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Atkinson SC, Dogovski C, Wood K, Griffin MDW, Gorman MA, Hor L, Reboul CF, Buckle AM, Wuttke J, Parker MW, Dobson RCJ, Perugini MA. Substrate Locking Promotes Dimer-Dimer Docking of an Enzyme Antibiotic Target. Structure 2018; 26:948-959.e5. [PMID: 29804823 DOI: 10.1016/j.str.2018.04.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 02/27/2018] [Accepted: 04/19/2018] [Indexed: 11/19/2022]
Abstract
Protein dynamics manifested through structural flexibility play a central role in the function of biological molecules. Here we explore the substrate-mediated change in protein flexibility of an antibiotic target enzyme, Clostridium botulinum dihydrodipicolinate synthase. We demonstrate that the substrate, pyruvate, stabilizes the more active dimer-of-dimers or tetrameric form. Surprisingly, there is little difference between the crystal structures of apo and substrate-bound enzyme, suggesting protein dynamics may be important. Neutron and small-angle X-ray scattering experiments were used to probe substrate-induced dynamics on the sub-second timescale, but no significant changes were observed. We therefore developed a simple technique, coined protein dynamics-mass spectrometry (ProD-MS), which enables measurement of time-dependent alkylation of cysteine residues. ProD-MS together with X-ray crystallography and analytical ultracentrifugation analyses indicates that pyruvate locks the conformation of the dimer that promotes docking to the more active tetrameric form, offering insight into ligand-mediated stabilization of multimeric enzymes.
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Affiliation(s)
- Sarah C Atkinson
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, University of Melbourne, Parkville, VIC 3010, Australia
| | - Con Dogovski
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, University of Melbourne, Parkville, VIC 3010, Australia
| | - Kathleen Wood
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia
| | - Michael D W Griffin
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, University of Melbourne, Parkville, VIC 3010, Australia
| | - Michael A Gorman
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Lilian Hor
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, University of Melbourne, Parkville, VIC 3010, Australia; Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, La Trobe University, Melbourne, VIC 3086, Australia
| | - Cyril F Reboul
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Ashley M Buckle
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Joachim Wuttke
- Juelich Centre for Neutron Science (JCNS), at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Juelich GmbH, Lichtenstrasse 1, Garching 85 747, Germany
| | - Michael W Parker
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, University of Melbourne, Parkville, VIC 3010, Australia; ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Renwick C J Dobson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, University of Melbourne, Parkville, VIC 3010, Australia; Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Private Bag, Christchurch 4800, New Zealand
| | - Matthew A Perugini
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, University of Melbourne, Parkville, VIC 3010, Australia; Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia.
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Xue S, Seki H, Remes M, Šilhár P, Janda K. Examination of α-exosite inhibitors against Botulinum neurotoxin A protease through structure-activity relationship studies of chicoric acid. Bioorg Med Chem Lett 2017; 27:4956-4959. [PMID: 29050781 PMCID: PMC5667901 DOI: 10.1016/j.bmcl.2017.10.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 10/09/2017] [Accepted: 10/10/2017] [Indexed: 12/20/2022]
Abstract
Botulinum neurotoxins (BoNT) are among the most toxic known substances and currently there are no effective treatments for intraneuronal BoNT intoxication. Chicoric acid (ChA) was previously reported as a BoNT/A inhibitor that binds to the enzyme's α-exosite. Herein, we report the synthesis and structure-activity relationships (SARs) of a series of ChA derivatives, which revealed essential binding interactions between ChA and BoNT/A. Moreover, several ChA-based inhibitors with improved potency against the BoNT/A were discovered.
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Affiliation(s)
- Song Xue
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States; Department of Immunology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States
| | - Hajime Seki
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States; Department of Immunology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States
| | - Marek Remes
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States; Department of Immunology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States
| | - Peter Šilhár
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States; Department of Immunology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States
| | - Kim Janda
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States; Department of Immunology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States; Worm Institute for Research Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States.
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3
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Shi J, Guo J, Bai G, Chan C, Liu X, Ye W, Hao J, Chen S, Yang M. A graphene oxide based fluorescence resonance energy transfer (FRET) biosensor for ultrasensitive detection of botulinum neurotoxin A (BoNT/A) enzymatic activity. Biosens Bioelectron 2014; 65:238-44. [PMID: 25461164 DOI: 10.1016/j.bios.2014.10.050] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 10/17/2014] [Accepted: 10/20/2014] [Indexed: 11/18/2022]
Abstract
Botulinum neurotoxins (BoNTs) are among the most potent toxic bacterial proteins for humans, which make them potential agents for bioterrorism. Therefore, an ultrasensitive detection of BoNTs and their active states is in great need as field-deployable systems for anti-terrorism applications. We report the construction of a novel graphene oxide (GO)-peptide based fluorescence resonance energy transfer (FRET) biosensor for ultrasensitive detection of the BoNT serotype A light chain (BoNT-LcA) protease activity. A green fluorescence protein (GFP) modified SNAP-25 peptide substrate (SNAP-25-GFP) was optimally designed and synthesized with the centralized recognition/cleavage sites. This FRET platform was constructed by covalent immobilization of peptide substrate on GO with BSA passivation which have advantages of low non-specific adsorption and high stability in protein abundant solution. BoNT-LcA can specifically cleave SNAP-25-GFP substrate covalently immobilized on GO to release the fragment with GFP. Based on fluorescence signal recovery measurement, the target BoNT-LcA was detected sensitively and selectively with the linear detection range from 1fg/mL to 1pg/mL. The limit of detection (LOD) for BoNT-LcA is around 1fg/mL.
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Affiliation(s)
- Jingyu Shi
- Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, PR China
| | - Jiubiao Guo
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, PR China
| | - Gongxun Bai
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, PR China
| | - Chunyu Chan
- Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, PR China
| | - Xuan Liu
- Institute of Textiles & Clothing, The Hong Kong Polytechnic University, Hong Kong, PR China
| | - Weiwei Ye
- Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, PR China
| | - Jianhua Hao
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, PR China
| | - Sheng Chen
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, PR China
| | - Mo Yang
- Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, PR China.
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4
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Masuyer G, Stancombe P, Chaddock JA, Acharya KR. Structures of engineered Clostridium botulinum neurotoxin derivatives. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:1466-72. [PMID: 22139146 PMCID: PMC3232119 DOI: 10.1107/s1744309111034671] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 08/23/2011] [Indexed: 11/10/2022]
Abstract
Targeted secretion inhibitors (TSIs) are a new class of engineered biopharmaceutical molecules derived from the botulinum neurotoxins (BoNTs). They consist of the metalloprotease light chain (LC) and translocation domain (Hn) of BoNT; they thus lack the native toxicity towards motor neurons but are able to target soluble N-ethylmaleimide-sensitive fusion protein attachment receptor (SNARE) proteins. These functional fragment (LHn) derivatives are expressed as single-chain proteins and require post-translational activation into di-chain molecules for function. A range of BoNT derivatives have been produced to demonstrate the successful use of engineered SNARE substrate peptides at the LC-Hn interface that gives these molecules self-activating capabilities. Alternatively, recognition sites for specific exoproteases can be engineered to allow controlled activation. Here, the crystal structures of three LHn derivatives are reported between 2.7 and 3.0 Å resolution. Two of these molecules are derivatives of serotype A that contain a SNARE peptide. Additionally, a third structure corresponds to LHn serotype B that includes peptide linkers at the exoprotease activation site. In all three cases the added engineered segments could not be modelled owing to disorder. However, these structures highlight the strong interactions holding the LHn fold together despite the inclusion of significant polypeptide sequences at the LC-Hn interface.
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Affiliation(s)
- Geoffrey Masuyer
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, England
| | - Patrick Stancombe
- Syntaxin Limited, Units 4–10, The Quadrant, Barton Lane, Abingdon, Oxon OX14 3YS, England
| | - John A. Chaddock
- Syntaxin Limited, Units 4–10, The Quadrant, Barton Lane, Abingdon, Oxon OX14 3YS, England
| | - K. Ravi Acharya
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, England
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5
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Tremblay JM, Kuo CL, Abeijon C, Sepulveda J, Oyler G, Hu X, Jin MM, Shoemaker CB. Camelid single domain antibodies (VHHs) as neuronal cell intrabody binding agents and inhibitors of Clostridium botulinum neurotoxin (BoNT) proteases. Toxicon 2010; 56:990-8. [PMID: 20637220 DOI: 10.1016/j.toxicon.2010.07.003] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Revised: 07/02/2010] [Accepted: 07/06/2010] [Indexed: 11/17/2022]
Abstract
Botulinum neurotoxins (BoNTs) function by delivering a protease to neuronal cells that cleave SNARE proteins and inactivate neurotransmitter exocytosis. Small (14 kDa) binding domains specific for the protease of BoNT serotypes A or B were selected from libraries of heavy chain only antibody domains (VHHs or nanobodies) cloned from immunized alpacas. Several VHHs bind the BoNT proteases with high affinity (K(D) near 1 nM) and include potent inhibitors of BoNT/A protease activity (K(i) near 1 nM). The VHHs retain their binding specificity and inhibitory functions when expressed within mammalian neuronal cells as intrabodies. A VHH inhibitor of BoNT/A protease was able to protect neuronal cell SNAP25 protein from cleavage following intoxication with BoNT/A holotoxin. These results demonstrate that VHH domains have potential as components of therapeutic agents for reversal of botulism intoxication.
