2023] [Accepted: 06/14/2024] [Indexed: 07/10/2024] Open
Abstract
An important question in cell biology is how cytoskeletal proteins evolved and drove the development of novel structures and functions. Here we address the origin of SPIRE actin nucleators. Mammalian SPIREs work with RAB GTPases, formin (FMN)-subgroup actin assembly proteins and class-5 myosin (MYO5) motors to transport organelles along actin filaments towards the cell membrane. However, the origin and extent of functional conservation of SPIRE among species is unknown. Our sequence searches show that SPIRE exist throughout holozoans (animals and their closest single-celled relatives), but not other eukaryotes. SPIRE from unicellular holozoans (choanoflagellate), interacts with RAB, FMN and MYO5 proteins, nucleates actin filaments and complements mammalian SPIRE function in organelle transport. Meanwhile SPIRE and MYO5 proteins colocalise to organelles in Salpingoeca rosetta choanoflagellates. Based on these observations we propose that SPIRE originated in unicellular ancestors of animals providing an actin-myosin driven exocytic transport mechanism that may have contributed to the evolution of complex multicellular animals.
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Affiliation(s)
- Martin Kollmar
- Group Systems Biology of Motor Proteins, Department of NMR-based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany.
| | - Tobias Welz
- Molecular Cell Biology Laboratory, Department of Neurology, University Hospital Regensburg, Regensburg, Germany
| | - Aishwarya Ravi
- Michael Sars Centre, University of Bergen, Bergen, Norway
| | - Thomas Kaufmann
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Noura Alzahofi
- School of Life Sciences, University of Nottingham, Nottingham, UK
- Biology Department, College of Science, Taibah University, Medina, Kingdom of Saudi Arabia
| | - Klas Hatje
- Group Systems Biology of Motor Proteins, Department of NMR-based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Asmahan Alghamdi
- School of Life Sciences, University of Nottingham, Nottingham, UK
- Department of Biology, College of Sciences, Princess Nourah bint Abdulrahman University, Riyadh, Kingdom of Saudi Arabia
| | - Jiyu Kim
- Molecular Cell Biology Laboratory, Department of Neurology, University Hospital Regensburg, Regensburg, Germany
- Department of Anatomy, University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Deborah A Briggs
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Annette Samol-Wolf
- Molecular Cell Biology Laboratory, Department of Neurology, University Hospital Regensburg, Regensburg, Germany
| | - Olena Pylypenko
- Dynamics of Intra-Cellular Organization, Institute Curie, PSL Research University, CNRS UMR144, Paris, France
| | - Alistair N Hume
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | | | - Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Eugen Kerkhoff
- Molecular Cell Biology Laboratory, Department of Neurology, University Hospital Regensburg, Regensburg, Germany.
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2
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Torres AA, Macilwee SL, Rashid A, Cox SE, Albarnaz JD, Bonjardim CA, Smith GL. The actin nucleator Spir-1 is a virus restriction factor that promotes innate immune signalling. PLoS Pathog 2022; 18:e1010277. [PMID: 35148361 PMCID: PMC8870497 DOI: 10.1371/journal.ppat.1010277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 02/24/2022] [Accepted: 01/12/2022] [Indexed: 12/12/2022] Open
Abstract
Cellular proteins often have multiple and diverse functions. This is illustrated with protein Spir-1 that is an actin nucleator, but, as shown here, also functions to enhance innate immune signalling downstream of RNA sensing by RIG-I/MDA-5. In human and mouse cells lacking Spir-1, IRF3 and NF-κB-dependent gene activation is impaired, whereas Spir-1 overexpression enhanced IRF3 activation. Furthermore, the infectious virus titres and sizes of plaques formed by two viruses that are sensed by RIG-I, vaccinia virus (VACV) and Zika virus, are increased in Spir-1 KO cells. These observations demonstrate the biological importance of Spir-1 in the response to virus infection. Like cellular proteins, viral proteins also have multiple and diverse functions. Here, we also show that VACV virulence factor K7 binds directly to Spir-1 and that a diphenylalanine motif of Spir-1 is needed for this interaction and for Spir-1-mediated enhancement of IRF3 activation. Thus, Spir-1 is a new virus restriction factor and is targeted directly by an immunomodulatory viral protein that enhances virus virulence and diminishes the host antiviral responses.
