Microbiology, Virology & Host Pathogen Interaction
- Type VI secretion system sheath inter‐subunit interactions modulate its contraction
- ↵*Corresponding author. Tel: +41 61 207 21 10; E‐mail: marek.basler{at}unibas.ch
The bacterial type VI secretion system translocates effectors by contracting a helical sheath polymer of interconnected subunits. A single residue and a specific subunit linker are critical for sheath contraction, and if mutated lock the T6SS in a pre‐firing state.
Synopsis
The bacterial type VI secretion system translocates effectors by contracting a helical sheath polymer of interconnected subunits. A single residue and a specific subunit linker are critical for sheath contraction, and if mutated lock the T6SS in a pre‐firing state.
Insertion of amino acid residues into the VipA linker abrogates T6SS sheath contraction.
Eliminating charge of specific VipB residues abolishes contraction and effector delivery.
Isolated non‐contractile sheaths stably associate with Hcp and components of the T6SS baseplate.
EMBO Reports (2018) 19: 225–233
- Received April 27, 2017.
- Revision received November 7, 2017.
- Accepted November 17, 2017.
- © 2017 The Authors. Published under the terms of the CC BY 4.0 license
This is an open access article under the terms of the Creative Commons Attribution 4.0 License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
- Bacterial cyclic β‐(1,2)‐glucans sequester iron to protect against iron‐induced toxicity
- Sreegowrinadh Javvadi1,†,
- Sheo Shankar Pandey1,2,†,
- Amita Mishra3,
- Binod Bihari Pradhan1 and
- Subhadeep Chatterjee (subhadeep{at}cdfd.org.in)*,1
- 1Centre for DNA Fingerprinting and Diagnostics, Nampally Hyderabad, India
- 2Graduate Studies, Manipal University, Manipal, India
- 3CSIR‐CCMB, Hyderabad, India
- ↵*Corresponding author. Tel: +91 40 24749425; Fax: +91 40 2474 9448; E‐mail: subhadeep{at}cdfd.org.in
↵† These authors contributed equally to this work
Gram‐negative bacteria produce cyclic glucans, which are components of the bacterial envelope and the periplasm. Periplasmic glucans sequester iron, serving as intracellular iron reservoir, and protecting the bacteria by limiting free iron‐induced toxicity under iron‐replete conditions.
Synopsis
Gram‐negative bacteria produce cyclic glucans, which are components of the bacterial envelope and the periplasm. Periplasmic glucans sequester iron, serving as intracellular iron reservoir, and protecting the bacteria by limiting free iron‐induced toxicity under iron‐replete conditions.
Under iron‐replete conditions, cyclic glucans sequester excess iron in the periplasm.
The glucan‐bound iron pool reduces free iron in the cell and iron‐induced ROS production.
Glucan‐bound iron is utilized for growth and metabolism under low‐iron conditions.
EMBO Reports (2018) 19: 172–186
- Received June 15, 2017.
- Revision received October 28, 2017.
- Accepted November 7, 2017.
- © 2017 The Authors
- Shigella hijacks the glomulin–cIAPs–inflammasome axis to promote inflammation
- Shiho Suzuki (ss.bact{at}tmd.ac.jp)*,1,2,
- Toshihiko Suzuki2,
- Hitomi Mimuro3,4,
- Tsunehiro Mizushima5 and
- Chihiro Sasakawa (sasakawa{at}ims.u-tokyo.ac.jp)*,1,6,7
- 1Division of Bacterial Infection Biology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
- 2Department of Bacterial Infection and Host Response, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
- 3Division of Bacteriology, Department of Infectious Diseases Control, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo, Japan
- 4Department of Infection Microbiology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
- 5Picobiology Institute, Graduate School of Life Science, University of Hyogo, Hyogo, Japan
- 6Medical Mycology Research Center, Chiba University, Chiba, Japan
- 7Nippon Institute for Biological Science, Tokyo, Japan
- ↵*
Corresponding author. Tel: +81 3 5803 4166; E‐mail: ss.bact{at}tmd.ac.jp
Corresponding author. Tel: +81 43 222 7171; E‐mail: sasakawa{at}ims.u-tokyo.ac.jp
Inflammasomes induce caspase‐1 activation, cytokine production and macrophage pyroptosis upon bacterial infection. GLMN, an inhibitor of RING‐type E3 ligases, targeted by the Shigella effector IpaH7.8, negatively regulates inflammasomes by interfering with cIAP E3 ligase activities.