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Affiliation(s)
- Jacqueline M Tremblay
- Tufts Cummings School of Veterinary Medicine, Department of Biomedical Sciences, 200 Westboro Road, North Grafton, MA 01536, USA
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6
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Šilhár P, Čapková K, Salzameda NT, Barbieri JT, Hixon MS, Janda KD. Botulinum neurotoxin A protease: discovery of natural product exosite inhibitors. J Am Chem Soc 2010; 132:2868-9. [PMID: 20158239 PMCID: PMC2832098 DOI: 10.1021/ja910761y] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A new mechanistic class of BoNT/A zinc metalloprotease inhibitors, from Echinacea, exemplified by the natural product d-chicoric acid (I1) is disclosed. A detailed evaluation of chicoric acid's mechanism of inhibition reveals that the inhibitor binds to an exosite, displays noncompetitive partial inhibition, and is synergistic with a competitive active site inhibitor when used in combination. Other components found in Echinacea, I3 and I4, were also inhibitors of the protease.
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Affiliation(s)
- Peter Šilhár
- Departments of Chemistry and Immunology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Kateřina Čapková
- Departments of Chemistry and Immunology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Nicholas T. Salzameda
- Departments of Chemistry and Immunology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Joseph T. Barbieri
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226
| | - Mark S. Hixon
- Discovery Biology, Takeda San Diego, Inc., San Diego CA, 10410 Science Center Dr, San Diego, CA 92121, USA
| | - Kim D. Janda
- Departments of Chemistry and Immunology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA
- Worm Institute for Research and Medicine (WIRM), The Scripps Research Institute,10550 North Torrey Pines Rd, La Jolla, CA 92037
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7
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Dobson RCJ, Atkinson SC, Gorman MA, Newman JM, Parker MW, Perugini MA. The purification, crystallization and preliminary X-ray diffraction analysis of dihydrodipicolinate synthase from Clostridium botulinum. Acta Crystallogr Sect F Struct Biol Cryst Commun 2008; 64:206-8. [PMID: 18323610 PMCID: PMC2374160 DOI: 10.1107/s1744309108002819] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2007] [Accepted: 01/24/2008] [Indexed: 11/10/2022]
Abstract
In recent years, dihydrodipicolinate synthase (DHDPS; EC 4.2.1.52) has received considerable attention from both mechanistic and structural viewpoints. This enzyme, which is part of the diaminopimelate pathway leading to lysine, couples (S)-aspartate-beta-semialdehyde with pyruvate via a Schiff base to a conserved active-site lysine. In this paper, the expression, purification, crystallization and preliminary X-ray diffraction analysis of DHDPS from Clostridium botulinum, an important bacterial pathogen, are presented. The enzyme was crystallized in a number of forms, predominantly using PEG precipitants, with the best crystal diffracting to beyond 1.9 A resolution and displaying P4(2)2(1)2 symmetry. The unit-cell parameters were a = b = 92.9, c = 60.4 A. The crystal volume per protein weight (V(M)) was 2.07 A(3) Da(-1), with an estimated solvent content of 41%. The structure of the enzyme will help guide the design of novel therapeutics against the C. botulinum pathogen.
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Affiliation(s)
- Renwick C J Dobson
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia.
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Kohda T, Ihara H, Seto Y, Tsutsuki H, Mukamoto M, Kozaki S. Differential contribution of the residues in C-terminal half of the heavy chain of botulinum neurotoxin type B to its binding to the ganglioside GT1b and the synaptotagmin 2/GT1b complex. Microb Pathog 2007; 42:72-9. [PMID: 17188834 DOI: 10.1016/j.micpath.2006.10.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Accepted: 10/31/2006] [Indexed: 10/23/2022]
Abstract
Clostridium botulinum type B neurotoxin was effectively bound to synaptotagmin 2 (Stg2) associated with ganglioside GT1b, however, the molecular interaction between the neurotoxin and the Stg2/GT1b complex has not been identified. Previously, we found that infant botulism-related strain 111 generated a low activity of the neurotoxin (111/NT), which differed in some amino acid residues, especially in the carboxyl terminal half of the heavy chain (H(C)), from the original neurotoxin of strain Okra (Okra/NT) associated with a food-borne botulism. In this study, we evaluated the binding capabilities of site-directed mutants of Okra/H(C) to the Stg2/GT1b complex and to GT1b alone, and investigated the relationship between the toxic action and receptor binding. Replacement of K1187 and E1190 with glutamic acid and lysine, respectively, which substituted for the 111/NT residues, caused a reduction of binding affinity to the Stg2/GT1b complex, suggesting that both these residues contribute to the different binding affinity between Okra/NT and 111/NT. Substitution of four residues, H1240, S1259, W1261 and Y1262, which form a ganglioside pocket, drastically decreased the binding of H(C) to the Stg2/GT1b complex and to GT1b. Mutation in the residues, K1186, E1189, K1191 and K1260 reduced the binding of H(C) to GT1b alone, but not to the Stg2/GT1b complex. Analyses of effects of mutant toxins on toxicity of BoNT/B to cerebellar granule cells suggest the association of cell toxicity with binding to Stg2/GT1b complex but not that to GT1b alone.
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Affiliation(s)
- Tomoko Kohda
- Department of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
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Abstract
Clostridium botulinum is capable of fermenting carbohydrates, but there have been no detailed studies of the uptake of sugars and related substrates. In bacteria, a common and often predominant system of carbohydrate uptake is the phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS). This multi-protein complex catalyses a group translocation involving both uptake and phosphorylation of carbohydrates, and is also known to play an important role in environmental sensing and metabolic regulation. The genome of C. botulinum encodes 15 PTSs which have a similar domain structure to the PTS in other bacteria. Based on phylogenetic relationships and analysis of gene clusters, the C. botulinum PTS appears to be involved in the uptake of hexoses, hexose derivatives and disaccharides. C. botulinum also contains the components of PTS-associated regulatory mechanisms which have been characterised in other bacteria. It therefore seems likely that the PTS plays a significant, and previously unrecognised, role in the physiology of this bacterium.
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Sutton JM, Wayne J, Scott-Tucker A, O'Brien SM, Marks PMH, Alexander FCG, Shone CC, Chaddock JA. Preparation of specifically activatable endopeptidase derivatives of Clostridium botulinum toxins type A, B, and C and their applications. Protein Expr Purif 2005; 40:31-41. [PMID: 15721769 DOI: 10.1016/j.pep.2004.06.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Indexed: 11/29/2022]
Abstract
Clostridium botulinum neurotoxins are potently toxic proteins of 150 kDa with specific endopeptidase activity for SNARE proteins involved in vesicle docking and release. Following treatment with trypsin, a fragment of botulinum neurotoxin serotype A that lacks the C-terminal domain responsible for neuronal cell binding, but retains full catalytic activity, can be obtained. Known as the LH(N) fragment, we report the development of a recombinant expression and purification scheme for the isolation of comparable fragments of neurotoxin serotypes B and C. Expressed as maltose-binding protein fusions, both have specific proteolytic sites present between the fusion tag and the light chain to facilitate removal of the fusion, and between the light chain endopeptidase and the H(N) translocation domains to facilitate activation of the single polypeptide. We have also used this approach to prepare a new variant of LH(N)/A with a specific activation site that avoids the need to use trypsin. All three LH(N)s are enzymatically active and are of low toxicity. The production of specifically activatable LH(N)/A, LH(N)/B, and LH(N)/C extends the opportunities for exploitation of neurotoxin fragments. The potential utility of these fragments is discussed.
