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Chen S, Li F, Liu G, Li Y, Li Z, Liu Y, Nakanishi H. Construction of a Yeast Cell-Based Assay System to Analyze SNAP25-Targeting Botulinum Neurotoxins. Microorganisms 2023; 11:1125. [PMID: 37317099 DOI: 10.3390/microorganisms11051125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/15/2023] [Accepted: 04/21/2023] [Indexed: 06/16/2023] Open
Abstract
Herein, we describe a yeast cell-based assay system to analyze SNAP25-targeting botulinum neurotoxins (BoNTs). BoNTs are protein toxins, and, upon incorporation into neuronal cells, their light chains (BoNT-LCs) target specific synaptosomal N-ethylmaleimide-sensitive attachment protein receptor (SNARE) proteins, including synaptosomal-associated protein 25 (SNAP25). BoNT-LCs are metalloproteases, and each BoNT-LC recognizes and cleaves conserved domains in SNAREs termed the SNARE domain. In the budding yeast Saccharomyces cerevisiae, the SNAP25 ortholog Spo20 is required for production of the spore plasma membrane; thus, defects in Spo20 cause sporulation deficiencies. We found that chimeric SNAREs in which SNARE domains in Spo20 are replaced with those of SNAP25 are functional in yeast cells. The Spo20/SNAP25 chimeras, but not Spo20, are sensitive to digestion by BoNT-LCs. We demonstrate that spo20∆ yeasts harboring the chimeras exhibit sporulation defects when various SNAP25-targeting BoNT-LCs are expressed. Thus, the activities of BoNT-LCs can be assessed by colorimetric measurement of sporulation efficiencies. Although BoNTs are notorious toxins, they are also used as therapeutic and cosmetic agents. Our assay system will be useful for analyzing novel BoNTs and BoNT-like genes, as well as their manipulation.
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Affiliation(s)
- Shilin Chen
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214126, China
| | - Feng Li
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214126, China
| | - Guoyu Liu
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214126, China
| | - Yuqing Li
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214126, China
| | - Zijie Li
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214126, China
| | - Yishi Liu
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214126, China
| | - Hideki Nakanishi
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214126, China
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Construction of functional chimeras of syntaxin-1A and its yeast orthologue, and their application to the yeast cell-based assay for botulinum neurotoxin serotype C. Biochim Biophys Acta Gen Subj 2019; 1863:129396. [PMID: 31302181 DOI: 10.1016/j.bbagen.2019.07.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 06/14/2019] [Accepted: 07/10/2019] [Indexed: 11/23/2022]
Abstract
BACKGROUND Botulinum neurotoxins (BoNTs) prevent synaptic transmission because they hydrolyze synaptic N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). BoNT serotype C (BoNT/C) targets syntaxin-1A and SNAP-25, and is expected to be applied to cosmetic and therapeutic uses. SNAREs are evolutionally conserved proteins and in yeast a syntaxin-1A orthologue Sso1 is involved in exocytosis. The substrate specificity of BoNT/C is strict and it cannot cleave Sso1. METHODS Domain swapping and mutational screenings were performed to generate functional chimeras SNAREs of syntaxin-1A and Sso1. Such chimeras are expressed in yeast cells and assessed whether they are susceptible to BoNT/C digestion. RESULTS The Sso1 and syntaxin-1A chimera (Sso1/STX1A), in which the SNARE domain in Sso1 was replaced with that of syntaxin-1A, was not functional in yeast. The functional incompatibility of Sso1/STX1A was attributable to its accumulation in the ER. We found several mutations that could release Sso1/STX1A from the ER to make the chimera functional in yeast. Yeast cells harboring the mutant chimeras grew similarly to wild-type cells. However, unlike wild-type, yeast harboring the mutant chimeras exhibited a severe growth defect upon expression of BoNT/C. Results of further domain swapping analyses suggest that Sso1 is not digested by BoNT/C because it lacks a binding region to BoNT/C (α-exosite-binding region). CONCLUSIONS We obtained functional Sso1/STX1A chimeras, which can be applied to a yeast cell-based BoNT/C assay. BoNT/C can recognize these chimeras in a similar manner to syntaxin-1A. GENERAL SIGNIFICANCE The yeast cell-based BoNT/C assay would be useful to characterize and engineer BoNT/C.