Synopsis
Inflammasomes induce caspase‐1 activation, cytokine production and macrophage pyroptosis upon bacterial infection. GLMN, an inhibitor of RING‐type E3 ligases, targeted by the Shigella effector IpaH7.8, negatively regulates inflammasomes by interfering with cIAP E3 ligase activities.
cIAP1 and cIAP2 E3 ligases, but not XIAP, promote NLR inflammasome activation.
Glomulin (GLMN) interacts with cIAP1 and cIAP2 to inhibit self‐ubiquitination of both cIAPs.
Shigella IpaH7.8 ubiquitinates GLMN, promoting its degradation and inflammasome activation.
A serine residue in the cIAP RING domain is critical for GLMN interaction, and inflammasome activation.
EMBO Reports (2018) 19: 89–101
- Received December 19, 2016.
- Revision received October 25, 2017.
- Accepted November 6, 2017.
- © 2017 The Authors
- We're on a road to nowhereCulture and adaptation to the environment are driving human evolution, but the destination of this journey is unpredictable
Culture and adaptation to the environment are driving human evolution, but the destination of this journey is unpredictable
- Andrea Rinaldi, Freelance science writer (rinaldi.ac{at}gmail.com)1
The invention of culture allowed mankind to create its own ecological niches. But does it mean that humans have stopped evolving biologically or are we still adapting to our artificial environment?
- © 2017 The Author
- ArfGAP1 restricts Mycobacterium tuberculosis entry by controlling the actin cytoskeleton
- Ok‐Ryul Song1,2,3,4,
- Christophe J Queval1,
- Raffaella Iantomasi1,
- Vincent Delorme1,4,
- Sabrina Marion1,
- Romain Veyron‐Churlet1,
- Elisabeth Werkmeister1,
- Michka Popoff1,5,
- Isabelle Ricard1,
- Samuel Jouny1,
- Nathalie Deboosere1,
- Frank Lafont1,
- Alain Baulard1,
- Edouard Yeramian6,†,
- Laurent Marsollier (laurent.marsollier{at}inserm.fr)*,2,3,†,
- Eik Hoffmann (eik.hoffmann{at}ibl.cnrs.fr)*,1,† and
- Priscille Brodin (priscille.brodin{at}inserm.fr)*,1,4,†
- 1CNRS, Inserm, CHU Lille, U1019 ‐ UMR8204 ‐ CIIL ‐ Centre d'Infection et d'Immunité de Lille, Institut Pasteur de Lille, Univ. Lille, Lille, France
- 2Equipe ATIP AVENIR, CRCINA, INSERM, Université de Nantes, Université d'Angers, Angers, France
- 3CRCINA, INSERM, Université de Nantes, Université d'Angers, Angers, France
- 4Institute Pasteur Korea, Seongnam‐si Gyeonggi‐do, South Korea
- 5CNRS, UMR8520, Institut d’électronique, de microélectronique et de nanotechnologie, Villeneuve d'Ascq, France
- 6Unité de Microbiologie Structurale, CNRS UMR3528, Institut Pasteur, Paris, France
- ↵*
Corresponding author. Tel: +33 244 688314; E‐mail: laurent.marsollier{at}inserm.fr
Corresponding author. Tel: +33 320 871035; E‐mail: eik.hoffmann{at}ibl.cnrs.fr
Corresponding author. Tel: +33 320 871184; E‐mail: priscille.brodin{at}inserm.fr
↵† These authors contributed equally to this work as senior authors
Mycobacterial uptake into epithelial cell is dependent on the receptor M3R and requires actin rearrangements regulated by Arf1. This pathway is controlled by ArfGAP1, demonstrating its role in the regulation of host‐pathogen interactions.
Synopsis
Mycobacterial uptake into epithelial cell is dependent on the receptor M3R and requires actin rearrangements regulated by Arf1. This pathway is controlled by ArfGAP1, demonstrating its role in the regulation of host‐pathogen interactions.
Colonization by M. tuberculosis depends on the M3 muscarinic receptor (M3R) and the activation of Arf1 and PLD1.
M3R‐mediated entry of M. tuberculosis into epithelial cells is restricted by the Arf GTPase‐activating protein ArfGAP1.
Mycobacterial entry involves rearrangements of the actin cytoskeleton controlled by ArfGAP1.
EMBO Reports (2018) 19: 29–42
- Received April 26, 2017.
- Revision received October 3, 2017.
- Accepted October 23, 2017.