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Affiliation(s)
- J Mark Sutton
- Health Protection Agency, Centre for Applied Microbiology and Research, Porton Down, Salisbury, Wiltshire SP4 0JG, UK
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Nevas M, Lindström M, Hielm S, Björkroth KJ, Peck MW, Korkeala H. Diversity of proteolytic Clostridium botulinum strains, determined by a pulsed-field gel electrophoresis approach. Appl Environ Microbiol 2005; 71:1311-7. [PMID: 15746333 PMCID: PMC1065132 DOI: 10.1128/aem.71.3.1311-1317.2005] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Pulsed-field gel electrophoresis (PFGE) was applied to the study of the similarity of 55 strains of proteolytic Clostridium botulinum (C. botulinum group I) types A, AB, B, and F. Rare-cutting restriction enzymes ApaI, AscI, MluI, NruI, PmeI, RsrII, SacII, SmaI, and XhoI were tested for their suitability for the cleavage of DNA of five proteolytic C. botulinum strains. Of these enzymes, SacII, followed by SmaI and XhoI, produced the most convenient number of fragments for genetic typing and were selected for analysis of the 55 strains. The proteolytic C. botulinum species was found to be heterogeneous. In the majority of cases, PFGE enabled discrimination between individual strains of proteolytic C. botulinum types A and B. The different toxin types were discriminated at an 86% similarity level with both SacII and SmaI and at an 83% similarity level with XhoI. Despite the high heterogeneity, three clusters at a 95% similarity level consisting of more than three strains of different origin were noted. The strains of types A and B showed higher diversity than the type F organisms which formed a single cluster. According to this survey, PFGE is to be considered a useful tool for molecular epidemiological analysis of proteolytic C. botulinum types A and B. However, epidemiological conclusions based on PFGE data only should be made with discretion, since highly similar PFGE patterns were noticed, especially within the type B strains.
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Affiliation(s)
- Mari Nevas
- Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, PO Box 66, 00014 Helsinki University, Finland.
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Holbourn KP, Sutton JM, Evans HR, Shone CC, Acharya KR. Molecular recognition of an ADP-ribosylating Clostridium botulinum C3 exoenzyme by RalA GTPase. Proc Natl Acad Sci U S A 2005; 102:5357-62. [PMID: 15809419 PMCID: PMC556266 DOI: 10.1073/pnas.0501525102] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2004] [Indexed: 01/19/2023] Open
Abstract
C3 exoenzymes (members of the ADP-ribosyltranferase family) are produced by Clostridium botulinum (C3bot1 and -2), Clostridium limosum (C3lim), Bacillus cereus (C3cer), and Staphylococcus aureus (C3stau1-3). These exoenzymes lack a translocation domain but are known to specifically inactivate Rho GTPases in host target cells. Here, we report the crystal structure of C3bot1 in complex with RalA (a GTPase of the Ras subfamily) and GDP at a resolution of 2.66 A. RalA is not ADP-ribosylated by C3 exoenzymes but inhibits ADP-ribosylation of RhoA by C3bot1, C3lim, and C3cer to different extents. The structure provides an insight into the molecular interactions between C3bot1 and RalA involving the catalytic ADP-ribosylating turn-turn (ARTT) loop from C3bot1 and helix alpha4 and strand beta6 (which are not part of the GDP-binding pocket) from RalA. The structure also suggests a molecular explanation for the different levels of C3-exoenzyme inhibition by RalA and why RhoA does not bind C3bot1 in this manner.
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Affiliation(s)
- Kenneth P Holbourn
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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13
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Abstract
Clostridal neurotoxins (CNTs) are the causative agents of the neuroparalytic diseases botulism and tetanus. CNTs impair neuronal exocytosis through specific proteolysis of essential proteins called SNAREs. SNARE assembly into a low-energy ternary complex is believed to catalyse membrane fusion, precipitating neurotransmitter release; this process is attenuated in response to SNARE proteolysis. Site-specific SNARE hydrolysis is catalysed by the CNT light chains, a unique group of zinc-dependent endopeptidases. The means by which a CNT properly identifies and cleaves its target SNARE has been a subject of much speculation; it is thought to use one or more regions of enzyme-substrate interaction remote from the active site (exosites). Here we report the first structure of a CNT endopeptidase in complex with its target SNARE at a resolution of 2.1 A: botulinum neurotoxin serotype A (BoNT/A) protease bound to human SNAP-25. The structure, together with enzyme kinetic data, reveals an array of exosites that determine substrate specificity. Substrate orientation is similar to that of the general zinc-dependent metalloprotease thermolysin. We observe significant structural changes near the toxin's catalytic pocket upon substrate binding, probably serving to render the protease competent for catalysis. The novel structures of the substrate-recognition exosites could be used for designing inhibitors specific to BoNT/A.
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Affiliation(s)
- Mark A Breidenbach
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, USA
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14
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Abstract
Clostridium botulinum C2 toxin is a member of the family of binary actin-ADP-ribosylating toxins. It consists of the enzyme component C2I, and the separated binding/translocation component C2II. Proteolytically activated C2II forms heptamers and binds to a carbohydrate cell surface receptor. After attachment of C2I, the toxin complex is endocytosed to reach early endosomes. At low pH of endosomes, C2II-heptamers insert into the membrane, form pores and deliver C2I into the cytosol. Here, C2I ADP-ribosylates actin at Arg177 to block actin polymerization and to induce depolymerization of actin filaments. The mini-review describes main properties of C2 toxin and discusses new findings on the involvement of chaperones in the up-take process of the toxin.
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Affiliation(s)
- Klaus Aktories
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.
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15
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Evans HR, Holloway DE, Sutton JM, Ayriss J, Shone CC, Acharya KR. C3 exoenzyme from Clostridium botulinum: structure of a tetragonal crystal form and a reassessment of NAD-induced flexure. Acta Crystallogr D Biol Crystallogr 2004; 60:1502-5. [PMID: 15272191 DOI: 10.1107/s0907444904011680] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Accepted: 05/12/2004] [Indexed: 11/10/2022]
Abstract
C3 exoenzyme from Clostridium botulinum (C3bot1) ADP-ribosylates and thereby inactivates Rho A, B and C GTPases in mammalian cells. The structure of a tetragonal crystal form has been determined by molecular replacement and refined to 1.89 A resolution. It is very similar to the apo structures determined previously from two different monoclinic crystal forms. An objective reassessment of available apo and nucleotide-bound C3bot1 structures indicates that, contrary to a previous report, the protein possesses a rigid core formed largely of beta-strands and that the general flexure that accompanies NAD binding is concentrated in two peripheral lobes. Tetragonal crystals disintegrate in the presence of NAD, most likely because of disruption of essential crystal contacts.
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Affiliation(s)
- Hazel R Evans
- Department of Biology and Biochemistry, University of Bath, Claverton Down, BA2 7AY, England
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16
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Agarwal R, Eswaramoorthy S, Kumaran D, Dunn JJ, Swaminathan S. Cloning, high level expression, purification, and crystallization of the full length Clostridium botulinum neurotoxin type E light chain. Protein Expr Purif 2004; 34:95-102. [PMID: 14766304 DOI: 10.1016/j.pep.2003.10.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2003] [Revised: 10/14/2003] [Indexed: 10/26/2022]
Abstract
The catalytic activity of the highly potent botulinum neurotoxins are confined to their N-terminal light chains ( approximately 50kDa). A full-length light chain for the type E neurotoxin with a C-terminal 6x His-tag, BoNT/E-LC, has been cloned in a pET-9c vector and over-expressed in BL21 (DE3) cells. BoNT/E-LC was purified to homogeneity by affinity chromatography on Ni-NTA agarose followed by exclusion chromatography using a Superdex-75 sizing column. The purified protein has very good solubility and can be stored stably at -20 degrees C; however, it seems to undergo auto-proteolysis when stored at temperature #10878;4-10 degrees C. BoNT/E-LC is active on its natural substrate, the synaptosomal associated 25kDa protein, SNAP-25, indicating that it retains a native-like conformation and therefore can be considered as a useful tool in studying the structure/function of the catalytic light chain. Recombinant BoNT/E-LC has been crystallized under five different conditions and at various pHs. Crystals diffract to better than 2.1A.
