1
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Hohl M, Banks EJ, Manley MP, Le TBK, Low HH. Bidirectional pilus processing in the Tad pilus system motor CpaF. Nat Commun 2024; 15:6635. [PMID: 39103374 DOI: 10.1038/s41467-024-50280-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 07/05/2024] [Indexed: 08/07/2024] Open
Abstract
The bacterial tight adherence pilus system (TadPS) assembles surface pili essential for adhesion and colonisation in many human pathogens. Pilus dynamics are powered by the ATPase CpaF (TadA), which drives extension and retraction cycles in Caulobacter crescentus through an unknown mechanism. Here we use cryogenic electron microscopy and cell-based light microscopy to characterise CpaF mechanism. We show that CpaF assembles into a hexamer with C2 symmetry in different nucleotide states. Nucleotide cycling occurs through an intra-subunit clamp-like mechanism that promotes sequential conformational changes between subunits. Moreover, a comparison of the active sites with different nucleotides bound suggests a mechanism for bidirectional motion. Conserved CpaF residues, predicted to interact with platform proteins CpaG (TadB) and CpaH (TadC), are mutated in vivo to establish their role in pilus processing. Our findings provide a model for how CpaF drives TadPS pilus dynamics and have broad implications for how other ancient type 4 filament family members power pilus assembly.
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Affiliation(s)
- Michael Hohl
- Department of Infectious Disease, Imperial College, London, UK
| | - Emma J Banks
- Department of Molecular Microbiology, John Innes Centre, Norwich, UK
| | - Max P Manley
- Department of Infectious Disease, Imperial College, London, UK
| | - Tung B K Le
- Department of Molecular Microbiology, John Innes Centre, Norwich, UK
| | - Harry H Low
- Department of Infectious Disease, Imperial College, London, UK.
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2
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Geiger CJ, Wong GCL, O'Toole GA. A bacterial sense of touch: T4P retraction motor as a means of surface sensing by Pseudomonas aeruginosa PA14. J Bacteriol 2024; 206:e0044223. [PMID: 38832786 PMCID: PMC11270903 DOI: 10.1128/jb.00442-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024] Open
Abstract
Most microbial cells found in nature exist in matrix-covered, surface-attached communities known as biofilms. This mode of growth is initiated by the ability of the microbe to sense a surface on which to grow. The opportunistic pathogen Pseudomonas aeruginosa (Pa) PA14 utilizes a single polar flagellum and type 4 pili (T4P) to sense surfaces. For Pa, T4P-dependent "twitching" motility is characterized by effectively pulling the cell across a surface through a complex process of cooperative binding, pulling, and unbinding. T4P retraction is powered by hexameric ATPases. Pa cells that have engaged a surface increase production of the second messenger cyclic AMP (cAMP) over multiple generations via the Pil-Chp system. This rise in cAMP allows cells and their progeny to become better adapted for surface attachment and activates virulence pathways through the cAMP-binding transcription factor Vfr. While many studies have focused on mechanisms of T4P twitching and regulation of T4P production and function by the Pil-Chp system, the mechanism by which Pa senses and relays a surface-engagement signal to the cell is still an open question. Here we review the current state of the surface sensing literature for Pa, with a focus on T4P, and propose an integrated model of surface sensing whereby the retraction motor PilT senses and relays the signal to the Pil-Chp system via PilJ to drive cAMP production and adaptation to a surface lifestyle.
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Affiliation(s)
- C. J. Geiger
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - G. C. L. Wong
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California, USA
| | - G. A. O'Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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3
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Chen X, Zhang R, Yuan J. Vertical confinement enhances surface exploration in bacterial twitching motility. Environ Microbiol 2024; 26:e16679. [PMID: 39039815 DOI: 10.1111/1462-2920.16679] [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: 01/25/2024] [Accepted: 07/06/2024] [Indexed: 07/24/2024]
Abstract
Bacteria are often found in environments where space is limited, and they attach themselves to surfaces. One common form of movement on these surfaces is bacterial twitching motility, which is powered by the extension and retraction of type IV pili. Although twitching motility in unrestricted conditions has been extensively studied, the effects of spatial confinement on this behaviour are not well understood. In this study, we explored the diffusive properties of individual twitching Pseudomonas aeruginosa cells in spatially confined conditions. We achieved this by placing the bacteria between layers of agarose and glass, and then tracking the long-term twitching motility of individual cells. Interestingly, we found that while confinement reduced the immediate speed of twitching, it paradoxically increased diffusion. Through a combination of mechanical and geometrical analysis, as well as numerical simulations, we showed that this increase in diffusion could be attributed to mechanical factors. The constraint imposed by the agarose altered the diffusion pattern of the bacteria from normal to superdiffusion. These findings provide valuable insights into the motile behaviour of bacteria in confined environments.
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Affiliation(s)
- Xiao Chen
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, China
| | - Rongjing Zhang
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, China
| | - Junhua Yuan
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, China
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4
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Zhang P, Huguet-Tapia J, Peng Z, Liu S, Obasa K, Block AK, White FF. Genome analysis and hyphal movement characterization of the hitchhiker endohyphal Enterobacter sp. from Rhizoctonia solani. Appl Environ Microbiol 2024; 90:e0224523. [PMID: 38319098 PMCID: PMC10952491 DOI: 10.1128/aem.02245-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 01/05/2024] [Indexed: 02/07/2024] Open
Abstract
Bacterial-fungal interactions are pervasive in the rhizosphere. While an increasing number of endohyphal bacteria have been identified, little is known about their ecology and impact on the associated fungal hosts and the surrounding environment. In this study, we characterized the genome of an Enterobacter sp. Crenshaw (En-Cren), which was isolated from the generalist fungal pathogen Rhizoctonia solani, and examined the genetic potential of the bacterium with regard to the phenotypic traits associated with the fungus. Overall, the En-Cren genome size was typical for members of the genus and was capable of free-living growth. The genome was 4.6 MB in size, and no plasmids were detected. Several prophage regions and genomic islands were identified that harbor unique genes in comparison with phylogenetically closely related Enterobacter spp. Type VI secretion system and cyanate assimilation genes were identified from the bacterium, while some common heavy metal resistance genes were absent. En-Cren contains the key genes for indole-3-acetic acid (IAA) and phenylacetic acid (PAA) biosynthesis, and produces IAA and PAA in vitro, which may impact the ecology or pathogenicity of the fungal pathogen in vivo. En-Cren was observed to move along hyphae of R. solani and on other basidiomycetes and ascomycetes in culture. The bacterial flagellum is essential for hyphal movement, while other pathways and genes may also be involved.IMPORTANCEThe genome characterization and comparative genomics analysis of Enterobacter sp. Crenshaw provided the foundation and resources for a better understanding of the ecology and evolution of this endohyphal bacteria in the rhizosphere. The ability to produce indole-3-acetic acid and phenylacetic acid may provide new angles to study the impact of phytohormones during the plant-pathogen interactions. The hitchhiking behavior of the bacterium on a diverse group of fungi, while inhibiting the growth of some others, revealed new areas of bacterial-fungal signaling and interaction, which have yet to be explored.
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Affiliation(s)
- Peiqi Zhang
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Jose Huguet-Tapia
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Zhao Peng
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
- College of Plant Protection, Jilin Agricultural University, Changchun, Jilin, China
| | - Sanzhen Liu
- Department of Plant Pathology, Kansas State University, Manhattan, Kansas, USA
| | - Ken Obasa
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
- High Plains Plant Disease Diagnostic Lab, Texas A&M AgriLife Extension Service, Amarillo, Texas, USA
| | - Anna K. Block
- Chemistry Research Unit, US Department of Agriculture-Agricultural Research Service, Gainesville, Florida, USA
| | - Frank F. White
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
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5
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Rhodes KA, Rendón MA, Ma MC, Agellon A, Johnson AC, So M. Type IV pilus retraction is required for Neisseria musculi colonization and persistence in a natural mouse model of infection. mBio 2024; 15:e0279223. [PMID: 38084997 PMCID: PMC10790696 DOI: 10.1128/mbio.02792-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 10/25/2023] [Indexed: 01/17/2024] Open
Abstract
IMPORTANCE We describe the importance of Type IV pilus retraction to colonization and persistence by a mouse commensal Neisseria, N. musculi, in its native host. Our findings have implications for the role of Tfp retraction in mediating interactions of human-adapted pathogenic and commensal Neisseria with their human host due to the relatedness of these species.
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Affiliation(s)
- Katherine A. Rhodes
- Immunobiology Department, University of Arizona College of Medicine, Tucson, Arizona, USA
- BIO5 Institute, University of Arizona, Tucson, Arizona, USA
| | - María A. Rendón
- Immunobiology Department, University of Arizona College of Medicine, Tucson, Arizona, USA
- BIO5 Institute, University of Arizona, Tucson, Arizona, USA
| | - Man Cheong Ma
- Immunobiology Department, University of Arizona College of Medicine, Tucson, Arizona, USA
- BIO5 Institute, University of Arizona, Tucson, Arizona, USA
| | - Al Agellon
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Andrew C.E. Johnson
- Immunobiology Department, University of Arizona College of Medicine, Tucson, Arizona, USA
| | - Magdalene So
- Immunobiology Department, University of Arizona College of Medicine, Tucson, Arizona, USA
- BIO5 Institute, University of Arizona, Tucson, Arizona, USA
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6
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Koskinen S, Kurkela J, Linhartová M, Tyystjärvi T. The genome sequence of Synechocystis sp. PCC 6803 substrain GT-T and its implications for the evolution of PCC 6803 substrains. FEBS Open Bio 2023; 13:701-712. [PMID: 36792971 PMCID: PMC10068330 DOI: 10.1002/2211-5463.13576] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 02/02/2023] [Accepted: 02/07/2023] [Indexed: 02/17/2023] Open
Abstract
Synechocystis sp. PCC 6803 is a model cyanobacterium, glucose-tolerant substrains of which are commonly used as laboratory strains. In recent years, it has become evident that 'wild-type' strains used in different laboratories show some differences in their phenotypes. We report here the chromosome sequence of our Synechocystis sp. PCC 6803 substrain, named substrain GT-T. The chromosome sequence of GT-T was compared to those of two other commonly used laboratory substrains, GT-S and PCC-M. We identified 11 specific mutations in the GT-T substrain, whose physiological consequences are discussed. We also provide an update on evolutionary relationships between different Synechocystis sp. PCC 6803 substrains.