- © 2017 The Authors
- NLRP11 disrupts MAVS signalosome to inhibit type I interferon signaling and virus‐induced apoptosis
- Yunfei Qin1,2,†,
- Zexiong Su1,†,
- Yaoxing Wu1,†,
- Chenglei Wu1,
- Shouheng Jin1,
- Weihong Xie1,
- Wei Jiang3,
- Rongbin Zhou3 and
- Jun Cui (cuij5{at}mail.sysu.edu.cn)*,1
- 1Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat‐sen University, Guangzhou, China
- 2School of Life Sciences, Zhengzhou University, Zhengzhou, Henan, China
- 3Institute of Immunology and the CAS Key Laboratory of Innate Immunity and Chronic Disease, CAS Center for Excellence in Molecular Cell Sciences, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, China
- ↵*Corresponding author. Tel: +86 20 39943429; E‐mail: cuij5{at}mail.sysu.edu.cn
↵† These authors contributed equally to this work
The MAVS signalosome mediates RIG‐I‐like receptor‐induced anti‐viral innate immune responses. NLRP11 inhibits MAVS‐dependent type I interferon signaling and virus‐induced apoptosis by disrupting the signalosome and promoting proteasomal degradation of TRAF6.
Synopsis
The MAVS signalosome mediates RIG‐I‐like receptor‐induced anti‐viral innate immune responses. NLRP11 inhibits MAVS‐dependent type I interferon signaling and virus‐induced apoptosis by disrupting the signalosome and promoting proteasomal degradation of TRAF6.
The Nod‐like receptor NLRP11 disrupts MAVS signalosomes by promoting TRAF6 degradation.
NLRP11 is induced by type I IFN upon viral infection and interacts with MAVS at mitochondria.
NLRP11 suppresses virus‐induced apoptosis in a MAVS‐dependent manner.
EMBO Reports (2017) 18: 2160–2171
- Received May 15, 2017.
- Revision received September 25, 2017.
- Accepted October 4, 2017.
- © 2017 The Authors
- Mycobacteria exploit nitric oxide‐induced transformation of macrophages into permissive giant cells
- Kourosh Gharun1,2,
- Julia Senges1,
- Maximilian Seidl1,3,
- Anne Lösslein1,
- Julia Kolter1,2,
- Florens Lohrmann1,4,5,
- Manfred Fliegauf1,
- Magdeldin Elgizouli1,
- Martina Vavra6,
- Kristina Schachtrup1,
- Anna L Illert7,8,
- Martine Gilleron9,
- Carsten J Kirschning10,
- Antigoni Triantafyllopoulou1,5 and
- Philipp Henneke (philipp.henneke{at}uniklinik-freiburg.de)*,1,11
- 1Center for Chronic Immunodeficiency (CCI), Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- 2Faculty of Biology, University of Freiburg, Freiburg, Germany
- 3Department of Pathology, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- 4Spemann Graduate School for Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
- 5Department of Rheumatology and Clinical Immunology, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- 6Division of Infectious Diseases, Department of Internal Medicine 2, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- 7Department of Medicine I, Medical Center, University of Freiburg, Faculty of Medicine University of Freiburg, Freiburg, Germany
- 8German Cancer Consortium (DKTK) and German Cancer Research Center (DKFZ), Heidelberg, Germany
- 9Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France
- 10Institute of Medical Microbiology, Medical Center, University Duisburg‐Essen, Essen, Germany
- 11Center for Pediatrics and Adolescent Medicine, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- ↵*Corresponding author. Tel: +49 761 270 77640; E‐mail: philipp.henneke{at}uniklinik-freiburg.de
Immunity to mycobacteria triggers granulomas, involving multinucleated giant cells as a unique macrophage species. Dysregulation of the TLR‐induced antimicrobial molecule nitric oxide propagates their transformation by interfering with the DNA damage response.
Synopsis
Immunity to mycobacteria triggers granulomas, involving multinucleated giant cells (MGC) as a unique macrophage species. Dysregulation of the TLR‐induced antimicrobial molecule nitric oxide propagates their transformation by interfering with the DNA damage response.
Nitric oxide (NO) drives the transformation of macrophages into MGC.
The underlying mechanism involves NO‐induced DNA damage and p53 impairment.
MGC show exceptional capacity to ingest apoptotic cells and are permissive for mycobacterial persistence.
EMBO Reports (2017) 18: 2144–2159
- Received February 21, 2017.
- Revision received September 23, 2017.
- Accepted October 2, 2017.
