1
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Weixler L, Ikenga NJ, Voorneveld J, Aydin G, Bolte TMHR, Momoh J, Bütepage M, Golzmann A, Lüscher B, Filippov DV, Žaja R, Feijs KLH. Protein and RNA ADP-ribosylation detection is influenced by sample preparation and reagents used. Life Sci Alliance 2022; 6:6/1/e202201455. [PMID: 36368907 PMCID: PMC9652768 DOI: 10.26508/lsa.202201455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 11/13/2022] Open
Abstract
The modification of substrates with ADP-ribose (ADPr) is important in, for example, antiviral immunity and cancer. Recently, several reagents were developed to detect ADP-ribosylation; however, it is unknown whether they recognise ADPr, specific amino acid-ADPr linkages, or ADPr with the surrounding protein backbone. We first optimised methods to prepare extracts containing ADPr-proteins and observe that depending on the amino acid modified, the modification is heatlabile. We tested the reactivity of available reagents with diverse ADP-ribosylated protein and RNA substrates and observed that not all reagents are equally suited for all substrates. Next, we determined cross-reactivity with adenylylated RNA, AMPylated proteins, and metabolites, including NADH, which are detected by some reagents. Lastly, we analysed ADP-ribosylation using confocal microscopy, where depending on the fixation method, either mitochondrion, nucleus, or nucleolus is stained. This study allows future work dissecting the function of ADP-ribosylation in cells, both on protein and on RNA substrates, as we optimised sample preparation methods and have defined the reagents suitable for specific methods and substrates.
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Affiliation(s)
- Lisa Weixler
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Aachen, Germany
| | - Nonso Josephat Ikenga
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Aachen, Germany
| | - Jim Voorneveld
- Leiden Institute of Chemistry, Leiden University Department of Bioorganic Synthesis, Leiden, Netherlands
| | - Gülcan Aydin
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Aachen, Germany
| | - Timo MHR Bolte
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Aachen, Germany
| | - Jeffrey Momoh
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Aachen, Germany
| | - Mareike Bütepage
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Aachen, Germany
| | - Alexandra Golzmann
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Aachen, Germany
| | - Bernhard Lüscher
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Aachen, Germany
| | - Dmitri V Filippov
- Leiden Institute of Chemistry, Leiden University Department of Bioorganic Synthesis, Leiden, Netherlands
| | - Roko Žaja
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Aachen, Germany
| | - Karla LH Feijs
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Aachen, Germany,Correspondence: ;
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2
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Weiss A, Lorthiois E, Barys L, Beyer KS, Bomio-Confaglia C, Burks H, Chen X, Cui X, de Kanter R, Dharmarajan L, Fedele C, Gerspacher M, Guthy DA, Head V, Jaeger A, Núñez EJ, Kearns JD, Leblanc C, Maira SM, Murphy J, Oakman H, Ostermann N, Ottl J, Rigollier P, Roman D, Schnell C, Sedrani R, Shimizu T, Stringer R, Vaupel A, Voshol H, Wessels P, Widmer T, Wilcken R, Xu K, Zecri F, Farago AF, Cotesta S, Brachmann SM. Discovery, Preclinical Characterization, and Early Clinical Activity of JDQ443, a Structurally Novel, Potent, and Selective Covalent Oral Inhibitor of KRASG12C. Cancer Discov 2022; 12:1500-1517. [PMID: 35404998 PMCID: PMC9394399 DOI: 10.1158/2159-8290.cd-22-0158] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/14/2022] [Accepted: 04/01/2022] [Indexed: 01/07/2023]
Abstract
Covalent inhibitors of KRASG12C have shown antitumor activity against advanced/metastatic KRASG12C-mutated cancers, though resistance emerges and additional strategies are needed to improve outcomes. JDQ443 is a structurally unique covalent inhibitor of GDP-bound KRASG12C that forms novel interactions with the switch II pocket. JDQ443 potently inhibits KRASG12C-driven cellular signaling and demonstrates selective antiproliferative activity in KRASG12C-mutated cell lines, including those with G12C/H95 double mutations. In vivo, JDQ443 induces AUC exposure-driven antitumor efficacy in KRASG12C-mutated cell-derived (CDX) and patient-derived (PDX) tumor xenografts. In PDX models, single-agent JDQ443 activity is enhanced by combination with inhibitors of SHP2, MEK, or CDK4/6. Notably, the benefit of JDQ443 plus the SHP2 inhibitor TNO155 is maintained at reduced doses of either agent in CDX models, consistent with mechanistic synergy. JDQ443 is in clinical development as monotherapy and in combination with TNO155, with both strategies showing antitumor activity in patients with KRASG12C-mutated tumors. SIGNIFICANCE JDQ443 is a structurally novel covalent KRASG12C inhibitor with a unique binding mode that demonstrates potent and selective antitumor activity in cell lines and in vivo models. In preclinical models and patients with KRASG12C-mutated malignancies, JDQ443 shows potent antitumor activity as monotherapy and in combination with the SHP2 inhibitor TNO155. This article is highlighted in the In This Issue feature, p. 1397.