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Affiliation(s)
- Satu Koskinen
- Department of Life Sciences/Molecular Plant Biology, University of Turku, Finland
| | - Juha Kurkela
- Department of Life Sciences/Molecular Plant Biology, University of Turku, Finland
| | - Markéta Linhartová
- Institute of Microbiology of the Czech Academy of Sciences, Třeboň, Czech Republic
| | - Taina Tyystjärvi
- Department of Life Sciences/Molecular Plant Biology, University of Turku, Finland
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7
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Abstract
Type IV pili (T4P) are retractable multifunctional nanofibers present on the surface of numerous bacterial and archaeal species. Their importance to microbiology is difficult to overstate. The scientific journey leading to our current understanding of T4P structure and function has included many innovative research milestones. Although multiple T4P reviews over the years have emphasized recent advances, we find that current reports often omit many of the landmark discoveries in this field. Here, we attempt to highlight chronologically the most important work on T4P, from the discovery of pili to the application of sophisticated contemporary methods, which has brought us to our current state of knowledge. As there remains much to learn about the complex machine that assembles and retracts T4P, we hope that this review will increase the interest of current researchers and inspire innovative progress.
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8
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Ellison CK, Whitfield GB, Brun YV. Type IV Pili: Dynamic Bacterial Nanomachines. FEMS Microbiol Rev 2021; 46:6425739. [PMID: 34788436 DOI: 10.1093/femsre/fuab053] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 11/08/2021] [Indexed: 01/19/2023] Open
Abstract
Bacteria and archaea rely on appendages called type IV pili (T4P) to participate in diverse behaviors including surface sensing, biofilm formation, virulence, protein secretion, and motility across surfaces. T4P are broadly distributed fibers that dynamically extend and retract, and this dynamic activity is essential for their function in broad processes. Despite the essentiality of dynamics in T4P function, little is known about the role of these dynamics and molecular mechanisms controlling them. Recent advances in microscopy have yielded insight into the role of T4P dynamics in their diverse functions and recent structural work has expanded what is known about the inner workings of the T4P motor. This review discusses recent progress in understanding the function, regulation, and mechanisms of T4P dynamics.
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Affiliation(s)
- Courtney K Ellison
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.,Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Gregory B Whitfield
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Yves V Brun
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
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9
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Llontop EE, Cenens W, Favaro DC, Sgro GG, Salinas RK, Guzzo CR, Farah CS. The PilB-PilZ-FimX regulatory complex of the Type IV pilus from Xanthomonas citri. PLoS Pathog 2021; 17:e1009808. [PMID: 34398935 PMCID: PMC8389850 DOI: 10.1371/journal.ppat.1009808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 08/26/2021] [Accepted: 07/17/2021] [Indexed: 11/19/2022] Open
Abstract
Type IV pili (T4P) are thin and flexible filaments found on the surface of a wide range of Gram-negative bacteria that undergo cycles of extension and retraction and participate in a variety of important functions related to lifestyle, defense and pathogenesis. During pilus extensions, the PilB ATPase energizes the polymerization of pilin monomers from the inner membrane. In Xanthomonas citri, two cytosolic proteins, PilZ and the c-di-GMP receptor FimX, are involved in the regulation of T4P biogenesis through interactions with PilB. In vivo fluorescence microscopy studies show that PilB, PilZ and FimX all colocalize to the leading poles of X. citri cells during twitching motility and that this colocalization is dependent on the presence of all three proteins. We demonstrate that full-length PilB, PilZ and FimX can interact to form a stable complex as can PilB N-terminal, PilZ and FimX C-terminal fragments. We present the crystal structures of two binary complexes: i) that of the PilB N-terminal domain, encompassing sub-domains ND0 and ND1, bound to PilZ and ii) PilZ bound to the FimX EAL domain within a larger fragment containing both GGDEF and EAL domains. Evaluation of PilZ interactions with PilB and the FimX EAL domain in these and previously published structures, in conjunction with mutagenesis studies and functional assays, allow us to propose an internally consistent model for the PilB-PilZ-FimX complex and its interactions with the PilM-PilN complex in the context of the inner membrane platform of the X. citri Type IV pilus.
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Affiliation(s)
- Edgar E. Llontop
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - William Cenens
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Denize C. Favaro
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- Departamento de Química Orgânica, Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil
| | - Germán G. Sgro
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Roberto K. Salinas
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Cristiane R. Guzzo
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Chuck S. Farah
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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10
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Zhang J, Li S, Sun T, Zong Y, Zhang W, Zhao K. A simple, switchable pili-labelling method by plasmid-based replacement of pilin. Environ Microbiol 2021; 23:2692-2703. [PMID: 33848059 DOI: 10.1111/1462-2920.15515] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 04/06/2021] [Indexed: 11/26/2022]
Abstract
Labelling of Type IV pili (TFP) can greatly improve our understanding of the pivotal roles of TFP in a variety of bacterial activities including motility, surface sensing and DNA-uptake etc. Here we show a simple and switchable pili-labelling method by plasmid-based inducible replacement of PilA without genetic modification in bacterial genome employed by complicated methods. Using this method, we characterized pili morphology and twitching motility of Pseudomonas aeruginosa in details. More importantly, we demonstrate its application in studying the replenishment dynamics of pilin pool of P. aeruginosa.
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Affiliation(s)
- Jingchao Zhang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Shubin Li
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Tao Sun
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.,Center for Biosafety Research and Strategy, Tianjin University, Tianjin, 300072, China
| | - Yiwu Zong
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Weiwen Zhang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.,Center for Biosafety Research and Strategy, Tianjin University, Tianjin, 300072, China
| | - Kun Zhao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
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11
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Naskar S, Hohl M, Tassinari M, Low HH. The structure and mechanism of the bacterial type II secretion system. Mol Microbiol 2020; 115:412-424. [PMID: 33283907 DOI: 10.1111/mmi.14664] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 12/03/2020] [Indexed: 12/17/2022]
Abstract
The type II secretion system (T2SS) is a multi-protein complex used by many bacteria to move substrates across their cell membrane. Substrates released into the environment serve as local and long-range effectors that promote nutrient acquisition, biofilm formation, and pathogenicity. In both animals and plants, the T2SS is increasingly recognized as a key driver of virulence. The T2SS spans the bacterial cell envelope and extrudes substrates through an outer membrane secretin channel using a pseudopilus. An inner membrane assembly platform and a cytoplasmic motor controls pseudopilus assembly. This microreview focuses on the structure and mechanism of the T2SS. Advances in cryo-electron microscopy are enabling increasingly elaborate sub-complexes to be resolved. However, key questions remain regarding the mechanism of pseudopilus extension and retraction, and how this is coupled with the choreography of the substrate moving through the secretion system. The T2SS is part of an ancient type IV filament superfamily that may have been present within the last universal common ancestor (LUCA). Overall, mechanistic principles that underlie T2SS function have implication for other closely related systems such as the type IV and tight adherence pilus systems.
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Affiliation(s)
- Souvik Naskar
- Department of Infectious Disease, Imperial College, London, UK
| | - Michael Hohl
- Department of Infectious Disease, Imperial College, London, UK
| | | | - Harry H Low
- Department of Infectious Disease, Imperial College, London, UK
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12
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The small GTPase MglA together with the TPR domain protein SgmX stimulates type IV pili formation in M. xanthus. Proc Natl Acad Sci U S A 2020; 117:23859-23868. [PMID: 32900945 PMCID: PMC7519303 DOI: 10.1073/pnas.2004722117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many bacteria move across surfaces using type IV pili (T4P). The piliation pattern varies between species; however, the underlying mechanisms governing these patterns remain largely unknown. Here, we demonstrate that in the rod-shaped Myxococcus xanthus cells, the unipolar formation of T4P at the leading cell pole is the result of stimulation by the small GTPase MglA together with the effector protein SgmX, while MglB, the cognate MglA GTPase activating protein (GAP) that localizes to the lagging cell pole, blocks this stimulation at the lagging pole due to its GAP activity. During reversals, MglA/SgmX and MglB switch polarity, laying the foundation for T4P formation at the new leading cell pole and inhibition of T4P formation at the former leading cell pole. Bacteria can move across surfaces using type IV pili (T4P), which undergo cycles of extension, adhesion, and retraction. The T4P localization pattern varies between species; however, the underlying mechanisms are largely unknown. In the rod-shaped Myxococcus xanthus cells, T4P localize at the leading cell pole. As cells reverse their direction of movement, T4P are disassembled at the old leading pole and then form at the new leading pole. Thus, cells can form T4P at both poles but engage only one pole at a time in T4P formation. Here, we address how this T4P unipolarity is realized. We demonstrate that the small Ras-like GTPase MglA stimulates T4P formation in its GTP-bound state by direct interaction with the tetratricopeptide repeat (TPR) domain-containing protein SgmX. SgmX, in turn, is important for polar localization of the T4P extension ATPase PilB. The cognate MglA GTPase activating protein (GAP) MglB, which localizes mainly to the lagging cell pole, indirectly blocks T4P formation at this pole by stimulating the conversion of MglA-GTP to MglA-GDP. Based on these findings, we propose a model whereby T4P unipolarity is accomplished by stimulation of T4P formation at the leading pole by MglA-GTP and SgmX and indirect inhibition of T4P formation at the lagging pole by MglB due to its MglA GAP activity. During reversals, MglA, SgmX, and MglB switch polarity, thus laying the foundation for T4P formation at the new leading pole and inhibition of T4P formation at the new lagging pole.
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13
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Craig L, Forest KT, Maier B. Type IV pili: dynamics, biophysics and functional consequences. Nat Rev Microbiol 2020; 17:429-440. [PMID: 30988511 DOI: 10.1038/s41579-019-0195-4] [Citation(s) in RCA: 222] [Impact Index Per Article: 55.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The surfaces of many bacteria are decorated with long, exquisitely thin appendages called type IV pili (T4P), dynamic filaments that are rapidly polymerized and depolymerized from a pool of pilin subunits. Cycles of pilus extension, binding and retraction enable T4P to perform a phenomenally diverse array of functions, including twitching motility, DNA uptake and microcolony formation. On the basis of recent developments, a comprehensive understanding is emerging of the molecular architecture of the T4P machinery and the filament it builds, providing mechanistic insights into the assembly and retraction processes. Combined microbiological and biophysical approaches have revealed how T4P dynamics influence self-organization of bacteria, how bacteria respond to external stimuli to regulate T4P activity for directed movement, and the role of T4P retraction in surface sensing. In this Review, we discuss the T4P machine architecture and filament structure and present current molecular models for T4P dynamics, with a particular focus on recent insights into T4P retraction. We also discuss the functional consequences of T4P dynamics, which have important implications for bacterial lifestyle and pathogenesis.
