1
|
Li S, Qin C, Peng SM, Wang YB, Wang Y, Wang XS, Shi JG, Li XC. A newly identified secretory phospholipase A2 group XIIA homolog (LcPLA2XIIA) in Larimichthys crocea exhibits antimicrobial and antitumor activities. FISH & SHELLFISH IMMUNOLOGY 2024; 154:109924. [PMID: 39332653 DOI: 10.1016/j.fsi.2024.109924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Revised: 09/22/2024] [Accepted: 09/24/2024] [Indexed: 09/29/2024]
Abstract
The phospholipase A2 (PLA2) superfamily has attracted increasing attention in recent years due to the multiple physiological and pathological functions exerted by its members. Up to date, the knowledge about the biological role of PLA2XIIA subfamily members remains limited. In this study, a new member of PLA2XIIA subfamily, LcPLA2XIIA, was characterized in large yellow croaker. Different from most members of the PLA2 superfamily with positive charge, LcPLA2XIIA encodes an anionic protein, which is similar to other members of PLA2XIIA subfamily. LcPLA2XIIA is highly expressed in the intestine, and afterwards, it is up-regulated after with Pseudomonas plecoglossicida or Staphylococcus aureus. LcPLA2XIIA exhibits strong inhibitory activity against these two bacteria. The results indicate that LcPLA2XIIA plays an important role in the antimicrobial immune responses of large yellow croaker. LcPLA2XIIA displays strong binding activity to all the tested bacteria. It specifically interacts with LTA, a unique component on the surface of Gram-positive bacteria. It also significantly promotes bacterial agglutination in the presence of Ca2+. These findings reveal that the binding and agglutinating abilities of LcPLA2XIIA to bacteria contribute greatly to its antibacterial activity. In addition, LcPLA2XIIA significantly inhibits the proliferation of infectious hematopoietic necrosis virus instead of recombinant human adenovirus type 5. It also suppresses the growth of human colorectal adenocarcinoma cells by inducing apoptosis, but it has no obvious inhibitory effect on the growth of epithelioma papulosum cyprinid cells. This study provides new insights into the antibacterial activity, and the mechanism of LcPLA2XIIA in large yellow croaker, and antiviral and antitumor functions of PLA2XIIA subfamily members.
Collapse
Affiliation(s)
- Shouhu Li
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, 200090, China; Key Laboratory of Inland Saline-alkaline Aquaculture, Ministry of Agriculture and Rural Affairs, Shanghai, 200090, China
| | - Chuang Qin
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, 200090, China; Key Laboratory of Inland Saline-alkaline Aquaculture, Ministry of Agriculture and Rural Affairs, Shanghai, 200090, China
| | - Shi-Ming Peng
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, 200090, China
| | - Ya-Bing Wang
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, 200090, China
| | - Yuan Wang
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, 200090, China; Key Laboratory of Inland Saline-alkaline Aquaculture, Ministry of Agriculture and Rural Affairs, Shanghai, 200090, China
| | - Xiao-Shan Wang
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, 200090, China
| | - Jian-Gao Shi
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, 200090, China.
| | - Xin-Cang Li
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, 200090, China; Key Laboratory of Inland Saline-alkaline Aquaculture, Ministry of Agriculture and Rural Affairs, Shanghai, 200090, China.