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Affiliation(s)
- Andreas Weiss
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Louise Barys
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Kim S. Beyer
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Heather Burks
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts
| | - Xueying Chen
- Novartis Pharmaceuticals Corporation, East Hanover, New Jersey
| | - Xiaoming Cui
- Novartis Pharmaceuticals Corporation, East Hanover, New Jersey
| | - Ruben de Kanter
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Carmine Fedele
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts
| | - Marc Gerspacher
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Victoria Head
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Ashley Jaeger
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts
| | | | - Jeffrey D. Kearns
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts
| | | | | | - Jason Murphy
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts
| | - Helen Oakman
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts
| | - Nils Ostermann
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Johannes Ottl
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Danielle Roman
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Richard Sedrani
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Rowan Stringer
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Andrea Vaupel
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Hans Voshol
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | | | - Rainer Wilcken
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Kun Xu
- Novartis Pharmaceuticals Corporation, East Hanover, New Jersey
| | - Frederic Zecri
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts
| | - Anna F. Farago
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts.,Corresponding Authors: Saskia M. Brachman, Novartis Institutes for BioMedical Research (NIBR), WSJ-386/3/13.01, Kohlenstrasse 84, 4056 Basel, Switzerland. Phone: 41-616-9640-63; E-mail: ; Anna F. Farago, NIBR, 250 Massachusetts Avenue, Cambridge, MA 02139. Phone: 617-871-8000; E-mail: ; and Simona Cotesta, NIBR, WSJ-386/13/10, Kohlenstrasse 84, 4056 Basel, Switzerland. Phone: 41-797-9792-70; E-mail:
| | - Simona Cotesta
- Novartis Institutes for BioMedical Research, Basel, Switzerland.,Corresponding Authors: Saskia M. Brachman, Novartis Institutes for BioMedical Research (NIBR), WSJ-386/3/13.01, Kohlenstrasse 84, 4056 Basel, Switzerland. Phone: 41-616-9640-63; E-mail: ; Anna F. Farago, NIBR, 250 Massachusetts Avenue, Cambridge, MA 02139. Phone: 617-871-8000; E-mail: ; and Simona Cotesta, NIBR, WSJ-386/13/10, Kohlenstrasse 84, 4056 Basel, Switzerland. Phone: 41-797-9792-70; E-mail:
| | - Saskia M. Brachmann
- Novartis Institutes for BioMedical Research, Basel, Switzerland.,Corresponding Authors: Saskia M. Brachman, Novartis Institutes for BioMedical Research (NIBR), WSJ-386/3/13.01, Kohlenstrasse 84, 4056 Basel, Switzerland. Phone: 41-616-9640-63; E-mail: ; Anna F. Farago, NIBR, 250 Massachusetts Avenue, Cambridge, MA 02139. Phone: 617-871-8000; E-mail: ; and Simona Cotesta, NIBR, WSJ-386/13/10, Kohlenstrasse 84, 4056 Basel, Switzerland. Phone: 41-797-9792-70; E-mail:
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The N-terminus of Paenibacillus larvae C3larvinA modulates catalytic efficiency. Biosci Rep 2021; 41:227200. [PMID: 33289829 PMCID: PMC7789906 DOI: 10.1042/bsr20203727] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 01/21/2023] Open
Abstract
C3larvinA was recently described as a mono-ADP-ribosyltransferase (mART) toxin from the enterobacterial repetitive intergenic consensus (ERIC) III genotype of the agricultural pathogen, Paenibacillus larvae. It was shown to be the full-length, functional version of the previously described C3larvintrunc toxin, due to a 33-residue extension of the N-terminus of the protein. In the present study, a series of deletions and substitutions were made to the N-terminus of C3larvinA to assess the contribution of the α1-helix to toxin structure and function. Catalytic characterization of these variants identified Asp23 and Ala31 residues as supportive to enzymatic function. A third residue, Lys36, was also found to contribute to the catalytic activity of the enzyme. Analysis of the C3larvinA homology model revealed that these three residues were participating in a series of interactions to properly orient both the Q-X-E and S-T-S motifs. Ala31 and Lys36 were found to associate with a structural network of residues previously identified in silico, whereas Asp23 forms novel interactions not previously described. At last, the membrane translocation activity into host target cells of each variant was assessed, highlighting a possible relationship between protein dipole and target cell entry.
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Abdizadeh H, Jalalypour F, Atilgan AR, Atilgan C. A Coarse-Grained Methodology Identifies Intrinsic Mechanisms That Dissociate Interacting Protein Pairs. Front Mol Biosci 2020; 7:210. [PMID: 33195399 PMCID: PMC7477071 DOI: 10.3389/fmolb.2020.00210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 08/03/2020] [Indexed: 11/13/2022] Open
Abstract
We address the problem of triggering dissociation events between proteins that have formed a complex. We have collected a set of 25 non-redundant, functionally diverse protein complexes having high-resolution three-dimensional structures in both the unbound and bound forms. We unify elastic network models with perturbation response scanning (PRS) methodology as an efficient approach for predicting residues that have the propensity to trigger dissociation of an interacting protein pair, using the three-dimensional structures of the bound and unbound proteins as input. PRS reveals that while for a group of protein pairs, residues involved in the conformational shifts are confined to regions with large motions, there are others where they originate from parts of the protein unaffected structurally by binding. Strikingly, only a few of the complexes have interface residues responsible for dissociation. We find two main modes of response: In one mode, remote control of dissociation in which disruption of the electrostatic potential distribution along protein surfaces play the major role; in the alternative mode, mechanical control of dissociation by remote residues prevail. In the former, dissociation is triggered by changes in the local environment of the protein, e.g., pH or ionic strength, while in the latter, specific perturbations arriving at the controlling residues, e.g., via binding to a third interacting partner is required for decomplexation. We resolve the observations by relying on an electromechanical coupling model which reduces to the usual elastic network result in the limit of the lack of coupling. We validate the approach by illustrating the biological significance of top residues selected by PRS on select cases where we show that the residues whose perturbation leads to the observed conformational changes correspond to either functionally important or highly conserved residues in the complex.
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Affiliation(s)
- Haleh Abdizadeh
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Farzaneh Jalalypour
- Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey
| | - Ali Rana Atilgan
- Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey
| | - Canan Atilgan
- Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey
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5
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Lugo MR, Merrill AR. An In-Silico Sequence-Structure-Function Analysis of the N-Terminal Lobe in CT Group Bacterial ADP-Ribosyltransferase Toxins. Toxins (Basel) 2019; 11:toxins11060365. [PMID: 31234283 PMCID: PMC6628389 DOI: 10.3390/toxins11060365] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 06/13/2019] [Accepted: 06/15/2019] [Indexed: 01/02/2023] Open
Abstract
The C3-like toxins are single-domain proteins that represent a minimal mono-ADP-ribosyl transferase (mART) enzyme with a simple model scaffold for the entire cholera toxin (CT)-group. These proteins possess a single (A-domain) that modifies Rho proteins. In contrast, C2-like toxins require a binding/translocation partner (B-component) for intoxication. These are A-only toxins that contain the E-x-E motif, modify G-actin, but are two-domains with a C-domain possessing enzymatic activity. The N-domain of the C2-like toxins is unstructured, and its function is currently unknown. A sequence-structure-function comparison was performed on the N-terminal region of the mART domain of the enzymatic component of the CT toxin group in the CATCH fold (3.90.210.10). Special consideration was given to the N-domain distal segment, the α-lobe (α1–α4), and its different roles in these toxin sub-groups. These results show that the role of the N-terminal α-lobe is to provide a suitable configuration (i) of the α2–α3 helices to feature the α3-motif that has a role in NAD+ substrate binding and possibly in the interaction with the protein target; (ii) the α3–α4 helices to provide the α3/4-loop with protein-protein interaction capability; and (iii) the α1-Ntail that features specialized motif(s) according to the toxin type (A-only or A-B toxins) exhibiting an effect on the catalytic activity via the ARTT-loop, with a role in the inter-domain stability, and with a function in the binding and/or translocation steps during the internalization process.