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Affiliation(s)
- Lisa Craig
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada.
| | - Katrina T Forest
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Berenike Maier
- Institute for Biological Physics, University of Cologne, Köln, Germany.
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14
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Chernyatina AA, Low HH. Core architecture of a bacterial type II secretion system. Nat Commun 2019; 10:5437. [PMID: 31780649 PMCID: PMC6882859 DOI: 10.1038/s41467-019-13301-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 10/25/2019] [Indexed: 01/01/2023] Open
Abstract
Bacterial type II secretion systems (T2SSs) translocate virulence factors, toxins and enzymes across the cell outer membrane. Here we use negative stain and cryo-electron microscopy to reveal the core architecture of an assembled T2SS from the pathogen Klebsiella pneumoniae. We show that 7 proteins form a ~2.4 MDa complex that spans the cell envelope. The outer membrane complex includes the secretin PulD, with all domains modelled, and the pilotin PulS. The inner membrane assembly platform components PulC, PulE, PulL, PulM and PulN have a relative stoichiometric ratio of 2:1:1:1:1. The PulE ATPase, PulL and PulM combine to form a flexible hexameric hub. Symmetry mismatch between the outer membrane complex and assembly platform is overcome by PulC linkers spanning the periplasm, with PulC HR domains binding independently at the secretin base. Our results show that the T2SS has a highly dynamic modular architecture, with implication for pseudo-pilus assembly and substrate loading.
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Affiliation(s)
| | - Harry H Low
- Department of Life Sciences, Imperial College, London, SW7 2AZ, UK.
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15
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McCallum M, Benlekbir S, Nguyen S, Tammam S, Rubinstein JL, Burrows LL, Howell PL. Multiple conformations facilitate PilT function in the type IV pilus. Nat Commun 2019; 10:5198. [PMID: 31729381 PMCID: PMC6858323 DOI: 10.1038/s41467-019-13070-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 10/18/2019] [Indexed: 12/13/2022] Open
Abstract
Type IV pilus-like systems are protein complexes that polymerize pilin fibres. They are critical for virulence in many bacterial pathogens. Pilin polymerization and depolymerization are powered by motor ATPases of the PilT/VirB11-like family. This family is thought to operate with C2 symmetry; however, most of these ATPases crystallize with either C3 or C6 symmetric conformations. The relevance of these conformations is unclear. Here, we determine the X-ray structures of PilT in four unique conformations and use these structures to classify the conformation of available PilT/VirB11-like family member structures. Single particle electron cryomicroscopy (cryoEM) structures of PilT reveal condition-dependent preferences for C2, C3, and C6 conformations. The physiologic importance of these conformations is validated by coevolution analysis and functional studies of point mutants, identifying a rare gain-of-function mutation that favours the C2 conformation. With these data, we propose a comprehensive model of PilT function with broad implications for PilT/VirB11-like family members.
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Affiliation(s)
- Matthew McCallum
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Program in Molecular Structure & Function, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Samir Benlekbir
- Program in Molecular Structure & Function, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Sheryl Nguyen
- Program in Molecular Structure & Function, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Stephanie Tammam
- Program in Molecular Structure & Function, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - John L Rubinstein
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- Program in Molecular Structure & Function, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada.
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 1l7, Canada.
| | - Lori L Burrows
- Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, L8S 4K1, Canada.
| | - P Lynne Howell
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- Program in Molecular Structure & Function, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada.
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16
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Chlebek JL, Hughes HQ, Ratkiewicz AS, Rayyan R, Wang JCY, Herrin BE, Dalia TN, Biais N, Dalia AB. PilT and PilU are homohexameric ATPases that coordinate to retract type IVa pili. PLoS Genet 2019; 15:e1008448. [PMID: 31626631 PMCID: PMC6821130 DOI: 10.1371/journal.pgen.1008448] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 10/30/2019] [Accepted: 09/27/2019] [Indexed: 12/26/2022] Open
Abstract
Bacterial type IV pili are critical for diverse biological processes including horizontal gene transfer, surface sensing, biofilm formation, adherence, motility, and virulence. These dynamic appendages extend and retract from the cell surface. In many type IVa pilus systems, extension occurs through the action of an extension ATPase, often called PilB, while optimal retraction requires the action of a retraction ATPase, PilT. Many type IVa systems also encode a homolog of PilT called PilU. However, the function of this protein has remained unclear because pilU mutants exhibit inconsistent phenotypes among type IV pilus systems and because it is relatively understudied compared to PilT. Here, we study the type IVa competence pilus of Vibrio cholerae as a model system to define the role of PilU. We show that the ATPase activity of PilU is critical for pilus retraction in PilT Walker A and/or Walker B mutants. PilU does not, however, contribute to pilus retraction in ΔpilT strains. Thus, these data suggest that PilU is a bona fide retraction ATPase that supports pilus retraction in a PilT-dependent manner. We also found that a ΔpilU mutant exhibited a reduction in the force of retraction suggesting that PilU is important for generating maximal retraction forces. Additional in vitro and in vivo data show that PilT and PilU act as independent homo-hexamers that may form a complex to facilitate pilus retraction. Finally, we demonstrate that the role of PilU as a PilT-dependent retraction ATPase is conserved in Acinetobacter baylyi, suggesting that the role of PilU described here may be broadly applicable to other type IVa pilus systems.
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Affiliation(s)
- Jennifer L. Chlebek
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Hannah Q. Hughes
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Aleksandra S. Ratkiewicz
- Biology Department and Graduate Center, City University of New York, Brooklyn, New York, United States of America
| | - Rasman Rayyan
- Biology Department and Graduate Center, City University of New York, Brooklyn, New York, United States of America
| | - Joseph Che-Yen Wang
- Electron Microscopy Center, Indiana University, Bloomington, Indiana, United States of America
| | - Brittany E. Herrin
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Triana N. Dalia
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Nicolas Biais
- Biology Department and Graduate Center, City University of New York, Brooklyn, New York, United States of America
| | - Ankur B. Dalia
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
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17
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Zöllner R, Cronenberg T, Maier B. Motor Properties of PilT-Independent Type 4 Pilus Retraction in Gonococci. J Bacteriol 2019; 201:e00778-18. [PMID: 30692169 PMCID: PMC6707916 DOI: 10.1128/jb.00778-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 01/17/2019] [Indexed: 01/25/2023] Open
Abstract
Bacterial type 4 pili (T4P) belong to the strongest molecular machines. The gonococcal T4P retraction ATPase PilT supports forces exceeding 100 pN during T4P retraction. Here, we address the question of whether gonococcal T4P retract in the absence of PilT. We show that pilT deletion strains indeed retract their T4P, but the maximum force is reduced to 5 pN. Similarly, the speed of T4P retraction is lower by orders of magnitude compared to that of T4P retraction driven by PilT. Deleting the pilT paralogue pilT2 further reduces the speed of T4P retraction, yet T4P retraction is detectable in the absence of all three pilT paralogues. Furthermore, we show that depletion of proton motive force (PMF) slows but does not inhibit pilT-independent T4P retraction. We conclude that the retraction ATPase is not essential for gonococcal T4P retraction. However, the force generated in the absence of PilT is too low to support important functions of T4P, including twitching motility, fluidization of colonies, and induction of host cell response.IMPORTANCE Bacterial type 4 pili (T4P) have been termed the "Swiss Army knives" of bacteria because they perform numerous functions, including host cell interaction, twitching motility, colony formation, DNA uptake, protein secretion, and surface sensing. The pilus fiber continuously elongates or retracts, and these dynamics are functionally important. Curiously, only a subset of T4P systems employ T4P retraction ATPases to power T4P retraction. Here, we show that one of the strongest T4P machines, the gonococcal T4P, retracts without a retraction ATPase. Biophysical characterization reveals strongly reduced force and speed compared to retraction with ATPase. We propose that bacteria encode retraction ATPases when T4P have to generate high-force-supporting functions like twitching motility, triggering host cell response, or fluidizing colonies.
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Affiliation(s)
- Robert Zöllner
- University of Cologne, Institute for Biological Physics, Cologne, Germany
| | - Tom Cronenberg
- University of Cologne, Institute for Biological Physics, Cologne, Germany
| | - Berenike Maier
- University of Cologne, Institute for Biological Physics, Cologne, Germany
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18
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Adams DW, Pereira JM, Stoudmann C, Stutzmann S, Blokesch M. The type IV pilus protein PilU functions as a PilT-dependent retraction ATPase. PLoS Genet 2019; 15:e1008393. [PMID: 31525185 PMCID: PMC6762196 DOI: 10.1371/journal.pgen.1008393] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/26/2019] [Accepted: 08/29/2019] [Indexed: 11/18/2022] Open
Abstract
Type IV pili are dynamic cell surface appendages found throughout the bacteria. The ability of these structures to undergo repetitive cycles of extension and retraction underpins their crucial roles in adhesion, motility and natural competence for transformation. In the best-studied systems a dedicated retraction ATPase PilT powers pilus retraction. Curiously, a second presumed retraction ATPase PilU is often encoded immediately downstream of pilT. However, despite the presence of two potential retraction ATPases, pilT deletions lead to a total loss of pilus function, raising the question of why PilU fails to take over. Here, using the DNA-uptake pilus and mannose-sensitive haemagglutinin (MSHA) pilus of Vibrio cholerae as model systems, we show that inactivated PilT variants, defective for either ATP-binding or hydrolysis, have unexpected intermediate phenotypes that are PilU-dependent. In addition to demonstrating that PilU can function as a bona fide retraction ATPase, we go on to make the surprising discovery that PilU functions exclusively in a PilT-dependent manner and identify a naturally occurring pandemic V. cholerae PilT variant that renders PilU essential for pilus function. Finally, we show that Pseudomonas aeruginosa PilU also functions as a PilT-dependent retraction ATPase, providing evidence that the functional coupling between PilT and PilU could be a widespread mechanism for optimal pilus retraction.
