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Murugan N, Krishnamoorthy R, Khan JM, Gatasheh MK, Malathi J, Madhavan HNR, Ramalingam G, Jayaramana S. Unveiling the ocular battlefield: Insights into Pseudomonas aeruginosa virulence factors and their implications for multidrug resistance. Int J Biol Macromol 2024; 267:131677. [PMID: 38641280 DOI: 10.1016/j.ijbiomac.2024.131677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/13/2024] [Accepted: 04/16/2024] [Indexed: 04/21/2024]
Abstract
The research investigates the virulence factors of Pseudomonas aeruginosa (P. aeruginosa), a pathogen known for its ability to cause human infections by releasing various exoenzymes and virulence factors. Particularly relevant in ocular infections, where tissue degeneration can occur, even after bacterial growth has ceased due to the potential role of secreted proteins/enzymes. Clinical isolates of P. aeruginosa, both ocular (146) and non-ocular (54), were examined to determine the frequency and mechanism of virulence factors. Phenotypic characterization revealed the production of alginate, biofilm, phospholipase C, and alkaline protease, while genotypic testing using internal uniplex PCR identified the presence of Exo U, S, T, Y, and LasB genes. Results showed a significant prevalence of Exo U and Y genes in ocular isolates, a finding unique to Indian studies. Additionally, the study noted that ocular isolates often contained all four secretomes, suggesting a potential link between these factors and ocular infections. These findings contribute to understanding the pathogenesis of P. aeruginosa infections, particularly in ocular contexts, and highlights the importance of comprehensive virulence factor analysis in clinical settings.
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Affiliation(s)
- Nandagopal Murugan
- Department of Microbiology, L & T Microbiology Research Centre, Vision Research Foundation, Sankara Nethralaya, Chennai-6000 06, India; Valluvar Rosalind Diagnostic & Research Lab, Tiruvotriyur, Chennai-600019, India
| | - Rajapandiyan Krishnamoorthy
- Department of Food Science and Nutrition, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Javed Masood Khan
- Department of Food Science and Nutrition, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Mansour K Gatasheh
- Department of Biochemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Jambulingam Malathi
- Department of Microbiology, L & T Microbiology Research Centre, Vision Research Foundation, Sankara Nethralaya, Chennai-6000 06, India; Valluvar Rosalind Diagnostic & Research Lab, Tiruvotriyur, Chennai-600019, India
| | - Hajib Narahari Rao Madhavan
- Department of Microbiology, L & T Microbiology Research Centre, Vision Research Foundation, Sankara Nethralaya, Chennai-6000 06, India; Valluvar Rosalind Diagnostic & Research Lab, Tiruvotriyur, Chennai-600019, India
| | - Gopinath Ramalingam
- Department of Microbiology, Government Theni Medical College and Hospital, Theni, Tamil Nadu-625512, India
| | - Selvaraj Jayaramana
- Centre of Molecular Medicine and Diagnostics (COMManD), Department of Biochemistry, Saveetha Dental College & Hospitals, Saveetha Institute of Medical & Technical Sciences, Saveetha University, Chennai-600077, India.
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Balczon R, Lin MT, Voth S, Nelson AR, Schupp JC, Wagener BM, Pittet JF, Stevens T. Lung endothelium, tau, and amyloids in health and disease. Physiol Rev 2024; 104:533-587. [PMID: 37561137 PMCID: PMC11281824 DOI: 10.1152/physrev.00006.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 06/26/2023] [Accepted: 08/04/2023] [Indexed: 08/11/2023] Open
Abstract
Lung endothelia in the arteries, capillaries, and veins are heterogeneous in structure and function. Lung capillaries in particular represent a unique vascular niche, with a thin yet highly restrictive alveolar-capillary barrier that optimizes gas exchange. Capillary endothelium surveys the blood while simultaneously interpreting cues initiated within the alveolus and communicated via immediately adjacent type I and type II epithelial cells, fibroblasts, and pericytes. This cell-cell communication is necessary to coordinate the immune response to lower respiratory tract infection. Recent discoveries identify an important role for the microtubule-associated protein tau that is expressed in lung capillary endothelia in the host-pathogen interaction. This endothelial tau stabilizes microtubules necessary for barrier integrity, yet infection drives production of cytotoxic tau variants that are released into the airways and circulation, where they contribute to end-organ dysfunction. Similarly, beta-amyloid is produced during infection. Beta-amyloid has antimicrobial activity, but during infection it can acquire cytotoxic activity that is deleterious to the host. The production and function of these cytotoxic tau and amyloid variants are the subject of this review. Lung-derived cytotoxic tau and amyloid variants are a recently discovered mechanism of end-organ dysfunction, including neurocognitive dysfunction, during and in the aftermath of infection.
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Affiliation(s)
- Ron Balczon
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, United States
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Mike T Lin
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, United States
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Sarah Voth
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Monroe, Louisiana, United States
| | - Amy R Nelson
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, United States
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Jonas C Schupp
- Pulmonary and Critical Care Medicine, Department of Internal Medicine, Yale University, New Haven, Connecticut, United States
- Department of Respiratory Medicine, Hannover Medical School, Hannover, Germany
- German Center for Lung Research (DZL), Hannover, Germany
| | - Brant M Wagener
- Department of Anesthesiology and Perioperative Medicine, University of Alabama-Birmingham, Birmingham, Alabama, United States
| | - Jean-Francois Pittet
- Department of Anesthesiology and Perioperative Medicine, University of Alabama-Birmingham, Birmingham, Alabama, United States
| | - Troy Stevens
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, United States
- Department of Internal Medicine, University of South Alabama, Mobile, Alabama, United States
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
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3
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14-3-3 Activated Bacterial Exotoxins AexT and ExoT Share Actin and the SH2 Domains of CRK Proteins as Targets for ADP-Ribosylation. Pathogens 2022; 11:pathogens11121497. [PMID: 36558830 PMCID: PMC9787417 DOI: 10.3390/pathogens11121497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/01/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022] Open
Abstract
Bacterial exotoxins with ADP-ribosyltransferase activity can be divided into distinct clades based on their domain organization. Exotoxins from several clades are known to modify actin at Arg177; but of the 14-3-3 dependent exotoxins only Aeromonas salmonicida exoenzyme T (AexT) has been reported to ADP-ribosylate actin. Given the extensive similarity among the 14-3-3 dependent exotoxins, we initiated a structural and biochemical comparison of these proteins. Structural modeling of AexT indicated a target binding site that shared homology with Pseudomonas aeruginosa Exoenzyme T (ExoT) but not with Exoenzyme S (ExoS). Biochemical analyses confirmed that the catalytic activities of both exotoxins were stimulated by agmatine, indicating that they ADP-ribosylate arginine residues in their targets. Side-by-side comparison of target protein modification showed that AexT had activity toward the SH2 domain of the Crk-like protein (CRKL), a known target for ExoT. We found that both AexT and ExoT ADP-ribosylated actin and in both cases, the modification compromised actin polymerization. Our results indicate that AexT and ExoT are functional homologs that affect cytoskeletal integrity via actin and signaling pathways to the cytoskeleton.
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Obsilova V, Obsil T. Structural insights into the functional roles of 14-3-3 proteins. Front Mol Biosci 2022; 9:1016071. [PMID: 36188227 PMCID: PMC9523730 DOI: 10.3389/fmolb.2022.1016071] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 09/02/2022] [Indexed: 12/02/2022] Open
Abstract
Signal transduction cascades efficiently transmit chemical and/or physical signals from the extracellular environment to intracellular compartments, thereby eliciting an appropriate cellular response. Most often, these signaling processes are mediated by specific protein-protein interactions involving hundreds of different receptors, enzymes, transcription factors, and signaling, adaptor and scaffolding proteins. Among them, 14-3-3 proteins are a family of highly conserved scaffolding molecules expressed in all eukaryotes, where they modulate the function of other proteins, primarily in a phosphorylation-dependent manner. Through these binding interactions, 14-3-3 proteins participate in key cellular processes, such as cell-cycle control, apoptosis, signal transduction, energy metabolism, and protein trafficking. To date, several hundreds of 14-3-3 binding partners have been identified, including protein kinases, phosphatases, receptors and transcription factors, which have been implicated in the onset of various diseases. As such, 14-3-3 proteins are promising targets for pharmaceutical interventions. However, despite intensive research into their protein-protein interactions, our understanding of the molecular mechanisms whereby 14-3-3 proteins regulate the functions of their binding partners remains insufficient. This review article provides an overview of the current state of the art of the molecular mechanisms whereby 14-3-3 proteins regulate their binding partners, focusing on recent structural studies of 14-3-3 protein complexes.
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Affiliation(s)
- Veronika Obsilova
- Institute of Physiology of the Czech Academy of Sciences, Laboratory of Structural Biology of Signaling Proteins, Division BIOCEV, Vestec, Czechia
- *Correspondence: Veronika Obsilova, ; Tomas Obsil,
| | - Tomas Obsil
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Prague, Czechia
- *Correspondence: Veronika Obsilova, ; Tomas Obsil,
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5
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Hardy KS, Tuckey AN, Housley NA, Andrews J, Patel M, Al-Mehdi AB, Barrington RA, Cassel SL, Sutterwala FS, Audia JP. The Pseudomonas aeruginosa Type III Secretion System Exoenzyme Effector ExoU Induces Mitochondrial Damage in a Murine Bone Marrow-Derived Macrophage Infection Model. Infect Immun 2022; 90:e0047021. [PMID: 35130452 PMCID: PMC8929383 DOI: 10.1128/iai.00470-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 01/18/2022] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative, opportunistic pathogen that causes nosocomial pneumonia, urinary tract infections, and bacteremia. A hallmark of P. aeruginosa pathogenesis is disruption of host cell function by the type III secretion system (T3SS) and its cognate exoenzyme effectors. The T3SS effector ExoU is phospholipase A2 (PLA2) that targets the host cell plasmalemmal membrane to induce cytolysis and is an important virulence factor that mediates immune avoidance. In addition, ExoU has been shown to subvert the host inflammatory response in a noncytolytic manner. In primary bone marrow-derived macrophages (BMDMs), P. aeruginosa infection is sensed by the nucleotide-binding domain containing leucine-rich repeats-like receptor 4 (NLRC4) inflammasome, which triggers caspase-1 activation and inflammation. ExoU transiently inhibits NLRC4 inflammasome-mediated activation of caspase-1 and its downstream target, interleukin 1β (IL-1β), to suppress activation of inflammation. In the present study, we sought to identify additional noncytolytic virulence functions for ExoU and discovered an unexpected association between ExoU, host mitochondria, and NLRC4. We show that infection of BMDMs with P. aeruginosa strains expressing ExoU elicited mitochondrial oxidative stress. In addition, mitochondria and mitochondrion-associated membrane fractions enriched from infected cells exhibited evidence of autophagy activation, indicative of damage. The observation that ExoU elicited mitochondrial stress and damage suggested that ExoU may also associate with mitochondria during infection. Indeed, ExoU phospholipase A2 enzymatic activity was present in enriched mitochondria and mitochondrion-associated membrane fractions isolated from P. aeruginosa-infected BMDMs. Intriguingly, enriched mitochondria and mitochondrion-associated membrane fractions isolated from infected Nlrc4 homozygous knockout BMDMs displayed significantly lower levels of ExoU enzyme activity, suggesting that NLRC4 plays a role in the ExoU-mitochondrion association. These observations prompted us to assay enriched mitochondria and mitochondrion-associated membrane fractions for NLRC4, caspase-1, and IL-1β. NLRC4 and pro-caspase-1 were detected in enriched mitochondria and mitochondrion-associated membrane fractions isolated from noninfected BMDMs, and active caspase-1 and active IL-1β were detected in response to P. aeruginosa infection. Interestingly, ExoU inhibited mitochondrion-associated caspase-1 and IL-1β activation. The implications of ExoU-mediated effects on mitochondria and the NLRC4 inflammasome during P. aeruginosa infection are discussed.