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Affiliation(s)
- Miguel R Lugo
- Department of Molecular and Cellular Biology, University of Guelph, Guelph N1G 2W1, Canada.
| | - A Rod Merrill
- Department of Molecular and Cellular Biology, University of Guelph, Guelph N1G 2W1, Canada.
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6
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Lüscher B, Bütepage M, Eckei L, Krieg S, Verheugd P, Shilton BH. ADP-Ribosylation, a Multifaceted Posttranslational Modification Involved in the Control of Cell Physiology in Health and Disease. Chem Rev 2017; 118:1092-1136. [PMID: 29172462 DOI: 10.1021/acs.chemrev.7b00122] [Citation(s) in RCA: 165] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Posttranslational modifications (PTMs) regulate protein functions and interactions. ADP-ribosylation is a PTM, in which ADP-ribosyltransferases use nicotinamide adenine dinucleotide (NAD+) to modify target proteins with ADP-ribose. This modification can occur as mono- or poly-ADP-ribosylation. The latter involves the synthesis of long ADP-ribose chains that have specific properties due to the nature of the polymer. ADP-Ribosylation is reversed by hydrolases that cleave the glycosidic bonds either between ADP-ribose units or between the protein proximal ADP-ribose and a given amino acid side chain. Here we discuss the properties of the different enzymes associated with ADP-ribosylation and the consequences of this PTM on substrates. Furthermore, the different domains that interpret either mono- or poly-ADP-ribosylation and the implications for cellular processes are described.
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Affiliation(s)
- Bernhard Lüscher
- Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University , 52057 Aachen, Germany
| | - Mareike Bütepage
- Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University , 52057 Aachen, Germany
| | - Laura Eckei
- Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University , 52057 Aachen, Germany
| | - Sarah Krieg
- Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University , 52057 Aachen, Germany
| | - Patricia Verheugd
- Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University , 52057 Aachen, Germany
| | - Brian H Shilton
- Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University , 52057 Aachen, Germany.,Department of Biochemistry, Schulich School of Medicine & Dentistry, The University of Western Ontario , Medical Sciences Building Room 332, London, Ontario Canada N6A 5C1
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7
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Vetter IR. Interface analysis of small GTP binding protein complexes suggests preferred membrane orientations. Biol Chem 2017; 398:637-651. [PMID: 28002022 DOI: 10.1515/hsz-2016-0287] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 12/12/2016] [Indexed: 11/15/2022]
Abstract
Crystal structures of small GTP binding protein complexes with their effectors and regulators reveal that one particularly flat side of the G domain that contains helix α4 and the C-terminal helix α5 is practically devoid of contacts. Although this observation seems trivial as the main binding targets are the switch I and II regions opposite of this side, the fact that all interacting proteins, even the largest ones, seem to avoid occupying this area (except for Ran, that does not localize to membranes) is very striking. An orientation with this 'flat' side parallel to the membrane was proposed before and would allow simultaneous interaction of the lipidated C-terminus and positive charges in the α4 helix with the membrane while being bound to effector or regulator molecules. Furthermore, this 'flat' side might be involved in regulatory mechanisms: a Ras dimer that is found in different crystal forms interacts exactly at this side. Additional interface analysis of GTPase complexes nicely confirms the effect of different flexibilities of the GTP and GDP forms. Besides Ran proteins, guanine nucleotide exchange factors (GEFs) bury the largest surface areas to provide the binding energy to open up the switch regions for nucleotide exchange.
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Affiliation(s)
- Ingrid R Vetter
- Max Planck Institute of Molecular Physiology, Department of Mechanistic Cell Biology, Otto-Hahn-Str. 11, D-44227 Dortmund
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8
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Structural constraints-based evaluation of immunogenic avirulent toxins from Clostridium botulinum C2 and C3 toxins as subunit vaccines. INFECTION GENETICS AND EVOLUTION 2016; 44:17-27. [PMID: 27320793 DOI: 10.1016/j.meegid.2016.06.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 05/26/2016] [Accepted: 06/13/2016] [Indexed: 12/11/2022]
Abstract
Clostridium botulinum (group-III) is an anaerobic bacterium producing C2 and C3 toxins in addition to botulinum neurotoxins in avian and mammalian cells. C2 and C3 toxins are members of bacterial ADP-ribosyltransferase superfamily, which modify the eukaryotic cell surface proteins by ADP-ribosylation reaction. Herein, the mutant proteins with lack of catalytic and pore forming function derived from C2 (C2I and C2II) and C3 toxins were computationally evaluated to understand their structure-function integrity. We have chosen many structural constraints including local structural environment, folding process, backbone conformation, conformational dynamic sub-space, NAD-binding specificity and antigenic determinants for screening of suitable avirulent toxins. A total of 20 avirulent mutants were identified out of 23 mutants, which were experimentally produced by site-directed mutagenesis. No changes in secondary structural elements in particular to α-helices and β-sheets and also in fold rate of all-β classes. Structural stability was maintained by reordered hydrophobic and hydrogen bonding patterns. Molecular dynamic studies suggested that coupled mutations may restrain the binding affinity to NAD(+) or protein substrate upon structural destabilization. Avirulent toxins of this study have stable energetic backbone conformation with a common blue print of folding process. Molecular docking studies revealed that avirulent mutants formed more favorable hydrogen bonding with the side-chain of amino acids near to conserved NAD-binding core, despite of restraining NAD-binding specificity. Thus, structural constraints in the avirulent toxins would determine their immunogenic nature for the prioritization of protein-based subunit vaccine/immunogens to avian and veterinary animals infected with C. botulinum.