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Affiliation(s)
- Alice A. Torres
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | | | - Amir Rashid
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Sarah E. Cox
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Jonas D. Albarnaz
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Claudio A. Bonjardim
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Geoffrey L. Smith
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
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3
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Scalzitti S, Mariani D, Setti A, Colantoni A, Lisi M, Bozzoni I, Martone J. Lnc-SMaRT Translational Regulation of Spire1, A New Player in Muscle Differentiation. J Mol Biol 2021; 434:167384. [PMID: 34863993 DOI: 10.1016/j.jmb.2021.167384] [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] [Received: 08/03/2021] [Revised: 11/15/2021] [Accepted: 11/26/2021] [Indexed: 11/19/2022]
Abstract
The destiny of a messenger RNA is determined from a combination of in cis elements, like peculiar secondary structures, and in trans modulators, such as RNA binding proteins and non-coding, regulatory RNAs. RNA guanine quadruplexes belong to the first group: these strong secondary structures have been characterized in many mRNAs, and their stabilization or unwinding provides an additional step for the fine tuning of mRNA stability and translation. On the other hand, many cytoplasmic long non-coding RNAs intervene in post-transcriptional regulation, frequently by direct base-pairing with their mRNA targets. We have previously identified the lncRNA SMaRT as a key modulator of the correct timing of murine skeletal muscle differentiation; when expressed, lnc-SMaRT interacts with a G-quadruplex-containing region of Mlx-γ mRNA, therefore inhibiting its translation by counteracting the DHX36 helicase activity. The "smart" mode of action of lnc-SMaRT led us to speculate whether this molecular mechanism could be extended to other targets and conserved in other species. Here, we show that the molecular complex composed by lnc-SMaRT and DHX36 also includes other mRNAs. We prove that lnc-SMaRT is able to repress Spire1 translation through base-pairing with its G-quadruplex-forming sequence, and that Spire1 modulation participates to the regulation of proper skeletal muscle differentiation. Moreover, we demonstrate that the interaction between DHX36 and lnc-SMaRT is indirect and mediated by the mRNAs present in the complex. Finally, we suggest an extendibility of the molecular mechanism of lnc-SMaRT from the mouse model to humans, identifying potential functional analogues.
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Affiliation(s)
- Silvia Scalzitti
- Department of Biology and Biotechnology "Charles Darwin" - Sapienza University of Rome, Rome, Italy
| | - Davide Mariani
- Center for Human Technologies@Istituto Italiano di Tecnologia, Genoa, Italy. https://twitter.com/@Dav_MarPhD
| | - Adriano Setti
- Department of Biology and Biotechnology "Charles Darwin" - Sapienza University of Rome, Rome, Italy
| | - Alessio Colantoni
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), Rome, Italy
| | - Michela Lisi
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), Rome, Italy
| | - Irene Bozzoni
- Department of Biology and Biotechnology "Charles Darwin" - Sapienza University of Rome, Rome, Italy; Center for Human Technologies@Istituto Italiano di Tecnologia, Genoa, Italy; Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), Rome, Italy
| | - Julie Martone
- Institute of Molecular Biology and Pathology, National Research Council, Sapienza University of Rome, Rome, Italy.
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Alzahofi N, Welz T, Robinson CL, Page EL, Briggs DA, Stainthorp AK, Reekes J, Elbe DA, Straub F, Kallemeijn WW, Tate EW, Goff PS, Sviderskaya EV, Cantero M, Montoliu L, Nedelec F, Miles AK, Bailly M, Kerkhoff E, Hume AN. Rab27a co-ordinates actin-dependent transport by controlling organelle-associated motors and track assembly proteins. Nat Commun 2020; 11:3495. [PMID: 32661310 PMCID: PMC7359353 DOI: 10.1038/s41467-020-17212-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 06/04/2020] [Indexed: 11/09/2022] Open
Abstract
Cell biologists generally consider that microtubules and actin play complementary roles in long- and short-distance transport in animal cells. On the contrary, using melanosomes of melanocytes as a model, we recently discovered that the motor protein myosin-Va works with dynamic actin tracks to drive long-range organelle dispersion in opposition to microtubules. This suggests that in animals, as in yeast and plants, myosin/actin can drive long-range transport. Here, we show that the SPIRE-type actin nucleators (predominantly SPIRE1) are Rab27a effectors that co-operate with formin-1 to generate actin tracks required for myosin-Va-dependent transport in melanocytes. Thus, in addition to melanophilin/myosin-Va, Rab27a can recruit SPIREs to melanosomes, thereby integrating motor and track assembly activity at the organelle membrane. Based on this, we suggest a model in which organelles and force generators (motors and track assemblers) are linked, forming an organelle-based, cell-wide network that allows their collective activity to rapidly disperse the population of organelles long-distance throughout the cytoplasm.
