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McCaslin PN, Andersen SE, Icardi CM, Faris R, Steiert B, Smith P, Haider J, Weber MM. Identification and Preliminary Characterization of Novel Type III Secreted Effector Proteins in Chlamydia trachomatis. Infect Immun 2023; 91:e0049122. [PMID: 37347192 PMCID: PMC10353436 DOI: 10.1128/iai.00491-22] [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: 11/19/2022] [Accepted: 05/28/2023] [Indexed: 06/23/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular pathogen that replicates in a host-derived vacuole termed the inclusion. Central to pathogenesis is a type III secretion system that translocates effector proteins into the host cell, which are predicted to play major roles in host cell invasion, nutrient acquisition, and immune evasion. However, until recently, the genetic intractability of C. trachomatis hindered identification and characterization of these important virulence factors. Here, we sought to expand the repertoire of identified effector proteins and confirm they are secreted during C. trachomatis infection. Utilizing bioinformatics, we identified 18 candidate substrates that had not been previously assessed for secretion, of which we show four to be secreted, using Yersinia pseudotuberculosis as a surrogate host. Using adenylate cyclase (CyaA), BlaM, and glycogen synthase kinase (GSK) secretion assays, we identified nine novel substrates that were secreted in at least one assay. Interestingly, only three of the substrates, shown to be translocated by C. trachomatis, were similarly secreted by Y. pseudotuberculosis. Using large-scale screens to determine subcellular localization and identify effectors that perturb crucial host cell processes, we identified one novel substrate, CT392, that is toxic when heterologously expressed in Saccharomyces cerevisiae. Toxicity required both the N- and C-terminal regions of the protein. Additionally, we show that these newly described substrates traffic to distinct host cell compartments, including vesicles and the cytoplasm. Collectively, our study expands the known repertoire of C. trachomatis secreted factors and highlights the importance of testing for secretion in the native host using multiple secretion assays when possible.
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Affiliation(s)
- Paige N. McCaslin
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Shelby E. Andersen
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Carolina M. Icardi
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Robert Faris
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Brianna Steiert
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Parker Smith
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Jawad Haider
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Mary M. Weber
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
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Functional Characterization of Non-Ankyrin Repeat Domains of Orientia tsutsugamushi Ank Effectors Reveals Their Importance for Molecular Pathogenesis. Infect Immun 2022; 90:e0062821. [PMID: 35435726 DOI: 10.1128/iai.00628-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Orientia tsutsugamushi is a genetically intractable obligate intracellular bacterium, causes scrub typhus, and has one of the largest known armamentariums of ankyrin repeat-containing effectors (Anks). Most have a C-terminal F-box presumed to interact with the SCF ubiquitin ligase complex primarily based on their ability to bind overexpressed Skp1. Whether all F-box-containing Anks bind endogenous SCF components and the F-box residues essential for such interactions has gone unexplored. Many O. tsutsugamushi Ank F-boxes occur as part of a PRANC (pox protein repeats of ankyrin-C-terminal) domain. Roles of the non-F-box portion of the PRANC and intervening sequence region (ISR) that links the ankyrin repeat and F-box/PRANC domains are unknown. The functional relevance of these effectors' non-ankyrin repeat domains was investigated. The F-box was necessary for Flag-tagged versions of most F-box-containing Anks to precipitate endogenous Skp1, Cul1, and/or Rbx1, while the ISR and PRANC were dispensable. Ank toxicity in yeast was predominantly F-box dependent. Interrogations of Ank1, Ank5, and Ank6 established that L1, P2, E4, I9, and D17 of the F-box consensus are key for binding native SCF components and for Ank1 and Ank6 to inhibit NF-κB. The ISR is also essential for Ank1 and Ank6 to impair NF-κB. Ectopically expressed Ank1 and Ank6 lacking the ISR or having a mutagenized F-box incapable of binding SCF components performed as dominant-negative inhibitors to block O. tsutsugamushi NF-κB modulation. This study advances knowledge of O. tsutsugamushi Ank functional domains and offers an approach for validating their roles in infection.
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Faris R, McCullough A, Andersen SE, Moninger TO, Weber MM. The Chlamydia trachomatis secreted effector TmeA hijacks the N-WASP-ARP2/3 actin remodeling axis to facilitate cellular invasion. PLoS Pathog 2020; 16:e1008878. [PMID: 32946535 PMCID: PMC7526919 DOI: 10.1371/journal.ppat.1008878] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 09/30/2020] [Accepted: 08/12/2020] [Indexed: 11/19/2022] Open
Abstract
As an obligate intracellular pathogen, host cell invasion is paramount to Chlamydia trachomatis proliferation. While the mechanistic underpinnings of this essential process remain ill-defined, it is predicted to involve delivery of prepackaged effector proteins into the host cell that trigger plasma membrane remodeling and cytoskeletal reorganization. The secreted effector proteins TmeA and TarP, have risen to prominence as putative key regulators of cellular invasion and bacterial pathogenesis. Although several studies have begun to unravel molecular details underlying the putative function of TarP, the physiological function of TmeA during host cell invasion is unknown. Here, we show that TmeA employs molecular mimicry to bind to the GTPase binding domain of N-WASP, which results in recruitment of the actin branching ARP2/3 complex to the site of chlamydial entry. Electron microscopy revealed that TmeA mutants are deficient in filopodia capture, suggesting that TmeA/N-WASP interactions ultimately modulate host cell plasma membrane remodeling events necessary for chlamydial entry. Importantly, while both TmeA and TarP are necessary for effective host cell invasion, we show that these effectors target distinct pathways that ultimately converge on activation of the ARP2/3 complex. In line with this observation, we show that a double mutant suffers from a severe entry defect nearly identical to that observed when ARP3 is chemically inhibited or knocked down. Collectively, our study highlights both TmeA and TarP as essential regulators of chlamydial invasion that modulate the ARP2/3 complex through distinct signaling platforms, resulting in plasma membrane remodeling events that are essential for pathogen uptake.