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Affiliation(s)
- David W. Adams
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH, Lausanne, Switzerland
| | - Jorge M. Pereira
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH, Lausanne, Switzerland
| | - Candice Stoudmann
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH, Lausanne, Switzerland
| | - Sandrine Stutzmann
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH, Lausanne, Switzerland
| | - Melanie Blokesch
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH, Lausanne, Switzerland
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19
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Abstract
The family Geobacteraceae, with its only valid genus Geobacter, comprises deltaproteobacteria ubiquitous in soil, sediments, and subsurface environments where metal reduction is an active process. Research for almost three decades has provided novel insights into environmental processes and biogeochemical reactions not previously known to be carried out by microorganisms. At the heart of the environmental roles played by Geobacter bacteria is their ability to integrate redox pathways and regulatory checkpoints that maximize growth efficiency with electron donors derived from the decomposition of organic matter while respiring metal oxides, particularly the often abundant oxides of ferric iron. This metabolic specialization is complemented by versatile metabolic reactions, respiratory chains, and sensory networks that allow specific members to adaptively respond to environmental cues to integrate organic and inorganic contaminants in their oxidative and reductive metabolism, respectively. Thus, Geobacteraceae are important members of the microbial communities that degrade hydrocarbon contaminants under iron-reducing conditions and that contribute, directly or indirectly, to the reduction of radionuclides, toxic metals, and oxidized species of nitrogen. Their ability to produce conductive pili as nanowires for discharging respiratory electrons to solid-phase electron acceptors and radionuclides, or for wiring cells in current-harvesting biofilms highlights the unique physiological traits that make these organisms attractive biological platforms for bioremediation, bioenergy, and bioelectronics application. Here we review some of the most notable physiological features described in Geobacter species since the first model representatives were recovered in pure culture. We provide a historical account of the environmental research that has set the foundation for numerous physiological studies and the laboratory tools that had provided novel insights into the role of Geobacter in the functioning of microbial communities from pristine and contaminated environments. We pay particular attention to latest research, both basic and applied, that has served to expand the field into new directions and to advance interdisciplinary knowledge. The electrifying physiology of Geobacter, it seems, is alive and well 30 years on.
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20
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Abstract
Type IV pilus (T4P)-like systems have been identified in almost every major phylum of prokaryotic life. They include the type IVa pilus (T4aP), type II secretion system (T2SS), type IVb pilus (T4bP), Tad/Flp pilus, Com pilus, and archaeal flagellum (archaellum). These systems are used for adhesion, natural competence, phage adsorption, folded-protein secretion, surface sensing, swimming motility, and twitching motility. The T4aP allows for all of these functions except swimming and is therefore a good model system for understanding T4P-like systems. Recent structural analyses have revolutionized our understanding of how the T4aP machinery assembles and functions. Here we review the structure and function of the T4aP.
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21
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Berry JL, Gurung I, Anonsen JH, Spielman I, Harper E, Hall AMJ, Goosens VJ, Raynaud C, Koomey M, Biais N, Matthews S, Pelicic V. Global biochemical and structural analysis of the type IV pilus from the Gram-positive bacterium Streptococcus sanguinis. J Biol Chem 2019; 294:6796-6808. [PMID: 30837269 PMCID: PMC6497953 DOI: 10.1074/jbc.ra118.006917] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 02/27/2019] [Indexed: 11/06/2022] Open
Abstract
Type IV pili (Tfp) are functionally versatile filaments, widespread in prokaryotes, that belong to a large class of filamentous nanomachines known as type IV filaments (Tff). Although Tfp have been extensively studied in several Gram-negative pathogens where they function as key virulence factors, many aspects of their biology remain poorly understood. Here, we performed a global biochemical and structural analysis of Tfp in a recently emerged Gram-positive model, Streptococcus sanguinis In particular, we focused on the five pilins and pilin-like proteins involved in Tfp biology in S. sanguinis We found that the two major pilins, PilE1 and PilE2, (i) follow widely conserved principles for processing by the prepilin peptidase PilD and for assembly into filaments; (ii) display only one of the post-translational modifications frequently found in pilins, i.e. a methylated N terminus; (iii) are found in the same heteropolymeric filaments; and (iv) are not functionally equivalent. The 3D structure of PilE1, solved by NMR, revealed a classical pilin-fold with a highly unusual flexible C terminus. Intriguingly, PilE1 more closely resembles pseudopilins forming shorter Tff than bona fide Tfp-forming major pilins, underlining the evolutionary relatedness among different Tff. Finally, we show that S. sanguinis Tfp contain a low abundance of three additional proteins processed by PilD, the minor pilins PilA, PilB, and PilC. These findings provide the first global biochemical and structural picture of a Gram-positive Tfp and have fundamental implications for our understanding of a widespread class of filamentous nanomachines.
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Affiliation(s)
- Jamie-Lee Berry
- From the Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Ishwori Gurung
- From the Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Jan Haug Anonsen
- the Department of Biological Sciences, Proteomics and Mass Spectrometry Unit, University of Oslo, 0371 Oslo, Norway.,the Department of Biological Sciences, Center for Integrative Microbial Evolution, University of Oslo, 0371 Oslo, Norway
| | - Ingrid Spielman
- the Department of Biology, Brooklyn College of the City University of New York, New York, New York 11210.,The Graduate Center of the City University of New York, New York, New York 10016, and
| | - Elliot Harper
- From the Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Alexander M J Hall
- From the Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Vivianne J Goosens
- From the Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Claire Raynaud
- From the Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Michael Koomey
- the Department of Biological Sciences, Center for Integrative Microbial Evolution, University of Oslo, 0371 Oslo, Norway
| | - Nicolas Biais
- the Department of Biology, Brooklyn College of the City University of New York, New York, New York 11210.,The Graduate Center of the City University of New York, New York, New York 10016, and
| | - Steve Matthews
- the Centre for Structural Biology, Imperial College London, London SW7 2AZ, United Kingdom
| | - Vladimir Pelicic
- From the Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom,
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22
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Oikonomou CM, Jensen GJ. Electron Cryotomography of Bacterial Secretion Systems. Microbiol Spectr 2019; 7:10.1128/microbiolspec.PSIB-0019-2018. [PMID: 30953431 PMCID: PMC6452891 DOI: 10.1128/microbiolspec.psib-0019-2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Indexed: 02/08/2023] Open
Abstract
In biology, function arises from form. For bacterial secretion systems, which often span two membranes, avidly bind to the cell wall, and contain hundreds of individual proteins, studying form is a daunting task, made possible by electron cryotomography (ECT). ECT is the highest-resolution imaging technique currently available to visualize unique objects inside cells, providing a three-dimensional view of the shapes and locations of large macromolecular complexes in their native environment. Over the past 15 years, ECT has contributed to the study of bacterial secretion systems in two main ways: by revealing intact forms for the first time and by mapping components into these forms. Here we highlight some of these contributions, revealing structural convergence in type II secretion systems, structural divergence in type III secretion systems, unexpected structures in type IV secretion systems, and unexpected mechanisms in types V and VI secretion systems. Together, they offer a glimpse into a world of fantastic forms-nanoscale rotors, needles, pumps, and dart guns-much of which remains to be explored.
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Affiliation(s)
- Catherine M. Oikonomou
- Department of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Grant J. Jensen
- Department of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Howard Hughes Medical Institute, Pasadena, CA, USA
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23
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Abstract
Bacterial uptake of DNA through type IV filaments is an essential component of natural competence in numerous gram-positive and gram-negative species. Recent advances in the field have broadened our understanding of the structures used to take up extracellular DNA. Here, we review seminal experiments in the literature describing DNA binding by type IV pili, competence pili and the flp pili of Micrococcus luteus; collectively referred to here as type IV filaments. We compare the current state of the field on mechanisms of DNA uptake for these three appendage systems and describe the current mechanistic understanding of both DNA-binding and DNA-uptake by these versatile molecular machines.
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Affiliation(s)
- Kurt H Piepenbrink
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, United States.,Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, NE, United States.,Nebraska Food for Health Center, University of Nebraska-Lincoln, Lincoln, NE, United States.,Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE, United States
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24
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Structural cycle of the Thermus thermophilus PilF ATPase: the powering of type IVa pilus assembly. Sci Rep 2018; 8:14022. [PMID: 30232337 PMCID: PMC6145873 DOI: 10.1038/s41598-018-32218-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 08/28/2018] [Indexed: 11/20/2022] Open
Abstract
Type IV pili are responsible for a diverse range of functions, including twitching motility and cell adhesion. Assembly of the pilus fiber is driven by a cytoplasmic ATPase: it interacts with an inner membrane complex of biogenesis proteins which, in turn, bind to nascent pilin subunits and mediate fiber assembly. Here we report the structural characterization of the PilF TFP assembly ATPase from Thermus thermophilus. The crystal structure of a recombinant C-terminal fragment of PilF revealed bound, unhydrolysed ATP, although the full length complex was enzymatically active. 3D reconstructions were carried out by single particle cryoelectron microscopy for full length apoprotein PilF and in complex with AMPPNP. The structure forms an hourglass-like shape, with the ATPase domains in one half and the N1 domains in the second half which, we propose, interact with the other pilus biogenesis components. Molecular models for both forms were generated: binding of AMPPNP causes an upward shift of the N1 domains towards the ATPase domains of ~8 Å. We advocate a model in which ATP hydrolysis is linked to displacement of the N1 domains which is associated with lifting pilin subunits out of the inner membrane, and provide the activation energy needed to form the pilus fiber.
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25
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Solanki V, Kapoor S, Thakur KG. Structural insights into the mechanism of Type IVa pilus extension and retraction ATPase motors. FEBS J 2018; 285:3402-3421. [PMID: 30066435 DOI: 10.1111/febs.14619] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 06/26/2018] [Accepted: 07/30/2018] [Indexed: 11/27/2022]
Abstract
Type IVa pili are bacterial appendages involved in diverse physiological processes, including electron transfer in Geobacter sulfurreducens. ATP hydrolysis coupled with conformational changes powers the extension (PilB) and retraction (PilT) motors in the pilus machinery. We report the unliganded crystal structures of the core ATPase domain of PilB and PilT-4 from G. sulfurreducens at 3.1 and 2.6 Å resolution, respectively. PilB structure revealed three distinct conformations, that is, open, closed, and open' which were previously proposed to be mediated by ATP/ADP binding. PilT-4 subunits, on the other hand, were observed in the closed state conformation. We further report that both PilB and PilT-4 hexamers have two high-affinity ATP-binding sites. Comparative structural analysis and solution data presented here supports the "symmetric rotary model" for these ATPase motors. Our data further suggest that pores of these motors rotate either clockwise or counterclockwise to facilitate assembly or disassembly of right-handed or left-handed pilus. DATABASE Structural data are available in the RCSB PDB database under the PDB ID 5ZFQ (PilT-4), 5ZFR (PilB).