| |
Collapse
|
2
|
Lakušić M, Damm M, Bjelica V, Anđelković M, Tomović L, Bonnet X, Arsovski D, Süssmuth RD, Calvete JJ, Martínez-Freiría F. Ontogeny, not prey availability, underlies allopatric venom variability in insular and mainland populations of Vipera ammodytes. J Proteomics 2024; 310:105320. [PMID: 39306033 DOI: 10.1016/j.jprot.2024.105320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2024] [Revised: 09/09/2024] [Accepted: 09/17/2024] [Indexed: 09/28/2024]
Abstract
Allopatric populations living under distinct ecological conditions are excellent systems to infer factors underlying intraspecific venom variation. The venom composition of two populations of Vipera ammodytes, insular with a diet based on ectotherms and mainland with a diet based on ectotherms and endotherms, was compared considering the sex and age of individuals. Ten toxin families, dominated by PLA2, svMP, svSP, and DI, were identified through a bottom-up approach. The venom profiles of adult females and males were similar. Results from 58 individual SDS-PAGE profiles and venom pool analysis revealed significant differences between juveniles compared to subadults and adults. Two venom phenotypes were identified: a juvenile svMP-dominated and KUN-lacking phenotype and an adult PLA2/svMP-balanced and KUN-containing phenotype. Despite differences in prey availability (and, therefore, diet) between populations, no significant differences in venom composition were found. As the populations are geographically isolated, the lack of venom diversification could be explained by insufficient time for natural selection and/or genetic drift to act on the venom composition of island vipers. However, substantial differences in proteomes were observed when compared to venoms from geographically distant populations inhabiting different conditions. These findings highlight the need to consider ecological and evolutionary processes when studying venom variability. SIGNIFICANCE: This study provides the first comprehensive analysis of the venom composition of two allopatric populations of Vipera ammodytes, living under similar abiotic (climate) but distinct biotic (prey availability) conditions. The ontogenetic changes in venom composition, coupled with the lack of differences between sex and between populations, shed light on the main determinants of venom evolution in this medically important snake. Seven new proteomes may facilitate future comparative studies of snake venom evolution. This study highlights the importance of considering ecological and evolutionary factors to understand snake venom variation.
Collapse
Affiliation(s)
- Margareta Lakušić
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal; Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4099-002 Porto, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661 Vairão, Portugal.
| | - Maik Damm
- Animal Venomics Lab, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Ohlebergsweg 12, 35392 Giessen, Germany; LOEWE-Centre for Translational Biodiversity Genomics, Senckenberganlage 25, 60325 Frankfurt, Germany; Institute for Insect Biotechnology, Justus-Liebig University Giessen, Heinrich-Buff-Ring 26-32, Gießen 35392, Germany; Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Vukašin Bjelica
- University of Belgrade, Faculty of Biology, Studentski trg 16, 11000 Belgrade, Serbia
| | - Marko Anđelković
- University of Belgrade, Institute for Biological Research "Siniša Stanković" - National Institute of Republic of Serbia, Bulevar despota Stefana 142, 11108 Belgrade, Serbia
| | - Ljiljana Tomović
- University of Belgrade, Faculty of Biology, Studentski trg 16, 11000 Belgrade, Serbia
| | - Xavier Bonnet
- CEBC, UMR-7372, CNRS Université de La Rochelle, 79360 Villiers en Bois, France
| | - Dragan Arsovski
- Macedonian Ecological Society, Arhimedova 5, 1000 Skopje, North Macedonia
| | - Roderich D Süssmuth
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Juan J Calvete
- Laboratorio de Venómica Evolutiva y Traslacional, Instituto de Biomedicina de Valencia, CSIC, Valencia 46010, Spain
| | - Fernando Martínez-Freiría
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661 Vairão, Portugal
| |
Collapse
|
3
|
Baudou FG, Rodriguez JP, Fusco L, de Roodt AR, De Marzi MC, Leiva L. South American snake venoms with abundant neurotoxic components. Composition and toxicological properties. A literature review. Acta Trop 2021; 224:106119. [PMID: 34481791 DOI: 10.1016/j.actatropica.2021.106119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/18/2021] [Accepted: 08/19/2021] [Indexed: 01/18/2023]
Abstract
In South America there are three snake genera with predominantly neurotoxic venoms: Crotalus, Micrurus and Hydrophis, which include nine species/subspecies, 97 species and a single marine species, respectively. Although accidents with neurotoxic venoms are less frequent than those with anticoagulant, cytotoxic or necrotic venoms (e.g. from Bothrops), they are of major public health importance. Venoms from genus Crotalus have been extensively studied, while data on the venoms from the other two genera are very limited, especially for Hydrophis. The venoms of North and South American Crotalus species show biochemical and physiopathological differences. The former species cause bothrops-like envenomation symptoms, while the latter mainly have neurotoxic and myotoxic effects, leading to respiratory paralysis and, occasionally, renal failure by myoglobinuria and death, often with no local lesions. Micrurus and Hydrophis also cause neurotoxic envenomations. Many studies have isolated, identified and characterized new enzymes and toxins, thus expanding the knowledge of snake venom composition. The present review summarizes the currently available information on neurotoxic venoms from South American snakes, with a focus on protein composition and toxicological properties. It also includes some comments concerning potential medical applications of elapid and crotalic toxins.