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Affiliation(s)
- Kierra S. Hardy
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Amanda N. Tuckey
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Nicole A. Housley
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Joel Andrews
- Mitchell Cancer Institute, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Mita Patel
- Department of Pharmcology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Abu-Bakr Al-Mehdi
- Department of Pharmcology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Robert A. Barrington
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Suzanne L. Cassel
- Women’s Guild Lung Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Fayyaz S. Sutterwala
- Women’s Guild Lung Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Jonathon P. Audia
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
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6
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Hardy KS, Tuckey AN, Renema P, Patel M, Al-Mehdi AB, Spadafora D, Schlumpf CA, Barrington RA, Alexeyev MF, Stevens T, Pittet JF, Wagener BM, Simmons JD, Alvarez DF, Audia JP. ExoU Induces Lung Endothelial Cell Damage and Activates Pro-Inflammatory Caspase-1 during Pseudomonas aeruginosa Infection. Toxins (Basel) 2022; 14:toxins14020152. [PMID: 35202178 PMCID: PMC8878379 DOI: 10.3390/toxins14020152] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/07/2022] [Accepted: 02/11/2022] [Indexed: 12/24/2022] Open
Abstract
The Gram-negative, opportunistic pathogen Pseudomonas aeruginosa utilizes a type III secretion system to inject exoenzyme effectors into a target host cell. Of the four best-studied exoenzymes, ExoU causes rapid cell damage and death. ExoU is a phospholipase A2 (PLA2) that hydrolyses host cell membranes, and P. aeruginosa strains expressing ExoU are associated with poor outcomes in critically ill patients with pneumonia. While the effects of ExoU on lung epithelial and immune cells are well studied, a role for ExoU in disrupting lung endothelial cell function has only recently emerged. Lung endothelial cells maintain a barrier to fluid and protein flux into tissue and airspaces and regulate inflammation. Herein, we describe a pulmonary microvascular endothelial cell (PMVEC) culture infection model to examine the effects of ExoU. Using characterized P. aeruginosa strains and primary clinical isolates, we show that strains expressing ExoU disrupt PMVEC barrier function by causing substantial PMVEC damage and lysis, in a PLA2-dependent manner. In addition, we show that strains expressing ExoU activate the pro-inflammatory caspase-1, in a PLA2-dependent manner. Considering the important roles for mitochondria and oxidative stress in regulating inflammatory responses, we next examined the effects of ExoU on reactive oxygen species production. Infection of PMVECs with P. aeruginosa strains expressing ExoU triggered a robust oxidative stress compared to strains expressing other exoenzyme effectors. We also provide evidence that, intriguingly, ExoU PLA2 activity was detectable in mitochondria and mitochondria-associated membrane fractions isolated from P. aeruginosa-infected PMVECs. Interestingly, ExoU-mediated activation of caspase-1 was partially inhibited by reactive oxygen species scavengers. Together, these data suggest ExoU exerts pleiotropic effects on PMVEC function during P. aeruginosa infection that may inhibit endothelial barrier and inflammatory functions.
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Affiliation(s)
- Kierra S. Hardy
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Amanda N. Tuckey
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
| | - Phoibe Renema
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
- Department of Biomedical Sciences, College of Allied Health, University of South Alabama Mobile, Mobile, AL 36688, USA
| | - Mita Patel
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Abu-Bakr Al-Mehdi
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Domenico Spadafora
- Flow Cytometry Core Lab, College of Medicine, University of South Alabama, Mobile, AL 36688, USA;
| | - Cody A. Schlumpf
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
| | - Robert A. Barrington
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Flow Cytometry Core Lab, College of Medicine, University of South Alabama, Mobile, AL 36688, USA;
| | - Mikhail F. Alexeyev
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Troy Stevens
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Jean-Francois Pittet
- Department of Anesthesiology and Perioperative Medicine, Birmingham School of Medicine, University of Alabama, Birmingham, AL 35294, USA; (J.-F.P.); (B.M.W.)
| | - Brant M. Wagener
- Department of Anesthesiology and Perioperative Medicine, Birmingham School of Medicine, University of Alabama, Birmingham, AL 35294, USA; (J.-F.P.); (B.M.W.)
| | - Jon D. Simmons
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
- Department of Surgery, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Diego F. Alvarez
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
- Department of Physiology and Pharmacology, College of Osteopathic Medicine, Sam Houston State University, Conroe, TX 77304, USA
| | - Jonathon P. Audia
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Correspondence:
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Xu Y, Cheng S, Zeng H, Zhou P, Ma Y, Li L, Liu X, Shao F, Ding J. ARF GTPases activate Salmonella effector SopF to ADP-ribosylate host V-ATPase and inhibit endomembrane damage-induced autophagy. Nat Struct Mol Biol 2022; 29:67-77. [PMID: 35046574 DOI: 10.1038/s41594-021-00710-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 12/02/2021] [Indexed: 12/19/2022]
Abstract
Selective autophagy helps eukaryotes to cope with endogenous dangers or foreign invaders; its initiation often involves membrane damage. By studying a Salmonella effector SopF, we recently identified the vacuolar ATPase (V-ATPase)-ATG16L1 axis that initiates bacteria-induced autophagy. Here we show that SopF is an ADP-ribosyltransferase specifically modifying Gln124 of ATP6V0C in V-ATPase. We identify GTP-bound ADP-ribosylation factor (ARF) GTPases as a cofactor required for SopF functioning. Crystal structures of SopF-ARF1 complexes not only reveal structural basis of SopF ADP-ribosyltransferase activity but also a unique effector-binding mode adopted by ARF GTPases. Further, the N terminus of ARF1, although dispensable for high-affinity binding to SopF, is critical for activating SopF to modify ATP6V0C. Moreover, lysosome or Golgi damage-induced autophagic LC3 activation is inhibited by SopF or Q124A mutation of ATP6V0C, thus also mediated by the V-ATPase-ATG16L1 axis. In this process, the V-ATPase functions to sense membrane damages, which can be uncoupled from its proton-pumping activity.
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Affiliation(s)
- Yue Xu
- National Institute of Biological Sciences, Beijing, China.,Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Sen Cheng
- Institute of Analytical Chemistry and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.,Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Huan Zeng
- National Institute of Biological Sciences, Beijing, China.,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Ping Zhou
- National Institute of Biological Sciences, Beijing, China
| | - Yan Ma
- National Institute of Biological Sciences, Beijing, China
| | - Lin Li
- National Institute of Biological Sciences, Beijing, China
| | - Xiaoyun Liu
- Institute of Analytical Chemistry and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.,Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Feng Shao
- National Institute of Biological Sciences, Beijing, China. .,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China. .,Research Unit of Pyroptosis and Immunity, Chinese Academy of Medical Sciences and National Institute of Biological Sciences, Beijing, China. .,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.
| | - Jingjin Ding
- National Institute of Biological Sciences, Beijing, China. .,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
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8
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Molecular Mechanisms Involved in Pseudomonas aeruginosa Bacteremia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:325-345. [DOI: 10.1007/978-3-031-08491-1_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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9
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Thompson WC, Goldspink PH. 14-3-3 protein regulation of excitation-contraction coupling. Pflugers Arch 2021; 474:267-279. [PMID: 34820713 PMCID: PMC8837530 DOI: 10.1007/s00424-021-02635-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/21/2021] [Accepted: 10/23/2021] [Indexed: 11/25/2022]
Abstract
14-3-3 proteins (14-3-3 s) are a family of highly conserved proteins that regulate many cellular processes in eukaryotes by interacting with a diverse array of client proteins. The 14-3-3 proteins have been implicated in several disease states and previous reviews have condensed the literature with respect to their structure, function, and the regulation of different cellular processes. This review focuses on the growing body of literature exploring the important role 14-3-3 proteins appear to play in regulating the biochemical and biophysical events associated with excitation-contraction coupling (ECC) in muscle. It presents both a timely and unique analysis that seeks to unite studies emphasizing the identification and diversity of 14-3-3 protein function and client protein interactions, as modulators of muscle contraction. It also highlights ideas within these two well-established but intersecting fields that support further investigation with respect to the mechanistic actions of 14-3-3 proteins in the modulation of force generation in muscle.
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Affiliation(s)
- Walter C Thompson
- Department of Physiology and Biophysics (M/C 901) and Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, 835 South Wolcott Avenue, RM E-202, Chicago, IL, 60612, USA
| | - Paul H Goldspink
- Department of Physiology and Biophysics (M/C 901) and Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, 835 South Wolcott Avenue, RM E-202, Chicago, IL, 60612, USA.
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10
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Wagener BM, Hu R, Wu S, Pittet JF, Ding Q, Che P. The Role of Pseudomonas aeruginosa Virulence Factors in Cytoskeletal Dysregulation and Lung Barrier Dysfunction. Toxins (Basel) 2021; 13:776. [PMID: 34822560 PMCID: PMC8625199 DOI: 10.3390/toxins13110776] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/24/2021] [Accepted: 10/28/2021] [Indexed: 12/19/2022] Open
Abstract
Pseudomonas (P.) aeruginosa is an opportunistic pathogen that causes serious infections and hospital-acquired pneumonia in immunocompromised patients. P. aeruginosa accounts for up to 20% of all cases of hospital-acquired pneumonia, with an attributable mortality rate of ~30-40%. The poor clinical outcome of P. aeruginosa-induced pneumonia is ascribed to its ability to disrupt lung barrier integrity, leading to the development of lung edema and bacteremia. Airway epithelial and endothelial cells are important architecture blocks that protect the lung from invading pathogens. P. aeruginosa produces a number of virulence factors that can modulate barrier function, directly or indirectly, through exploiting cytoskeleton networks and intercellular junctional complexes in eukaryotic cells. This review summarizes the current knowledge on P. aeruginosa virulence factors, their effects on the regulation of the cytoskeletal network and associated components, and molecular mechanisms regulating barrier function in airway epithelial and endothelial cells. A better understanding of these processes will help to lay the foundation for new therapeutic approaches against P. aeruginosa-induced pneumonia.
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Affiliation(s)
- Brant M. Wagener
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (B.M.W.); (R.H.); (S.W.); (J.-F.P.); (Q.D.)
- Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Division of Critical Care Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Ruihan Hu
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (B.M.W.); (R.H.); (S.W.); (J.-F.P.); (Q.D.)
- Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Department of Internal Medicine, Guiqian International General Hospital, Guiyang 550024, China
| | - Songwei Wu
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (B.M.W.); (R.H.); (S.W.); (J.-F.P.); (Q.D.)
- Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jean-Francois Pittet
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (B.M.W.); (R.H.); (S.W.); (J.-F.P.); (Q.D.)
- Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Division of Critical Care Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Qiang Ding
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (B.M.W.); (R.H.); (S.W.); (J.-F.P.); (Q.D.)
- Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Pulin Che
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (B.M.W.); (R.H.); (S.W.); (J.-F.P.); (Q.D.)
- Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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11
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Akaki K, Ogata K, Yamauchi Y, Iwai N, Tse KM, Hia F, Mochizuki A, Ishihama Y, Mino T, Takeuchi O. IRAK1-dependent Regnase-1-14-3-3 complex formation controls Regnase-1-mediated mRNA decay. eLife 2021; 10:71966. [PMID: 34636324 PMCID: PMC8553338 DOI: 10.7554/elife.71966] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 10/08/2021] [Indexed: 01/14/2023] Open
Abstract
Regnase-1 is an endoribonuclease crucial for controlling inflammation by degrading mRNAs encoding cytokines and inflammatory mediators in mammals. However, it is unclear how Regnase-1-mediated mRNA decay is controlled in interleukin (IL)-1β- or Toll-like receptor (TLR) ligand-stimulated cells. Here, by analyzing the Regnase-1 interactome, we found that IL-1β or TLR stimulus dynamically induced the formation of Regnase-1-β-transducin repeat-containing protein (βTRCP) complex. Importantly, we also uncovered a novel interaction between Regnase-1 and 14-3-3 in both mouse and human cells. In IL-1R/TLR-stimulated cells, the Regnase-1-14-3-3 interaction is mediated by IRAK1 through a previously uncharacterized C-terminal structural domain. Phosphorylation of Regnase-1 at S494 and S513 is critical for Regnase-1-14-3-3 interaction, while a different set of phosphorylation sites of Regnase-1 is known to be required for the recognition by βTRCP and proteasome-mediated degradation. We found that Regnase-1-14-3-3 and Regnase-1-βTRCP interactions are not sequential events. Rather, 14-3-3 protects Regnase-1 from βTRCP-mediated degradation. On the other hand, 14-3-3 abolishes Regnase-1-mediated mRNA decay by inhibiting Regnase-1-mRNA association. In addition, nuclear-cytoplasmic shuttling of Regnase-1 is abrogated by 14-3-3 interaction. Taken together, the results suggest that a novel inflammation-induced interaction of 14-3-3 with Regnase-1 stabilizes inflammatory mRNAs by sequestering Regnase-1 in the cytoplasm to prevent mRNA recognition.
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Affiliation(s)
- Kotaro Akaki
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan.,Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Kosuke Ogata
- Department of Molecular and Cellular BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yuhei Yamauchi
- Laboratory of Mathematical Biology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Noriki Iwai
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Ka Man Tse
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Fabian Hia
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Atsushi Mochizuki
- Laboratory of Mathematical Biology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Yasushi Ishihama
- Department of Molecular and Cellular BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Takashi Mino
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Osamu Takeuchi
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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12
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Guillory X, Hadrović I, de Vink PJ, Sowislok A, Brunsveld L, Schrader T, Ottmann C. Supramolecular Enhancement of a Natural 14-3-3 Protein Ligand. J Am Chem Soc 2021; 143:13495-13500. [PMID: 34427424 DOI: 10.1021/jacs.1c07095] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Rational design of protein-protein interaction (PPI) inhibitors is challenging. Connecting a general supramolecular protein binder with a specific peptidic ligand provides a novel conceptual approach. Thus, lysine-specific molecular tweezers were conjugated to a peptide-based 14-3-3 ligand and produced a strong PPI inhibitor with 100-fold elevated protein affinity. X-ray crystal structure elucidation of this supramolecular directed assembly provides unique molecular insight into the binding mode and fully aligns with Molecular Dynamics (MD) simulations. This new supramolecular chemical biology concept opens the path to novel chemical tools for studying PPIs.