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9
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Prathiviraj R, Prisilla A, Chellapandi P. Structure–function discrepancy inClostridium botulinumC3 toxin for its rational prioritization as a subunit vaccine. J Biomol Struct Dyn 2015; 34:1317-29. [DOI: 10.1080/07391102.2015.1078745] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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10
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Barth H, Fischer S, Möglich A, Förtsch C. Clostridial C3 Toxins Target Monocytes/Macrophages and Modulate Their Functions. Front Immunol 2015; 6:339. [PMID: 26175735 PMCID: PMC4485225 DOI: 10.3389/fimmu.2015.00339] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 06/17/2015] [Indexed: 12/01/2022] Open
Abstract
The C3 enzymes from Clostridium (C.) botulinum (C3bot) and Clostridium limosum (C3lim) are single chain protein toxins of about 25 kDa that mono-ADP-ribosylate Rho-A, -B, and -C in the cytosol of mammalian cells. We discovered that both C3 proteins are selectively internalized into the cytosol of monocytes and macrophages by an endocytotic mechanism, comparable to bacterial AB-type toxins, while they are not efficiently taken up into the cytosol of other cell types including epithelial cells and fibroblasts. C3-treatment results in disturbed macrophage functions, such as migration and phagocytosis, suggesting a novel function of clostridial C3 toxins as virulence factors, which selectively interfere with these immune cells. Moreover, enzymatic inactive C3 protein serves as a transport system to selectively deliver pharmacologically active molecules into the cytosol of monocytes/macrophages without damaging these cells. This review addresses also the generation of C3-based molecular tools for experimental macrophage pharmacology and cell biology as well as the exploitation of C3 for development of novel therapeutic strategies against monocyte/macrophage-associated diseases.
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Affiliation(s)
- Holger Barth
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center , Ulm , Germany
| | - Stephan Fischer
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center , Ulm , Germany ; Institute of Organic Chemistry III, University of Ulm , Ulm , Germany
| | - Amelie Möglich
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center , Ulm , Germany
| | - Christina Förtsch
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center , Ulm , Germany
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11
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Toda A, Tsurumura T, Yoshida T, Tsumori Y, Tsuge H. Rho GTPase Recognition by C3 Exoenzyme Based on C3-RhoA Complex Structure. J Biol Chem 2015; 290:19423-32. [PMID: 26067270 DOI: 10.1074/jbc.m115.653220] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Indexed: 12/18/2022] Open
Abstract
C3 exoenzyme is a mono-ADP-ribosyltransferase (ART) that catalyzes transfer of an ADP-ribose moiety from NAD(+) to Rho GTPases. C3 has long been used to study the diverse regulatory functions of Rho GTPases. How C3 recognizes its substrate and how ADP-ribosylation proceeds are still poorly understood. Crystal structures of C3-RhoA complex reveal that C3 recognizes RhoA via the switch I, switch II, and interswitch regions. In C3-RhoA(GTP) and C3-RhoA(GDP), switch I and II adopt the GDP and GTP conformations, respectively, which explains why C3 can ADP-ribosylate both nucleotide forms. Based on structural information, we successfully changed Cdc42 to an active substrate with combined mutations in the C3-Rho GTPase interface. Moreover, the structure reflects the close relationship among Gln-183 in the QXE motif (C3), a modified Asn-41 residue (RhoA) and NC1 of NAD(H), which suggests that C3 is the prototype ART. These structures show directly for the first time that the ARTT loop is the key to target protein recognition, and they also serve to bridge the gaps among independent studies of Rho GTPases and C3.
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Affiliation(s)
- Akiyuki Toda
- From the Department of Bioresource and Environmental Sciences, Faculty of Life Sciences, and
| | - Toshiharu Tsurumura
- From the Department of Bioresource and Environmental Sciences, Faculty of Life Sciences, and the Structural Biology Research Center, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto 603-8555, Japan
| | - Toru Yoshida
- From the Department of Bioresource and Environmental Sciences, Faculty of Life Sciences, and the Structural Biology Research Center, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto 603-8555, Japan
| | - Yayoi Tsumori
- From the Department of Bioresource and Environmental Sciences, Faculty of Life Sciences, and
| | - Hideaki Tsuge
- From the Department of Bioresource and Environmental Sciences, Faculty of Life Sciences, and the Structural Biology Research Center, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto 603-8555, Japan
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12
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Yan C, Liu D, Li L, Wempe MF, Guin S, Khanna M, Meier J, Hoffman B, Owens C, Wysoczynski CL, Nitz MD, Knabe WE, Ahmed M, Brautigan DL, Paschal BM, Schwartz MA, Jones DNM, Ross D, Meroueh SO, Theodorescu D. Discovery and characterization of small molecules that target the GTPase Ral. Nature 2014; 515:443-7. [PMID: 25219851 DOI: 10.1038/nature13713] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 07/24/2014] [Indexed: 12/22/2022]
Abstract
The Ras-like GTPases RalA and RalB are important drivers of tumour growth and metastasis. Chemicals that block Ral function would be valuable as research tools and for cancer therapeutics. Here we used protein structure analysis and virtual screening to identify drug-like molecules that bind to a site on the GDP-bound form of Ral. The compounds RBC6, RBC8 and RBC10 inhibited the binding of Ral to its effector RALBP1, as well as inhibiting Ral-mediated cell spreading of murine embryonic fibroblasts and anchorage-independent growth of human cancer cell lines. The binding of the RBC8 derivative BQU57 to RalB was confirmed by isothermal titration calorimetry, surface plasmon resonance and (1)H-(15)N transverse relaxation-optimized spectroscopy (TROSY) NMR spectroscopy. RBC8 and BQU57 show selectivity for Ral relative to the GTPases Ras and RhoA and inhibit tumour xenograft growth to a similar extent to the depletion of Ral using RNA interference. Our results show the utility of structure-based discovery for the development of therapeutics for Ral-dependent cancers.