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Affiliation(s)
- Noura Alzahofi
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Tobias Welz
- University Hospital Regensburg, Regensburg, Germany
| | | | - Emma L Page
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Deborah A Briggs
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Amy K Stainthorp
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - James Reekes
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - David A Elbe
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Felix Straub
- University Hospital Regensburg, Regensburg, Germany
| | - Wouter W Kallemeijn
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, W12 0BZ, UK
| | - Edward W Tate
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, W12 0BZ, UK
| | - Philip S Goff
- Cell Biology and Genetics Research Centre, St. George's, University of London, London, SW17 0RE, UK
| | - Elena V Sviderskaya
- Cell Biology and Genetics Research Centre, St. George's, University of London, London, SW17 0RE, UK
| | - Marta Cantero
- Centro Nacional de Biotecnologia (CNB-CSIC), Madrid, 28049, Spain
- CIBERER-ISCIII, Madrid, Spain
| | - Lluis Montoliu
- Centro Nacional de Biotecnologia (CNB-CSIC), Madrid, 28049, Spain
- CIBERER-ISCIII, Madrid, Spain
| | - Francois Nedelec
- Sainsbury Laboratory, Cambridge University, Cambridge, CB2 1LR, UK
| | - Amanda K Miles
- John van Geest Cancer Research Centre, Nottingham Trent University, Nottingham, NG11 8NS, UK
| | - Maryse Bailly
- UCL Institute of Ophthalmology, 11-43 Bath St, London, EC1V 9EL, UK
| | | | - Alistair N Hume
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK.
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5
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Wellbourne-Wood J, Chatton JY. From Cultured Rodent Neurons to Human Brain Tissue: Model Systems for Pharmacological and Translational Neuroscience. ACS Chem Neurosci 2018; 9:1975-1985. [PMID: 29847093 DOI: 10.1021/acschemneuro.8b00098] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
To investigate the enormous complexity of the functional and pathological brain there are a number of possible experimental model systems to choose from. Depending on the research question choosing the appropriate model may not be a trivial task, and given the dynamic and intricate nature of an intact living brain several models might be needed to properly address certain questions. In this review, we aim to provide an overview of neural cell and tissue culture, reflecting on historic methodological milestones and providing a brief overview of the state-of-the-art. We additionally present an example of an effective model system pipeline, composed of dissociated mouse cultures, organotypics, acute mouse brain slices, and acute human brain slices, in that order. The sequential use of these four model systems allows a balance and progression from experimental control to human applicability, and provides a meta-model that can help validate basic research findings in a translational setting. We then conclude with a few remarks regarding the necessity of an integrated approach when performing translational and neuropharmacological studies.
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Affiliation(s)
- Joel Wellbourne-Wood
- Department of Fundamental Neurosciences, University of Lausanne, 1005 Lausanne, Switzerland
| | - Jean-Yves Chatton
- Department of Fundamental Neurosciences, University of Lausanne, 1005 Lausanne, Switzerland
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6
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Faw TD, Lerch JK, Thaxton TT, Deibert RJ, Fisher LC, Basso DM. Unique Sensory and Motor Behavior in Thy1-GFP-M Mice before and after Spinal Cord Injury. J Neurotrauma 2018; 35:2167-2182. [PMID: 29385890 DOI: 10.1089/neu.2017.5395] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Sensorimotor recovery after spinal cord injury (SCI) is of utmost importance to injured individuals and will rely on improved understanding of SCI pathology and recovery. Novel transgenic mouse lines facilitate discovery, but must be understood to be effective. The purpose of this study was to characterize the sensory and motor behavior of a common transgenic mouse line (Thy1-GFP-M) before and after SCI. Thy1-GFP-M positive (TG+) mice and their transgene negative littermates (TG-) were acquired from two sources (in-house colony, n = 32, Jackson Laboratories, n = 4). C57BL/6J wild-type (WT) mice (Jackson Laboratories, n = 10) were strain controls. Moderate-severe T9 contusion (SCI) or transection (TX) occurred in TG+ (SCI, n = 25, TX, n = 5), TG- (SCI, n = 5), and WT (SCI, n = 10) mice. To determine responsiveness to rehabilitation, a cohort of TG+ mice with SCI (n = 4) had flat treadmill (TM) training 42-49 days post-injury (dpi). To characterize recovery, we performed Basso Mouse Scale, Grid Walk, von Frey Hair, and Plantar Heat Testing before and out to day 42 post-SCI. Open field locomotion was significantly better in the Thy1 SCI groups (TG+ and TG-) compared with WT by 7 dpi (p < 0.01) and was maintained through 42 dpi (p < 0.01). These unexpected locomotor gains were not apparent during grid walking, indicating severe impairment of precise motor control. Thy1 derived mice were hypersensitive to mechanical stimuli at baseline (p < 0.05). After SCI, mechanical hyposensitivity emerged in Thy1 derived groups (p < 0.001), while thermal hyperalgesia occurred in all groups (p < 0.001). Importantly, consistent findings across TG+ and TG- groups suggest that the effects are mediated by the genetic background rather than transgene manipulation itself. Surprisingly, TM training restored mechanical and thermal sensation to baseline levels in TG+ mice with SCI. This behavioral profile and responsiveness to chronic training will be important to consider when choosing models to study the mechanisms underlying sensorimotor recovery after SCI.