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Affiliation(s)
- Rakhi Agarwal
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
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17
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Slater LN, Greenfield RA. Biological toxins as potential agents of bioterrorism. J Okla State Med Assoc 2003; 96:73-6. [PMID: 12674908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
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18
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Kamata Y, Hoshi H, Choki H, Kozaki S. Characterization of a neutralizing monoclonal antibody against botulinum ADP-ribosyltransferase, C3 exoenzyme. J Vet Med Sci 2002; 64:767-71. [PMID: 12399599 DOI: 10.1292/jvms.64.767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A monoclonal antibody, named C302, was prepared and characterized against botulinum ADP-ribosyltransferase C3 exoenzyme that inactivates RhoA GTP-binding protein, resulting in the neurite outgrowth of human neuroblastoma GOTO cells. C302 bound not to the smaller fragments derived from the protease-treated C3 exoenzyme but to the intact C3 exoenzyme. It seems that the C302 epitope may depend on the three-dimensional structure of C3 exoenzyme molecule. C302 depressed the enzymatic and biological actions of C3 exoenzyme. The dose-dependent depression pattern of C302 on the enzyme activity was similar to that to the biological one. C302 turned the neurite-bearing shape of the C3 exoenzyme-treated GOTO cells into the intact shape. By using of C302 mAb and C3 exoenzyme, the research concerning GTP-binding proteins would be improved.
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Affiliation(s)
- Yoichi Kamata
- Department of Veterinary Science, College of Agriculture, Osaka Prefecture University, Gakuen-cho, Sakai, Osaka, Japan
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19
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Affiliation(s)
- C Wilde
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie der Albert-Ludwigs-Universität Freiburg, Albertstr. 25, D-79104, Freiburg, Germany
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20
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Abstract
AIMS An immuno-polymerase chain reaction (immuno-PCR) has been developed for the sensitive detection of antigens, which greatly extends the detection limits of immunoassays. In the current study, the method was applied to the detection of Clostridium botulinum neurotoxin type A (BTx-A). METHODS AND RESULTS Anti-BTx-A antibody-DNA conjugates were synthesized using a heterobifunctional cross-linker reagent to covalently link the reporter DNA and the antibodies. The antibody-DNA conjugates with antigens were amplified by PCR, and dose-dependent relationships for each analyte were demonstrated. Detection limits of immuno-PCR for BTx-A (3.33 x 10(-17) mol) exceeded the conventional enzyme-linked immunosorbent assay (3.33 x 10(-14) mol) by a 1000-fold enhancement in detection sensitivity. CONCLUSION Detection of BTx-A antigens by immuno-PCR demonstrated 100% sensitivity and 100% specificity in 100-fold magnitude below the detection limit of ELISA. SIGNIFICANCE AND IMPACT OF THE STUDY It is concluded that the immuno-PCR method could be used to detect a very low level of BTx-A for clinical diagnosis.
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Affiliation(s)
- H C Wu
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan, Republic of China.
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21
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Han S, Arvai AS, Clancy SB, Tainer JA. Crystal structure and novel recognition motif of rho ADP-ribosylating C3 exoenzyme from Clostridium botulinum: structural insights for recognition specificity and catalysis. J Mol Biol 2001; 305:95-107. [PMID: 11114250 DOI: 10.1006/jmbi.2000.4292] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Clostridium botulinum C3 exoenzyme inactivates the small GTP-binding protein family Rho by ADP-ribosylating asparagine 41, which depolymerizes the actin cytoskeleton. C3 thus represents a major family of the bacterial toxins that transfer the ADP-ribose moiety of NAD to specific amino acids in acceptor proteins to modify key biological activities in eukaryotic cells, including protein synthesis, differentiation, transformation, and intracellular signaling. The 1.7 A resolution C3 exoenzyme structure establishes the conserved features of the core NAD-binding beta-sandwich fold with other ADP-ribosylating toxins despite little sequence conservation. Importantly, the central core of the C3 exoenzyme structure is distinguished by the absence of an active site loop observed in many other ADP-ribosylating toxins. Unlike the ADP-ribosylating toxins that possess the active site loop near the central core, the C3 exoenzyme replaces the active site loop with an alpha-helix, alpha3. Moreover, structural and sequence similarities with the catalytic domain of vegetative insecticidal protein 2 (VIP2), an actin ADP-ribosyltransferase, unexpectedly implicates two adjacent, protruding turns, which join beta5 and beta6 of the toxin core fold, as a novel recognition specificity motif for this newly defined toxin family. Turn 1 evidently positions the solvent-exposed, aromatic side-chain of Phe209 to interact with the hydrophobic region of Rho adjacent to its GTP-binding site. Turn 2 evidently both places the Gln212 side-chain for hydrogen bonding to recognize Rho Asn41 for nucleophilic attack on the anomeric carbon of NAD ribose and holds the key Glu214 catalytic side-chain in the adjacent catalytic pocket. This proposed bipartite ADP-ribosylating toxin turn-turn (ARTT) motif places the VIP2 and C3 toxin classes into a single ARTT family characterized by analogous target protein recognition via turn 1 aromatic and turn 2 hydrogen-bonding side-chain moieties. Turn 2 centrally anchors the catalytic Glu214 within the ARTT motif, and furthermore distinguishes the C3 toxin class by a conserved turn 2 Gln and the VIP2 binary toxin class by a conserved turn 2 Glu for appropriate target side-chain hydrogen-bonding recognition. Taken together, these structural results provide a molecular basis for understanding the coupled activity and recognition specificity for C3 and for the newly defined ARTT toxin family, which acts in the depolymerization of the actin cytoskeleton. This beta5 to beta6 region of the toxin fold represents an experimentally testable and potentially general recognition motif region for other ADP-ribosylating toxins that have a similar beta-structure framework.
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Affiliation(s)
- S Han
- Department of Molecular Biology, Skaggs Institute for Chemical Biology, The Scripps Research Institute, MB 4, 10550 North Torrey Pines Rd., La Jolla, CA 92037, USA
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22
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Affiliation(s)
- T Borbiev
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21224, USA
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23
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Sagane Y, Watanabe T, Kouguchi H, Sunagawa H, Inoue K, Fujinaga Y, Oguma K, Ohyama T. Characterization of nicking of the nontoxic-nonhemagglutinin components of Clostridium botulinum types C and D progenitor toxin. J Protein Chem 2000; 19:575-81. [PMID: 11233171 DOI: 10.1023/a:1007198202016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Clostridium botulinum C and D strains produce two types of progenitor toxins, M and L. Previously we reported that a 130-kDa nontoxic-nonhemagglutinin (NTNHA) component of the M toxin produced by type D strain CB16 was nicked at a unique site, leading to a 15-kDa N-terminal fragment and a 115-kDa C-terminal fragment. In this study, we identified the amino acid sequences around the nicking sites in the NTNHAs of the M toxins produced by C. botulinum type C and D strains by analysis of their C-terminal and N-terminal sequences and mass spectrometry. The C-terminus of the 15-kDa fragments was identified as Lys127 from these strains, indicating that a bacterial trypsin-like protease is responsible for the nicking. The 115-kDa fragment had mixtures of three different N-terminal amino acid sequences beginning with Leu135, Val139, and Ser141, indicating that 7-13 amino acid residues were deleted from the nicking site. The sequence beginning with Leu135 would also suggest cleavage by a trypsin-like protease, while the other two N-terminal amino acid sequences beginning with Val139 and Ser141 would imply proteolysis by an unknown protease. The nicked NTNHA forms a binary complex of two fragments that could not be separated without sodium dodecyl sulfate.
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Affiliation(s)
- Y Sagane
- Department of Food Science, Faculty of Bioindustry, Tokyo University of Agriculture, Abashiri, Japan
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24
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Abstract
During the early stages of thymopoiesis, cell survival is controlled by cytokines that regulate the expression of antiapoptotic proteins such as Bcl-2. At the pre-T cell stage, a critical checkpoint for beta chain selection is monitored by the tumor suppressor p53: pre-T cells can survive and differentiate when p53 is removed genetically or when its proapoptotic function is inactivated physiologically as a consequence of signaling through the pre-T cell receptor complex. Previous work has shown that the guanine nucleotide binding protein Rho controls cell survival in T cell progenitors. Here we define the survival pathways controlled by Rho in pre-T cells and show that this GTPase is a pivotal regulator of the p53-mediated checkpoint operating at the time of beta selection: loss of Rho function results in apoptosis in pre-T cells, but this cell death is prevented by loss of p53. The prevention of cell death by loss of p53 restored numbers of early T cell progenitors but did not fully restore thymic cellularity. Further analysis revealed that loss of Rho function caused survival defects in CD4/8 double-positive thymocytes that is independent of p53 but can be prevented by ectopic expression of Bcl-2. These studies highlight that the GTPase Rho is a crucial component of survival signaling pathways in at least two different thymocyte subpopulations: Rho controls the p53 survival checkpoint in pre-T cells and is also crucial for a p53 independent survival signaling pathway in CD4/8 double positives.