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Affiliation(s)
- Chao Yan
- Department of Surgery, University of Colorado, Aurora, Colorado 80045, USA
| | - Degang Liu
- Department of Biochemistry, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
| | - Liwei Li
- Department of Biochemistry, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
| | - Michael F Wempe
- Department of Pharmaceutical Sciences, University of Colorado, Aurora, Colorado 80045, USA
| | - Sunny Guin
- Department of Surgery, University of Colorado, Aurora, Colorado 80045, USA
| | - May Khanna
- Department of Biochemistry, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
| | - Jeremy Meier
- Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Brenton Hoffman
- Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Charles Owens
- Department of Surgery, University of Colorado, Aurora, Colorado 80045, USA
| | | | - Matthew D Nitz
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - William E Knabe
- Department of Biochemistry, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
| | - Mansoor Ahmed
- 1] Department of Cardiology, Yale University, New Haven, Connecticut 06511, USA [2] Department of Cell Biology, Yale University, New Haven, Connecticut 06511, USA
| | - David L Brautigan
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Bryce M Paschal
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Martin A Schwartz
- 1] Department of Cardiology, Yale University, New Haven, Connecticut 06511, USA [2] Department of Cell Biology, Yale University, New Haven, Connecticut 06511, USA
| | - David N M Jones
- Department of Pharmacology, University of Colorado, Aurora, Colorado 80045, USA
| | - David Ross
- Department of Pharmaceutical Sciences, University of Colorado, Aurora, Colorado 80045, USA
| | - Samy O Meroueh
- 1] Department of Biochemistry, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA [2] Department of Chemistry and Chemical Biology, Indiana University - Purdue University, Indianapolis, Indiana 46202, USA
| | - Dan Theodorescu
- 1] Department of Surgery, University of Colorado, Aurora, Colorado 80045, USA [2] Department of Pharmacology, University of Colorado, Aurora, Colorado 80045, USA [3] University of Colorado Comprehensive Cancer Center, Aurora, Colorado 80045, USA
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13
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Simon NC, Aktories K, Barbieri JT. Novel bacterial ADP-ribosylating toxins: structure and function. Nat Rev Microbiol 2014; 12:599-611. [PMID: 25023120 PMCID: PMC5846498 DOI: 10.1038/nrmicro3310] [Citation(s) in RCA: 154] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Bacterial ADP-ribosyltransferase toxins (bARTTs) transfer ADP-ribose to eukaryotic proteins to promote bacterial pathogenesis. In this Review, we use prototype bARTTs, such as diphtheria toxin and pertussis toxin, as references for the characterization of several new bARTTs from human, insect and plant pathogens, which were recently identified by bioinformatic analyses. Several of these toxins, including cholix toxin (ChxA) from Vibrio cholerae, SpyA from Streptococcus pyogenes, HopU1 from Pseudomonas syringae and the Tcc toxins from Photorhabdus luminescens, ADP-ribosylate novel substrates and have unique organizations, which distinguish them from the reference toxins. The characterization of these toxins increases our appreciation of the range of structural and functional properties that are possessed by bARTTs and their roles in bacterial pathogenesis.
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Affiliation(s)
- Nathan C. Simon
- Medical College of Wisconsin, Microbiology and Molecular Genetics, Milwaukee, WI, USA
| | - Klaus Aktories
- Institute of Experimental and Clinical Pharmacology and Toxicology; Albert-Ludwigs-University Freiburg; Freiburg, Germany
| | - Joseph T. Barbieri
- Medical College of Wisconsin, Microbiology and Molecular Genetics, Milwaukee, WI, USA
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14
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Popoff MR. Bacterial factors exploit eukaryotic Rho GTPase signaling cascades to promote invasion and proliferation within their host. Small GTPases 2014; 5:28209. [PMID: 25203748 DOI: 10.4161/sgtp.28209] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Actin cytoskeleton is a main target of many bacterial pathogens. Among the multiple regulation steps of the actin cytoskeleton, bacterial factors interact preferentially with RhoGTPases. Pathogens secrete either toxins which diffuse in the surrounding environment, or directly inject virulence factors into target cells. Bacterial toxins, which interfere with RhoGTPases, and to some extent with RasGTPases, catalyze a covalent modification (ADPribosylation, glucosylation, deamidation, adenylation, proteolysis) blocking these molecules in their active or inactive state, resulting in alteration of epithelial and/or endothelial barriers, which contributes to dissemination of bacteria in the host. Injected bacterial virulence factors preferentially manipulate the RhoGTPase signaling cascade by mimicry of eukaryotic regulatory proteins leading to local actin cytoskeleton rearrangement, which mediates bacterial entry into host cells or in contrast escape to phagocytosis and immune defense. Invasive bacteria can also manipulate RhoGTPase signaling through recognition and stimulation of cell surface receptor(s). Changes in RhoGTPase activation state is sensed by the innate immunity pathways and allows the host cell to adapt an appropriate defense response.
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Affiliation(s)
- Michel R Popoff
- Unité des Bactéries anaérobies et Toxines; Institut Pasteur; Paris, France
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15
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Structural biology of the writers, readers, and erasers in mono- and poly(ADP-ribose) mediated signaling. Mol Aspects Med 2013; 34:1088-108. [PMID: 23458732 PMCID: PMC3726583 DOI: 10.1016/j.mam.2013.02.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 02/01/2013] [Accepted: 02/18/2013] [Indexed: 12/19/2022]
Abstract
ADP-ribosylation of proteins regulates protein activities in various processes including transcription control, chromatin organization, organelle assembly, protein degradation, and DNA repair. Modulating the proteins involved in the metabolism of ADP-ribosylation can have therapeutic benefits in various disease states. Protein crystal structures can help understand the biological functions, facilitate detailed analysis of single residues, as well as provide a basis for development of small molecule effectors. Here we review recent advances in our understanding of the structural biology of the writers, readers, and erasers of ADP-ribosylation.