- © 2017 The Authors
- Identification of the centromeres of Leishmania major: revealing the hidden pieces
- Maria‐Rosa Garcia‐Silva1,2,
- Lauriane Sollelis1,2,
- Cameron Ross MacPherson3,4,5,
- Slavica Stanojcic1,2,
- Nada Kuk1,2,
- Lucien Crobu2,
- Frédéric Bringaud6,7,
- Patrick Bastien1,2,8,
- Michel Pagès2,
- Artur Scherf3,4,5 and
- Yvon Sterkers (yvon.sterkers{at}umontpellier.fr)*,1,2,8,9
- 1Department of Parasitology‐Mycology, Faculty of Medicine, University of Montpellier, Montpellier, France
- 2CNRS 5290 ‐ IRD 224 ‐ University of Montpellier (UMR “MiVEGEC”), Montpellier, France
- 3Biology of Host‐Parasite Interactions Unit, Institut Pasteur, Paris, France
- 4CNRS, ERL 9195, Paris, France
- 5INSERM, Unit U1201, Paris, France
- 6Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), University of Bordeaux, Bordeaux, France
- 7CNRS, UMR 5234, Bordeaux, France
- 8Department of Parasitology‐Mycology, University Hospital Centre (CHU), Montpellier, France
- 9Present Address: Laboratoire de Parasitologie‐Mycologie, CHU de Montpellier, Montpellier Cedex 5, France
- ↵*Corresponding author. Tel: +33 467 63 55 13; Fax: +33 467 63 00 49; E‐mail: yvon.sterkers{at}umontpellier.fr
LmKKT1 is a Leishmania kinetoplastid kinetochore protein that shows single ChIP‐Seq peaks corresponding to the 36 centromeres. As a centrosomal marker, LmKKT1 is found at the periphery of the nucleolus during interphase and relocates to the spindle poles during mitosis.
Synopsis
LmKKT1 is a Leishmania kinetoplastid kinetochore protein that shows single ChIP‐Seq peaks corresponding to the 36 centromeres. As a centrosomal marker, LmKKT1 is found at the periphery of the nucleolus during interphase and relocates to the spindle poles during mitosis.
LmKKT1 displays “kinetochore‐like” dynamics of intranuclear localization throughout the cell cycle.
LmKKT1 shows single narrow peaks per chromosome that correspond to the centromeres.
Leishmania major centromeres are essentially non‐repetitive and display great inter‐chromosomal sequence heterogeneity.
L. major centromeres are characterised by two conserved motifs and a higher density of retroposons.
EMBO Reports (2017) 18: 1968–1977
- Received March 17, 2017.
- Revision received August 15, 2017.
- Accepted August 28, 2017.
- © 2017 The Authors
- Type VI secretion system MIX‐effectors carry both antibacterial and anti‐eukaryotic activities
- Ann Ray1,2,
- Nika Schwartz3,
- Marcela de Souza Santos1,
- Junmei Zhang1,2,
- Kim Orth1,2,4 and
- Dor Salomon (dorsalomon{at}mail.tau.ac.il)*,3
- 1Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- 2Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
- 3Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- 4Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
- ↵*Corresponding author. Tel: +972 3 6408583; E‐mail: dorsalomon{at}mail.tau.ac.il
Type VI secretion systems are protein delivery apparatuses that mediate predominately bactericidal activities. This study shows that a Vibrio T6SS utilizes a versatile repertoire of effectors to target both competing bacteria and neighbouring eukaryotic cells.
Synopsis
Type VI secretion systems are protein delivery apparatuses that mediate predominately bactericidal activities. This study shows that a Vibrio T6SS utilizes a versatile repertoire of effectors to target both competing bacteria and neighbouring eukaryotic cells.
The Vibrio proteolyticus T6SS1 mediates bacterial killing under warm marine‐like conditions.
The Vibrio T6SS1 delivers a suite of effectors with predicted bactericidal and virulence activities.
A CNF1‐containing Vibrio T6SS1 MIX‐effector induces actin rearrangements and morphological changes upon infection of macrophages.
EMBO Reports (2017) 18: 1978–1990
- Received March 15, 2017.
- Revision received August 14, 2017.
- Accepted August 16, 2017.
- © 2017 The Authors. Published under the terms of the CC BY 4.0 license
This is an open access article under the terms of the Creative Commons Attribution 4.0 License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
- Viral taxonomyThe effect of metagenomics on understanding the diversity and evolution of viruses
The effect of metagenomics on understanding the diversity and evolution of viruses
- Philip Hunter, Freelance journalist (ph{at}philiphunter.com)1
The advent of next‐generation sequencing and metagenomics is challenging viral taxonomy to define and characterize viruses along with providing novel insights into the vast diversity of viruses and their evolution.
- © 2017 The Author
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