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Affiliation(s)
- Patrick S. Costello
- Lymphocyte Activation Laboratory, Imperial Cancer Research Fund, London WC2A 3PX, United Kingdom
| | - Steve C. Cleverley
- Lymphocyte Activation Laboratory, Imperial Cancer Research Fund, London WC2A 3PX, United Kingdom
| | - Ricciarda Galandrini
- Lymphocyte Activation Laboratory, Imperial Cancer Research Fund, London WC2A 3PX, United Kingdom
| | - Stefan W. Henning
- Lymphocyte Activation Laboratory, Imperial Cancer Research Fund, London WC2A 3PX, United Kingdom
| | - Doreen A. Cantrell
- Lymphocyte Activation Laboratory, Imperial Cancer Research Fund, London WC2A 3PX, United Kingdom
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25
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Abstract
The C3-like ADP-ribosyltransferases exhibit a very confined substrate specificity compared with other Rho-modifying bacterial toxins; they selectively modify the RhoA, -B, and -C isoforms but not other members of the Rho or Ras subfamilies. In this study, the amino acid residues involved in the RhoA substrate recognition by C3 from Clostridium botulinum are identified by applying mutational analyses of the nonsubstrate Rac. First, the minimum domain responsible for the recognition by C3 was identified as the N-terminal 90 residues. Second, the combination of the N-terminal basic amino acids ((Rho)Arg(5)-Lys(6)), the acid residues (Rho)Glu(47) and (Rho)Glu(54) only slightly increases ADP-ribosylation but fully restores the binding of the respective mutant Rac to C3. Third, the residues (Rho)Glu(40) and (Rho)Val(43) also participate in binding to C3 but they are mainly involved in the correct formation of the ternary complex between Rho, C3, and NAD(+). Thus, these six residues (Arg(5), Lys(6), Glu(40), Val(43), Glu(47), and Glu(54)) distributed over the N-terminal part of Rho are involved in the correct binding of Rho to C3. Mutant Rac harboring these residues shows a kinetic property with regard to ADP-ribosylation, which is identical with that of RhoA. Differences in the conformation of Rho given by the nucleotide occupancy have only minor effects on ADP-ribosylation.
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Affiliation(s)
- C Wilde
- Institut für Pharmakologie und Toxikologie der Universität Freiburg, Hermann-Herder-Strasse 5, D-79104 Freiburg, Germany
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26
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Shome K, Rizzo MA, Vasudevan C, Andresen B, Romero G. The activation of phospholipase D by endothelin-1, angiotensin II, and platelet-derived growth factor in vascular smooth muscle A10 cells is mediated by small G proteins of the ADP-ribosylation factor family. Endocrinology 2000; 141:2200-8. [PMID: 10830309 DOI: 10.1210/endo.141.6.7517] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We show here that A10 cells express the phospholipase D (PLD) isoforms PLD1b and PLD2. The activation of PLD in these cells by angiotensin II (AngII), endothelin-1 (ET-1), and platelet-derived growth factor (PDGF) was found to be sensitive to inhibitors of the activation of ADP-ribosylation factor (ARF) but not to blockers of Rho protein function. PDGF, AngII, and ET-1 induced the binding of ARF proteins to cell membranes in a permeabilized cell assay. Cells permeabilized and depleted of ARF were no longer sensitive to stimulation with AngII, ET-1, or PDGF, but the addition of recombinant myristoylated human ARF1 restored agonist-dependent PLD activity. Expression of dominant negative ARF mutants blocked receptor-dependent activation of PLD. PLD activity was also potently stimulated by treatment with phorbol esters, but this activity was only partially inhibited by brefeldin A or by the overexpression of ARF dominant negative mutants. Transient expression of catalytically inactive mutants of PLD2, but not PLD1, inhibited significantly PDGF- and AngII-dependent PLD activity. We conclude: 1) the activation of PLD by cell surface receptors occurs primarily by an ARF-dependent mechanism in A10 cells, whereas the activation of PLD by protein kinase C-dependent pathways is only partially dependent on the regulation of ARF proteins; and 2) cell surface receptors, such as AngII and PDGF, signal primarily via PLD2 in A10 cells.
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Affiliation(s)
- K Shome
- Department of Pharmacology of the University of Pittsburgh School of Medicine, Pennsylvania 15261, USA
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27
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Abstract
Changes in the lactate dehydrogenase (LDH) isozyme pattern of primary culture of neurons treated with botulinum C3 enzyme were examined in order to elucidate the functional changes accompanying the morphological change that follows ADP-ribosylation of Rho protein. Primary neurons were prepared from the cerebrum of ICR mouse embryos on day 15. Neurons were cultured in MEM with 10% fetal calf serum at 37 degrees C. In the neurons treated with C3 enzyme, a typical morphological change was observed after 24 hr, and the LDH isozyme pattern was changed after 72 hr. The ratio of H-subunit to M-subunit in LDH was decreased by C3 treatment, suggesting the induction of a state of lower intracellular oxygen consumption in neurons in the primary cultures.
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Affiliation(s)
- Y Watanabe
- Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Japan
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28
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Angkachatchai V, Finkel TH. ADP-ribosylation of rho by C3 ribosyltransferase inhibits IL-2 production and sustained calcium influx in activated T cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1999; 163:3819-25. [PMID: 10490980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Activation of the T lymphocyte induces dramatic cytoskeletal changes, and there is increasing evidence that disruption of the cytoskeleton inhibits early and late events of T cell signal transduction. However, relatively little is known about the signaling molecules involved in activation-induced cytoskeletal rearrangement. The rho family of small GTP-binding proteins, which include rho, rac, and cdc42, regulates the cytoskeleton and coordinates various cellular functions via their many effector targets. In prior studies, the Clostridium botulinum toxin C3 exoenzyme has been used to ADP-ribosylate and inactivate rho. In this study, we demonstrate that treatment of T cells with C3 exoenzyme inhibits IL-2 transcription following ligation of the TCR. Inhibition of IL-2 expression correlated with loss of sustained increase in [Ca+2]i and mitogen activated protein kinase (MAPK/Erk) activity, but not with activation of the tyrosine kinase, lck. These findings are the first to show that ADP-ribosylation of rho by C3 ribosyltransferase (exoenzyme) inhibits IL-2 production due, in part, to the requirement for sustained calcium influx and MAPK activation after Ag receptor ligation.
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Affiliation(s)
- V Angkachatchai
- Division of Basic Sciences, Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206, USA
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29
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Abstract
Development of thymocytes can be staged according to the levels of expression of the cell-surface markers CD4, CD8, CD44, CD25 and CD2. Thymocyte development is regulated by a complex signalling network [1], one component of which is the GTPase Rho. The bacterial enzyme C3 transferase from Clostridium botulinum selectively ADP-ribosylates Rho in its effector-binding domain and thereby abolishes its biological function [2,3]. To explore the function of Rho in thymocyte development, we previously used the proximal promoter of the gene encoding the Src-family kinase p56lck to make transgenic mice that selectively express C3 transferase in the thymus [4,6]. In these mice, which lack Rho function from the earliest thymocyte stages, thymocyte numbers are reduced by approximately 50- to 100-fold. Here, we describe transgenic mice that express C3 transferase under the control of the locus control region (LCR) of the CD2 gene; this regulatory element drives expression at a later stage of thymocyte development than the lck proximal promoter [7]. In these mice, thymocyte numbers were also reduced by 50- to 100-fold, but unlike the lck-C3 mice, in which the reduction predominantly results from defects in cell survival of CD25(+) thymocyte progenitors, the CD2-C3 transgenic mice had a pre-T-cell differentiation block at the CD25(+) stage after rearrangement of the T-cell receptor (TCR) beta chains. Analysis of CD2-C3 mice demonstrated that Rho acts as an intracellular switch for TCR beta selection, the critical thymic-differentiation checkpoint. These results show that Rho-mediated survival signals for CD25(+) pre-T cells are generated by the extracellular signals that act on earlier thymocyte precursors and also that temporal cell-type-specific elimination of Rho can reveal different functions of this GTPase in vivo.
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Affiliation(s)
- S Cleverley
- Lymphocyte Activation Laboratory, Imperial Cancer Research Fund, 44 Lincoln's Inn Fields, London, WC2A 3PX, UK.