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Belyy A, Tabakova I, Lang AE, Jank T, Belyi Y, Aktories K. Roles of Asp179 and Glu270 in ADP-Ribosylation of Actin by Clostridium perfringens Iota Toxin. PLoS One 2015; 10:e0145708. [PMID: 26713879 PMCID: PMC4699905 DOI: 10.1371/journal.pone.0145708] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 12/08/2015] [Indexed: 12/19/2022] Open
Abstract
Clostridium perfringens iota toxin is a binary toxin composed of the enzymatically active component Ia and receptor binding component Ib. Ia is an ADP-ribosyltransferase, which modifies Arg177 of actin. The previously determined crystal structure of the actin-Ia complex suggested involvement of Asp179 of actin in the ADP-ribosylation reaction. To gain more insights into the structural requirements of actin to serve as a substrate for toxin-catalyzed ADP-ribosylation, we engineered Saccharomyces cerevisiae strains, in which wild type actin was replaced by actin variants with substitutions in residues located on the Ia-actin interface. Expression of the actin mutant Arg177Lys resulted in complete resistance towards Ia. Actin mutation of Asp179 did not change Ia-induced ADP-ribosylation and growth inhibition of S. cerevisiae. By contrast, substitution of Glu270 of actin inhibited the toxic action of Ia and the ADP-ribosylation of actin. In vitro transcribed/translated human β-actin confirmed the crucial role of Glu270 in ADP-ribosylation of actin by Ia.
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Affiliation(s)
- Alexander Belyy
- Gamaleya Research Institute, Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | | | - Alexander E. Lang
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany
| | - Thomas Jank
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany
| | - Yury Belyi
- Gamaleya Research Institute, Moscow, Russia
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Freiburg, Germany
| | - Klaus Aktories
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Freiburg, Germany
- Centre for Biological Signalling Studies (BIOSS), University of Freiburg, Freiburg, Germany
- * E-mail:
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Pantano S, Montecucco C. The blockade of the neurotransmitter release apparatus by botulinum neurotoxins. Cell Mol Life Sci 2014; 71:793-811. [PMID: 23749048 PMCID: PMC11113401 DOI: 10.1007/s00018-013-1380-7] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 05/15/2013] [Accepted: 05/16/2013] [Indexed: 12/22/2022]
Abstract
The high toxicity of the seven serotypes of botulinum neurotoxins (BoNT/A to G), together with their specificity and reversibility, includes them in the list A of potential bioterrorism weapons and, at the same time, among the therapeutics of choice for a variety of human syndromes. They invade nerve terminals and cleave specifically the three proteins which form the heterotrimeric SNAP REceptors (SNARE) complex that mediates neurotransmitter release. The BoNT-induced cleavage of the SNARE proteins explains by itself the paralysing activity of the BoNTs because the truncated proteins cannot form the SNARE complex. However, in the case of BoNT/A, the most widely used toxin in therapy, additional factors come into play as it only removes a few residues from the synaptosomal associate protein of 25 kDa C-terminus and this results in a long duration of action. To explain these facts and other experimental data, we present here a model for the assembly of the neuroexocytosis apparatus in which Synaptotagmin and Complexin first assist the zippering of the SNARE complex, and then stabilize and clamp an octameric radial assembly of the SNARE complexes.