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Affiliation(s)
- Xavier Guillory
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular System, Eindhoven University of Technology, (TU/e) Den Dolech 2, 5612 AZ Eindhoven, The Netherlands.,Department of Chemistry, University of Duisburg-Essen, Universitätsstraße 7, 45117 Essen, Germany
| | - Inesa Hadrović
- Department of Chemistry, University of Duisburg-Essen, Universitätsstraße 7, 45117 Essen, Germany
| | - Pim J de Vink
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular System, Eindhoven University of Technology, (TU/e) Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Andrea Sowislok
- University Clinics Essen, Experimental Orthopedics and Trauma Surgery, 45147 Essen, Germany
| | - Luc Brunsveld
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular System, Eindhoven University of Technology, (TU/e) Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Thomas Schrader
- Department of Chemistry, University of Duisburg-Essen, Universitätsstraße 7, 45117 Essen, Germany
| | - Christian Ottmann
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular System, Eindhoven University of Technology, (TU/e) Den Dolech 2, 5612 AZ Eindhoven, The Netherlands.,Department of Chemistry, University of Duisburg-Essen, Universitätsstraße 7, 45117 Essen, Germany
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13
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Du J, Wrisberg MKV, Gulen B, Stahl M, Pett C, Hedberg C, Lang K, Schneider S, Itzen A. Rab1-AMPylation by Legionella DrrA is allosterically activated by Rab1. Nat Commun 2021; 12:460. [PMID: 33469029 PMCID: PMC7815794 DOI: 10.1038/s41467-020-20702-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 12/16/2020] [Indexed: 01/29/2023] Open
Abstract
Legionella pneumophila infects eukaryotic cells by forming a replicative organelle - the Legionella containing vacuole. During this process, the bacterial protein DrrA/SidM is secreted and manipulates the activity and post-translational modification (PTM) states of the vesicular trafficking regulator Rab1. As a result, Rab1 is modified with an adenosine monophosphate (AMP), and this process is referred to as AMPylation. Here, we use a chemical approach to stabilise low-affinity Rab:DrrA complexes in a site-specific manner to gain insight into the molecular basis of the interaction between the Rab protein and the AMPylation domain of DrrA. The crystal structure of the Rab:DrrA complex reveals a previously unknown non-conventional Rab-binding site (NC-RBS). Biochemical characterisation demonstrates allosteric stimulation of the AMPylation activity of DrrA via Rab binding to the NC-RBS. We speculate that allosteric control of DrrA could in principle prevent random and potentially cytotoxic AMPylation in the host, thereby perhaps ensuring efficient infection by Legionella.
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Affiliation(s)
- Jiqing Du
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technical University of Munich, Garching, 85748, Germany.,Center for Experimental Medicine, Institute of Biochemistry and Signal Transduction, Universitätsklinikum Hamburg-Eppendorf (UKE), Hamburg, 20246, Germany
| | - Marie-Kristin von Wrisberg
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technical University of Munich, Institute for Advanced Study, Garching, 85748, Germany
| | - Burak Gulen
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technical University of Munich, Garching, 85748, Germany.,Center for Experimental Medicine, Institute of Biochemistry and Signal Transduction, Universitätsklinikum Hamburg-Eppendorf (UKE), Hamburg, 20246, Germany
| | - Matthias Stahl
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technical University of Munich, Garching, 85748, Germany.,Science for Life Laboratory, Department of Oncology-Pathology, Karolinska Institutet, Box 1031, 171 21 Solna, Stockholm, Sweden
| | - Christian Pett
- Chemical Biology Center (KBC), Department of Chemistry, Umeå University, Linnaeus väg 10, 90187, Umeå, Sweden
| | - Christian Hedberg
- Chemical Biology Center (KBC), Department of Chemistry, Umeå University, Linnaeus väg 10, 90187, Umeå, Sweden
| | - Kathrin Lang
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technical University of Munich, Institute for Advanced Study, Garching, 85748, Germany.
| | - Sabine Schneider
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Ludwig-Maximilians-University Munich, München, 81377, Germany.
| | - Aymelt Itzen
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technical University of Munich, Garching, 85748, Germany. .,Center for Experimental Medicine, Institute of Biochemistry and Signal Transduction, Universitätsklinikum Hamburg-Eppendorf (UKE), Hamburg, 20246, Germany. .,Center for Structural Systems Biology (CSSB), University Medical Centre Hamburg-Eppendorf (UKE), Hamburg, Germany.
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14
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Fleiszig SMJ, Kroken AR, Nieto V, Grosser MR, Wan SJ, Metruccio MME, Evans DJ. Contact lens-related corneal infection: Intrinsic resistance and its compromise. Prog Retin Eye Res 2019; 76:100804. [PMID: 31756497 DOI: 10.1016/j.preteyeres.2019.100804] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 11/05/2019] [Accepted: 11/12/2019] [Indexed: 12/20/2022]
Abstract
Contact lenses represent a widely utilized form of vision correction with more than 140 million wearers worldwide. Although generally well-tolerated, contact lenses can cause corneal infection (microbial keratitis), with an approximate annualized incidence ranging from ~2 to ~20 cases per 10,000 wearers, and sometimes resulting in permanent vision loss. Research suggests that the pathogenesis of contact lens-associated microbial keratitis is complex and multifactorial, likely requiring multiple conspiring factors that compromise the intrinsic resistance of a healthy cornea to infection. Here, we outline our perspective of the mechanisms by which contact lens wear sometimes renders the cornea susceptible to infection, focusing primarily on our own research efforts during the past three decades. This has included studies of host factors underlying the constitutive barrier function of the healthy cornea, its response to bacterial challenge when intrinsic resistance is not compromised, pathogen virulence mechanisms, and the effects of contact lens wear that alter the outcome of host-microbe interactions. For almost all of this work, we have utilized the bacterium Pseudomonas aeruginosa because it is the leading cause of lens-related microbial keratitis. While not yet common among corneal isolates, clinical isolates of P. aeruginosa have emerged that are resistant to virtually all currently available antibiotics, leading the United States CDC (Centers for Disease Control) to add P. aeruginosa to its list of most serious threats. Compounding this concern, the development of advanced contact lenses for biosensing and augmented reality, together with the escalating incidence of myopia, could portent an epidemic of vision-threatening corneal infections in the future. Thankfully, technological advances in genomics, proteomics, metabolomics and imaging combined with emerging models of contact lens-associated P. aeruginosa infection hold promise for solving the problem - and possibly life-threatening infections impacting other tissues.
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Affiliation(s)
- Suzanne M J Fleiszig
- School of Optometry, University of California, Berkeley, CA, USA; Graduate Group in Vision Science, University of California, Berkeley, CA, USA; Graduate Groups in Microbiology and Infectious Diseases & Immunity, University of California, Berkeley, CA, USA.
| | - Abby R Kroken
- School of Optometry, University of California, Berkeley, CA, USA
| | - Vincent Nieto
- School of Optometry, University of California, Berkeley, CA, USA
| | | | - Stephanie J Wan
- Graduate Group in Vision Science, University of California, Berkeley, CA, USA
| | | | - David J Evans
- School of Optometry, University of California, Berkeley, CA, USA; College of Pharmacy, Touro University California, Vallejo, CA, USA
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15
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Sawa T, Kinoshita M, Inoue K, Ohara J, Moriyama K. Immunoglobulin for Treating Bacterial Infections: One More Mechanism of Action. Antibodies (Basel) 2019; 8:antib8040052. [PMID: 31684203 PMCID: PMC6963986 DOI: 10.3390/antib8040052] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/17/2019] [Accepted: 10/28/2019] [Indexed: 02/08/2023] Open
Abstract
The mechanisms underlying the effects of immunoglobulins on bacterial infections are thought to involve bacterial cell lysis via complement activation, phagocytosis via bacterial opsonization, toxin neutralization, and antibody-dependent cell-mediated cytotoxicity. Nevertheless, recent advances in the study of the pathogenicity of Gram-negative bacteria have raised the possibility of an association between immunoglobulin and bacterial toxin secretion. Over time, new toxin secretion systems like the type III secretion system have been discovered in many pathogenic Gram-negative bacteria. With this system, the bacterial toxins are directly injected into the cytoplasm of the target cell through a special secretory apparatus without any exposure to the extracellular environment, and therefore with no opportunity for antibodies to neutralize the toxin. However, antibodies against the V-antigen, which is located on the needle-shaped tip of the bacterial secretion apparatus, can inhibit toxin translocation, thus raising the hope that the toxin may be susceptible to antibody targeting. Because multi-drug resistant bacteria are now prevalent, inhibiting this secretion mechanism is an attractive alternative or adjunctive therapy against lethal bacterial infections. Thus, it is not unreasonable to define the blocking effect of anti-V-antigen antibodies as the fifth mechanism for immunoglobulin action against bacterial infections.
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Affiliation(s)
- Teiji Sawa
- Department of Anesthesiology, School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Mao Kinoshita
- Department of Anesthesiology, School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Keita Inoue
- Department of Anesthesiology, School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Junya Ohara
- Department of Anesthesiology, School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Kiyoshi Moriyama
- Department of Anesthesiology, Kyorin University School of Medicine, Tokyo 181-8611, Japan.
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16
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Lindsey AS, Sullivan LM, Housley NA, Koloteva A, King JA, Audia JP, Alvarez DF. Analysis of pulmonary vascular injury and repair during Pseudomonas aeruginosa infection-induced pneumonia and acute respiratory distress syndrome. Pulm Circ 2019; 9:2045894019826941. [PMID: 30632898 PMCID: PMC6388462 DOI: 10.1177/2045894019826941] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Herein we describe lung vascular injury and repair using a rodent model of Pseudomonas aeruginosa pneumonia-induced acute respiratory distress syndrome (ARDS) during: 1) the exudative phase (48-hour survivors) and 2) the reparative/fibro-proliferative phase (1-week survivors). Pneumonia was induced by intratracheal instillation of P. aeruginosa strain PA103, and lung morphology and pulmonary vascular function were determined subsequently. Pulmonary vascular function was assessed in mechanically ventilated animals in vivo (air dead space, PaO2, and lung mechanics) and lung permeability was determined in isolated perfused lungs ex vivo (vascular filtration coefficient and extravascular lung water). At 48 hours post infection, histological analyses demonstrated capillary endothelial disruption, diffuse alveolar damage, perivascular cuffs, and neutrophil influx into lung parenchyma. Infected animals displayed clinical hallmarks of ARDS, including increased vascular permeability, increased dead space, impaired gas exchange, and decreased lung compliance. Overall, the animal infection model recapitulated the morphological and functional changes typically observed in lungs from patients during the exudative phase of ARDS. At 1 week post infection, there was lung histological and pulmonary vascular functional evidence of repair when compared with 48 hours post infection; however, some parameters were still impaired when compared with uninfected controls. Importantly, lungs displayed increased fibrosis and cellular hyperplasia reminiscent of lungs from patients during the fibro-proliferative phase of ARDS. Control, sham inoculated animals showed normal lung histology and function. These data represent the first comprehensive assessment of lung pathophysiology during the exudative and reparative/fibro-proliferative phases of P. aeruginosa pneumonia-induced ARDS, and position this pre-clinical model for use in interventional studies aimed at advancing clinical care.