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Affiliation(s)
- Timothy D Faw
- 1 Neuroscience Graduate Program, The Ohio State University , Columbus, Ohio.,2 School of Health and Rehabilitation Sciences, The Ohio State University , Columbus, Ohio.,3 Center for Brain and Spinal Cord Repair, The Ohio State University , Columbus, Ohio
| | - Jessica K Lerch
- 3 Center for Brain and Spinal Cord Repair, The Ohio State University , Columbus, Ohio.,4 Department of Neuroscience, The Ohio State University , Columbus, Ohio
| | - Tyler T Thaxton
- 2 School of Health and Rehabilitation Sciences, The Ohio State University , Columbus, Ohio.,3 Center for Brain and Spinal Cord Repair, The Ohio State University , Columbus, Ohio
| | - Rochelle J Deibert
- 2 School of Health and Rehabilitation Sciences, The Ohio State University , Columbus, Ohio.,3 Center for Brain and Spinal Cord Repair, The Ohio State University , Columbus, Ohio
| | - Lesley C Fisher
- 2 School of Health and Rehabilitation Sciences, The Ohio State University , Columbus, Ohio.,3 Center for Brain and Spinal Cord Repair, The Ohio State University , Columbus, Ohio
| | - D Michele Basso
- 2 School of Health and Rehabilitation Sciences, The Ohio State University , Columbus, Ohio.,3 Center for Brain and Spinal Cord Repair, The Ohio State University , Columbus, Ohio
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7
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Wen Q, Li N, Xiao X, Lui WY, Chu DS, Wong CKC, Lian Q, Ge R, Lee WM, Silvestrini B, Cheng CY. Actin nucleator Spire 1 is a regulator of ectoplasmic specialization in the testis. Cell Death Dis 2018; 9:208. [PMID: 29434191 PMCID: PMC5833730 DOI: 10.1038/s41419-017-0201-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 11/10/2017] [Accepted: 12/06/2017] [Indexed: 01/26/2023]
Abstract
Germ cell differentiation during the epithelial cycle of spermatogenesis is accompanied by extensive remodeling at the Sertoli cell-cell and Sertoli cell-spermatid interface to accommodate the transport of preleptotene spermatocytes and developing spermatids across the blood-testis barrier (BTB) and the adluminal compartment of the seminiferous epithelium, respectively. The unique cell junction in the testis is the actin-rich ectoplasmic specialization (ES) designated basal ES at the Sertoli cell-cell interface, and the apical ES at the Sertoli-spermatid interface. Since ES dynamics (i.e., disassembly, reassembly and stabilization) are supported by actin microfilaments, which rapidly converts between their bundled and unbundled/branched configuration to confer plasticity to the ES, it is logical to speculate that actin nucleation proteins play a crucial role to ES dynamics. Herein, we reported findings that Spire 1, an actin nucleator known to polymerize actins into long stretches of linear microfilaments in cells, is an important regulator of ES dynamics. Its knockdown by RNAi in Sertoli cells cultured in vitro was found to impede the Sertoli cell tight junction (TJ)-permeability barrier through changes in the organization of F-actin across Sertoli cell cytosol. Unexpectedly, Spire 1 knockdown also perturbed microtubule (MT) organization in Sertoli cells cultured in vitro. Biochemical studies using cultured Sertoli cells and specific F-actin vs. MT polymerization assays supported the notion that a transient loss of Spire 1 by RNAi disrupted Sertoli cell actin and MT polymerization and bundling activities. These findings in vitro were reproduced in studies in vivo by RNAi using Spire 1-specific siRNA duplexes to transfect testes with Polyplus in vivo-jetPEI as a transfection medium with high transfection efficiency. Spire 1 knockdown in the testis led to gross disruption of F-actin and MT organization across the seminiferous epithelium, thereby impeding the transport of spermatids and phagosomes across the epithelium and perturbing spermatogenesis. In summary, Spire 1 is an ES regulator to support germ cell development during spermatogenesis.