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Affiliation(s)
- Sergio Pantano
- Institut Pasteur de Montevideo, Calle Mataojo 2020, CP 11400 Montevideo, Uruguay
| | - Cesare Montecucco
- Department of Biomedical Sciences, University of Padova, Padua, Italy
- Institute of Neuroscience, National Research Council, Viale G. Colombo 3, 35121 Padua, Italy
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Mattiazzi M, Petrovič U, Križaj I. Yeast as a model eukaryote in toxinology: a functional genomics approach to studying the molecular basis of action of pharmacologically active molecules. Toxicon 2012; 60:558-71. [PMID: 22465496 DOI: 10.1016/j.toxicon.2012.03.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 03/13/2012] [Indexed: 10/28/2022]
Abstract
Yeast Saccharomyces cerevisiae has proven to be a relevant and convenient model organism for the study of diverse biological phenomena, due to its straightforward genetics, cost-effectiveness and rapid growth, combined with the typical characteristics of a eukaryotic cell. More than 40% of yeast proteins share at least part of their primary amino acid sequence with the corresponding human protein, making yeast a valuable model in biomedical research. In the last decade, high-throughput and genome-wide experimental approaches developed in yeast have paved the way to functional genomics that aims at a global understanding of the relationship between genotype and phenotype. In this review we first present the yeast strain and plasmid collections for genome-wide experimental approaches to study complex interactions between genes, proteins and endo- or exogenous small molecules. We describe methods for protein-protein, protein-DNA, genetic and chemo-genetic interactions, as well as localization studies, focussing on their application in research on small pharmacologically active molecules. Next we review the use of yeast as a model organism in neurobiology, emphasizing work done towards elucidating the pathogenesis of neurodegenerative diseases and the mechanism of action of neurotoxic phospholipases A(2).
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Affiliation(s)
- Mojca Mattiazzi
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
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Towards new uses of botulinum toxin as a novel therapeutic tool. Toxins (Basel) 2011; 3:63-81. [PMID: 22069690 PMCID: PMC3210455 DOI: 10.3390/toxins3010063] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 01/03/2011] [Accepted: 01/04/2011] [Indexed: 12/31/2022] Open
Abstract
The uses of botulinum toxin in the fields of neurology, ophthalmology, urology, rehabilitation medicine and aesthetic applications have been revolutionary for the treatment of patients. This non-invasive therapeutic has continually been developed since first discovered in the 1970s as a new approach to what were previously surgical treatments. As these applications develop, so also the molecules are developing into tools with new therapeutic properties in specific clinical areas. This review examines how the botulinum toxin molecule is being adapted to new therapeutic uses and also how new areas of use for the existing molecules are being identified. Prospects for future developments are also considered.
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Clostridial neurotoxins: mechanism of SNARE cleavage and outlook on potential substrate specificity reengineering. Toxins (Basel) 2010; 2:665-82. [PMID: 22069605 PMCID: PMC3153214 DOI: 10.3390/toxins2040665] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2010] [Revised: 03/30/2010] [Accepted: 04/09/2010] [Indexed: 11/17/2022] Open
Abstract
The clostridial neurotoxin family consists of tetanus neurotoxin and seven distinct botulinum neurotoxins which cause the diseases tetanus and botulism. The extreme potency of these toxins primarily relies not only on their ability to specifically enter motoneurons but also on the activity their catalytic domains display inside presynaptic motoneuronal terminals. Subsequent to neurotoxin binding and endocytosis the catalytic domains become translocated across endosomal membranes and proteolyze unique peptide bonds of one of three soluble N-ethylmaleimide-sensitive fusion protein attachment receptors (SNAREs), vesicle associated membrane protein/synaptobrevin, synaptosome associated protein of 25 kDa, or syntaxin. As these substrate proteins are core components of the vesicular membrane fusion apparatus, cleavage of any of the substrate molecules results in the blockade of neurotransmitter release. This review summarizes the present knowledge about the molecular basis of the specific substrate recognition and cleavage mechanism and assesses the feasibility of reengineering catalytic domains to hydrolyze non-substrate members of the three SNARE families in order to expand the therapeutic application of botulinum neurotoxins.