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30
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Abstract
The large-scale production of recombinant proteins in plants is limited by relatively low yields and difficulties in extraction and purification. These problems were addressed by engineering tobacco plants to continuously secrete recombinant proteins from their roots into a simple hydroponic medium. Three heterologous proteins of diverse origins (green fluorescent protein of jellyfish, human placental alkaline phosphatase [SEAP], and bacterial xylanase) were produced using the root secretion method (rhizosecretion). Protein secretion was dependent on the presence of the endoplasmic reticulum signal peptide fused to the recombinant protein sequence. All three secreted proteins retained their biological activity and, as shown for SEAP, accumulated in much higher amounts in the medium than in the root tissue.
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Affiliation(s)
- N V Borisjuk
- Biotech Center, Cook College, Rutgers University, New Brunswick, NJ 08901-8520, USA
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31
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Imamura F, Mukai M, Ayaki M, Takemura K, Horai T, Shinkai K, Nakamura H, Akedo H. Involvement of small GTPases Rho and Rac in the invasion of rat ascites hepatoma cells. Clin Exp Metastasis 1999; 17:141-8. [PMID: 10411106 DOI: 10.1023/a:1006598531238] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Lysophosphatidic acid (LPA) triggers the invasion of a mesothelial cell monolayer by rat ascites hepatoma (MM1) cells. LPA also induces rapid morphological changes of MM1 cells, cell surface blebbing and pseudopodia formation. Pseudopodia formation is tightly correlated with cellular invasiveness. Clostridium Botulinum C3 exoenzyme and genistein abrogated the formation of blebs and pseudopodia together with the inhibition of invasion, indicating that GTPase Rho and certain tyrosine kinases are involved in both processes. MM1 cells expressing constitutively active Rho exhibited the invasion and the formation of blebs and pseudopodia in the absence of LPA. In contrast, MM1 cells expressing constitutively active Rac were not invasive in the absence of LPA, but were invasive in the presence of LPA. Their morphological response to LPA was almost the same as that of parental MM1 cells. Expression of dominant negative Rac suppressed the invasiveness to approximately 3% of that of parental MM1 cells, together with the inhibition of pseudopodia formation. Thus, Rho and Rac are cooperatively involved in both the invasion and the related morphological changes of MM1 cells. Rho activation is sufficient both for the induction of invasion and the morphological changes leading to the invasion, whereas Rac activation is necessary but not sufficient by itself. We propose that Rho activation is not mediated by Rac but the cooperation of both GTPases is essential to trigger the invasive behavior of MM1 cells.
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Affiliation(s)
- F Imamura
- Department of Pulmonary Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Japan.
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32
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Abstract
Rho family GTP-binding proteins have been demonstrated to play a role in the regulation of phospholipase D (PLD) activity. In the present study, we examined the role of Rho proteins in PLD activation in differentiated HL-60 cells using C3 exoenzyme from Clostridium botulinum, which ADP-ribosylates and inactivates Rho proteins. Introduction of C3 exoenzyme into differentiated HL-60 cells by electroporation resulted in complete inhibition of PLD activity stimulated by formyl methionine-leucine-phenylalanine (fMLP) and ATP, two receptor agonists. Phorbol myristate acetate-induced PLD activation was also inhibited in C3 exoenzyme-treated cells, but the inhibition was only partial. GTPgammaS-dependent activation of PLD, measured in the absence or presence of ATP in permeabilized cells, was also partially affected by C3 exoenzyme treatment. Thus, these results indicate that Rho proteins play a key role in receptor-mediated PLD regulation in differentiated HL-60 cells, but play a partial role in the in vivo action of PMA and in vitro action of GTPgammaS on PLD. ATP produced a significant enhancement of the in vitro effect of GTPgammaS on PLD activity, but the effect of ATP was not altered by inhibitors of serine/threonine and tyrosine kinases. However, it was markedly reduced by neomycin and accompanied by an increase in phosphatidylinositol 4,5-bisphosphate (PtdInsP2) synthesis. These data indicate that in permeabilized HL-60 cells, the stimulatory effect of ATP on PLD does not involve protein phosphorylation but is due to an increase in PtdInsP2.
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Affiliation(s)
- I Guillemain
- Howard Hughes Medical Institute and Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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33
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Abstract
The neurotoxins produced by Clostridium botulinum are amongst the most potent known to man. Toxin production is detected by a mouse bioassay, which requires several days for a result and is not acceptable for routine use unless there is a high level of suspicion. The Rapid ID32 A kit produced by bioMerieux gives an identification of an isolate within 4 h. The aim of this study was to examine the efficiency of the identification of Cl. botulinum using the Rapid ID32 A. Forty-two strains of Cl. botulinum, one strain each of botulinum toxin-producing Cl. butyricum and Cl. baratii, and four strains of Cl. sporogenes, were tested. One strain of Group I Cl. botulinum gave a presumptive identification of Group II Cl. botulinum, six strains of Cl. botulinum were identified as 50-98% Cl. botulinum in some tests, and 17 strains of Cl. botulinum were identified as < 50% Cl. botulinum. Thirteen strains of Cl. botulinum were identified as > 99% Cl. sporogenes or 86% Cl. histolyticum, and five strains gave a combination of these results. All strains of Cl. sporogenes were correctly identified. These results show that some strains of Cl. botulinum may not be correctly identified using the Rapid ID32A.
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Affiliation(s)
- M M Brett
- Food Hygiene Laboratory, PHLS Central Public Health Laboratory, London, UK
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Ekong TAN, Feavers IM, Sesardic D. Recombinant SNAP-25 is an effective substrate for Clostridium botulinum type A toxin endopeptidase activity in vitro. Microbiology (Reading) 1997; 143 ( Pt 10):3337-3347. [PMID: 9353935 DOI: 10.1099/00221287-143-10-3337] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Bacterial neurotoxins are now being used routinely for the treatment of neuromuscular conditions. Alternative assays to replace or to complement in vivo bioassay methods for assessment of the safety and potency of these botulinum neurotoxin-based therapeutic products are urgently needed. Advances made in understanding the mode of action of clostridial neurotoxins have provided the basis for the development of alternative mechanism-based assay methods. Thus, the identification of SNAP-25 (synaptosomal-associated protein of molecular mass 25 kDa) as the intracellular protein target which is selectively cleaved during poisoning by botulinum neurotoxin type A (BoNT/A) has enabled the development of a functional in vitro assay for this toxin. Using recombinant DNA methods, a segment of SNAP-25 (aa residues 134-206) spanning the toxin cleavage site was prepared as a fusion protein to the maltose-binding protein in Escherichia coli. The fusion protein was purified by affinity chromatography and the fragment isolated after cleavage with Factor Xa. Targeted antibodies specific for the N and C termini of SNAP-25, as well as the toxin cleavage site, were prepared and used in an immunoassay to demonstrate BoNT/A endopeptidase activity towards recombinant SNAP-25 substrates. The reaction required low concentrations of reducing agents which were inhibitory at higher concentrations as were metal chelators and some inhibitors of metallopeptidases. The endopeptidase assay has proved to be more sensitive than the mouse bioassay for detection of toxin in therapeutic preparations. A good correlation with results obtained in the in vivo bioassay (r = 0.95, n = 23) was demonstrated. The endopeptidase assay described here may provide a suitable replacement assay for the estimation of the potency of type A toxin in therapeutic preparations.
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Affiliation(s)
- Theresa A N Ekong
- Division of Bacteriology, National Institute for Biological Standards and Control, South Mimms, Potters Bar, Hertfordshire EN6 3QG, UK
| | - Ian M Feavers
- Division of Bacteriology, National Institute for Biological Standards and Control, South Mimms, Potters Bar, Hertfordshire EN6 3QG, UK
| | - Dorothea Sesardic
- Division of Bacteriology, National Institute for Biological Standards and Control, South Mimms, Potters Bar, Hertfordshire EN6 3QG, UK
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Verschueren H, De Baetselier P, De Braekeleer J, Dewit J, Aktories K, Just I. ADP-ribosylation of Rho-proteins with botulinum C3 exoenzyme inhibits invasion and shape changes of T-lymphoma cells. Eur J Cell Biol 1997; 73:182-7. [PMID: 9208232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
C3 exoenzyme from Clostridium botulinum ADP-ribosylates the small GTP-binding protein Rho with a high specificity. The use of C3 has shown that Rho-mediated signaling is involved in the regulation of actin-dependent processes in various cell types. In order to investigate the role of Rho-proteins in lymphocyte crawling, we have analyzed the effects of C3 on a T-cell line derived from the murine BW5147 lymphoma. Pretreatment of the lymphoma cells with C3, in conditions where Rho was actually ADP-ribosylated, strongly inhibited the characteristic shape changes resulting from extension and retraction of pseudopodia. Concomitantly, invasion of the cells through a monolayer of fibroblast-like cells was also inhibited. C3-treatment did not affect the total F-actin content of the cells, as measured by flow cytometry of cells stained with phalloidin. Yet, microscopical observation revealed that the accumulations of F-actin, which were seen in the pseudopodia of untreated cells, were absent after treatment with C3. This suggests that C3 may affect actin polymerization locally. The inhibitory effect of C3 on invasion was not restricted to the murine BW5147 lymphoma cell line, as it occurred also with CCRF-CEM, a human T-cell lymphoma line. Our results demonstrate that invasion-bound motility of lymphocytes depends on a Rho-mediated signal transduction pathway.