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Affiliation(s)
- Ashley S Lindsey
- 1 Department of Physiology and Cell Biology, University of South Alabama, Alabama, USA.,2 Department of Microbiology and Immunology, University of South Alabama, Alabama, USA.,3 Center for Lung Biology, University of South Alabama, Alabama, USA
| | - Lydia M Sullivan
- 1 Department of Physiology and Cell Biology, University of South Alabama, Alabama, USA.,3 Center for Lung Biology, University of South Alabama, Alabama, USA
| | - Nicole A Housley
- 2 Department of Microbiology and Immunology, University of South Alabama, Alabama, USA.,3 Center for Lung Biology, University of South Alabama, Alabama, USA
| | - Anna Koloteva
- 3 Center for Lung Biology, University of South Alabama, Alabama, USA
| | - Judy A King
- 4 Department of Pathology and Translational Pathobiology, Louisiana State University Health, Louisiana, USA
| | - Jonathon P Audia
- 2 Department of Microbiology and Immunology, University of South Alabama, Alabama, USA.,3 Center for Lung Biology, University of South Alabama, Alabama, USA
| | - Diego F Alvarez
- 1 Department of Physiology and Cell Biology, University of South Alabama, Alabama, USA.,3 Center for Lung Biology, University of South Alabama, Alabama, USA.,5 University of South Alabama College of Medicine, Alabama, USA
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17
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Belyy A, Santecchia I, Renault L, Bourigault B, Ladant D, Mechold U. The extreme C terminus of the Pseudomonas aeruginosa effector ExoY is crucial for binding to its eukaryotic activator, F-actin. J Biol Chem 2018; 293:19785-19796. [PMID: 30377256 DOI: 10.1074/jbc.ra118.003784] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 10/22/2018] [Indexed: 12/25/2022] Open
Abstract
Bacterial nucleotidyl cyclase toxins are potent virulence factors that upon entry into eukaryotic cells are stimulated by endogenous cofactors to catalyze the production of large amounts of 3'5'-cyclic nucleoside monophosphates. The activity of the effector ExoY from Pseudomonas aeruginosa is stimulated by the filamentous form of actin (F-actin). Utilizing yeast phenotype analysis, site-directed mutagenesis, functional biochemical assays, and confocal microscopy, we demonstrate that the last nine amino acids of the C terminus of ExoY are crucial for the interaction with F-actin and, consequently, for ExoY's enzymatic activity in vitro and toxicity in a yeast model. We observed that isolated C-terminal sequences of P. aeruginosa ExoY that had been fused to a carrier protein bind to F-actin and that synthetic peptides corresponding to the extreme ExoY C terminus inhibit ExoY enzymatic activity in vitro and compete with the full-length enzyme for F-actin binding. Interestingly, we noted that various P. aeruginosa isolates of the PA14 family, including highly virulent strains, harbor ExoY variants with a mutation altering the C terminus of this effector. We found that these naturally occurring ExoY variants display drastically reduced enzymatic activity and toxicity. Our findings shed light on the molecular basis of the ExoY-F-actin interaction, revealing that the extreme C terminus of ExoY is critical for binding to F-actin in target cells and that some P. aeruginosa isolates carry C-terminally mutated, low-activity ExoY variants.
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Affiliation(s)
- Alexander Belyy
- From the Institut Pasteur, CNRS UMR 3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie and
| | - Ignacio Santecchia
- Unité Biologie et Génétique de la Paroi Bactérienne, Département de Microbiologie, 75724 Paris cedex 15, France and
| | - Louis Renault
- the Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Blandine Bourigault
- the Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Daniel Ladant
- From the Institut Pasteur, CNRS UMR 3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie and
| | - Undine Mechold
- From the Institut Pasteur, CNRS UMR 3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie and
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18
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Karlberg T, Hornyak P, Pinto AF, Milanova S, Ebrahimi M, Lindberg M, Püllen N, Nordström A, Löverli E, Caraballo R, Wong EV, Näreoja K, Thorsell AG, Elofsson M, De La Cruz EM, Björkegren C, Schüler H. 14-3-3 proteins activate Pseudomonas exotoxins-S and -T by chaperoning a hydrophobic surface. Nat Commun 2018; 9:3785. [PMID: 30224724 PMCID: PMC6141617 DOI: 10.1038/s41467-018-06194-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 08/15/2018] [Indexed: 12/11/2022] Open
Abstract
Pseudomonas are a common cause of hospital-acquired infections that may be lethal. ADP-ribosyltransferase activities of Pseudomonas exotoxin-S and -T depend on 14-3-3 proteins inside the host cell. By binding in the 14-3-3 phosphopeptide binding groove, an amphipathic C-terminal helix of ExoS and ExoT has been thought to be crucial for their activation. However, crystal structures of the 14-3-3β:ExoS and -ExoT complexes presented here reveal an extensive hydrophobic interface that is sufficient for complex formation and toxin activation. We show that C-terminally truncated ExoS ADP-ribosyltransferase domain lacking the amphipathic binding motif is active when co-expressed with 14-3-3. Moreover, swapping the amphipathic C-terminus with a fragment from Vibrio Vis toxin creates a 14-3-3 independent toxin that ADP-ribosylates known ExoS targets. Finally, we show that 14-3-3 stabilizes ExoS against thermal aggregation. Together, this indicates that 14-3-3 proteins activate exotoxin ADP-ribosyltransferase domains by chaperoning their hydrophobic surfaces independently of the amphipathic C-terminal segment. The cellular toxicity of Pseudomonas exotoxin-S and -T depends on their activation by 14-3-3 but the underlying molecular mechanism is not fully understood. Here, the authors show that a previously unrecognized 14-3-3:exotoxin binding interface is sufficient for complex formation and toxin activation.
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Affiliation(s)
- Tobias Karlberg
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 4c, 14157, Huddinge, Sweden
| | - Peter Hornyak
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 4c, 14157, Huddinge, Sweden
| | - Ana Filipa Pinto
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 4c, 14157, Huddinge, Sweden
| | - Stefina Milanova
- Department of Cellular and Molecular Biology, Karolinska Institutet, Berzelius väg 35, 17165, Solna, Sweden
| | - Mahsa Ebrahimi
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 4c, 14157, Huddinge, Sweden
| | - Mikael Lindberg
- Protein Expertise Platform, Umeå University, Kemihuset, 90187, Umeå, Sweden
| | - Nikolai Püllen
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 4c, 14157, Huddinge, Sweden
| | - Axel Nordström
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 4c, 14157, Huddinge, Sweden
| | - Elinor Löverli
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 4c, 14157, Huddinge, Sweden
| | - Rémi Caraballo
- Department of Chemistry, Umeå University, Kemihuset, 90187, Umeå, Sweden
| | - Emily V Wong
- Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA.,University of California, San Francisco Medical School, Department of Biochemistry and Biophysics, San Francisco, CA, 94158, USA
| | - Katja Näreoja
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 4c, 14157, Huddinge, Sweden
| | - Ann-Gerd Thorsell
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 4c, 14157, Huddinge, Sweden
| | - Mikael Elofsson
- Department of Chemistry, Umeå University, Kemihuset, 90187, Umeå, Sweden
| | - Enrique M De La Cruz
- Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Camilla Björkegren
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 4c, 14157, Huddinge, Sweden.,Department of Cellular and Molecular Biology, Karolinska Institutet, Berzelius väg 35, 17165, Solna, Sweden
| | - Herwig Schüler
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 4c, 14157, Huddinge, Sweden.
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19
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The Eukaryotic Host Factor 14-3-3 Inactivates Adenylate Cyclase Toxins of Bordetella bronchiseptica and B. parapertussis, but Not B. pertussis. mBio 2018; 9:mBio.00628-18. [PMID: 30154257 PMCID: PMC6113625 DOI: 10.1128/mbio.00628-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Bordetella pertussis, Bordetella bronchiseptica, and Bordetella parapertussis share highly homologous virulence factors and commonly cause respiratory infections in mammals; however, their host specificities and disease severities differ, and the reasons for this remain largely unknown. Adenylate cyclase toxin (CyaA) is a homologous virulence factor that is thought to play crucial roles in Bordetella infections. We herein demonstrate that CyaAs function as virulence factors differently between B. bronchiseptica/B. parapertussis and B. pertussis. B. bronchiseptica CyaA bound to target cells, and its enzyme domain was translocated into the cytosol similarly to B. pertussis CyaA. The hemolytic activity of B. bronchiseptica CyaA on sheep erythrocytes was also preserved. However, in nucleated target cells, B. bronchiseptica CyaA was phosphorylated at Ser375, which constitutes a motif (RSXpSXP [pS is phosphoserine]) recognized by the host factor 14-3-3, resulting in the abrogation of adenylate cyclase activity. Consequently, the cytotoxic effects of B. bronchiseptica CyaA based on its enzyme activity were markedly attenuated. B. parapertussis CyaA carries the 14-3-3 motif, indicating that its intracellular enzyme activity is abrogated similarly to B. bronchiseptica CyaA; however, B. pertussis CyaA has Phe375 instead of Ser, and thus, was not affected by 14-3-3. In addition, B. pertussis CyaA impaired the barrier function of epithelial cells, whereas B. bronchiseptica CyaA did not. Rat infection experiments suggested that functional differences in CyaA are related to differences in pathogenicity between B. bronchiseptica/B. parapertussis and B. pertussis. Bordetella pertussis, B. bronchiseptica, and B. parapertussis are bacterial respiratory pathogens that are genetically close to each other and produce many homologous virulence factors; however, their host specificities and disease severities differ, and the reasons for this remain unknown. Previous studies attempted to explain these differences by the distinct virulence factors produced by each Bordetella species. In contrast, we indicated functional differences in adenylate cyclase toxin, a homologous virulence factor of Bordetella. The toxins of B. bronchiseptica and presumably B. parapertussis were inactivated by the host factor 14-3-3 after phosphorylation in target cells, whereas the B. pertussis toxin was not inactivated because of the lack of the phosphorylation site. This is the first study to show that 14-3-3 inactivates the virulence factors of pathogens. The present results suggest that pathogenic differences in Bordetella are attributed to the different activities of adenylate cyclase toxins.
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20
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Gerber KJ, Squires KE, Hepler JR. 14-3-3γ binds regulator of G protein signaling 14 (RGS14) at distinct sites to inhibit the RGS14:Gα i-AlF 4- signaling complex and RGS14 nuclear localization. J Biol Chem 2018; 293:14616-14631. [PMID: 30093406 DOI: 10.1074/jbc.ra118.002816] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 07/23/2018] [Indexed: 11/06/2022] Open
Abstract
Regulator of G protein signaling 14 (RGS14) is a multifunctional brain scaffolding protein that integrates G protein and Ras/ERK signaling pathways. It is also a nucleocytoplasmic shuttling protein. RGS14 binds active Gαi/o via its RGS domain, Raf and active H-Ras-GTP via its R1 Ras-binding domain (RBD), and inactive Gαi1/3 via its G protein regulatory (GPR) domain. RGS14 suppresses long-term potentiation (LTP) in the CA2 region of the hippocampus, thereby regulating hippocampally based learning and memory. The 14-3-3 family of proteins is necessary for hippocampal LTP and associative learning and memory. Here, we show direct interaction between RGS14 and 14-3-3γ at two distinct sties, one phosphorylation-independent and the other phosphorylation-dependent at Ser-218 that is markedly potentiated by signaling downstream of active H-Ras. Using bioluminescence resonance energy transfer (BRET), we show that the pSer-218-dependent RGS14/14-3-3γ interaction inhibits active Gαi1-AlF4- binding to the RGS domain of RGS14 but has no effect on active H-Ras and inactive Gαi1-GDP binding to RGS14. By contrast, the phosphorylation-independent binding of 14-3-3 has no effect on RGS14/Gαi interactions but, instead, inhibits (directly or indirectly) RGS14 nuclear import and nucleocytoplasmic shuttling. Together, our findings describe a novel mechanism of negative regulation of RGS14 functions, specifically interactions with active Gαi and nuclear import, while leaving the function of other RGS14 domains intact. Ongoing studies will further elucidate the physiological function of this interaction between RGS14 and 14-3-3γ, providing insight into the functions of both RGS14 and 14-3-3 in their roles in modulating synaptic plasticity in the hippocampus.
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Affiliation(s)
- Kyle J Gerber
- From the Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Katherine E Squires
- From the Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - John R Hepler
- From the Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322
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21
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The Impact of ExoS on Pseudomonas aeruginosa Internalization by Epithelial Cells Is Independent of fleQ and Correlates with Bistability of Type Three Secretion System Gene Expression. mBio 2018; 9:mBio.00668-18. [PMID: 29717012 PMCID: PMC5930308 DOI: 10.1128/mbio.00668-18] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Pseudomonas aeruginosa is internalized into multiple types of epithelial cell in vitro and in vivo and yet is often regarded as an exclusively extracellular pathogen. Paradoxically, ExoS, a type three secretion system (T3SS) effector, has antiphagocytic activities but is required for intracellular survival of P. aeruginosa and its occupation of bleb niches in epithelial cells. Here, we addressed mechanisms for this dichotomy using invasive (ExoS-expressing) P. aeruginosa and corresponding effector-null isogenic T3SS mutants, effector-null mutants of cytotoxic P. aeruginosa with and without ExoS transformation, antibiotic exclusion assays, and imaging using a T3SS-GFP reporter. Except for effector-null PA103, all strains were internalized while encoding ExoS. Intracellular bacteria showed T3SS activation that continued in replicating daughter cells. Correcting the fleQ mutation in effector-null PA103 promoted internalization by >10-fold with or without ExoS. Conversely, mutating fleQ in PAO1 reduced internalization by >10-fold, also with or without ExoS. Effector-null PA103 remained less well internalized than PAO1 matched for fleQ status, but only with ExoS expression, suggesting additional differences between these strains. Quantifying T3SS activation using GFP fluorescence and quantitative reverse transcription-PCR (qRT-PCR) showed that T3SS expression was hyperinducible for strain PA103ΔexoUT versus other isolates and was unrelated to fleQ status. These findings support the principle that P. aeruginosa is not exclusively an extracellular pathogen, with internalization influenced by the relative proportions of T3SS-positive and T3SS-negative bacteria in the population during host cell interaction. These data also challenge current thinking about T3SS effector delivery into host cells and suggest that T3SS bistability is an important consideration in studying P. aeruginosa pathogenesis. P. aeruginosa is often referred to as an extracellular pathogen, despite its demonstrated capacity to invade and survive within host cells. Fueling the confusion, P. aeruginosa encodes T3SS effectors with anti-internalization activity that, paradoxically, play critical roles in intracellular survival. Here, we sought to address why ExoS does not prevent internalization of the P. aeruginosa strains that natively encode it. Results showed that ExoS exerted unusually strong anti-internalization activity under conditions of expression in the effector-null background of strain PA103, often used to study T3SS effector activity. Inhibition of internalization was associated with T3SS hyperinducibility and ExoS delivery. PA103 fleQ mutation, preventing flagellar assembly, further reduced internalization but did so independently of ExoS. The results revealed intracellular T3SS expression by all strains and suggested that T3SS bistability influences P. aeruginosa internalization. These findings reconcile controversies in the literature surrounding P. aeruginosa internalization and support the principle that P. aeruginosa is not exclusively an extracellular pathogen.