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Affiliation(s)
- Vipul Solanki
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh, India
| | - Srajan Kapoor
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh, India
| | - Krishan Gopal Thakur
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh, India
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26
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Chaudhury P, van der Does C, Albers SV. Characterization of the ATPase FlaI of the motor complex of the Pyrococcus furiosus archaellum and its interactions between the ATP-binding protein FlaH. PeerJ 2018; 6:e4984. [PMID: 29938130 PMCID: PMC6011876 DOI: 10.7717/peerj.4984] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 05/25/2018] [Indexed: 01/09/2023] Open
Abstract
The archaellum, the rotating motility structure of archaea, is best studied in the crenarchaeon Sulfolobus acidocaldarius. To better understand how assembly and rotation of this structure is driven, two ATP-binding proteins, FlaI and FlaH of the motor complex of the archaellum of the euryarchaeon Pyrococcus furiosus, were overexpressed, purified and studied. Contrary to the FlaI ATPase of S. acidocaldarius, which only forms a hexamer after binding of nucleotides, FlaI of P. furiosus formed a hexamer in a nucleotide independent manner. In this hexamer only 2 of the ATP binding sites were available for binding of the fluorescent ATP-analog MANT-ATP, suggesting a twofold symmetry in the hexamer. P. furiosus FlaI showed a 250-fold higher ATPase activity than S. acidocaldarius FlaI. Interaction studies between the isolated N- and C-terminal domains of FlaI showed interactions between the N- and C-terminal domains and strong interactions between the N-terminal domains not previously observed for ATPases involved in archaellum assembly. These interactions played a role in oligomerization and activity, suggesting a conformational state of the hexamer not observed before. Further interaction studies show that the C-terminal domain of PfFlaI interacts with the nucleotide binding protein FlaH. This interaction stimulates the ATPase activity of FlaI optimally at a 1:1 stoichiometry, suggesting that hexameric PfFlaI interacts with hexameric PfFlaH. These data help to further understand the complex interactions that are required to energize the archaellar motor.
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Affiliation(s)
- Paushali Chaudhury
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Freiburg, Germany
| | - Chris van der Does
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Freiburg, Germany
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Freiburg, Germany
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27
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Abstract
In this issue of Structure, Mancl et al. (2016) elucidate the crystal structure of the PilB ATPase domain in complex with ATPγS and unveil how ATP binding and hydrolysis coordinates conformational change. Their results reveal a distinct symmetric rotary mechanism for ATP hydrolysis to power bacterial pilus assembly.
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Affiliation(s)
- Chi-Lin Tsai
- Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - John A Tainer
- Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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28
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Gu S, Shevchik VE, Shaw R, Pickersgill RW, Garnett JA. The role of intrinsic disorder and dynamics in the assembly and function of the type II secretion system. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:1255-1266. [PMID: 28733198 DOI: 10.1016/j.bbapap.2017.07.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/02/2017] [Accepted: 07/17/2017] [Indexed: 10/19/2022]
Abstract
Many Gram-negative commensal and pathogenic bacteria use a type II secretion system (T2SS) to transport proteins out of the cell. These exported proteins or substrates play a major role in toxin delivery, maintaining biofilms, replication in the host and subversion of host immune responses to infection. We review the current structural and functional work on this system and argue that intrinsically disordered regions and protein dynamics are central for assembly, exo-protein recognition, and secretion competence of the T2SS. The central role of intrinsic disorder-order transitions in these processes may be a particular feature of type II secretion.
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Affiliation(s)
- Shuang Gu
- Queen Mary University of London, School of Biological and Chemical Sciences, London E1 4NS, United Kingdom
| | - Vladimir E Shevchik
- Université de Lyon, F-69003, Université Lyon 1, Lyon, F-69622, INSA-Lyon, Villeurbanne F-69621, CNRS, UMR5240, Microbiologie Adaptation et Pathogénie, Lyon F-69622, France
| | - Rosie Shaw
- Queen Mary University of London, School of Biological and Chemical Sciences, London E1 4NS, United Kingdom
| | - Richard W Pickersgill
- Queen Mary University of London, School of Biological and Chemical Sciences, London E1 4NS, United Kingdom.
| | - James A Garnett
- Queen Mary University of London, School of Biological and Chemical Sciences, London E1 4NS, United Kingdom.
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29
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Thomassin JL, Santos Moreno J, Guilvout I, Tran Van Nhieu G, Francetic O. The trans-envelope architecture and function of the type 2 secretion system: new insights raising new questions. Mol Microbiol 2017; 105:211-226. [DOI: 10.1111/mmi.13704] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Jenny-Lee Thomassin
- Department of structural biology and chemistry, Biochemistry of Macromolecular Interactions Unit; Institut Pasteur; 28 rue du Dr Roux 75724 Paris Cedex 15 France
- Centre National de la Recherche Scientifique (CNRS); ERL6002 75724 Paris France
| | - Javier Santos Moreno
- Université Paris Diderot (Paris 7) Sorbonne Paris Cité; Paris France
- Laboratory of Intercellular Communication and Microbial Infections; CIRB, Collège de France; 11 Place Marcelin Berthelot 75005 Paris France
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1050; 75005 Paris France
- Centre National de la Recherche Scientifique (CNRS), UMR7241; 75005 Paris France
- MEMOLIFE Laboratory of Excellence and Paris Sciences et Lettres; 75005 Paris France
| | - Ingrid Guilvout
- Department of structural biology and chemistry, Biochemistry of Macromolecular Interactions Unit; Institut Pasteur; 28 rue du Dr Roux 75724 Paris Cedex 15 France
- Centre National de la Recherche Scientifique (CNRS); ERL6002 75724 Paris France
| | - Guy Tran Van Nhieu
- Laboratory of Intercellular Communication and Microbial Infections; CIRB, Collège de France; 11 Place Marcelin Berthelot 75005 Paris France
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1050; 75005 Paris France
- Centre National de la Recherche Scientifique (CNRS), UMR7241; 75005 Paris France
- MEMOLIFE Laboratory of Excellence and Paris Sciences et Lettres; 75005 Paris France
| | - Olivera Francetic
- Department of structural biology and chemistry, Biochemistry of Macromolecular Interactions Unit; Institut Pasteur; 28 rue du Dr Roux 75724 Paris Cedex 15 France
- Centre National de la Recherche Scientifique (CNRS); ERL6002 75724 Paris France
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30
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McCallum M, Tammam S, Khan A, Burrows LL, Howell PL. The molecular mechanism of the type IVa pilus motors. Nat Commun 2017; 8:15091. [PMID: 28474682 PMCID: PMC5424180 DOI: 10.1038/ncomms15091] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 02/24/2017] [Indexed: 02/05/2023] Open
Abstract
Type IVa pili are protein filaments essential for virulence in many bacterial pathogens; they extend and retract from the surface of bacterial cells to pull the bacteria forward. The motor ATPase PilB powers pilus assembly. Here we report the structures of the core ATPase domains of Geobacter metallireducens PilB bound to ADP and the non-hydrolysable ATP analogue, AMP-PNP, at 3.4 and 2.3 Å resolution, respectively. These structures reveal important differences in nucleotide binding between chains. Analysis of these differences reveals the sequential turnover of nucleotide, and the corresponding domain movements. Our data suggest a clockwise rotation of the central sub-pores of PilB, which through interactions with PilC, would support the assembly of a right-handed helical pilus. Our analysis also suggests a counterclockwise rotation of the C2 symmetric PilT that would enable right-handed pilus disassembly. The proposed model provides insight into how this family of ATPases can power pilus extension and retraction.
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Affiliation(s)
- Matthew McCallum
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8.,Program in Molecular Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4
| | - Stephanie Tammam
- Program in Molecular Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4
| | - Ahmad Khan
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Lori L Burrows
- Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada L8N 3Z5
| | - P Lynne Howell
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8.,Program in Molecular Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4
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31
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Wu Y, Hu K, Li D, Bai L, Yang S, Jastrab JB, Xiao S, Hu Y, Zhang S, Darwin KH, Wang T, Li H. Mycobacterium tuberculosis proteasomal ATPase Mpa has a β-grasp domain that hinders docking with the proteasome core protease. Mol Microbiol 2017; 105:227-241. [PMID: 28419599 DOI: 10.1111/mmi.13695] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2017] [Indexed: 12/21/2022]
Abstract
Mycobacterium tuberculosis (Mtb) has a proteasome system that is essential for its ability to cause lethal infections in mice. A key component of the system is the proteasomal adenosine triphosphatase (ATPase) Mpa, which captures, unfolds, and translocates protein substrates into the Mtb proteasome core particle for degradation. Here, we report the crystal structures of near full-length hexameric Mtb Mpa in apo and ADP-bound forms. Surprisingly, the structures revealed a ubiquitin-like β-grasp domain that precedes the proteasome-activating carboxyl terminus. This domain, which was only found in bacterial proteasomal ATPases, buries the carboxyl terminus of each protomer in the central channel of the hexamer and hinders the interaction of Mpa with the proteasome core protease. Thus, our work reveals the structure of a bacterial proteasomal ATPase in the hexameric form, and the structure finally explains why Mpa is unable to stimulate robust protein degradation in vitro in the absence of other, yet-to-be-identified co-factors.