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Affiliation(s)
- Qing Wen
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, 1230 York Avenue, New York, NY, 10065, USA
| | - Nan Li
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, 1230 York Avenue, New York, NY, 10065, USA
| | - Xiang Xiao
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, 1230 York Avenue, New York, NY, 10065, USA
- Department of Reproductive Physiology, Zhejiang Academy of Medical Sciences, Hangzhou, China
| | - Wing-Yee Lui
- School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - Darren S Chu
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, 1230 York Avenue, New York, NY, 10065, USA
| | - Chris K C Wong
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Qingquan Lian
- The Second Affiliated Hospital & Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Renshan Ge
- The Second Affiliated Hospital & Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Will M Lee
- School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | | | - C Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, 1230 York Avenue, New York, NY, 10065, USA.
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Andritschke D, Dilling S, Emmenlauer M, Welz T, Schmich F, Misselwitz B, Rämö P, Rottner K, Kerkhoff E, Wada T, Penninger JM, Beerenwinkel N, Horvath P, Dehio C, Hardt WD. A Genome-Wide siRNA Screen Implicates Spire1/2 in SipA-Driven Salmonella Typhimurium Host Cell Invasion. PLoS One 2016; 11:e0161965. [PMID: 27627128 PMCID: PMC5023170 DOI: 10.1371/journal.pone.0161965] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/15/2016] [Indexed: 12/20/2022] Open
Abstract
Salmonella Typhimurium (S. Tm) is a leading cause of diarrhea. The disease is triggered by pathogen invasion into the gut epithelium. Invasion is attributed to the SPI-1 type 3 secretion system (T1). T1 injects effector proteins into epithelial cells and thereby elicits rearrangements of the host cellular actin cytoskeleton and pathogen invasion. The T1 effector proteins SopE, SopB, SopE2 and SipA are contributing to this. However, the host cell factors contributing to invasion are still not completely understood. To address this question comprehensively, we used Hela tissue culture cells, a genome-wide siRNA library, a modified gentamicin protection assay and S. TmSipA, a sopBsopE2sopE mutant which strongly relies on the T1 effector protein SipA to invade host cells. We found that S. TmSipA invasion does not elicit membrane ruffles, nor promote the entry of non-invasive bacteria "in trans". However, SipA-mediated infection involved the SPIRE family of actin nucleators, besides well-established host cell factors (WRC, ARP2/3, RhoGTPases, COPI). Stage-specific follow-up assays and knockout fibroblasts indicated that SPIRE1 and SPIRE2 are involved in different steps of the S. Tm infection process. Whereas SPIRE1 interferes with bacterial binding, SPIRE2 influences intracellular replication of S. Tm. Hence, these two proteins might fulfill non-redundant functions in the pathogen-host interaction. The lack of co-localization hints to a short, direct interaction between S. Tm and SPIRE proteins or to an indirect effect.