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22
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Abstract
ExoU is a type III-secreted cytotoxin expressing A2 phospholipase activity when injected into eukaryotic target cells by the bacterium Pseudomonas aeruginosa The enzymatic activity of ExoU is undetectable in vitro unless ubiquitin, a required cofactor, is added to the reaction. The role of ubiquitin in facilitating ExoU enzymatic activity is poorly understood but of significance for designing inhibitors to prevent tissue injury during infections with strains of P. aeruginosa producing this toxin. Most ubiquitin-binding proteins, including ExoU, demonstrate a low (micromolar) affinity for monoubiquitin (monoUb). Additionally, ExoU is a large and dynamic protein, limiting the applicability of traditional structural techniques such as NMR and X-ray crystallography to define this protein-protein interaction. Recent advancements in computational methods, however, have allowed high-resolution protein modeling using sparse data. In this study, we combine double electron-electron resonance (DEER) spectroscopy and Rosetta modeling to identify potential binding interfaces of ExoU and monoUb. The lowest-energy scoring model was tested using biochemical, biophysical, and biological techniques. To verify the binding interface, Rosetta was used to design a panel of mutations to modulate binding, including one variant with enhanced binding affinity. Our analyses show the utility of computational modeling when combined with sensitive biological assays and biophysical approaches that are exquisitely suited for large dynamic proteins.
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23
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ExoY, an actin-activated nucleotidyl cyclase toxin from P. aeruginosa: A minireview. Toxicon 2017; 149:65-71. [PMID: 29258848 DOI: 10.1016/j.toxicon.2017.12.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 11/23/2022]
Abstract
ExoY is one of four well-characterized Pseudomonas aeruginosa type 3 secretion system (T3SS) effectors. It is a nucleotidyl cyclase toxin that is inactive inside the bacteria, but becomes potently activated once it is delivered into the eukaryotic target cells. Recently, filamentous actin was identified as the eukaryotic cofactor that stimulates specifically ExoY enzymatic activity by several orders of magnitude. In this review, we discuss recent advances in understanding the biochemistry of nucleotidyl cyclase activity of ExoY and its regulation by interaction with filamentous actin.
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24
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Stevers LM, Sijbesma E, Botta M, MacKintosh C, Obsil T, Landrieu I, Cau Y, Wilson AJ, Karawajczyk A, Eickhoff J, Davis J, Hann M, O'Mahony G, Doveston RG, Brunsveld L, Ottmann C. Modulators of 14-3-3 Protein-Protein Interactions. J Med Chem 2017; 61:3755-3778. [PMID: 28968506 PMCID: PMC5949722 DOI: 10.1021/acs.jmedchem.7b00574] [Citation(s) in RCA: 184] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
![]()
Direct
interactions between proteins are essential for the regulation
of their functions in biological pathways. Targeting the complex network
of protein–protein interactions (PPIs) has now been widely
recognized as an attractive means to therapeutically intervene in
disease states. Even though this is a challenging endeavor and PPIs
have long been regarded as “undruggable” targets, the
last two decades have seen an increasing number of successful examples
of PPI modulators, resulting in growing interest in this field. PPI
modulation requires novel approaches and the integrated efforts of
multiple disciplines to be a fruitful strategy. This perspective focuses
on the hub-protein 14-3-3, which has several hundred identified protein
interaction partners, and is therefore involved in a wide range of
cellular processes and diseases. Here, we aim to provide an integrated
overview of the approaches explored for the modulation of 14-3-3 PPIs
and review the examples resulting from these efforts in both inhibiting
and stabilizing specific 14-3-3 protein complexes by small molecules,
peptide mimetics, and natural products.
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Affiliation(s)
- Loes M Stevers
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems (ICMS) , Eindhoven University of Technology , P.O. Box 513, 5600 MB , Eindhoven , The Netherlands
| | - Eline Sijbesma
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems (ICMS) , Eindhoven University of Technology , P.O. Box 513, 5600 MB , Eindhoven , The Netherlands
| | - Maurizio Botta
- Department of Biotechnology, Chemistry and Pharmacy , University of Siena , Via Aldo Moro 2 , 53100 Siena , Italy
| | - Carol MacKintosh
- Division of Cell and Developmental Biology, School of Life Sciences , University of Dundee , Dundee DD1 4HN , United Kingdom
| | - Tomas Obsil
- Department of Physical and Macromolecular Chemistry, Faculty of Science , Charles University , Prague 116 36 , Czech Republic
| | | | - Ylenia Cau
- Department of Biotechnology, Chemistry and Pharmacy , University of Siena , Via Aldo Moro 2 , 53100 Siena , Italy
| | - Andrew J Wilson
- School of Chemistry , University of Leeds , Woodhouse Lane , Leeds LS2 9JT , United Kingdom.,Astbury Center For Structural Molecular Biology , University of Leeds , Woodhouse Lane , Leeds LS2 9JT , United Kingdom
| | | | - Jan Eickhoff
- Lead Discovery Center GmbH , Dortmund 44227 , Germany
| | - Jeremy Davis
- UCB Celltech , 216 Bath Road , Slough SL1 3WE , United Kingdom
| | - Michael Hann
- GlaxoSmithKline , Gunnels Wood Road , Stevenage, Hertfordshire SG1 2NY , United Kingdom
| | - Gavin O'Mahony
- Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit , AstraZeneca Gothenburg , Pepparedsleden 1 , SE-431 83 Mölndal , Sweden
| | - Richard G Doveston
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems (ICMS) , Eindhoven University of Technology , P.O. Box 513, 5600 MB , Eindhoven , The Netherlands
| | - Luc Brunsveld
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems (ICMS) , Eindhoven University of Technology , P.O. Box 513, 5600 MB , Eindhoven , The Netherlands
| | - Christian Ottmann
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems (ICMS) , Eindhoven University of Technology , P.O. Box 513, 5600 MB , Eindhoven , The Netherlands.,Department of Chemistry , University of Duisburg-Essen , Universitätstraße 7 , 45141 Essen , Germany
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25
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Cornell B, Toyo-Oka K. 14-3-3 Proteins in Brain Development: Neurogenesis, Neuronal Migration and Neuromorphogenesis. Front Mol Neurosci 2017; 10:318. [PMID: 29075177 PMCID: PMC5643407 DOI: 10.3389/fnmol.2017.00318] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/19/2017] [Indexed: 11/13/2022] Open
Abstract
The 14-3-3 proteins are a family of highly conserved, multifunctional proteins that are highly expressed in the brain during development. Cumulatively, the seven 14-3-3 isoforms make up approximately 1% of total soluble brain protein. Over the last decade, evidence has accumulated implicating the importance of the 14-3-3 protein family in the development of the nervous system, in particular cortical development, and have more recently been recognized as key regulators in a number of neurodevelopmental processes. In this review we will discuss the known roles of each 14-3-3 isoform in the development of the cortex, their relation to human neurodevelopmental disorders, as well as the challenges and questions that are left to be answered. In particular, we focus on the 14-3-3 isoforms and their involvement in the three key stages of cortical development; neurogenesis and differentiation, neuronal migration and neuromorphogenesis and synaptogenesis.
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Affiliation(s)
- Brett Cornell
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Kazuhito Toyo-Oka
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States
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26
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Structural interface between LRRK2 and 14-3-3 protein. Biochem J 2017; 474:1273-1287. [PMID: 28202711 DOI: 10.1042/bcj20161078] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 02/09/2017] [Accepted: 02/14/2017] [Indexed: 02/03/2023]
Abstract
Binding of 14-3-3 proteins to leucine-rich repeat protein kinase 2 (LRRK2) is known to be impaired by many Parkinson's disease (PD)-relevant mutations. Abrogation of this interaction is connected to enhanced LRRK2 kinase activity, which in turn is implicated in increased ubiquitination of LRRK2, accumulation of LRRK2 into inclusion bodies and reduction in neurite length. Hence, the interaction between 14-3-3 and LRRK2 is of significant interest as a possible drug target for the treatment of PD. However, LRRK2 possesses multiple sites that, upon phosphorylation, can bind to 14-3-3, thus rendering the interaction relatively complex. Using biochemical assays and crystal structures, we characterize the multivalent interaction between these two proteins.
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27
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Sawa T, Hamaoka S, Kinoshita M, Kainuma A, Naito Y, Akiyama K, Kato H. Pseudomonas aeruginosa Type III Secretory Toxin ExoU and Its Predicted Homologs. Toxins (Basel) 2016; 8:toxins8110307. [PMID: 27792159 PMCID: PMC5127104 DOI: 10.3390/toxins8110307] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 10/20/2016] [Accepted: 10/21/2016] [Indexed: 11/16/2022] Open
Abstract
Pseudomonas aeruginosa ExoU, a type III secretory toxin and major virulence factor with patatin-like phospholipase activity, is responsible for acute lung injury and sepsis in immunocompromised patients. Through use of a recently updated bacterial genome database, protein sequences predicted to be homologous to Ps. aeruginosa ExoU were identified in 17 other Pseudomonas species (Ps. fluorescens, Ps. lundensis, Ps. weihenstephanensis, Ps. marginalis, Ps. rhodesiae, Ps. synxantha, Ps. libanensis, Ps. extremaustralis, Ps. veronii, Ps. simiae, Ps. trivialis, Ps. tolaasii, Ps. orientalis, Ps. taetrolens, Ps. syringae, Ps. viridiflava, and Ps. cannabina) and 8 Gram-negative bacteria from three other genera (Photorhabdus, Aeromonas, and Paludibacterium). In the alignment of the predicted primary amino acid sequences used for the phylogenetic analyses, both highly conserved and nonconserved parts of the toxin were discovered among the various species. Further comparative studies of the predicted ExoU homologs should provide us with more detailed information about the unique characteristics of the Ps. aeruginosa ExoU toxin.
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Affiliation(s)
- Teiji Sawa
- Department of Anesthesiology, School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Saeko Hamaoka
- Department of Anesthesiology, School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Mao Kinoshita
- Department of Anesthesiology, School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Atsushi Kainuma
- Department of Anesthesiology, School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Yoshifumi Naito
- Department of Anesthesiology, School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Koichi Akiyama
- Department of Anesthesiology, School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Hideya Kato
- Department of Anesthesiology, School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
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28
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Colmer-Hamood JA, Dzvova N, Kruczek C, Hamood AN. In Vitro Analysis of Pseudomonas aeruginosa Virulence Using Conditions That Mimic the Environment at Specific Infection Sites. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 142:151-91. [PMID: 27571695 DOI: 10.1016/bs.pmbts.2016.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes chronic lung infection in patients with cystic fibrosis (CF) and acute systemic infections in severely burned patients and immunocompromised patients including cancer patients undergoing chemotherapy and HIV infected individuals. In response to the environmental conditions at specific infection sites, P. aeruginosa expresses certain sets of cell-associated and extracellular virulence factors that produce tissue damage. Analyzing the mechanisms that govern the production of these virulence factors in vitro requires media that closely mimic the environmental conditions within the infection sites. In this chapter, we review studies based on media that closely resemble three in vivo conditions, the thick mucus accumulated within the lung alveoli of CF patients, the serum-rich wound bed and the bloodstream. Media resembling the CF alveolar mucus include standard laboratory media supplemented with sputum obtained from CF patients as well as prepared synthetic mucus media formulated to contain the individual components of CF sputum. Media supplemented with serum or individual serum components have served as surrogates for the soluble host components of wound infections, while whole blood has been used to investigate the adaptation of pathogens to the bloodstream. Studies using these media have provided valuable information regarding P. aeruginosa gene expression in different host environments as varying sets of genes were differentially regulated during growth in each medium. The unique effects observed indicate the essential role of these in vitro media that closely mimic the in vivo conditions in providing accurate information regarding the pathogenesis of P. aeruginosa infections.