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Affiliation(s)
- Yujie Wu
- Department of Biology, Southern University of Science and Technology, 1088 Xueyuan Road, Nanshan District, Shenzhen, 518055, China
| | - Kuan Hu
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, MI, 49503, USA.,Biochemistry and Structural Biology Graduate Program, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Defeng Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China
| | - Lin Bai
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Shaoqing Yang
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Jordan B Jastrab
- Department of Microbiology, New York University School of Medicine, 450 East 29th Street, New York, NY, 10016, USA
| | - Shuhao Xiao
- Department of Biology, Southern University of Science and Technology, 1088 Xueyuan Road, Nanshan District, Shenzhen, 518055, China
| | - Yonglin Hu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China
| | - Susan Zhang
- Department of Microbiology, New York University School of Medicine, 450 East 29th Street, New York, NY, 10016, USA
| | - K Heran Darwin
- Department of Microbiology, New York University School of Medicine, 450 East 29th Street, New York, NY, 10016, USA
| | - Tao Wang
- Department of Biology, Southern University of Science and Technology, 1088 Xueyuan Road, Nanshan District, Shenzhen, 518055, China.,SZCDC-SUSTech Joint Key Laboratory for Tropical Diseases, Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, China
| | - Huilin Li
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
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32
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Zhai B, DuPrez K, Doukov TI, Li H, Huang M, Shang G, Ni J, Gu L, Shen Y, Fan L. Structure and Function of a Novel ATPase that Interacts with Holliday Junction Resolvase Hjc and Promotes Branch Migration. J Mol Biol 2017; 429:1009-1029. [PMID: 28238763 PMCID: PMC5565510 DOI: 10.1016/j.jmb.2017.02.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 01/25/2017] [Accepted: 02/19/2017] [Indexed: 11/15/2022]
Abstract
Holliday junction (HJ) is a hallmark intermediate in DNA recombination and must be processed by dissolution (for double HJ) or resolution to ensure genome stability. Although HJ resolvases have been identified in all domains of life, there is a long-standing effort to search in prokaryotes and eukarya for proteins promoting HJ migration. Here, we report the structural and functional characterization of a novel ATPase, Sulfolobus islandicusPilT N-terminal-domain-containing ATPase (SisPINA), encoded by the gene adjacent to the resolvase Hjc coding gene. PINA is conserved in archaea and vital for S. islandicus viability. Purified SisPINA forms hexameric rings in the crystalline state and in solution, similar to the HJ migration helicase RuvB in Gram-negative bacteria. Structural analysis suggests that ATP binding and hydrolysis cause conformational changes in SisPINA to drive branch migration. Further studies reveal that SisPINA interacts with SisHjc and coordinates HJ migration and cleavage.
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Affiliation(s)
- Binyuan Zhai
- State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nan Road, Jinan 250100, PR China
| | - Kevin DuPrez
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
| | - Tzanko I Doukov
- Macromolecular Crystallography Group, Stanford Synchrotron Radiation Light Source, SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94309, USA
| | - Huan Li
- State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nan Road, Jinan 250100, PR China
| | - Mengting Huang
- State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nan Road, Jinan 250100, PR China
| | - Guijun Shang
- State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nan Road, Jinan 250100, PR China
| | - Jinfeng Ni
- State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nan Road, Jinan 250100, PR China
| | - Lichuan Gu
- State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nan Road, Jinan 250100, PR China
| | - Yulong Shen
- State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nan Road, Jinan 250100, PR China.
| | - Li Fan
- Department of Biochemistry, University of California, Riverside, CA 92521, USA.
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33
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Chang YW, Kjær A, Ortega DR, Kovacikova G, Sutherland JA, Rettberg LA, Taylor RK, Jensen GJ. Architecture of the Vibrio cholerae toxin-coregulated pilus machine revealed by electron cryotomography. Nat Microbiol 2017; 2:16269. [PMID: 28165453 PMCID: PMC5302817 DOI: 10.1038/nmicrobiol.2016.269] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 12/14/2016] [Indexed: 01/22/2023]
Affiliation(s)
- Yi-Wei Chang
- California Institute of Technology, Pasadena, California 91125, USA
| | - Andreas Kjær
- University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Davi R Ortega
- California Institute of Technology, Pasadena, California 91125, USA
| | | | - John A Sutherland
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, USA
| | - Lee A Rettberg
- Howard Hughes Medical Institute, Pasadena, California 91125, USA
| | - Ronald K Taylor
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, USA
| | - Grant J Jensen
- California Institute of Technology, Pasadena, California 91125, USA.,Howard Hughes Medical Institute, Pasadena, California 91125, USA
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34
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Attenuation of the Type IV Pilus Retraction Motor Influences Neisseria gonorrhoeae Social and Infection Behavior. mBio 2016; 7:mBio.01994-16. [PMID: 27923924 PMCID: PMC5142622 DOI: 10.1128/mbio.01994-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Retraction of the type IV pilus (Tfp) mediates DNA uptake, motility, and social and infection behavior in a wide variety of prokaryotes. To date, investigations into Tfp retraction-dependent activities have used a mutant deleted of PilT, the ATPase motor protein that causes the pilus fiber to retract. ΔpilT cells are nontransformable, nonmotile, and cannot aggregate into microcolonies. We tested the hypothesis that these retraction-dependent activities are sensitive to the strength of PilT enzymatic activity by using the pathogen Neisseria gonorrhoeae as a model. We constructed an N. gonorrhoeae mutant with an amino acid substitution in the PilT Walker B box (a substitution of cysteine for leucine at position 201, encoded by pilTL201C). Purified PilTL201C forms a native hexamer, but mutant hexamers hydrolyze ATP at half the maximal rate. N. gonorrhoeae pilTL201C cells produce Tfp fibers, crawl at the same speed as the wild-type (wt) parent, and are equally transformable. However, the social behavior of pilTL201C cells is intermediate between the behaviors of wt and ΔpilT cells. The infection behavior of pilTL201C is also defective, due to its failure to activate the epidermal growth factor receptor (EGFR)-heparin-binding EGF-like growth factor (HB-EGF) pathway. Our study indicates that pilus retraction, per se, is not sufficient for N. gonorrhoeae microcolony formation or infectivity; rather, these activities are sensitive to the strength of PilT enzymatic activity. We discuss the implications of these findings for Neisseria pathogenesis in the context of mechanobiology. Type IV pili are fibers expressed on the surface of many bacteria. Neisseria gonorrhoeae cells crawl, take up DNA, and communicate with each other and with human cells by retracting these fibers. Here, we show that an N. gonorrhoeae mutant expressing an enzymatically weakened type IV pilus retraction motor still crawls and takes up DNA normally. However, mutant cells exhibit abnormal social behavior, and they are less infective because they fail to activate the epidermal growth factor receptor. Our study shows that N. gonorrhoeae social and infection behaviors are sensitive to the strength of the retraction motor enzyme.
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35
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Koo J, Lamers R, Rubinstein J, Burrows L, Howell P. Structure of the Pseudomonas aeruginosa Type IVa Pilus Secretin at 7.4 Å. Structure 2016; 24:1778-1787. [DOI: 10.1016/j.str.2016.08.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 07/19/2016] [Accepted: 08/10/2016] [Indexed: 02/06/2023]
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36
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Mancl JM, Black WP, Robinson H, Yang Z, Schubot FD. Crystal Structure of a Type IV Pilus Assembly ATPase: Insights into the Molecular Mechanism of PilB from Thermus thermophilus. Structure 2016; 24:1886-1897. [PMID: 27667690 DOI: 10.1016/j.str.2016.08.010] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 07/21/2016] [Accepted: 08/10/2016] [Indexed: 12/12/2022]
Abstract
Type IV pili (T4P) mediate bacterial motility and virulence. The PilB/GspE family ATPases power the assembly of T4P and type 2 secretion systems. We determined the structure of the ATPase region of PilB (PilBATP) in complex with ATPγS to provide a model of a T4P assembly ATPase and a view of a PilB/GspE family hexamer at better than 3-Å resolution. Spatial positioning and conformations of the protomers suggest a mechanism of force generation. All six PilBATP protomers contain bound ATPγS. Two protomers form a closed conformation poised for ATP hydrolysis. The other four molecules assume an open conformation but separate into two pairs with distinct active-site accessibilities. We propose that one pair represents the post-hydrolysis phase while the other pair appears poised for ADP/ATP exchange. Collectively, the data suggest that T4P assembly is powered by coordinating concurrent substrate binding with ATP hydrolysis across the PilB hexamer.
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Affiliation(s)
- Jordan M Mancl
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, 125 Life Sciences 1 (MC 0910), 970 Washington Street Southwest, Blacksburg, VA 24061, USA
| | - Wesley P Black
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, 125 Life Sciences 1 (MC 0910), 970 Washington Street Southwest, Blacksburg, VA 24061, USA
| | - Howard Robinson
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973-5000, USA
| | - Zhaomin Yang
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, 125 Life Sciences 1 (MC 0910), 970 Washington Street Southwest, Blacksburg, VA 24061, USA
| | - Florian D Schubot
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, 125 Life Sciences 1 (MC 0910), 970 Washington Street Southwest, Blacksburg, VA 24061, USA.
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37
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Rule CS, Patrick M, Camberg JL, Maricic N, Hol WG, Sandkvist M. Zinc coordination is essential for the function and activity of the type II secretion ATPase EpsE. Microbiologyopen 2016; 5:870-882. [PMID: 27168165 PMCID: PMC5061722 DOI: 10.1002/mbo3.376] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 04/05/2016] [Accepted: 04/11/2016] [Indexed: 11/10/2022] Open
Abstract
The type II secretion system Eps in Vibrio cholerae promotes the extracellular transport of cholera toxin and several hydrolytic enzymes and is a major virulence system in many Gram‐negative pathogens which is structurally related to the type IV pilus system. The cytoplasmic ATPase EpsE provides the energy for exoprotein secretion through ATP hydrolysis. EpsE contains a unique metal‐binding domain that coordinates zinc through a tetracysteine motif (CXXCX29CXXC), which is also present in type IV pilus assembly but not retraction ATPases. Deletion of the entire domain or substitution of any of the cysteine residues that coordinate zinc completely abrogates secretion in an EpsE‐deficient strain and has a dominant negative effect on secretion in the presence of wild‐type EpsE. Consistent with the in vivo data, chemical depletion of zinc from purified EpsE hexamers results in loss of in vitro ATPase activity. In contrast, exchanging the residues between the two dicysteines with those from the homologous ATPase XcpR from Pseudomonas aeruginosa does not have a significant impact on EpsE. These results indicate that, although the individual residues in the metal‐binding domain are generally interchangeable, zinc coordination is essential for the activity and function of EpsE.
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Affiliation(s)
- Chelsea S Rule
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Marcella Patrick
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Jodi L Camberg
- Division of Infectious Diseases, Department of Medicine, University of Maryland School of Medicine, Rockville, Maryland
| | - Natalie Maricic
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Wim G Hol
- Department of Biochemistry, Biomolecular Structure Center, University of Washington, Seattle, Washington
| | - Maria Sandkvist
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan.