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16
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A recombinant fusion toxin based on enzymatic inactive C3bot1 selectively targets macrophages. PLoS One 2013; 8:e54517. [PMID: 23349915 PMCID: PMC3549961 DOI: 10.1371/journal.pone.0054517] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 12/12/2012] [Indexed: 01/08/2023] Open
Abstract
Background The C3bot1 protein (∼23 kDa) from Clostridium botulinum ADP-ribosylates and thereby inactivates Rho. C3bot1 is selectively taken up into the cytosol of monocytes/macrophages but not of other cell types such as epithelial cells or fibroblasts. Most likely, the internalization occurs by a specific endocytotic pathway via acidified endosomes. Methodology/Principal Findings Here, we tested whether enzymatic inactive C3bot1E174Q serves as a macrophage-selective transport system for delivery of enzymatic active proteins into the cytosol of such cells. Having confirmed that C3bot1E174Q does not induce macrophage activation, we used the actin ADP-ribosylating C2I (∼50 kDa) from Clostridium botulinum as a reporter enzyme for C3bot1E174Q-mediated delivery into macrophages. The recombinant C3bot1E174Q-C2I fusion toxin was cloned and expressed as GST-protein in Escherichia coli. Purified C3bot1E174Q-C2I was recognized by antibodies against C2I and C3bot and showed C2I-specific enzyme activity in vitro. When applied to cultured cells C3bot1E174Q-C2I ADP-ribosylated actin in the cytosol of macrophages including J774A.1 and RAW264.7 cell lines as well as primary cultured human macrophages but not of epithelial cells. Together with confocal fluorescence microscopy experiments, the biochemical data indicate the selective uptake of a recombinant C3-fusion toxin into the cytosol of macrophages. Conclusions/Significance In summary, we demonstrated that C3bot1E174Q can be used as a delivery system for fast, selective and specific transport of enzymes into the cytosol of living macrophages. Therefore, C3-based fusion toxins can represent valuable molecular tools in experimental macrophage pharmacology and cell biology as well as attractive candidates to develop new therapeutic approaches against macrophage-associated diseases.
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17
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Brymora A, Duggin IG, Berven LA, van Dam EM, Roufogalis BD, Robinson PJ. Identification and characterisation of the RalA-ERp57 interaction: evidence for GDI activity of ERp57. PLoS One 2012; 7:e50879. [PMID: 23226417 PMCID: PMC3511393 DOI: 10.1371/journal.pone.0050879] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 10/25/2012] [Indexed: 01/03/2023] Open
Abstract
RalA is a membrane-associated small GTPase that regulates vesicle trafficking. Here we identify a specific interaction between RalA and ERp57, an oxidoreductase and signalling protein. ERp57 bound specifically to the GDP-bound form of RalA, but not the GTP-bound form, and inhibited the dissociation of GDP from RalA in vitro. These activities were inhibited by reducing agents, but no disulphide bonds were detected between RalA and ERp57. Mutation of all four of ERp57’s active site cysteine residues blocked sensitivity to reducing agents, suggesting that redox-dependent conformational changes in ERp57 affect binding to RalA. Mutations in the switch II region of the GTPase domain of RalA specifically reduced or abolished binding to ERp57, but did not block GTP-specific binding to known RalA effectors, the exocyst and RalBP1. Oxidative treatment of A431 cells with H2O2 inhibited cellular RalA activity, and the effect was exacerbated by expression of recombinant ERp57. The oxidative treatment significantly increased the amount of RalA localised to the cytosol. These findings suggest that ERp57 regulates RalA signalling by acting as a redox-sensitive guanine-nucleotide dissociation inhibitor (RalGDI).
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Affiliation(s)
- Adam Brymora
- Cell Signalling Unit, Children’s Medical Research Institute, The University of Sydney, Sydney, Australia
| | - Iain G. Duggin
- Faculty of Pharmacy, The University of Sydney, Sydney, Australia
| | - Leise A. Berven
- Cell Signalling Unit, Children’s Medical Research Institute, The University of Sydney, Sydney, Australia
| | - Ellen M. van Dam
- Cell Signalling Unit, Children’s Medical Research Institute, The University of Sydney, Sydney, Australia
| | | | - Phillip J. Robinson
- Cell Signalling Unit, Children’s Medical Research Institute, The University of Sydney, Sydney, Australia
- * E-mail:
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18
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Fieldhouse RJ, Jørgensen R, Lugo MR, Merrill AR. The 1.8 Å cholix toxin crystal structure in complex with NAD+ and evidence for a new kinetic model. J Biol Chem 2012; 287:21176-88. [PMID: 22535961 DOI: 10.1074/jbc.m111.337311] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Certain Vibrio cholerae strains produce cholix, a potent protein toxin that has diphthamide-specific ADP-ribosyltransferase activity against eukaryotic elongation factor 2. Here we present a 1.8 Å crystal structure of cholix in complex with its natural substrate, nicotinamide adenine dinucleotide (NAD(+)). We also substituted hallmark catalytic residues by site-directed mutagenesis and analyzed both NAD(+) binding and ADP-ribosyltransferase activity using a fluorescence-based assay. These data are the basis for a new kinetic model of cholix toxin activity. Further, the new structural data serve as a reference for continuing inhibitor development for this toxin class.
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Affiliation(s)
- Robert J Fieldhouse
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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19
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Clostridial C3 proteins: Recent approaches to improve neuronal growth and regeneration. Ann Anat 2011; 193:314-20. [DOI: 10.1016/j.aanat.2011.01.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 01/11/2011] [Accepted: 01/11/2011] [Indexed: 12/13/2022]
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20
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Abstract
Many bacterial pathogens produce protein toxins to outmanoeuvre the immune system of the host. Some of these proteins target regulatory GTPases such as those belonging to the RHO family, which control the actin cytoskeleton of the host cell. In this Review, I discuss a diversity of mechanisms that are used by bacterial effectors and toxins to modulate the activity of host GTPases, with a focus on covalent modifications such as ADP-ribosylation, glucosylation, adenylylation, proteolysis, deamidation and transglutamination.
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Affiliation(s)
- Klaus Aktories
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität Freiburg, Albertstr. 25, 79104 Freiburg, Germany.