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Affiliation(s)
- J A Colmer-Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States; Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, TX, United States.
| | - N Dzvova
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - C Kruczek
- Honors College, Texas Tech University, Lubbock, TX, United States
| | - A N Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States; Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States
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29
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Park MH, Kim SY, Roh EY, Lee HS. Difference of Type 3 secretion system (T3SS) effector gene genotypes (exoU and exoS) and its implication to antibiotics resistances in isolates of Pseudomonas aeruginosa from chronic otitis media. Auris Nasus Larynx 2016; 44:258-265. [PMID: 27461174 DOI: 10.1016/j.anl.2016.07.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 06/30/2016] [Accepted: 07/05/2016] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Type 3 secretion system (T3SS) is the most important virulence factor in Pseudomonas aeruginosa infection. Of the various T3SS effector genes, exoS and exoU showed mutually exclusive distributions, and these two genes showed varied virulence. In many pseudomonal infections, the distribution of these genes showed different pattern and it influenced severity of infection. This study was aimed to evaluate differences of virulence factors and antibiotics resistance between chronic otitis media and other body infection caused by P. aeruginosa. METHODS To estimate the prevalence of effector genes of T3SS, especially the distributions of exoS and exoU genes and their association with antibiotic resistance in COM, we compared the prevalence of T3SS genes in isolates from COM with those from lower respiratory infection and bacteremia. Other virulence genes, including groEL, pilA, ndvB, lasB, rhlI, and apr, were also studied to evaluate prevalence. These isolates were tested for antibiotic susceptibility, and we examined the association between antibiotic susceptibility and the prevalence of T3SS effector genes. RESULTS The COM group showed a significantly higher exoU-positive rate than the control group (70.6% vs. 6.7%; P<0.01). Furthermore, COM patients with exoU showed significant antibiotic resistance to ciprofloxacin and tobramycin (P=0.035), whereas there was no significant difference in the control group. CONCLUSIONS The high incidence of exoU-positive P. aeruginosa and ciprofloxacin resistance can explain the chronicity and intractability of infection in COM. Elucidation of this pathogenicity will facilitate the development of new treatment options for COM patients.
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Affiliation(s)
- Min-Hyun Park
- Department of Otorhinolaryngology-Head and Neck Surgery, Boramae Medical Center, Seoul Metropolitan Government-Seoul National University, Seoul, Republic of Korea
| | - So Young Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea.
| | - Eun Yun Roh
- Department of Clinical Laboratory Medicine, Boramae Medical Center, Seoul Metropolitan Government-Seoul National University, Seoul, Republic of Korea
| | - Ho Sun Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Boramae Medical Center, Seoul Metropolitan Government-Seoul National University, Seoul, Republic of Korea
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30
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Popa CM, Tabuchi M, Valls M. Modification of Bacterial Effector Proteins Inside Eukaryotic Host Cells. Front Cell Infect Microbiol 2016; 6:73. [PMID: 27489796 PMCID: PMC4951486 DOI: 10.3389/fcimb.2016.00073] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 06/27/2016] [Indexed: 12/16/2022] Open
Abstract
Pathogenic bacteria manipulate their hosts by delivering a number of virulence proteins -called effectors- directly into the plant or animal cells. Recent findings have shown that such effectors can suffer covalent modifications inside the eukaryotic cells. Here, we summarize the recent reports where effector modifications by the eukaryotic machinery have been described. We restrict our focus on proteins secreted by the type III or type IV systems, excluding other bacterial toxins. We describe the known examples of effectors whose enzymatic activity is triggered by interaction with plant and animal cell factors, including GTPases, E2-Ubiquitin conjugates, cyclophilin and thioredoxins. We focus on the structural interactions with these factors and their influence on effector function. We also review the described examples of host-mediated post-translational effector modifications which are required for proper subcellular location and function. These host-specific covalent modifications include phosphorylation, ubiquitination, SUMOylation, and lipidations such as prenylation, fatty acylation and phospholipid binding.
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Affiliation(s)
- Crina M Popa
- Department of Genetics, Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB), Universitat de Barcelona Barcelona, Spain
| | - Mitsuaki Tabuchi
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University Kagawa, Japan
| | - Marc Valls
- Department of Genetics, Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB), Universitat de Barcelona Barcelona, Spain
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31
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Tu X, Xiong J, Li Z, Zhou L, Emmanouil C, Zeng Q. CuI-catalyzed synthesis of 2-(tert-butyldisulfanyl) heterocycles from 2-mercaptoheterocycles and tert-butanesulfinamide. MONATSHEFTE FUR CHEMIE 2016. [DOI: 10.1007/s00706-015-1618-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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32
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Petta I, Lievens S, Libert C, Tavernier J, De Bosscher K. Modulation of Protein-Protein Interactions for the Development of Novel Therapeutics. Mol Ther 2016; 24:707-18. [PMID: 26675501 PMCID: PMC4886928 DOI: 10.1038/mt.2015.214] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 11/12/2015] [Indexed: 01/10/2023] Open
Abstract
Protein-protein interactions (PPIs) underlie most biological processes. An increasing interest to investigate the unexplored potential of PPIs in drug discovery is driven by the need to find novel therapeutic targets for a whole range of diseases with a high unmet medical need. To date, PPI inhibition with small molecules is the mechanism that has most often been explored, resulting in significant progress towards drug development. However, also PPI stabilization is gradually gaining ground. In this review, we provide a focused overview of a number of PPIs that control critical regulatory pathways and constitute targets for the design of novel therapeutics. We discuss PPI-modulating small molecules that are already pursued in clinical trials. In addition, we review a number of PPIs that are still under preclinical investigation but for which preliminary data support their use as therapeutic targets.
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Affiliation(s)
- Ioanna Petta
- Receptor Research Laboratories, Cytokine Receptor Lab (CRL), VIB Department of Medical Protein Research, Ghent, Belgium
- Department of Biochemistry, Ghent University, Ghent, Belgium
- Inflammation Research Center, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Sam Lievens
- Receptor Research Laboratories, Cytokine Receptor Lab (CRL), VIB Department of Medical Protein Research, Ghent, Belgium
- Department of Biochemistry, Ghent University, Ghent, Belgium
| | - Claude Libert
- Inflammation Research Center, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Jan Tavernier
- Receptor Research Laboratories, Cytokine Receptor Lab (CRL), VIB Department of Medical Protein Research, Ghent, Belgium
- Department of Biochemistry, Ghent University, Ghent, Belgium
| | - Karolien De Bosscher
- Receptor Research Laboratories, Cytokine Receptor Lab (CRL), VIB Department of Medical Protein Research, Ghent, Belgium
- Department of Biochemistry, Ghent University, Ghent, Belgium
- Receptor Research Laboratories, Nuclear Receptor Lab (NRL), VIB Department of Medical Protein Research, Ghent, Belgium
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Pinto AF, Ebrahimi M, Saleeb M, Forsberg Å, Elofsson M, Schüler H. Identification of Inhibitors of Pseudomonas aeruginosa Exotoxin-S ADP-Ribosyltransferase Activity. ACTA ACUST UNITED AC 2016; 21:590-5. [PMID: 26850638 DOI: 10.1177/1087057116629923] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 01/11/2016] [Indexed: 11/16/2022]
Abstract
The gram-negative bacterium Pseudomonas aeruginosa is an opportunistic pathogen associated with drug resistance complications and, as such, an important object for drug discovery efforts. One attractive target for development of therapeutics is the ADP-ribosyltransferase Exotoxin-S (ExoS), an early effector of the type III secretion system that is delivered into host cells to affect their transcription pattern and cytoskeletal dynamics. The purpose of this study was to formulate a real-time assay of purified recombinant ExoS activity for high-throughput application. We characterized the turnover kinetics of the fluorescent dinucleotide 1,N(6)-etheno-NAD+ as co-substrate for ExoS. Further, we found that the toxin relied on any of five tested isoforms of human 14-3-3 to modify vH-Ras and the Rho-family GTPases Rac1, -2, and -3 and RhoC. We then used 14-3-3β-stimulated ExoS modification of vH-Ras to screen a collection of low-molecular-weight compounds selected to target the poly-ADP ribose polymerase family and identified 3-(4-oxo-3,5,6,7-tetrahydro-4H-cyclopenta[4,5]thieno[2,3-d]pyrimidin-2-yl)propanoic acid as an ExoS inhibitor with micromolar potency. Thus, we present an optimized method to screen for inhibitors of ExoS activity that is amenable to high-throughput format and an intermediate affinity inhibitor that can serve both as assay control and as a starting point for further development.
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Affiliation(s)
- Ana Filipa Pinto
- Department of Medicinal Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Mahsa Ebrahimi
- Department of Medicinal Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | | | - Åke Forsberg
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | | | - Herwig Schüler
- Department of Medicinal Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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Fujiwara S, Kawazoe T, Ohnishi K, Kitagawa T, Popa C, Valls M, Genin S, Nakamura K, Kuramitsu Y, Tanaka N, Tabuchi M. RipAY, a Plant Pathogen Effector Protein, Exhibits Robust γ-Glutamyl Cyclotransferase Activity When Stimulated by Eukaryotic Thioredoxins. J Biol Chem 2016; 291:6813-30. [PMID: 26823466 DOI: 10.1074/jbc.m115.678953] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Indexed: 12/17/2022] Open
Abstract
The plant pathogenic bacterium Ralstonia solanacearum injects more than 70 effector proteins (virulence factors) into the host plant cells via the needle-like structure of a type III secretion system. The type III secretion system effector proteins manipulate host regulatory networks to suppress defense responses with diverse molecular activities. Uncovering the molecular function of these effectors is essential for a mechanistic understanding of R. solanacearum pathogenicity. However, few of the effectors from R. solanacearum have been functionally characterized, and their plant targets remain largely unknown. Here, we show that the ChaC domain-containing effector RipAY/RSp1022 from R. solanacearum exhibits γ-glutamyl cyclotransferase (GGCT) activity to degrade the major intracellular redox buffer, glutathione. Heterologous expression of RipAY, but not other ChaC family proteins conserved in various organisms, caused growth inhibition of yeast Saccharomyces cerevisiae, and the intracellular glutathione level was decreased to ∼30% of the normal level following expression of RipAY in yeast. Although active site mutants of GGCT activity were non-toxic, the addition of glutathione did not reverse the toxicity, suggesting that the toxicity might be a consequence of activity against other γ-glutamyl compounds. Intriguingly, RipAY protein purified from a bacterial expression system did not exhibit any GGCT activity, whereas it exhibited robust GGCT activity upon its interaction with eukaryotic thioredoxins, which are important for intracellular redox homeostasis during bacterial infection in plants. Our results suggest that RipAY has evolved to sense the host intracellular redox environment, which triggers its enzymatic activity to create a favorable environment for R. solanacearum infection.
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Affiliation(s)
- Shoko Fujiwara
- From the Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa, 761-0795, Japan
| | - Tomoki Kawazoe
- From the Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa, 761-0795, Japan
| | - Kouhei Ohnishi
- the Research Institute of Molecular Genetics, Kochi University, Nankoku 783-0093, Japan
| | - Takao Kitagawa
- the Department of Biochemistry and Functional Proteomics, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Crina Popa
- the Departament de Genètica, Universitat de Barcelona and Centre for Research in Agricultural Genomics, Bellaterra, Catalonia, Spain
| | - Marc Valls
- the Departament de Genètica, Universitat de Barcelona and Centre for Research in Agricultural Genomics, Bellaterra, Catalonia, Spain
| | - Stéphane Genin
- INRA-CNRS, Laboratoire des Interactions Plantes-Microoganismes, UMR441-2594, Castanet-Tolosan, France, and
| | - Kazuyuki Nakamura
- the Center of Clinical Laboratories, Tokuyama Medical Association Hospital, Shunan 745-0846, Japan
| | - Yasuhiro Kuramitsu
- the Department of Biochemistry and Functional Proteomics, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Naotaka Tanaka
- From the Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa, 761-0795, Japan
| | - Mitsuaki Tabuchi
- From the Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa, 761-0795, Japan,
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Abstract
Modulation of protein-protein interactions (PPIs) is becoming increasingly important in drug discovery and chemical biology. While a few years ago this 'target class' was deemed to be largely undruggable an impressing number of publications and success stories now show that targeting PPIs with small, drug-like molecules indeed is a feasible approach. Here, we summarize the current state of small-molecule inhibition and stabilization of PPIs and review the active molecules from a structural and medicinal chemistry angle, especially focusing on the key examples of iNOS, LFA-1 and 14-3-3.