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38
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EssC: domain structures inform on the elusive translocation channel in the Type VII secretion system. Biochem J 2016; 473:1941-52. [PMID: 27130157 PMCID: PMC4925161 DOI: 10.1042/bcj20160257] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 04/29/2016] [Indexed: 11/30/2022]
Abstract
Structural dissection of EssC, a membrane-bound component of the bacterial Type VII secretion system, reveals two β-sandwich domains at the N-terminus and two ATPase domains at the C-terminus. A structure for the potential pore of the secretion system is proposed. The membrane-bound protein EssC is an integral component of the bacterial Type VII secretion system (T7SS), which is a determinant of virulence in important Gram-positive pathogens. The protein is predicted to consist of an intracellular repeat of forkhead-associated (FHA) domains at the N-terminus, two transmembrane helices and three P-loop-containing ATPase-type domains, D1–D3, forming the C-terminal intracellular segment. We present crystal structures of the N-terminal FHA domains (EssC-N) and a C-terminal fragment EssC-C from Geobacillus thermodenitrificans, encompassing two of the ATPase-type modules, D2 and D3. Module D2 binds ATP with high affinity whereas D3 does not. The EssC-N and EssC-C constructs are monomeric in solution, but the full-length recombinant protein, with a molecular mass of approximately 169 kDa, forms a multimer of approximately 1 MDa. The observation of protomer contacts in the crystal structure of EssC-C together with similarity to the DNA translocase FtsK, suggests a model for a hexameric EssC assembly. Such an observation potentially identifies the key, and to date elusive, component of pore formation required for secretion by this recently discovered secretion system. The juxtaposition of the FHA domains suggests potential for interacting with other components of the secretion system. The structural data were used to guide an analysis of which domains are required for the T7SS machine to function in pathogenic Staphylococcus aureus. The extreme C-terminal ATPase domain appears to be essential for EssC activity as a key part of the T7SS, whereas D2 and FHA domains are required for the production of a stable and functional protein.
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39
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Gold V, Kudryashev M. Recent progress in structure and dynamics of dual-membrane-spanning bacterial nanomachines. Curr Opin Struct Biol 2016; 39:1-7. [PMID: 26995496 DOI: 10.1016/j.sbi.2016.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 02/05/2023]
Abstract
Advances in hard-ware and soft-ware for electron cryo-microscopy and tomography have provided unprecedented structural insights into large protein complexes in bacterial membranes. Tomographic volumes of native complexes in situ, combined with other structural and functional data, reveal functionally important conformational changes. Here, we review recent progress in elucidating the structure and mechanism of dual-membrane-spanning nanomachines involved in bacterial motility, adhesion, pathogenesis and biofilm formation, including the type IV pilus assembly machinery and the type III and VI secretions systems. We highlight how these new structural data shed light on the assembly and action of such machines and discuss future directions for more detailed mechanistic understanding of these massive, fascinating complexes.
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Affiliation(s)
- Vicki Gold
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue Str. 3, 60438 Frankfurt am Main, Germany.
| | - Mikhail Kudryashev
- Max Planck Institute of Biophysics, Max-von-Laue Str. 3, 60438 Frankfurt am Main, Germany; Buchmann Institute for Molecular Life Sciences, Goethe University of Frankfurt, Max-von-Laue Str. 17, 60438 Frankfurt am Main, Germany.
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40
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Chang YW, Rettberg LA, Treuner-Lange A, Iwasa J, Søgaard-Andersen L, Jensen GJ. Architecture of the type IVa pilus machine. Science 2016; 351:aad2001. [PMID: 26965631 DOI: 10.1126/science.aad2001] [Citation(s) in RCA: 259] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 01/13/2016] [Indexed: 12/28/2022]
Abstract
Type IVa pili are filamentous cell surface structures observed in many bacteria. They pull cells forward by extending, adhering to surfaces, and then retracting. We used cryo-electron tomography of intact Myxococcus xanthus cells to visualize type IVa pili and the protein machine that assembles and retracts them (the type IVa pilus machine, or T4PM) in situ, in both the piliated and nonpiliated states, at a resolution of 3 to 4 nanometers. We found that T4PM comprises an outer membrane pore, four interconnected ring structures in the periplasm and cytoplasm, a cytoplasmic disc and dome, and a periplasmic stem. By systematically imaging mutants lacking defined T4PM proteins or with individual proteins fused to tags, we mapped the locations of all 10 T4PM core components and the minor pilins, thereby providing insights into pilus assembly, structure, and function.
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Affiliation(s)
- Yi-Wei Chang
- California Institute of Technology, Pasadena, CA 91125, USA. Howard Hughes Medical Institute, Pasadena, CA 91125, USA
| | - Lee A Rettberg
- Howard Hughes Medical Institute, Pasadena, CA 91125, USA
| | - Anke Treuner-Lange
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Janet Iwasa
- University of Utah, Salt Lake City, UT 84112, USA
| | | | - Grant J Jensen
- California Institute of Technology, Pasadena, CA 91125, USA. Howard Hughes Medical Institute, Pasadena, CA 91125, USA.
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41
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Dunger G, Llontop E, Guzzo CR, Farah CS. The Xanthomonas type IV pilus. Curr Opin Microbiol 2016; 30:88-97. [PMID: 26874963 DOI: 10.1016/j.mib.2016.01.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 01/14/2016] [Accepted: 01/17/2016] [Indexed: 02/07/2023]
Abstract
Type IV pili, a special class of bacterial surface filaments, are key behavioral mediators for many important human pathogens. However, we know very little about the role of these structures in the lifestyles of plant-associated bacteria. Over the past few years, several groups studying the extensive genus of Xanthomonas spp. have gained insights into the roles of played by type IV pili in bacteria-host interactions and pathogenesis, motility, biofilm formation, and interactions with bacteriophages. Protein-protein interaction studies have identified T4P regulators and these, along with structural studies, have begun to reveal some of the possible molecular mechanisms that may control the extension/retraction cycles of these dynamic filaments.
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Affiliation(s)
- German Dunger
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP 05508-000, Brazil
| | - Edgar Llontop
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP 05508-000, Brazil
| | - Cristiane R Guzzo
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes 1374, São Paulo, SP CEP 05508-900, Brazil
| | - Chuck S Farah
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP 05508-000, Brazil.
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42
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Bischof LF, Friedrich C, Harms A, Søgaard-Andersen L, van der Does C. The Type IV Pilus Assembly ATPase PilB of Myxococcus xanthus Interacts with the Inner Membrane Platform Protein PilC and the Nucleotide-binding Protein PilM. J Biol Chem 2016; 291:6946-57. [PMID: 26851283 DOI: 10.1074/jbc.m115.701284] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Indexed: 01/01/2023] Open
Abstract
Type IV pili (T4P) are ubiquitous bacterial cell surface structures, involved in processes such as twitching motility, biofilm formation, bacteriophage infection, surface attachment, virulence, and natural transformation. T4P are assembled by machinery that can be divided into the outer membrane pore complex, the alignment complex that connects components in the inner and outer membrane, and the motor complex in the inner membrane and cytoplasm. Here, we characterize the inner membrane platform protein PilC, the cytosolic assembly ATPase PilB of the motor complex, and the cytosolic nucleotide-binding protein PilM of the alignment complex of the T4P machinery ofMyxococcus xanthus PilC was purified as a dimer and reconstituted into liposomes. PilB was isolated as a monomer and bound ATP in a non-cooperative manner, but PilB fused to Hcp1 ofPseudomonas aeruginosaformed a hexamer and bound ATP in a cooperative manner. Hexameric but not monomeric PilB bound to PilC reconstituted in liposomes, and this binding stimulated PilB ATPase activity. PilM could only be purified when it was stabilized by a fusion with a peptide corresponding to the first 16 amino acids of PilN, supporting an interaction between PilM and PilN(1-16). PilM-N(1-16) was isolated as a monomer that bound but did not hydrolyze ATP. PilM interacted directly with PilB, but only with PilC in the presence of PilB, suggesting an indirect interaction. We propose that PilB interacts with PilC and with PilM, thus establishing the connection between the alignment and the motor complex.
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Affiliation(s)
- Lisa Franziska Bischof
- From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and the Institute of Biology II, Molecular Biology of Archaea, University of Freiburg, D-79104 Freiburg, Germany
| | - Carmen Friedrich
- From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and
| | - Andrea Harms
- From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and
| | - Lotte Søgaard-Andersen
- From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and
| | - Chris van der Does
- From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and the Institute of Biology II, Molecular Biology of Archaea, University of Freiburg, D-79104 Freiburg, Germany
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Gurung I, Spielman I, Davies MR, Lala R, Gaustad P, Biais N, Pelicic V. Functional analysis of an unusual type IV pilus in the Gram-positive Streptococcus sanguinis. Mol Microbiol 2015; 99:380-92. [PMID: 26435398 PMCID: PMC4832360 DOI: 10.1111/mmi.13237] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2015] [Indexed: 12/30/2022]
Abstract
Type IV pili (Tfp), which have been studied extensively in a few Gram‐negative species, are the paradigm of a group of widespread and functionally versatile nano‐machines. Here, we performed the most detailed molecular characterisation of Tfp in a Gram‐positive bacterium. We demonstrate that the naturally competent Streptococcus sanguinis produces retractable Tfp, which like their Gram‐negative counterparts can generate hundreds of piconewton of tensile force and promote intense surface‐associated motility. Tfp power ‘train‐like’ directional motion parallel to the long axis of chains of cells, leading to spreading zones around bacteria grown on plates. However, S. sanguinis
Tfp are not involved in DNA uptake, which is mediated by a related but distinct nano‐machine, and are unusual because they are composed of two pilins in comparable amounts, rather than one as normally seen. Whole genome sequencing identified a locus encoding all the genes involved in Tfp biology in S. sanguinis. A systematic mutational analysis revealed that Tfp biogenesis in S. sanguinis relies on a more basic machinery (only 10 components) than in Gram‐negative species and that a small subset of four proteins dispensable for pilus biogenesis are essential for motility. Intriguingly, one of the piliated mutants that does not exhibit spreading retains microscopic motility but moves sideways, which suggests that the corresponding protein controls motion directionality. Besides establishing S. sanguinis as a useful new model for studying Tfp biology, these findings have important implications for our understanding of these widespread filamentous nano‐machines.