Collapse
Affiliation(s)
- Federico G Baudou
- Universidad Nacional de Luján (UNLu), Depto. de Ciencias Básicas, Luján, Buenos Aires, Argentina; Laboratorio de Inmunología, Instituto de Ecología y Desarrollo Sustentable (INEDES), UNLu-CONICET, Luján, Buenos Aires, Argentina.
| | - Juan P Rodriguez
- Laboratorio de Investigaciones Bioquímicas de la Facultad de Medicina (LIBIM), Instituto de Química Básica y Aplicada del Nordeste Argentino (IQUIBA-NEA), Universidad Nacional del Nordeste, Consejo Nacional de Investigaciones Científicas y Técnicas (UNNE-CONICET), Corrientes, Argentina
| | - Luciano Fusco
- Laboratorio de Investigación en Proteínas (LabInPro), IQUIBA-NEA (UNNE, CONICET), FaCENA, (UNNE), Corrientes, Argentina
| | - Adolfo R de Roodt
- Área Investigación y Desarrollo-Venenos, Instituto Nacional de Producción de Biológicos, Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán", Ministerio de Salud de la Nación, Argentina; Primera Cátedra de Toxicología, Facultad de Medicina, Universidad de Buenos Aires, Argentina; Laboratorio de Toxinopatología, Centro de Patología Experimental y Aplicada, Facultad de Medicina, Universidad de Buenos Aires, Argentina
| | - Mauricio C De Marzi
- Universidad Nacional de Luján (UNLu), Depto. de Ciencias Básicas, Luján, Buenos Aires, Argentina; Laboratorio de Inmunología, Instituto de Ecología y Desarrollo Sustentable (INEDES), UNLu-CONICET, Luján, Buenos Aires, Argentina
| | - Laura Leiva
- Laboratorio de Investigación en Proteínas (LabInPro), IQUIBA-NEA (UNNE, CONICET), FaCENA, (UNNE), Corrientes, Argentina
| |
Collapse
|
4
|
Montoni F, Andreotti DZ, Eichler RADS, Santos WDS, Kisaki CY, Arcos SSS, Lima IF, Soares MAM, Nishiyama-Jr MY, Nava-Rodrigues D, Ferro ES, Carvalho VM, Iwai LK. The impact of rattlesnake venom on mice cerebellum proteomics points to synaptic inhibition and tissue damage. J Proteomics 2020; 221:103779. [DOI: 10.1016/j.jprot.2020.103779] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 03/30/2020] [Accepted: 04/02/2020] [Indexed: 02/06/2023]
|
5
|
Muller SP, Silva VAO, Silvestrini AVP, de Macedo LH, Caetano GF, Reis RM, Mazzi MV. Crotoxin from Crotalus durissus terrificus venom: In vitro cytotoxic activity of a heterodimeric phospholipase A2 on human cancer-derived cell lines. Toxicon 2018; 156:13-22. [DOI: 10.1016/j.toxicon.2018.10.306] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/03/2018] [Accepted: 10/29/2018] [Indexed: 12/15/2022]
|
6
|
Abstract
Snakebite is classified by the WHO as a neglected tropical disease. Envenoming is a significant public health problem in tropical and subtropical regions. Neurotoxicity is a key feature of some envenomings, and there are many unanswered questions regarding this manifestation. Acute neuromuscular weakness with respiratory involvement is the most clinically important neurotoxic effect. Data is limited on the many other acute neurotoxic manifestations, and especially delayed neurotoxicity. Symptom evolution and recovery, patterns of weakness, respiratory involvement, and response to antivenom and acetyl cholinesterase inhibitors are variable, and seem to depend on the snake species, type of neurotoxicity, and geographical variations. Recent data have challenged the traditional concepts of neurotoxicity in snake envenoming, and highlight the rich diversity of snake neurotoxins. A uniform system of classification of the pattern of neuromuscular weakness and models for predicting type of toxicity and development of respiratory weakness are still lacking, and would greatly aid clinical decision making and future research. This review attempts to update the reader on the current state of knowledge regarding this important issue.