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21
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Fieldhouse RJ, Turgeon Z, White D, Merrill AR. Cholera- and anthrax-like toxins are among several new ADP-ribosyltransferases. PLoS Comput Biol 2010; 6:e1001029. [PMID: 21170356 PMCID: PMC3000352 DOI: 10.1371/journal.pcbi.1001029] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Accepted: 11/10/2010] [Indexed: 11/19/2022] Open
Abstract
Chelt, a cholera-like toxin from Vibrio cholerae, and Certhrax, an anthrax-like toxin from Bacillus cereus, are among six new bacterial protein toxins we identified and characterized using in silico and cell-based techniques. We also uncovered medically relevant toxins from Mycobacterium avium and Enterococcus faecalis. We found agriculturally relevant toxins in Photorhabdus luminescens and Vibrio splendidus. These toxins belong to the ADP-ribosyltransferase family that has conserved structure despite low sequence identity. Therefore, our search for new toxins combined fold recognition with rules for filtering sequences--including a primary sequence pattern--to reduce reliance on sequence identity and identify toxins using structure. We used computers to build models and analyzed each new toxin to understand features including: structure, secretion, cell entry, activation, NAD+ substrate binding, intracellular target binding and the reaction mechanism. We confirmed activity using a yeast growth test. In this era where an expanding protein structure library complements abundant protein sequence data--and we need high-throughput validation--our approach provides insight into the newest toxin ADP-ribosyltransferases.
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Affiliation(s)
- Robert J. Fieldhouse
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Zachari Turgeon
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Dawn White
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - A. Rod Merrill
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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22
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Boato F, Hendrix S, Huelsenbeck SC, Hofmann F, Große G, Djalali S, Klimaschewski L, Auer M, Just I, Ahnert-Hilger G, Höltje M. C3 peptide enhances recovery from spinal cord injury by improved regenerative growth of descending fiber tracts. J Cell Sci 2010; 123:1652-62. [DOI: 10.1242/jcs.066050] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Functional recovery and regeneration of corticospinal tract (CST) fibers following spinal cord injury by compression or dorsal hemisection in mice was monitored after application of the enzyme-deficient Clostridium botulinum C3-protein-derived 29-amino-acid fragment C3bot154-182. This peptide significantly improved locomotor restoration in both injury models as assessed by the open-field Basso Mouse Scale for locomotion test and Rotarod treadmill experiments. These data were supported by tracing studies showing an enhanced regenerative growth of CST fibers in treated animals as visualized by anterograde tracing. Additionally, C3bot154-182 stimulated regenerative growth of raphespinal fibers and improved serotonergic input to lumbar α-motoneurons. These in vivo data were confirmed by in vitro data, showing an enhanced axon outgrowth of α-motoneurons and hippocampal neurons cultivated on normal or growth-inhibitory substrates after application of C3bot154-182. The observed effects were probably caused by a non-enzymatic downregulation of active RhoA by the C3 peptide as indicated by pull-down experiments. By contrast, C3bot154-182 did not induce neurite outgrowth in primary cultures of dorsal root ganglion cells. In conclusion, C3bot154-182 represents a novel, promising tool to foster axonal protection and/or repair, as well as functional recovery after traumatic CNS injury.
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Affiliation(s)
- Francesco Boato
- Center for Anatomy, Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Sven Hendrix
- Center for Anatomy, Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
- Department of Morphology and BIOMED Institute, Hasselt University, Agoralaangebouw A, B-3590 Diepenbeek, Belgium
| | - Stefanie C. Huelsenbeck
- Institute of Toxicology, Hannover Medical School (MHH), Carl-Neuberg-Straße 1, D-30625 Hannover, Germany
| | - Fred Hofmann
- Institute of Toxicology, Hannover Medical School (MHH), Carl-Neuberg-Straße 1, D-30625 Hannover, Germany
| | - Gisela Große
- Center for Anatomy, Functional Cell Biology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Susann Djalali
- Center for Anatomy, Functional Cell Biology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Lars Klimaschewski
- Division of Neuroanatomy, Department of Anatomy, Histology and Embryology, Innsbruck Medical University, Müllerstraße 59, A-6020 Innsbruck, Austria
| | - Maria Auer
- Division of Neuroanatomy, Department of Anatomy, Histology and Embryology, Innsbruck Medical University, Müllerstraße 59, A-6020 Innsbruck, Austria
| | - Ingo Just
- Institute of Toxicology, Hannover Medical School (MHH), Carl-Neuberg-Straße 1, D-30625 Hannover, Germany
| | - Gudrun Ahnert-Hilger
- Center for Anatomy, Functional Cell Biology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Markus Höltje
- Center for Anatomy, Functional Cell Biology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
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23
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Fahrer JÃ, Kuban J, Heine K, Rupps G, Kaiser E, Felder E, Benz R, Barth H. Selective and specific internalization of clostridial C3 ADP-ribosyltransferases into macrophages and monocytes. Cell Microbiol 2010; 12:233-47. [DOI: 10.1111/j.1462-5822.2009.01393.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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24
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Abstract
Clostridia produce the highest number of toxins of any type of bacteria and are involved in severe diseases in humans and other animals. Most of the clostridial toxins are pore-forming toxins responsible for gangrenes and gastrointestinal diseases. Among them, perfringolysin has been extensively studied and it is the paradigm of the cholesterol-dependent cytolysins, whereas Clostridium perfringens epsilon-toxin and Clostridium septicum alpha-toxin, which are related to aerolysin, are the prototypes of clostridial toxins that form small pores. Other toxins active on the cell surface possess an enzymatic activity, such as phospholipase C and collagenase, and are involved in the degradation of specific cell-membrane or extracellular-matrix components. Three groups of clostridial toxins have the ability to enter cells: large clostridial glucosylating toxins, binary toxins and neurotoxins. The binary and large clostridial glucosylating toxins alter the actin cytoskeleton by enzymatically modifying the actin monomers and the regulatory proteins from the Rho family, respectively. Clostridial neurotoxins proteolyse key components of neuroexocytosis. Botulinum neurotoxins inhibit neurotransmission at neuromuscular junctions, whereas tetanus toxin targets the inhibitory interneurons of the CNS. The high potency of clostridial toxins results from their specific targets, which have an essential cellular function, and from the type of modification that they induce. In addition, clostridial toxins are useful pharmacological and biological tools.
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Affiliation(s)
- Michel R Popoff
- Institut Pasteur, Bactéries Anaérobies et Toxines, 75724 Paris cedex 15, France.