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Abstract
The present study employs a genetic approach to explore the role of Rho GTPases in murine thymic development. Inactivation of Rho function in the thymus was achieved by thymic targeting of a transgene encoding C3 transferase from Clostridium botulinum which selectively ADP-ribosylates Rho within its effector domain and thereby abolishes its biological function. Thymi lacking functional Rho isolated from C3 transgenic mice were strikingly smaller and showed a marked (90%) decrease in cellularity compared with their normal litter mates. We also observed a similar decrease in levels of peripheral T cells in C3 transgenic mice. Analysis of the maturation status of thymocytes indicated that differentiation of progenitor cells to mature T cells can occur in the absence of Rho function, and both positive and negative selection of T cells appear to be intact. However, transgenic mice that lack Rho function in the thymus show maturational, proliferative and cell survival defects during T-cell development that severely impair the generation of normal numbers of thymocytes and mature peripheral T cells. The present study thus identifies a role for Rho-dependent signalling pathways in thymocyte development. The data show that the function of Rho GTPases is critical for the proliferative expansion of thymocytes. This defines a selective role for the GTPase Rho in early thymic development as a critical integrator of proliferation and cell survival signals.
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Affiliation(s)
- S W Henning
- Lymphocyte Activation Laboratory, Imperial Cancer Research Fund, London, UK.
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37
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Sah VP, Hoshijima M, Chien KR, Brown JH. Rho is required for Galphaq and alpha1-adrenergic receptor signaling in cardiomyocytes. Dissociation of Ras and Rho pathways. J Biol Chem 1996; 271:31185-90. [PMID: 8940118 DOI: 10.1074/jbc.271.49.31185] [Citation(s) in RCA: 170] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
G protein-coupled receptor agonists initiate a cascade of signaling events in neonatal rat ventricular myocytes that culminates in changes in gene expression and cell growth characteristic of hypertrophy. These responses have been previously shown to be dependent on Gq and Ras. Rho, a member of the Ras superfamily of GTPases, regulates cytoskeletal rearrangement and transcriptional activation of the c-fos serum response element. Immunofluorescence staining of cardiomyocytes shows that Rho is present and predominantly cytosolic. We used two inhibitors of Rho function, dominant negative N19RhoA and Clostridium botulinum C3 transferase, to examine the possible requirement for Rho in alpha1-adrenergic receptor-mediated hypertrophy. Both inhibitors markedly attenuated atrial natriuretic factor (ANF) reporter gene expression induced by alpha1-adrenergic receptor stimulation with phenylephrine, and virtually abolished the increase in ANF reporter gene expression induced by GTPase-deficient Galphaq. These effects were reproduced with the myosin light chain-2 reporter gene. Notably, N19RhoA did not block the ability of activated Ras to induce ANF and myosin light chain-2 reporter gene expression. Furthermore, activation of the extracellular signal-regulated kinase by phenylephrine was not blocked by N19RhoA, nor was it stimulated by an activated mutant of RhoA. Since activated RhoA and Ras produce a large synergistic effect on ANF-luciferase gene expression, we conclude that Rho functions in a pathway separate from but complementary to Ras. Our results provide direct evidence that Rho is an effector of Galphaq signaling and suggest for the first time that a low molecular weight GTPase other than Ras is involved in regulating myocardial cell growth and gene expression in response to heterotrimeric G protein-linked receptor activation.
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Affiliation(s)
- V P Sah
- Department of Pharmacology and Graduate Program in Biomedical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
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Aepfelbacher M, Essler M, Huber E, Czech A, Weber PC. Rho is a negative regulator of human monocyte spreading. J Immunol 1996; 157:5070-5. [PMID: 8943416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Monocyte spreading is a sequential series of events including cell flattening, formation of new actin structures and focal adhesions, as well as development of cytoplasmic projections. To investigate the involvement of the GTP-binding protein Rho in spreading, we treated human blood monocytes or PMA-stimulated U937 or THP1 cells with Clostridium botulinum C3-transferase (C3), which ADP-ribosylates and inactivates Rho in intact cells. The C3 treatment caused 1) a four- to fivefold increase in the number of THP1 cells that spread on fibronectin within 24 h of PMA stimulation, 2) a greater area covered by the spread cells, and 3) accelerated and enhanced development of macrophage-like filopodial and pseudopodial projections. Similar results were obtained with PMA-stimulated U937 cells and human blood monocytes. Furthermore, cell staining revealed disorganization of subcortical actin in C3-treated THP1 cells, whereas circular actin formations at the substrate-attached part of the cells and vinculin-containing focal complexes/adhesions were unaffected. Finally, we found a decrease in membrane-associated RhoA in normal spreading THP1 cells, which suggests endogenous inactivation of Rho and might provide an explanation for the acceleration of spreading caused by the C3-transferase. In conclusion, these results indicate that active Rho is an important, negative regulator of human monocyte spreading by maintaining cell tension and cortical actin organization.
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Affiliation(s)
- M Aepfelbacher
- Institute for Prevention of Cardiovascular Diseases, University of Munich, Germany
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Abstract
In the yeast Saccharomyces cerevisiae, the family of RHO genes are implicated in the control of morphogenetic events although the molecular targets of these GTP-binding proteins remain largely unknown. The activity of 1,3-beta-D-glucan synthase, the product of which is essential for cell wall integrity, is regulated by a GTP-binding protein, which we here present evidence to be Rho1p. Rho1p was found to copurify with Fks1p, a glucan synthase subunit, in preparations of the enzyme purified by product entrapment and was also shown to be depleted by a detergent extraction procedure known to remove the GTP-binding regulatory component. Specific ADP-ribosylation of Rho1p by exoenzyme C3 inactivates glucan synthase activity specified by FKS1 and FKS2 as demonstrated in membrane preparations from fks2 and fks1 deletion strains, respectively, and in the purified enzyme containing Fks1p. Rho1p and Fks1p were co-immunoprecipitated from purified glucan synthase under conditions that maintained enzyme activity in the immunoprecipitate. Putative Rho homologs were also identified and implicated in the regulation of glucan synthase activity from Candida albicans, Aspergillus nidulans, and Cryptococcus neoformans by ribosylation studies. The regulation of 1,3-beta-D-glucan synthase activity by RHO1 is consistent with its observed role in morphogenetic control and osmotic integrity.
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Affiliation(s)
- P Mazur
- Department of Biochemistry, Merck Research Laboratories, Rahway, New Jersey 07065, USA
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Abstract
Mechanisms of vanadate-induced actin reorganization were examined in cultured astrocytes. Treatment of protoplasmic astrocytes with 0.5 mM dibutyryl cAMP (DBcAMP) caused the disappearance of stress fibers (SFs) and focal adhesions (FAs) accompanied with cellular stellation. A subsequent addition of 1 mM orthovanadate (VO4(3-) reorganized SFs and FAs in DBcAMP-treated cells. The newly formed FAs had increased phosphotyrosine levels. VO4(3-) reorganized SFs and FAs in stellate astrocytes induced by 5 microM cytochalasin B, 50 microM ML-9 and 20 microM W-7. Cytoplasmic microinjection of 20 micrograms/ml C3 ADP-ribosyltransferase of C. botulinum, which inactivates rho proteins, caused disappearance of SFs. The effect of C3 enzyme on SFs was not reversed by a subsequent addition of VO4(3-). These results suggest that rho proteins are involved in vanadate-induced reorganization of cytoskeletal actin.