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Affiliation(s)
- Daniel Andritschke
- Institute of Microbiology, Eidgenössische Technische Hochschule Zurich, CH-8093, Zurich, Switzerland
| | - Sabrina Dilling
- Institute of Microbiology, Eidgenössische Technische Hochschule Zurich, CH-8093, Zurich, Switzerland
| | | | - Tobias Welz
- Department of Neurology, University of Regensburg, DE- 93040, Regensburg, Germany
| | - Fabian Schmich
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule Zurich, CH-4058, Basel, Switzerland
- SIB Swiss Institute for Bioinformatics, 4058, Basel, Switzerland
| | - Benjamin Misselwitz
- Institute of Microbiology, Eidgenössische Technische Hochschule Zurich, CH-8093, Zurich, Switzerland
- Division of Gastroenterology and Hepatology, University Hospital Zurich, University of Zurich, CH-8091, Zurich, Switzerland
| | - Pauli Rämö
- Biozentrum, University of Basel, CH-4056, Basel, Switzerland
| | - Klemens Rottner
- Zoological Institute, Technische Universität Braunschweig, D-38106, Braunschweig, Germany
- Department of Cell Biology, Helmholtz Centre for Infection Research, D-38124, Braunschweig, Germany
| | - Eugen Kerkhoff
- Department of Neurology, University of Regensburg, DE- 93040, Regensburg, Germany
| | - Teiji Wada
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), A-1030, Vienna, Austria
| | - Josef M. Penninger
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), A-1030, Vienna, Austria
| | - Niko Beerenwinkel
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule Zurich, CH-4058, Basel, Switzerland
- SIB Swiss Institute for Bioinformatics, 4058, Basel, Switzerland
| | - Peter Horvath
- Light Microscopy Center, Eidgenössische Technische Hochschule Zurich, CH-8093, Zurich, Switzerland
| | - Christoph Dehio
- Biozentrum, University of Basel, CH-4056, Basel, Switzerland
| | - Wolf-Dietrich Hardt
- Institute of Microbiology, Eidgenössische Technische Hochschule Zurich, CH-8093, Zurich, Switzerland
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9
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Tittel J, Welz T, Czogalla A, Dietrich S, Samol-Wolf A, Schulte M, Schwille P, Weidemann T, Kerkhoff E. Membrane targeting of the Spir·formin actin nucleator complex requires a sequential handshake of polar interactions. J Biol Chem 2015; 290:6428-44. [PMID: 25564607 DOI: 10.1074/jbc.m114.602672] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Spir and formin (FMN)-type actin nucleators initiate actin polymerization at vesicular membranes necessary for long range vesicular transport processes. Here we studied in detail the membrane binding properties and protein/protein interactions that govern the assembly of the membrane-associated Spir·FMN complex. Using biomimetic membrane models we show that binding of the C-terminal Spir-2 FYVE-type zinc finger involves both the presence of negatively charged lipids and hydrophobic contributions from the turret loop that intrudes the lipid bilayer. In solution, we uncovered a yet unknown intramolecular interaction between the Spir-2 FYVE-type domain and the N-terminal kinase non-catalytic C-lobe domain (KIND) that could not be detected in the membrane-bound state. Interestingly, we found that the intramolecular Spir-2 FYVE/KIND and the trans-regulatory Fmn-2-FSI/Spir-2-KIND interactions are competitive. We therefore characterized co-expressed Spir-2 and Fmn-2 fluorescent protein fusions in living cells by fluorescence cross-correlation spectroscopy. The data corroborate a model according to which Spir-2 exists in two different states, a cytosolic monomeric conformation and a membrane-bound state in which the KIND domain is released and accessible for subsequent Fmn-2 recruitment. This sequence of interactions mechanistically couples membrane binding of Spir to the recruitment of FMN, a pivotal step for initiating actin nucleation at vesicular membranes.
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Affiliation(s)
- Janine Tittel
- From the Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany, Biotechnology Center (BIOTEC), Biophysics Research Group and
| | - Tobias Welz
- Molecular Cell Biology Laboratory, Department of Neurology, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, D-93053 Regensburg, Germany, and
| | - Aleksander Czogalla
- Paul Langerhans Institute, Technische Universität (TU) Dresden, Tatzberg 47-51, D-01307 Dresden, Germany, German Center for Diabetes Research (Deutsches Zentrum für Diabetesforschung), 85764 Neuherberg, Germany
| | - Susanne Dietrich
- Molecular Cell Biology Laboratory, Department of Neurology, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, D-93053 Regensburg, Germany, and
| | - Annette Samol-Wolf
- Molecular Cell Biology Laboratory, Department of Neurology, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, D-93053 Regensburg, Germany, and
| | - Markos Schulte
- Molecular Cell Biology Laboratory, Department of Neurology, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, D-93053 Regensburg, Germany, and
| | - Petra Schwille
- From the Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany, Biotechnology Center (BIOTEC), Biophysics Research Group and
| | - Thomas Weidemann
- From the Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany, Biotechnology Center (BIOTEC), Biophysics Research Group and
| | - Eugen Kerkhoff
- Molecular Cell Biology Laboratory, Department of Neurology, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, D-93053 Regensburg, Germany, and
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