Collapse
Affiliation(s)
- Udaya K. Ranawaka
- Faculty of Medicine, University of Kelaniya, Ragama, Sri Lanka
- * E-mail:
| | - David G. Lalloo
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | |
Collapse
|
7
|
Sampaio SC, Hyslop S, Fontes MR, Prado-Franceschi J, Zambelli VO, Magro AJ, Brigatte P, Gutierrez VP, Cury Y. Crotoxin: Novel activities for a classic β-neurotoxin. Toxicon 2010; 55:1045-60. [DOI: 10.1016/j.toxicon.2010.01.011] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 12/17/2009] [Accepted: 01/09/2010] [Indexed: 10/19/2022]
|
8
|
Ponce-Soto LA, Martins-de-Souza D, Marangoni S. Neurotoxic, Myotoxic and Cytolytic Activities of the New Basic PLA2 Isoforms BmjeTX-I and BmjeTX-II Isolated from the Bothrops marajoensis (Marajó Lancehead) Snake Venom. Protein J 2010; 29:103-13. [DOI: 10.1007/s10930-010-9229-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
9
|
Martín R, Hernández M, Ibeas E, Fuentes L, Salicio V, Arnés M, Nieto ML. Secreted phospholipase A2-IIA modulates key regulators of proliferation on astrocytoma cells. J Neurochem 2009; 111:988-99. [DOI: 10.1111/j.1471-4159.2009.06377.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
10
|
Gao W, Starkov VG, He ZX, Wang QH, Tsetlin VI, Utkin YN, Lin ZJ, Bi RC. Functions, structures and Triton X-100 effect for the catalytic subunits of heterodimeric phospholipases A2 from Vipera nikolskii venom. Toxicon 2009; 54:709-16. [DOI: 10.1016/j.toxicon.2009.05.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 04/16/2009] [Accepted: 05/25/2009] [Indexed: 10/20/2022]
|
11
|
Prijatelj P, Jenko Pražnikar Z, Petan T, Križaj I, Pungerčar J. Mapping the structural determinants of presynaptic neurotoxicity of snake venom phospholipases A2. Toxicon 2008; 51:1520-9. [DOI: 10.1016/j.toxicon.2008.03.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Revised: 03/28/2008] [Accepted: 03/28/2008] [Indexed: 11/15/2022]
|
12
|
Generation of ammodytoxin-anti-cathepsin B immuno-conjugate as a model for delivery of secretory phospholipase A2 into cancer cells. Toxicon 2008; 51:754-64. [DOI: 10.1016/j.toxicon.2007.12.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Revised: 12/05/2007] [Accepted: 12/06/2007] [Indexed: 01/28/2023]
|
13
|
Characterization of a human coagulation factor Xa-binding site on Viperidae snake venom phospholipases A2 by affinity binding studies and molecular bioinformatics. BMC STRUCTURAL BIOLOGY 2007; 7:82. [PMID: 18062812 PMCID: PMC2248580 DOI: 10.1186/1472-6807-7-82] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2007] [Accepted: 12/06/2007] [Indexed: 11/20/2022]
Abstract
Background The snake venom group IIA secreted phospholipases A2 (SVPLA2), present in the Viperidae snake family exhibit a wide range of toxic and pharmacological effects. They exert their different functions by catalyzing the hydrolysis of phospholipids (PL) at the membrane/water interface and by highly specific direct binding to: (i) presynaptic membrane-bound or intracellular receptors; (ii) natural PLA2-inhibitors from snake serum; and (iii) coagulation factors present in human blood. Results Using surface plasmon resonance (SPR) protein-protein interaction measurements and an in vitro biological test of inhibition of