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Affiliation(s)
- Y Koyama
- Department of Pharmacology, Faculty Pharmaceutical Sciences, Osaka University, Suita, Japan
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Miyaoka T, Tsuchiya M, Hara N, Ishino H, Shimoyama M. Activation of Clostridium botulinum C3 exoenzyme-catalyzed ADP-ribosylation of RhoA by K+ in a Mg2+ -dependent manner. J Biochem 1996; 119:200-7. [PMID: 8907197 DOI: 10.1093/oxfordjournals.jbchem.a021209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The effect of KCl on ADP-ribosylation of the recombinant RhoA protein catalyzed by the Clostridium botulinum C3 enzyme was studied. When the recombinant glutathione S-transferase-RhoA fusion protein (GST-RhoA) was incubated with C3 and [adenylate-32P]NAD, incorporation of radioactivity into the recombinant RhoA increased in the presence of KCl. The increase in ADP-ribose incorporation into RhoA due to KCl appeared in the presence of MgCl2 and was abolished by EDTA. C3 was stabilized by KCl, but the stabilization was also seen with BSA. The KCl-induced increase in the ADP-ribosylation was observed even in the presence of BSA during the modification reaction, thus the effect of KCl was not due to the stabilization of C3. While the initial rate of the reaction was increased by KCl, maximum incorporation of ADP-ribose per GST-RhoA molecule did not increase in the presence of KCl. Kinetic analysis revealed that KCl increased Vmax but did not alter Km for either NAD or RhoA. The NAD glycohydrolase activity of C3 was also increased by KCl. These results indicate that KCl directly activates the C3 enzyme.
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Affiliation(s)
- T Miyaoka
- Departments of Biochemistry and Psychiatry, Shimane Medical University, Izumo
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Balboa MA, Insel PA. Nuclear phospholipase D in Madin-Darby canine kidney cells. Guanosine 5'-O-(thiotriphosphate)-stimulated activation is mediated by RhoA and is downstream of protein kinase C. J Biol Chem 1995; 270:29843-7. [PMID: 8530380 DOI: 10.1074/jbc.270.50.29843] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We have recently demonstrated the existence of an ATP-activated phospholipase D (PLD) in the nuclei of MDCK-D1 cells (Balboa, M. A., Balsinde, J., Dennis, E. A., and Insel, P. A. (1995) J. Biol. Chem. 270, 11738-11740). We have now found that nuclear PLD is synergistically activated by guanosine 5'-O-(thiotriphosphate) (GTP gamma S) and ATP in a time- and concentration-dependent manner, but these compounds do not alter the sensitivity of the enzyme to activation by Ca2+. The synergistic stimulation of PLD activity could be blocked by addition of the protein kinase C inhibitors chelerythrine and calphostin C. Stimulation by GTP gamma S was abolished by guanosine 5'-O-(2-thiodiphosphate). Incubation of isolated nuclei with Clostridium botulinum C3 exoenzyme inhibited the potentiating effect of GTP gamma S on ATP-dependent nuclear PLD activity. Moreover, use of the Rho GDP dissociation inhibitor to extract Rho family G proteins from cell nuclei also inhibits PLD activity. Western blot analyses of isolated nuclei revealed the presence of the small G protein RhoA, but not of RhoB or the ADP-ribosylation factor. GTP gamma S-stimulated ATP-dependent PLD activity could be reconstituted in Rho GDP dissociation inhibitor-washed nuclei by addition of recombinant prenylated RhoA, but not by addition of non-prenylated RhoA. Taken together, these results indicate that nuclear PLD activity is modulated via a RhoA-dependent activation that occurs downstream of protein kinase C. Nuclear PLD, which appears to be a previously unrecognized effector regulated by protein kinase C and G proteins, may be involved in the regulation of nuclear function or structure.
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Affiliation(s)
- M A Balboa
- Department of Pharmacology, University of California at San Diego, La Jolla 92093-0636, USA
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Yonei SG, Oishi K, Uchida MK. Regulation of exocytosis by the small GTP-binding protein Rho in rat basophilic leukemia (RBL-2H3) cells. Gen Pharmacol 1995; 26:1583-9. [PMID: 8690250 DOI: 10.1016/0306-3623(95)00054-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
1. We investigated the effect of Clostridium botulinum C3 ADP-ribosyltransferase upon beta-hexosaminidase release induced by various stimuli from streptolysin-O (0.5-1 U/ml)-permeabilized rat basophilic leukemia (RBL-2H3) cells. 2. The C3 transferase inhibited beta-hexosaminidase release induced by Ca2+ or by guanosine-5'-(3-thiotriphosphate) (GTP gamma S) plus Ca2+. 3. The C3 transferase also inhibited beta-hexosaminidase release induced by stimulating high affinity IgE and m3 muscarinic acetylcholine receptors. 4. The substrate for the C3 transferase was present in cytosol of RBL-2H3 cells, indicating the presence of rho p21. About 60% of the total cellular substrate protein remained within the cells permeabilized by 1 U/ml of streptolysin-O. 5. The protein rho p21 appears to be regulated by several pathways and it may function as an integration point for exocytosis.
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Affiliation(s)
- S G Yonei
- Department of Molecular Pharmacology, Meiji College of Pharmacy, Tokyo, Japan
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Aepfelbacher M, Essler M, Luber De Quintana K, Weber PC. ADP-ribosylation of the GTP-binding protein RhoA blocks cytoplasmic division in human myelomonocytic cells. Biochem J 1995; 308 ( Pt 3):853-8. [PMID: 8948442 PMCID: PMC1136802 DOI: 10.1042/bj3080853] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
To test the role of Rho GTP-binding proteins in growth regulation of human myelomonocytic tumour cells we used recombinant C3 exoenzyme of Clostridium botulinum to specifically ADP-ribosylate and inactivate Rho proteins in situ. In homogenates of HL60 cells, the C3 exoenzyme [32P]ADP-ribosylated one protein that was identified as RhoA by immunoblot and two-dimensional gel electrophoresis. [32P]ADP ribosylation of RhoA in HL60 homogenates in vitro was reduced to 10-20% when cells in culture were pretreated with C3 exoenzyme (10 micrograms, 24 h), indicating that 80-90% of RhoA could be ADP-ribosylated in situ. The C3 exoenzyme inhibited HL60 cell proliferation by up to 80% and the degree of growth inhibition correlated with the amount of in situ ADP-ribosylated RhoA in a time- and dose-dependent manner. Cell cycle analysis demonstrated that the C3 exoenzyme-treated HL60 cells accumulated in mitosis, and nuclear staining revealed binucleated cells. These findings suggest that RhoA has a key role in human myelomonocytic tumour cell growth by regulating cytoplasmic division.
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Affiliation(s)
- M Aepfelbacher
- Institut für Prophylaxe und Epidemiologie der Kreislaufkrankheiten, University of Munich, Germany
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Morii N, Narumiya S. Preparation of native and recombinant Clostridium botulinum C3 ADP-ribosyltransferase and identification of Rho proteins by ADP-ribosylation. Methods Enzymol 1995; 256:196-206. [PMID: 7476433 DOI: 10.1016/0076-6879(95)56024-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- N Morii
- Department of Pharmacology, Kyoto University Faculty of Medicine, Japan
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Affiliation(s)
- P Boquet
- Unité des Toxines Microbiennes, Institut Pasteur, Paris, France
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47
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Affiliation(s)
- K Aktories
- Institute of Pharmacology and Toxicology, Albert-Ludwigs University, Freiburg, Germany
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48
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Affiliation(s)
- S E Rittenhouse
- Jefferson Cancer Institute, Philadelphia, Pennsylvania 19107, USA
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49
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Aktories K, Jung M, Böhmer J, Fritz G, Vandekerckhove J, Just I. Studies on the active-site structure of C3-like exoenzymes: involvement of glutamic acid in catalysis of ADP-ribosylation. Biochimie 1995; 77:326-32. [PMID: 8527485 DOI: 10.1016/0300-9084(96)88142-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Various C3-like ADP-ribosyltransferases like Clostridium botulinum exoenzyme C3, C limosum transferase, B cereus transferase and a transferase from Staphylococcus aureus (EDIN) selectively modify the low-molecular mass GTP-binding proteins RhoA,B,C. UV-irradiation of C limosum transferase in the presence of [carbonyl-14C]NAD resulted in radiolabeling of Glu-174. Concomitantly, ADP-ribosyltransferase and NAD glycohydrolase activities were inhibited. Site-directed mutagenesis of Glu-174 (E174D, E174Q) which resulted in more than 1000-fold reduction of enzyme activity, suggests that the glutamic acid residue is essentially involved in the catalytic action of C3-like transferases. These findings support the view that all bacterial ADP-ribosyltransferases share a similar active-site structure.
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Affiliation(s)
- K Aktories
- Institut für Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg-Saar, Germany
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Affiliation(s)
- S T Dillon
- Department of Microbiology and Molecular Biology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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