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Henkel JS, Jacobson M, Tepp W, Pier C, Johnson EA, Barbieri JT. Catalytic properties of botulinum neurotoxin subtypes A3 and A4. Biochemistry 2010; 48:2522-8. [PMID: 19256469 DOI: 10.1021/bi801686b] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Botulinum toxins (BoNT) are zinc proteases (serotypes A-G) which cause flaccid paralysis through the cleavage of SNARE proteins within motor neurons. BoNT/A was originally organized into two subtypes, BoNT/A1 and BoNT/A2, which are approximately 95% homologous and possess similar catalytic activities. Subsequently, two additional subtypes were identified, BoNT/A3 (Loch Maree) and BoNT/A4 (657Ba), which are 81 and 88% homologous with BoNT/A1, respectively. Alignment studies predicted that BoNT/A3 and BoNT/A4 were sufficiently different from BoNT/A1 to affect SNAP25 binding and cleavage. Recombinant light chain (LC) of BoNT/A3 (LC/A3) and BoNT/A4 (LC/A4) were subjected to biochemical analysis. LC/A3 cleaved SNAP25 at 50% of the rate of LC/A1 but cleaved SNAPtide at a faster rate than LC/A1, while LC/A4 cleaved SNAP25 and SNAPtide at slower rates than LC/A1. LC/A3 and LC/A4 had similar K(m) values for SNAP25 relative to LC/A1, while the k(cat) for LC/A4 was 10-fold slower than that for LC/A1, suggesting a defect in substrate cleavage. Neither LC/A3 nor LC/A4 possessed autocatalytic activity, a property of LC/A1 and LC/A2. Thus, the four subtypes of BoNT/A bind SNAP25 with similar affinity but have different catalytic capacities for SNAP25 cleavage, SNAPtide cleavage, and autocatalysis. The catalytic properties identified among the subtypes of LC/A may influence strategies for the development of small molecule or peptide inhibitors as therapies against botulism.
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Affiliation(s)
- James S Henkel
- Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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Hakami RM, Ruthel G, Stahl AM, Bavari S. Gaining ground: assays for therapeutics against botulinum neurotoxin. Trends Microbiol 2010; 18:164-72. [DOI: 10.1016/j.tim.2010.02.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 01/20/2010] [Accepted: 02/01/2010] [Indexed: 11/15/2022]
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Abstract
Toxins that alter neurotransmitter release from nerve terminals are of considerable scientific and clinical importance. Many advances were recently made in the understanding of their molecular mechanisms of action and use in human therapy. Here, we focus on presynaptic neurotoxins, which are very potent inhibitors of the neurotransmitter release because they are endowed with specific enzymatic activities: (1) clostridial neurotoxins with a metallo-proteolytic activity and (2) snake presynaptic neurotoxins with a phospholipase A2 activity.
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Affiliation(s)
- Ornella Rossetto
- Departimento de Scienze Biomediche and Istituto CNR di Neuroscienze, Universita di Padova, Viale G. Colombo 3, 35121, Padova, Italy
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Purcell AL, Hoard-Fruchey HM. A capillary electrophoresis method to assay catalytic activity of botulinum neurotoxin serotypes: Implications for substrate specificity. Anal Biochem 2007; 366:207-17. [PMID: 17548044 DOI: 10.1016/j.ab.2007.04.048] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Revised: 04/26/2007] [Accepted: 04/29/2007] [Indexed: 10/23/2022]
Abstract
The potent botulinum neurotoxin inhibits neurotransmitter release at cholinergic nerve terminals, causing a descending flaccid paralysis characteristic of the disease botulism. The currently expanding medical use of the neurotoxin to treat several disorders, as well as the potential misuse of the neurotoxin as an agent in biowarfare, has made understanding of the nature of the toxin's catalytic activity and development of inhibitors critical. To study the catalytic activity of botulinum neurotoxin more thoroughly and characterize potential inhibitors, we have developed a capillary electrophoresis method to measure catalytic activity of different serotypes of botulinum neurotoxin using peptides derived from the native substrates. This assay requires only a minute amount of sample (25 nl), is relatively rapid (15 min/sample), and allows the determination of enzyme kinetic constants for a more sophisticated characterization of inhibitors and neurotoxin catalytic activity. Using this method, we can measure activity of five of the seven serotypes of botulinum neurotoxin (A, B, E, F, and G) with two peptide substrates. Botulinum neurotoxin serotypes C and D did not cleave our peptides, lending insight into potential substrate requirements among the serotypes.
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Affiliation(s)
- Angela L Purcell
- Division of Analytical Toxicology, Neurobehavioral Toxicology Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA.
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