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Affiliation(s)
- Robert Faris
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Alix McCullough
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Shelby E. Andersen
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Thomas O. Moninger
- Central Microscopy Research Facility, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Mary M. Weber
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
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Dresler J, Klimentova J, Pajer P, Salovska B, Fucikova AM, Chmel M, Schmoock G, Neubauer H, Mertens-Scholz K. Quantitative Proteome Profiling of Coxiella burnetii Reveals Major Metabolic and Stress Differences Under Axenic and Cell Culture Cultivation. Front Microbiol 2019; 10:2022. [PMID: 31620097 PMCID: PMC6759588 DOI: 10.3389/fmicb.2019.02022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/19/2019] [Indexed: 12/14/2022] Open
Abstract
Coxiella burnetii is the causative agent of the zoonotic disease Q fever. To date, the lipopolysaccharide (LPS) is the only defined and characterized virulence determinant of C. burnetii. In this study, proteome profiles of C. burnetii Nine Mile phase I (RSA 493, NMI) and its isogenic Nine Mile phase II (RSA 439 NMII) isolate with a deep rough LPS were compared on L-929 mouse fibroblasts and in complex (ACCM-2), and defined (ACCM-D) media. Whole proteome extracts were analyzed using a label-free quantification approach. Between 659 and 1,046 C. burnetii proteins of the 2,132 annotated coding sequences (CDS) were identified in any particular experiment. Proteome profiles clustered according to the cultivation conditions used, indicating different regulation patterns. NMI proteome profiles compared to NMII in ACCM-D indicate transition from an exponential to a stationary phase. The levels of regulatory proteins such as RpoS, CsrA2, UspA1, and UspA2 were increased. Comparison of the oxidative stress response of NMI and NMII indicated that ACCM-2 represents a high oxidative stress environment. Expression of peroxidases, superoxide dismutases, as well as thioredoxins was increased for NMI. In contrast, in ACCM-D, only osmoregulation seems to be necessary. Proteome profiles of NMII do not differ and indicate that both axenic media represent similar oxidative stress environments. Deep rough LPS causes changes of the outer membrane stability and fluidity. This might be one reason for the observed differences. Proteins associated with the T4SS and Sec translocon as well as several effector proteins were detectable under all three conditions. Interestingly, none of these putatively secreted proteins are upregulated in ACCM-2 compared to ACCM-D, and L-929 mouse fibroblasts. Curiously, a higher similarity of proteomic patterns (overlapping up- and downregulated proteins) of ACCM-D and bacteria grown in cell culture was observed. Particularly, the proteins involved in a better adaptation or homeostasis in response to the harsh environment of the parasitophorous vacuole were demonstrated for NMI. This semi-quantitative proteomic analysis of C. burnetii compared axenically grown bacteria to those propagated in cell culture.
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Affiliation(s)
| | - Jana Klimentova
- Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
| | - Petr Pajer
- Military Health Institute, Prague, Czechia
| | - Barbora Salovska
- Department of Genome Integrity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | | | - Martin Chmel
- Department of Infectious Diseases, First Faculty of Medicine, Charles University and Military University Hospital Prague, Prague, Czechia
| | - Gernot Schmoock
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Jena, Germany
| | - Heinrich Neubauer
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Jena, Germany
| | - Katja Mertens-Scholz
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Jena, Germany
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Guo P, Driver D, Zhao Z, Zheng Z, Chan C, Cheng X. Controlling the Revolving and Rotating Motion Direction of Asymmetric Hexameric Nanomotor by Arginine Finger and Channel Chirality. ACS NANO 2019; 13:6207-6223. [PMID: 31067030 PMCID: PMC6595433 DOI: 10.1021/acsnano.8b08849] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Nanomotors in nanotechnology are as important as engines in daily life. Many ATPases are nanoscale biomotors classified into three categories based on the motion mechanisms in transporting substrates: linear, rotating, and the recently discovered revolving motion. Most biomotors adopt a multisubunit ring-shaped structure that hydrolyzes ATP to generate force. How these biomotors control the motion direction and regulate the sequential action of their multiple subunits is intriguing. Many ATPases are hexameric with each monomer containing a conserved arginine finger. This review focuses on recent findings on how the arginine finger controls motion direction and coordinates adjacent subunit interactions in both revolving and rotating biomotors. Mechanisms of intersubunit interactions and sequential movements of individual subunits are evidenced by the asymmetrical appearance of one dimer and four monomers in high-resolution structural complexes. The arginine finger is situated at the interface of two subunits and extends into the ATP binding pocket of the downstream subunit. An arginine finger mutation results in deficiency in ATP binding/hydrolysis, substrate binding, and transport, highlighting the importance of the arginine finger in regulating energy transduction and motor function. Additionally, the roles of channel chirality and channel size are discussed as related to controlling one-way trafficking and differentiating the revolving and rotating mechanisms. Finally, the review concludes by discussing the conformational changes and entropy conversion triggered by ATP binding/hydrolysis, offering a view different from the traditional concept of ATP-mediated mechanochemical energy coupling. The elucidation of the motion mechanism and direction control in ATPases could facilitate nanomotor fabrication in nanotechnology.
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Affiliation(s)
- Peixuan Guo
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
- E-mail:
| | - Dana Driver
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
| | - Zhengyi Zhao
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
| | - Zhen Zheng
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
| | - Chun Chan
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
| | - Xiaolin Cheng
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
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