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25
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Fenwick RB, Prasannan S, Campbell LJ, Nietlispach D, Evetts KA, Camonis J, Mott HR, Owen D. Solution structure and dynamics of the small GTPase RalB in its active conformation: significance for effector protein binding. Biochemistry 2009; 48:2192-206. [PMID: 19166349 DOI: 10.1021/bi802129d] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The small G proteins RalA/B have a crucial function in the regulatory network that couples extracellular signals with appropriate cellular responses. RalA/B are an important component of the Ras signaling pathway and, in addition to their role in membrane trafficking, are implicated in the initiation and maintenance of tumorigenic transformation of human cells. RalA and RalB share 85% sequence identity and collaborate in supporting cancer cell proliferation but have markedly different effects. RalA is important in mediating proliferation, while depletion of RalB results in transformed cells undergoing apoptosis. Crystal structures of RalA in the free form and in complex with its effectors, Sec5 and Exo84, have been solved. Here we have determined the solution structure of free RalB bound to the GTP analogue GMPPNP to an RMSD of 0.6 A. We show that, while the overall architecture of RalB is very similar to the crystal structure of RalA, differences exist in the switch regions, which are sensitive to the bound nucleotide. Backbone 15N dynamics suggest that there are four regions of disorder in RalB: the P-loop, switch I, switch II, and the loop comprising residues 116-121, which has a single residue insertion compared to RalA. 31P NMR data and the structure of RalB.GMPPNP show that the switch regions predominantly adopt state 1 (Ras nomenclature) in the unbound form, which in Ras is not competent to bind effectors. In contrast, 31P NMR analysis of RalB.GTP reveals that conformations corresponding to states 1 and 2 are both sampled in solution and that addition of an effector protein only partially stabilizes state 2.
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26
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The small GTPase Ral mediates SDF-1-induced migration of B cells and multiple myeloma cells. Blood 2008; 111:3364-72. [PMID: 18227351 DOI: 10.1182/blood-2007-08-106583] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Chemokine-controlled migration plays a critical role in B-cell development, differentiation, and function, as well as in the pathogenesis of B-cell malignancies, including the plasma cell neoplasm multiple myeloma (MM). Here, we demonstrate that stimulation of B cells and MM cells with the chemokine stromal cell-derived factor-1 (SDF-1) induces strong migration and activation of the Ras-like GTPase Ral. Inhibition of Ral, by expression of the dominant negative RalN28 mutant or of RalBPDeltaGAP, a Ral effector mutant that sequesters active Ral, results in impaired SDF-1-induced migration of B cells and MM cells. Of the 2 Ral isoforms, RalA and RalB, RalB was found to mediate SDF-1-induced migration. We have recently shown that Btk, PLCgamma2, and Lyn/Syk mediate SDF-1-controlled B-cell migration; however, SDF-1-induced Ral activation is not affected in B cells deficient in these proteins. In addition, treatment with pharmacological inhibitors against PI3K and PLC or expression of dominant-negative Ras did not impair SDF-1-induced Ral activation. Taken together, these results reveal a novel function for Ral, that is, regulation of SDF-1-induced migration of B cells and MM cells, thereby providing new insights into the control of B-cell homeostasis, trafficking, and function, as well as into the pathogenesis of MM.
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27
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Nimchuk ZL, Fisher EJ, Desveaux D, Chang JH, Dangl JL. The HopX (AvrPphE) family of Pseudomonas syringae type III effectors require a catalytic triad and a novel N-terminal domain for function. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2007; 20:346-57. [PMID: 17427805 DOI: 10.1094/mpmi-20-4-0346] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Many gram-negative plant pathogenic bacteria employ type III secretion systems to deliver effector proteins directly into the host cell during infection. On susceptible hosts, type III effectors aid pathogen growth by manipulating host defense pathways. On resistant hosts, some effectors can activate specific host disease resistance (R) genes, leading to generation of rapid and effective immune responses. The biochemical basis of these processes is poorly understood. The HopX (AvrPphE) family is a widespread type III effector among phytopathogenic bacteria. We determined that HopX family members are modular proteins composed of a conserved putative cysteine-based catalytic triad and a conserved potential target/cofactor interaction domain. HopX is soluble in host cells. Putative catalytic triad residues are required for avirulence activity on resistant bean hosts and for the generation of a cell-death response in specific Arabidopsis genotypes. The putative target/cofactor interaction domain is also required for these activities. Our data suggest that specific interaction with and modification of a cytosolic host target drives HopX recognition in resistant hosts and may contribute to virulence in susceptible hosts. Surprisingly, the Legionella pneumophila genome was found to contain a protein with similarity to HopX in sequence and domain arrangement, suggesting that these proteins might also contribute to animal pathogenesis and could be delivered to plant and animal hosts by diverse secretion systems.
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Affiliation(s)
- Zachary L Nimchuk
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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28
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Vogelsgesang M, Pautsch A, Aktories K. C3 exoenzymes, novel insights into structure and action of Rho-ADP-ribosylating toxins. Naunyn Schmiedebergs Arch Pharmacol 2006; 374:347-60. [PMID: 17146673 DOI: 10.1007/s00210-006-0113-y] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2006] [Accepted: 10/18/2006] [Indexed: 12/19/2022]
Abstract
The family of C3-like exoenzymes comprises seven bacterial ADP-ribosyltransferases of different origin. The common hallmark of these exoenzymes is the selective N-ADP-ribosylation of the low molecular mass GTP-binding proteins RhoA, B, and C and inhibition of signal pathways controlled by Rho GTPases. Therefore, C3-like exoenzymes were applied as pharmacological tools for analyses of cellular functions of Rho protein in numerous studies. Recent structural and functional analyses of C3-like exoenzymes provide detailed information on the molecular mechanisms and functional consequences of ADP-ribosylation catalyzed by these toxins. More recently additional non-enzymatic actions of C3-like ADP-ribosyltransferases have been identified showing that C3 transferases from Clostridium botulinum and Clostridium limosum form a GDI-like complex with the Ras-like low molecular mass GTPase Ral without ADP-ribosylation. These results add novel information on the molecular mode of action(s) of C3-like exoenzymes and are discussed in this review.
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Affiliation(s)
- Martin Vogelsgesang
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-University Freiburg, Otto-Krayer-Haus, Albertstrasse 25, Freiburg, Germany
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