prothrombinase activity, we identify a number of Viperidae venom SVPLA2s that inhibit blood coagulation through direct binding to human blood coagulation factor Xa (FXa) via a non-catalytic, PL-independent mechanism. We classify the SVPLA2s in four groups, depending on the strength of their binding. Molecular electrostatic potentials calculated at the surface of 3D homology-modeling models show a correlation with inhibition of prothrombinase activity. In addition, molecular docking simulations between SVPLA2 and FXa guided by the experimental data identify the potential FXa binding site on the SVPLA2s. This site is composed of the following regions: helices A and B, the Ca2+ loop, the helix C-β-wing loop, and the C-terminal fragment. Some of the SVPLA2 binding site residues belong also to the interfacial binding site (IBS). The interface in FXa involves both, the light and heavy chains. Conclusion We have experimentally identified several strong FXa-binding SVPLA2s that disrupt the function of the coagulation cascade by interacting with FXa by the non-catalytic PL-independent mechanism. By theoretical methods we mapped the interaction sites on both, the SVPLA2s and FXa. Our findings may lead to the design of novel, non-competitive FXa inhibitors.
Collapse
|
14
|
Halassy B, Brgles M, Habjanec L, Lang Balija M, Tomašić J, Križaj I, Štrancar A, Barut M. Use of Convective Interaction Media for Analysis of Long‐Nosed Viper Venom. J LIQ CHROMATOGR R T 2007. [DOI: 10.1080/10826070701665535] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
| | | | | | | | | | - Igor Križaj
- b Jožef Stefan Institute , Ljubljana, Slovenia
| | | | | |
Collapse
|
15
|
Sribar J, Kovacic L, Draskovic P, Faure G, Krizaj I. The first phospholipase inhibitor from the serum of Vipera ammodytes ammodytes. FEBS J 2007; 274:6055-64. [PMID: 17970753 DOI: 10.1111/j.1742-4658.2007.06127.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ammodytoxins are neurotoxic secretory phospholipase A(2) molecules, some of the most toxic components of the long-nosed viper (Vipera ammodytes ammodytes) venom. Envenomation by this and by closely related vipers is quite frequent in southern parts of Europe and serotherapy is used in the most severe cases. Because of occasional complications, alternative medical treatment of envenomation is needed. In the present study, ammodytoxin inhibitor was purified from the serum of V. a. ammodytes using two affinity procedures and a gel exclusion chromatography step. The ammodytoxin inhibitor from V. a. ammodytes serum consists of 23- and 25-kDa glycoproteins that form an oligomer, probably a tetramer, of about 100 kDa. N-terminal sequencing and immunological analysis revealed that both types of subunit are very similar to gamma-type secretory phospholipase A(2) inhibitors. The ammodytoxin inhibitor from V. a. ammodytes serum is a potent inhibitor of phospholipase activity and hence probably also the neurotoxicity of ammodytoxins. Discovery of the novel natural inhibitor of these potent secretory phospholipase A(2) toxins opens up prospects for the development of new types of small peptide inhibitors for use in regulating the physiological and pathological activities of secretory phospholipases A(2).