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Joo Y, Schumacher B, Landrieu I, Bartel M, Smet-Nocca C, Jang A, Choi HS, Jeon NL, Chang KA, Kim HS, Ottmann C, Suh YH. Involvement of 14-3-3 in tubulin instability and impaired axon development is mediated by Tau. FASEB J 2015; 29:4133-44. [PMID: 26103986 DOI: 10.1096/fj.14-265009] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 06/15/2015] [Indexed: 01/06/2023]
Abstract
14-3-3 proteins act as adapters that exert their function by interacting with their various protein partners. 14-3-3 proteins have been implicated in a variety of human diseases including neurodegenerative diseases. 14-3-3 proteins have recently been reported to be abundant in the neurofibrillary tangles (NFTs) observed inside the neurons of brains affected by Alzheimer's disease (AD). These NFTs are mainly constituted of phosphorylated Tau protein, a microtubule-associated protein known to bind 14-3-3. Despite this indication of 14-3-3 protein involvement in the AD pathogenesis, the role of 14-3-3 in the Tauopathy remains to be clarified. In the present study, we shed light on the role of 14-3-3 proteins in the molecular pathways leading to Tauopathies. Overexpression of the 14-3-3σ isoform resulted in a disruption of the tubulin cytoskeleton and prevented neuritic outgrowth in neurons. NMR studies validated the phosphorylated residues pSer214 and pSer324 in Tau as the 2 primary sites for 14-3-3 binding, with the crystal structure of 14-3-3σ in complex with Tau-pSer214 and Tau-pSer324 revealing the molecular details of the interaction. These data suggest a rationale for a possible pharmacologic intervention of the Tau/14-3-3 interaction.
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Affiliation(s)
- Yuyoung Joo
- *Department of Pharmacology, College of Medicine and Neuroscience Research Institute, Medical Research Council, and School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea; Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea; Chemical Genomics Centre of the Max Planck Society, Dortmund, Germany; Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique-University of Lille, Villeneuve d'Ascq, France; Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands; and Korea Brain Research Institute, Daegu, Republic of Korea
| | - Benjamin Schumacher
- *Department of Pharmacology, College of Medicine and Neuroscience Research Institute, Medical Research Council, and School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea; Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea; Chemical Genomics Centre of the Max Planck Society, Dortmund, Germany; Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique-University of Lille, Villeneuve d'Ascq, France; Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands; and Korea Brain Research Institute, Daegu, Republic of Korea
| | - Isabelle Landrieu
- *Department of Pharmacology, College of Medicine and Neuroscience Research Institute, Medical Research Council, and School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea; Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea; Chemical Genomics Centre of the Max Planck Society, Dortmund, Germany; Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique-University of Lille, Villeneuve d'Ascq, France; Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands; and Korea Brain Research Institute, Daegu, Republic of Korea
| | - Maria Bartel
- *Department of Pharmacology, College of Medicine and Neuroscience Research Institute, Medical Research Council, and School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea; Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea; Chemical Genomics Centre of the Max Planck Society, Dortmund, Germany; Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique-University of Lille, Villeneuve d'Ascq, France; Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands; and Korea Brain Research Institute, Daegu, Republic of Korea
| | - Caroline Smet-Nocca
- *Department of Pharmacology, College of Medicine and Neuroscience Research Institute, Medical Research Council, and School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea; Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea; Chemical Genomics Centre of the Max Planck Society, Dortmund, Germany; Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique-University of Lille, Villeneuve d'Ascq, France; Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands; and Korea Brain Research Institute, Daegu, Republic of Korea
| | - Ahram Jang
- *Department of Pharmacology, College of Medicine and Neuroscience Research Institute, Medical Research Council, and School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea; Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea; Chemical Genomics Centre of the Max Planck Society, Dortmund, Germany; Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique-University of Lille, Villeneuve d'Ascq, France; Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands; and Korea Brain Research Institute, Daegu, Republic of Korea
| | - Hee Soon Choi
- *Department of Pharmacology, College of Medicine and Neuroscience Research Institute, Medical Research Council, and School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea; Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea; Chemical Genomics Centre of the Max Planck Society, Dortmund, Germany; Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique-University of Lille, Villeneuve d'Ascq, France; Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands; and Korea Brain Research Institute, Daegu, Republic of Korea
| | - Noo Li Jeon
- *Department of Pharmacology, College of Medicine and Neuroscience Research Institute, Medical Research Council, and School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea; Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea; Chemical Genomics Centre of the Max Planck Society, Dortmund, Germany; Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique-University of Lille, Villeneuve d'Ascq, France; Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands; and Korea Brain Research Institute, Daegu, Republic of Korea
| | - Keun-A Chang
- *Department of Pharmacology, College of Medicine and Neuroscience Research Institute, Medical Research Council, and School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea; Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea; Chemical Genomics Centre of the Max Planck Society, Dortmund, Germany; Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique-University of Lille, Villeneuve d'Ascq, France; Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands; and Korea Brain Research Institute, Daegu, Republic of Korea
| | - Hye-Sun Kim
- *Department of Pharmacology, College of Medicine and Neuroscience Research Institute, Medical Research Council, and School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea; Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea; Chemical Genomics Centre of the Max Planck Society, Dortmund, Germany; Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique-University of Lille, Villeneuve d'Ascq, France; Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands; and Korea Brain Research Institute, Daegu, Republic of Korea
| | - Christian Ottmann
- *Department of Pharmacology, College of Medicine and Neuroscience Research Institute, Medical Research Council, and School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea; Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea; Chemical Genomics Centre of the Max Planck Society, Dortmund, Germany; Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique-University of Lille, Villeneuve d'Ascq, France; Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands; and Korea Brain Research Institute, Daegu, Republic of Korea
| | - Yoo-Hun Suh
- *Department of Pharmacology, College of Medicine and Neuroscience Research Institute, Medical Research Council, and School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea; Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea; Chemical Genomics Centre of the Max Planck Society, Dortmund, Germany; Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique-University of Lille, Villeneuve d'Ascq, France; Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands; and Korea Brain Research Institute, Daegu, Republic of Korea
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Kodama T, Hiyoshi H, Okada R, Matsuda S, Gotoh K, Iida T. Regulation of Vibrio parahaemolyticus T3SS2 gene expression and function of T3SS2 effectors that modulate actin cytoskeleton. Cell Microbiol 2015; 17:183-90. [PMID: 25495647 DOI: 10.1111/cmi.12408] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 12/09/2014] [Accepted: 12/11/2014] [Indexed: 12/17/2022]
Abstract
Vibrio parahaemolyticus is a leading causative agent of seafood-borne gastroenteritis worldwide. Most clinical isolates from patients with diarrhoea possess two sets of genes for the type III secretion system (T3SS) on each chromosome (T3SS1 and T3SS2). T3SS is a protein secretion system that delivers effector proteins directly into eukaryotic cells. The injected effectors modify the normal cell functions by altering or disrupting the normal cell signalling pathways. Of the two sets of T3SS genes present in V. parahaemolyticus, T3SS2 is essential for enterotoxicity in several animal models. Recent studies have elucidated the biological activities of several T3SS2 effectors and their roles in virulence. This review focuses on the regulation of T3SS2 gene expression and T3SS2 effectors that specifically target the actin cytoskeleton.
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Affiliation(s)
- Toshio Kodama
- Pathogenic Microbes Repository Unit, International Research Center for Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
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Kubota R, Hamachi I. Protein recognition using synthetic small-molecular binders toward optical protein sensing in vitro and in live cells. Chem Soc Rev 2015; 44:4454-71. [DOI: 10.1039/c4cs00381k] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This review describes the recognition and sensing techniques of proteins and their building blocks by use of small synthetic binders.
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Affiliation(s)
- Ryou Kubota
- Department of Synthetic Chemistry and Biological Chemistry
- Graduate School of Engineering
- Kyoto University
- Katsura
- Japan
| | - Itaru Hamachi
- Department of Synthetic Chemistry and Biological Chemistry
- Graduate School of Engineering
- Kyoto University
- Katsura
- Japan
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40
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Abstract
"Protein-protein interactions (PPIs) are one of the most promising new targets in drug discovery. With estimates between 300,000 and 650,000 in human physiology, targeted modulation of PPIs would tremendously extend the "druggable" genome. In fact, in every disease a wealth of potentially addressable PPIs can be found making pharmacological intervention based on PPI modulators in principle a generally applicable technology. An impressing number of success stories in small-molecule PPI inhibition and natural-product PPI stabilization increasingly encourage academia and industry to invest in PPI modulation. In this chapter examples of both inhibition as well as stabilization of PPIs are reviewed including some of the technologies which has been used for their identification."
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Sawa T, Shimizu M, Moriyama K, Wiener-Kronish JP. Association between Pseudomonas aeruginosa type III secretion, antibiotic resistance, and clinical outcome: a review. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2014; 18:668. [PMID: 25672496 PMCID: PMC4331484 DOI: 10.1186/s13054-014-0668-9] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Pseudomonas aeruginosa uses a complex type III secretion system to inject the toxins ExoS, ExoT, ExoU, and ExoY into the cytosol of target eukaryotic cells. This system is regulated by the exoenzyme S regulon and includes the transcriptional activator ExsA. Of the four toxins, ExoU is characterized as the major virulence factor responsible for alveolar epithelial injury in patients with P. aeruginosa pneumonia. Virulent strains of P. aeruginosa possess the exoU gene, whereas non-virulent strains lack this particular gene. The mechanism of virulence for the exoU+ genotype relies on the presence of a pathogenic gene cluster (PAPI-2) encoding exoU and its chaperone, spcU. The ExoU toxin has a patatin-like phospholipase domain in its N-terminal, exhibits phospholipase A2 activity, and requires a eukaryotic cell factor for activation. The C-terminal of ExoU has a ubiquitinylation mechanism of activation. This probably induces a structural change in enzymatic active sites required for phospholipase A2 activity. In P. aeruginosa clinical isolates, the exoU+ genotype correlates with a fluoroquinolone resistance phenotype. Additionally, poor clinical outcomes have been observed in patients with pneumonia caused by exoU+-fluoroquinolone-resistant isolates. Therefore, the potential exists to improve clinical outcomes in patients with P. aeruginosa pneumonia by identifying virulent and antimicrobial drug-resistant strains through exoU genotyping or ExoU protein phenotyping or both.
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Mori M, Vignaroli G, Cau Y, Dinić J, Hill R, Rossi M, Colecchia D, Pešić M, Link W, Chiariello M, Ottmann C, Botta M. Discovery of 14-3-3 Protein-Protein Interaction Inhibitors that Sensitize Multidrug-Resistant Cancer Cells to Doxorubicin and the Akt Inhibitor GSK690693. ChemMedChem 2014; 9:973-83. [DOI: 10.1002/cmdc.201400044] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Indexed: 11/06/2022]
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Hu G, Li H, Liu JY, Wang J. Insight into conformational change for 14-3-3σ protein by molecular dynamics simulation. Int J Mol Sci 2014; 15:2794-810. [PMID: 24552877 PMCID: PMC3958882 DOI: 10.3390/ijms15022794] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 01/18/2014] [Accepted: 02/07/2014] [Indexed: 01/09/2023] Open
Abstract
14-3-3σ is a member of a highly conserved family of 14-3-3 proteins that has a double-edged sword role in human cancers. Former reports have indicated that the 14-3-3 protein may be in an open or closed state. In this work, we found that the apo-14-3-3σ is in an open state compared with the phosphopeptide bound 14-3-3σ complex which is in a more closed state based on our 80 ns molecular dynamics (MD) simulations. The interaction between the two monomers of 14-3-3σ in the open state is the same as that in the closed state. In both open and closed states, helices A to D, which are involved in dimerization, are stable. However, large differences are found in helices E and F. The hydrophobic contacts and hydrogen bonds between helices E and G in apo-14-3-3σ are different from those in the bound 14-3-3σ complex. The restrained and the mutated (Arg56 or Arg129 to alanine) MD simulations indicate that the conformation of four residues (Lys49, Arg56, Arg129 and Tyr130) may play an important role to keep the 14-3-3σ protein in an open or closed state. These results would be useful to evaluate the 14-3-3σ protein structure-function relationship.
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Affiliation(s)
- Guodong Hu
- Shandong Provincial Key Laboratory of Functional Macromolecular Biophysics, College of Physics and Electronic Information, Dezhou University, Dezhou 253023, China.
| | - Haiyan Li
- Shandong Provincial Key Laboratory of Functional Macromolecular Biophysics, College of Physics and Electronic Information, Dezhou University, Dezhou 253023, China.
| | - Jing-Yuan Liu
- Department of Computer and Information Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA.
| | - Jihua Wang
- Shandong Provincial Key Laboratory of Functional Macromolecular Biophysics, College of Physics and Electronic Information, Dezhou University, Dezhou 253023, China.