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Affiliation(s)
- Ishwori Gurung
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Ingrid Spielman
- Department of Biology, Brooklyn College of the City University of New York, New York, NY, USA
| | - Mark R Davies
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Rajan Lala
- Department of Biology, Brooklyn College of the City University of New York, New York, NY, USA
| | - Peter Gaustad
- Department of Microbiology, Oslo University Hospital, Oslo, Norway
| | - Nicolas Biais
- Department of Biology, Brooklyn College of the City University of New York, New York, NY, USA
| | - Vladimir Pelicic
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
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Leighton TL, Buensuceso RNC, Howell PL, Burrows LL. Biogenesis of Pseudomonas aeruginosa type IV pili and regulation of their function. Environ Microbiol 2015; 17:4148-63. [PMID: 25808785 DOI: 10.1111/1462-2920.12849] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 03/13/2015] [Accepted: 03/14/2015] [Indexed: 12/27/2022]
Abstract
Type IV pili (T4P) are bacterial virulence factors involved in a wide variety of functions including deoxyribonucleic acid uptake, surface attachment, biofilm formation and twitching motility. While T4P are common surface appendages, the systems that assemble them and the regulation of their function differ between species. Pseudomonas aeruginosa, Neisseria spp. and Myxococcus xanthus are common model systems used to study T4P biology. This review focuses on recent advances in P. aeruginosa T4P structural biology, and the regulatory pathways controlling T4P biogenesis and function.
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Affiliation(s)
- Tiffany L Leighton
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - Ryan N C Buensuceso
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - P Lynne Howell
- Program in Molecular Structure & Function, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Lori L Burrows
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
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45
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Eriksson J, Eriksson OS, Maudsdotter L, Palm O, Engman J, Sarkissian T, Aro H, Wallin M, Jonsson AB. Characterization of motility and piliation in pathogenic Neisseria. BMC Microbiol 2015; 15:92. [PMID: 25925502 PMCID: PMC4449605 DOI: 10.1186/s12866-015-0424-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 04/15/2015] [Indexed: 11/29/2022] Open
Abstract
Background The type IV pili (Tfp) of pathogenic Neisseria (i.e., N. gonorrhoeae and N. meningitidis) are essential for twitching motility. Tfp retraction, which is dependent on the ATPase PilT, generates the forces that move bacteria over surfaces. Neisseria motility has mainly been studied in N. gonorrhoeae whereas the motility of N. meningitidis has not yet been characterized. Results In this work, we analyzed bacterial motility and monitored Tfp retraction using live-cell imaging of freely moving bacteria. We observed that N. meningitidis moved over surfaces at an approximate speed of 1.6 μm/s, whereas N. gonorrhoeae moved with a lower speed (1.0 μm/s). An alignment of the meningococcal and gonococcal pilT promoters revealed a conserved single base pair variation in the −10 promoter element that influence PilT expression. By tracking mutants with altered pilT expression or pilE sequence, we concluded that the difference in motility speed was independent of both. Live-cell imaging using total internal reflection fluorescence microscopy demonstrated that N. gonorrhoeae more often moved with fewer visible retracting filaments when compared to N. meningitidis. Correspondingly, meningococci also displayed a higher level of piliation in transmission electron microscopy. Nevertheless, motile gonococci that had the same number of filaments as N. meningitidis still moved with a lower speed. Conclusions These data reveal differences in both speed and piliation between the pathogenic Neisseria species during twitching motility, suggesting a difference in Tfp-dynamics. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0424-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jens Eriksson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden.
| | - Olaspers Sara Eriksson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden.
| | - Lisa Maudsdotter
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden.
| | - Oskar Palm
- Theoretical Physics, KTH Royal Institute of Technology, Stockholm, Sweden.
| | - Jakob Engman
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden.
| | - Tim Sarkissian
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden.
| | - Helena Aro
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden.
| | - Mats Wallin
- Theoretical Physics, KTH Royal Institute of Technology, Stockholm, Sweden.
| | - Ann-Beth Jonsson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden.
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46
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Affiliation(s)
- Alain Filloux
- Alain Filloux, MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London SW7 2AZ, UK; E-mail:
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47
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Ghosh R, Kumar A, Vaziri A. Type-IV Pilus deformation can explain retraction behavior. PLoS One 2014; 9:e114613. [PMID: 25502696 PMCID: PMC4264779 DOI: 10.1371/journal.pone.0114613] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 11/11/2014] [Indexed: 11/18/2022] Open
Abstract
Polymeric filament like type IV Pilus (TFP) can transfer forces in excess of 100 pN during their retraction before stalling, powering surface translocation(twitching). Single TFP level experiments have shown remarkable nonlinearity in the retraction behavior influenced by the external load as well as levels of PilT molecular motor protein. This includes reversal of motion near stall forces when the concentration of the PilT protein is loweblack significantly. In order to explain this behavior, we analyze the coupling of TFP elasticity and interfacial behavior with PilT kinetics. We model retraction as reaction controlled and elongation as transport controlled process. The reaction rates vary with TFP deformation which is modeled as a compound elastic body consisting of multiple helical strands under axial load. Elongation is controlled by monomer transport which suffer entrapment due to excess PilT in the cell periplasm. Our analysis shows excellent agreement with a host of experimental observations and we present a possible biophysical relevance of model parameters through a mechano-chemical stall force map.
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Affiliation(s)
- Ranajay Ghosh
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts, United States of America
| | - Aloke Kumar
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Ashkan Vaziri
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts, United States of America
- * E-mail:
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48
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Berry JL, Pelicic V. Exceptionally widespread nanomachines composed of type IV pilins: the prokaryotic Swiss Army knives. FEMS Microbiol Rev 2014; 39:134-54. [PMID: 25793961 PMCID: PMC4471445 DOI: 10.1093/femsre/fuu001] [Citation(s) in RCA: 178] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Prokaryotes have engineered sophisticated surface nanomachines that have allowed them to colonize Earth and thrive even in extreme environments. Filamentous machineries composed of type IV pilins, which are associated with an amazing array of properties ranging from motility to electric conductance, are arguably the most widespread since distinctive proteins dedicated to their biogenesis are found in most known species of prokaryotes. Several decades of investigations, starting with type IV pili and then a variety of related systems both in bacteria and archaea, have outlined common molecular and structural bases for these nanomachines. Using type IV pili as a paradigm, we will highlight in this review common aspects and key biological differences of this group of filamentous structures. Using type IV pili as a paradigm, we review common genetic, structural and mechanistic features (many) as well as differences (few) of the exceptionally widespread and functionally versatile prokaryotic nano-machines composed of type IV pilins.
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Affiliation(s)
- Jamie-Lee Berry
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Vladimir Pelicic
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
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49
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Transmission of a signal that synchronizes cell movements in swarms of Myxococcus xanthus. Proc Natl Acad Sci U S A 2014; 111:13105-10. [PMID: 25149859 DOI: 10.1073/pnas.1411925111] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We offer evidence for a signal that synchronizes the behavior of hundreds of Myxococcus xanthus cells in a growing swarm. Swarms are driven to expand by the periodic reversing of direction by members. By using time-lapse photomicroscopy, two organized multicellular elements of the swarm were analyzed: single-layered, rectangular rafts and round, multilayered mounds. Rafts of hundreds of cells with their long axes aligned in parallel enlarge as individual cells from the neighborhood join them from either side. Rafts can also add a second layer piece by piece. By repeating layer additions to a raft and rounding each layer, a regular multilayered mound can be formed. About an hour after a five-layered mound had formed, all of the cells from its top layer descended to the periphery of the fourth layer, both rapidly and synchronously. Following the first synchronized descent and spaced at constant time intervals, a new fifth layer was (re)constructed from fourth-layer cells, in very close proximity to its old position and with a number of cells similar to that before the "explosive" descent. This unexpected series of changes in mound structure can be explained by the spread of a signal that synchronizes the reversals of large groups of individual cells.
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50
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Lu C, Korotkov KV, Hol WGJ. Crystal structure of the full-length ATPase GspE from the Vibrio vulnificus type II secretion system in complex with the cytoplasmic domain of GspL. J Struct Biol 2014; 187:223-235. [PMID: 25092625 DOI: 10.1016/j.jsb.2014.07.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 07/24/2014] [Accepted: 07/25/2014] [Indexed: 11/15/2022]
Abstract
The type II secretion system (T2SS) is present in many Gram-negative bacteria and is responsible for secreting a large number of folded proteins, including major virulence factors, across the outer membrane. The T2SS consists of 11-15 different proteins most of which are present in multiple copies in the assembled secretion machinery. The ATPase GspE, essential for the functioning of the T2SS, contains three domains (N1E, N2E and CTE) of which the N1E domain is associated with the cytoplasmic domain of the inner membrane protein GspL. Here we describe and analyze the structure of the GspE•cyto-GspL complex from Vibrio vulnificus in the presence of an ATP analog, AMPPNP. There are three such ∼83 kDa complexes per asymmetric unit with essentially the same structure. The N2E and CTE domains of a single V. vulnificus GspE subunit adopt a mutual orientation that has not been seen before in any of the previous GspE structures, neither in structures of related ATPases from other secretion systems. This underlines the tremendous conformational flexibility of the T2SS secretion ATPase. Cyto-GspL interacts not only with the N1E domain, but also with the CTE domain and is even in contact with AMPPNP. Moreover, the cyto-GspL domains engage in two types of mutual interactions, resulting in two essentially identical, but crystallographically independent, "cyto-GspL rods" that run throughout the crystal. Very similar rods are present in previous crystals of cyto-GspL and of the N1E•cyto-GspL complex. This arrangement, now seen four times in three entirely different crystal forms, involves contacts between highly conserved residues suggesting a role in the biogenesis or the secretion mechanism or both of the T2SS.
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Affiliation(s)
- Connie Lu
- Department of Biochemistry and Biomolecular Structure Center, University of Washington, Seattle, WA 98195, United States
| | - Konstantin V Korotkov
- Department of Biochemistry and Biomolecular Structure Center, University of Washington, Seattle, WA 98195, United States
| | - Wim G J Hol
- Department of Biochemistry and Biomolecular Structure Center, University of Washington, Seattle, WA 98195, United States.
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