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The molecular mechanism of acute lung injury caused by Pseudomonas aeruginosa: from bacterial pathogenesis to host response. J Intensive Care 2014; 2:10. [PMID: 25520826 PMCID: PMC4267601 DOI: 10.1186/2052-0492-2-10] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Accepted: 01/28/2014] [Indexed: 12/25/2022] Open
Abstract
Pseudomonas aeruginosa is the most common gram-negative pathogen causing pneumonia in immunocompromised patients. Acute lung injury induced by bacterial exoproducts is associated with a poor outcome in P. aeruginosa pneumonia. The major pathogenic toxins among the exoproducts of P. aeruginosa and the mechanism by which they cause acute lung injury have been investigated: exoenzyme S and co-regulated toxins were found to contribute to acute lung injury. P. aeruginosa secretes these toxins through the recently defined type III secretion system (TTSS), by which gram-negative bacteria directly translocate toxins into the cytosol of target eukaryotic cells. TTSS comprises the secretion apparatus (termed the injectisome), translocators, secreted toxins, and regulatory components. In the P. aeruginosa genome, a pathogenic gene cluster, the exoenzyme S regulon, encodes genes underlying the regulation, secretion, and translocation of TTSS. Four type III secretory toxins, namely ExoS, ExoT, ExoU, and ExoY, have been identified in P. aeruginosa. ExoS is a 49-kDa form of exoenzyme S, a bifunctional toxin that exerts ADP-ribosyltransferase and GTPase-activating protein (GAP) activity to disrupt endocytosis, the actin cytoskeleton, and cell proliferation. ExoT, a 53-kDa form of exoenzyme S with 75% sequence homology to ExoS, also exerts GAP activity to interfere with cell morphology and motility. ExoY is a nucleotidal cyclase that increases the intracellular levels of cyclic adenosine and guanosine monophosphates, resulting in edema formation. ExoU, which exhibits phospholipase A2 activity activated by host cell ubiquitination after translocation, is a major pathogenic cytotoxin that causes alveolar epithelial injury and macrophage necrosis. Approximately 20% of clinical isolates also secrete ExoU, a gene encoded within an insertional pathogenic gene cluster named P. aeruginosa pathogenicity island-2. The ExoU secretory phenotype is associated with a poor clinical outcome in P. aeruginosa pneumonia. Blockade of translocation by TTSS or inhibition of the enzymatic activity of translocated toxins has the potential to decrease acute lung injury and improve clinical outcome.
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Liu M, Liu X, Ren P, Li J, Chai Y, Zheng SJ, Chen Y, Duan ZP, Li N, Zhang JY. A cancer-related protein 14-3-3ζ is a potential tumor-associated antigen in immunodiagnosis of hepatocellular carcinoma. Tumour Biol 2014; 35:4247-56. [PMID: 24390614 DOI: 10.1007/s13277-013-1555-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 12/13/2013] [Indexed: 12/15/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is the fifth most common cancer and the third leading cause of cancer-related deaths worldwide. Serum alpha-fetoprotein (AFP) is the conventional biomarker currently used in clinical diagnosis of this malignancy. However, AFP is not reliable for early diagnosis, and especially the sensitivity and specificity of AFP in HCC diagnosis are not optimal. Early detection of HCC is an important issue because of the very poor prognosis and usually no more than 6 months survival after diagnosis. Therefore, there is a need for the development of more sensitive and specific methods that can supplement AFP in the early detection of this cancer. In this study, autoantibody responses to 14-3-3ζ in HCC were evaluated by enzyme-linked immunosorbent assay (ELISA), western blot, and indirect immunofluorescence assay. Immunohistochemistry (IHC) with tissue array slides was also performed to analyze protein expression of 14-3-3ζ in HCC and control tissues. The prevalence of autoantibodies against 14-3-3ζ was 16.7% (28/168) in HCC, which was significantly higher than that in liver cirrhosis (LC), chronic hepatitis (CH), and normal human sera (NHS) (P < 0.01). The average titer of autoantibodies against 14-3-3ζ in HCC sera was higher compared to that in LC, CH, and NHS (P < 0.01). In the further study, anti-14-3-3ζ antibodies have been detected in the sera from several HCC patients with serial bleeding samples. A stronger reactive band with 14-3-3ζ in western blot can be seen in sera at 9 months before the clinical diagnosis of HCC. Our preliminary data indicate that anti-14-3-3ζ autoantibodies may be potential biomarkers for early-stage HCC screening and diagnosis.
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Affiliation(s)
- Mei Liu
- Beijing You'an Hospital, Capital Medical University, Beijing, 100069, China,
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46
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Rolsma SL, Frank DW. In vitro assays to monitor the activity of Pseudomonas aeruginosa Type III secreted proteins. Methods Mol Biol 2014; 1149:171-84. [PMID: 24818904 PMCID: PMC5860653 DOI: 10.1007/978-1-4939-0473-0_14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Pseudomonas aeruginosa secretes numerous toxins and destructive enzymes that play distinct roles in pathogenesis. The Type III secretion system (T3SS) of Pseudomonas is a system that delivers a subset of toxins directly into the cytoplasm of eukaryotic cells. The secreted effectors include ExoS, ExoT, ExoU, and ExoY. In this chapter, we describe methods to induce T3S expression and measure the enzymatic activities of each effector in in vitro assays. ExoU is a phospholipase and its activity can be measured in a fluorescence-based assay monitoring the cleavage of the fluorogenic substrate, PED6. ExoS and ExoT both possess ADP-ribosyltransferase (ADPRT) and GTPase-activating protein (GAP) activity. ADPRT activity can be assessed by using radiolabeled nicotinamide adenine dinucleotide (NAD(+)) and measuring the covalent incorporation of ADP-ribose into a target protein. GAP activity is measured by the release of radiolabeled phosphate from [γ-(32)P]GTP-bound target proteins. In accordance with recent trends towards reducing the use of radioactivity in the laboratory, alternative assays using fluorescent or biotin-labeled reagents are described. ExoY is a nucleotidyl cyclase; cAMP production stimulated by ExoY can be monitored using reverse-phase HPLC or with commercially available immunological assays.
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Affiliation(s)
- Stephanie L Rolsma
- Department of Microbiology and Molecular Genetics, Center of Infectious Disease Research, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI, 53226, USA
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Exoenzyme S ADP-ribosylates Rab5 effector sites to uncouple intracellular trafficking. Infect Immun 2013; 82:21-8. [PMID: 24101692 DOI: 10.1128/iai.01059-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pseudomonas aeruginosa exoenzyme S (ExoS) ADP-ribosylates multiple eukaryotic targets to promote cytopathology and bacterial colonization. ADP-ribosylation of the small GTPase Rab5 has previously been shown to block fluid-phase endocytosis and trafficking of plasma membrane receptors to the early endosomes as well as inhibit phagocytosis of the bacterium. In this study, ExoS is shown to be capable of ADP-ribosylating 6 candidate arginine residues that are located in the effector binding region or in the C terminus of Rab5. Two Rab5 derivatives were engineered, which contained Arg→Ala mutations at four Arg residues within the effector binding region (EF) or two Arg residues within the C-terminal tail (TL). Expression of Rab5(TL) does not affect the ability of ExoS to modify intracellular trafficking, while expression of Rab5(EF) rescued the ability of ExoS to inhibit intracellular trafficking. ADP-ribosylation of effector arginines likely uncouples Rab5 signaling to downstream effectors. This is a different mechanism for inhibition than observed for the ADP-ribosylation of Ras by ExoS, where ADP-ribosylated Ras loses the ability to bind guanine nucleotide exchange factor (GEF). Other experiments showed that expression of dominant negative Rab5(Ser34Asn) does not inhibit ExoS trafficking to the perinuclear region of intoxicated cells. This study provides insight into a mechanism for how ExoS ADP-ribosylation of Rab5 inhibits Rab5 function.
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48
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Anderson DM, Feix JB, Monroe AL, Peterson FC, Volkman BF, Haas AL, Frank DW. Identification of the major ubiquitin-binding domain of the Pseudomonas aeruginosa ExoU A2 phospholipase. J Biol Chem 2013; 288:26741-52. [PMID: 23908356 DOI: 10.1074/jbc.m113.478529] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Numerous Gram-negative bacterial pathogens use type III secretion systems to deliver effector molecules into the cytoplasm of a host cell. Many of these effectors have evolved to manipulate the host ubiquitin system to alter host cell physiology or the location, stability, or function of the effector itself. ExoU is a potent A2 phospholipase used by Pseudomonas aeruginosa to destroy membranes of infected cells. The enzyme is held in an inactive state inside of the bacterium due to the absence of a required eukaryotic activator, which was recently identified as ubiquitin. This study sought to identify the region of ExoU required to mediate this interaction and determine the properties of ubiquitin important for binding, ExoU activation, or both. Biochemical and biophysical approaches were used to map the ubiquitin-binding domain to a C-terminal four-helix bundle of ExoU. The hydrophobic patch of ubiquitin is required for full binding affinity and activation. Binding and activation were uncoupled by introducing an L8R substitution in ubiquitin. Purified L8R demonstrated a parental binding phenotype to ExoU but did not activate the phospholipase in vitro. Utilizing these new biochemical data and intermolecular distance measurements by double electron-electron resonance, we propose a model for an ExoU-monoubiquitin complex.
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Affiliation(s)
- David M Anderson
- From the Department of Microbiology and Molecular Genetics and the Center for Infectious Disease Research and
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49
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Du Y, Fu RW, Lou B, Zhao J, Qui M, Khuri FR, Fu H. A time-resolved fluorescence resonance energy transfer assay for high-throughput screening of 14-3-3 protein-protein interaction inhibitors. Assay Drug Dev Technol 2013; 11:367-81. [PMID: 23906346 DOI: 10.1089/adt.2013.507] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Protein-protein interaction networks mediate diverse biological processes by regulating various signaling hubs and clusters. 14-3-3 proteins, a family of phosphoserine/threonine-binding molecules, serve as major interaction hubs in eukaryotic cells and have emerged as promising therapeutic targets for various human diseases. In order to identify chemical probes for mechanistic studies and for potential therapeutic development, we have developed highly sensitive bioassays to monitor the interaction of 14-3-3 with a client protein. In this study, we describe a homogenous time-resolved fluorescence resonance energy transfer (TR-FRET) assay to detect the interaction of 14-3-3 with Bad, a proapoptotic member of the Bcl-2 family. Through a series of titration studies in which europium-labeled 14-3-3 serves as an FRET donor and a Dy647-labeled phosphorylated Bad, the peptide acts as an FRET acceptor, we have achieved a robust TR-FRET assay that is suitable for high-throughput screening (HTS) with an excellent signal-to-background ratio of >20 and Z' values >0.7. This assay was further miniaturized to a 1,536-well format for ultra-HTS (uHTS), and exhibited a similar robust performance. The utility and performance of the assay for uHTS were validated by (i) known inhibitors, including peptide R18 and small molecule FOBISIN101, and (ii) screening of a 51,200 compound library. This simple and robust assay is generally applicable to detect the interaction of 14-3-3 with other client proteins. It provides a sensitive and easy-to-use tool to facilitate the discovery of 14-3-3 protein inhibitors as well as to study 14-3-3-mediated protein-protein interactions.
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Affiliation(s)
- Yuhong Du
- Department of Pharmacology and Emory Chemical Biology Discovery Center, Emory University School of Medicine, Atlanta, GA 30322, USA.
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Phosphatidylinositol 4,5-bisphosphate is a novel coactivator of the Pseudomonas aeruginosa cytotoxin ExoU. Infect Immun 2013; 81:2873-81. [PMID: 23716613 DOI: 10.1128/iai.00414-13] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ExoU is a potent phospholipase A2 effector protein secreted by the type III secretion system of Pseudomonas aeruginosa. By cleaving plasma membrane phospholipids, it causes rapid lysis of eukaryotic cells. However, ExoU does not exhibit activity on its own but instead requires eukaryotic cell cofactors for activation. Ubiquitin and ubiquitinated proteins have been shown to activate ExoU, but previous work suggested that other cofactors are also involved. In this study, we demonstrate that phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is another important coactivator of ExoU. PI(4,5)P2 works synergistically with ubiquitin to greatly enhance the phospholipase A2 activity of ExoU. Distinct residues of ExoU were critical for activation by PI(4,5)P2 and by ubiquitin, indicating that these factors activate ExoU by discrete mechanisms. In support of the biological relevance of PI(4,5)P2 coactivation, a yeast mutant with reduced PI(4,5)P2 levels was less susceptible to the cytotoxic activity of ExoU. Together, these findings further elaborate the molecular mechanism of ExoU.
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