Collapse
Affiliation(s)
- Jernej Sribar
- Department of Molecular and Biomedical Sciences, Jozef Stefan Institute, Ljubljana, Slovenia
| | | | | | | | | |
Collapse
|
16
|
Pungercar J, Krizaj I. Understanding the molecular mechanism underlying the presynaptic toxicity of secreted phospholipases A2. Toxicon 2007; 50:871-92. [PMID: 17905401 DOI: 10.1016/j.toxicon.2007.07.025] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Revised: 07/13/2007] [Accepted: 07/20/2007] [Indexed: 11/24/2022]
Abstract
An important group of toxins, whose action at the molecular level is still a matter of debate, is secreted phospholipases A(2) (sPLA(2)s) endowed with presynaptic or beta-neurotoxicity. The current belief is that these beta-neurotoxins (beta-ntxs) exert their toxicity primarily due to their extracellular enzymatic action on the plasma membrane of motoneurons at the neuromuscular junction. However, the discovery of several extra- and intracellular proteins, with high binding affinity for snake venom beta-ntxs, has raised the question as to whether this explanation is adequate to account for all the observed phenomena in the process of presynaptic toxicity. The purpose of this review is to critically examine the various published studies, including the most recent results on internalization of a beta-ntx into motor nerve terminals, in order to contribute to a better understanding of the molecular mechanism of beta-neurotoxicity. As a result, we propose that presynaptic neurotoxicity of sPLA(2)s is a result of both extra- and intracellular actions of beta-ntxs, involving enzymatic activity as well as interaction of the toxins with intracellular proteins affecting the cycling of synaptic vesicles in the axon terminals of vertebrate motoneurons.
Collapse
Affiliation(s)
- Joze Pungercar
- Department of Molecular and Biomedical Sciences, Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | | |
Collapse
|
17
|
Chioato L, Aragão EA, Lopes Ferreira T, Medeiros AID, Faccioli LH, Ward RJ. Mapping of the structural determinants of artificial and biological membrane damaging activities of a Lys49 phospholipase A2 by scanning alanine mutagenesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1247-57. [PMID: 17346668 DOI: 10.1016/j.bbamem.2007.01.023] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Revised: 01/22/2007] [Accepted: 01/24/2007] [Indexed: 11/21/2022]
Abstract
Scanning alanine mutagenesis has been used to study the structural determinants of several activities of bothropstoxin-I (BthTx-I), a lysine 49 Phospholipases A(2) from the venom of Bothrops jararacussu. A total of 31 mutants were generated in the interfacial recognition site and C-terminal loop regions of the protein. The effects of mutagenesis on the in vivo myotoxic activity, the cytolytic activity against cultured C2C12 myoblasts, the bactericidal activity, and the Ca(2+)-independent membrane damaging activity against liposome membranes were compared. Residues 116-119 and 122-125 in the C-terminal loop region are structural determinants for these activities, indicating that membrane permeabilization by the BthTx-I is an important general property in all the measured effects. The structural determinants of myotoxicity and myoblast membrane permeabilization are highly correlated, demonstrating that cultured C2C12 myoblasts are a good model for the myotoxic effect. However, comparison of the structural determinants for all activities revealed several differences in the structural determinants between the effects against myoblast and bacterial membranes, and further differences when compared to the liposome membrane damaging effect. These membrane dependent effects are interpreted to be the consequence of differences in the activation of the membrane bound form of the protein on biological and artificial membranes.
Collapse
Affiliation(s)
- Lucimara Chioato
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brazil
| | | | | | | | | | | |
Collapse
|
18
|
Chang Y, Li Y, Bao Y, An L. Neurotoxic activity of Gln49 phospholipase A2 fromGloydius ussuriensis snake venom. J Appl Toxicol 2007; 27:447-52. [PMID: 17299814 DOI: 10.1002/jat.1222] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A novel neurotoxic protein phospholipase A(2) (PLA(2)), molecular weight 13 881.83 Da, has been isolated from snake venom of Gloydius ussuriensis, named as Gln49-PLA(2), which shows weak lethal toxic, myotoxic and apparent anticoagulant activity, but lacks phospholipase activity. The Gln49-PLA(2) obviously induced an increase of the pain threshold in intoxicated 615 mice compared with the control group, suggesting it is a neurotoxin. Hot-plate tests also showed that its analgesic activity was dose-dependent, and naloxone antagonized the analgesic effect, implying the mechanism of action of Gln49-sPLA(2) is correlated with opioid receptors. Electrophysiology studies revealed decreases in the action potential and the nerve conduction velocity in isolated hoptoad (Bufo bufo gargarizans Cantor) sciatic nerve, indicating Gln49-PLA(2) most probably had effects on ion channels.
Collapse
Affiliation(s)
- Yan Chang
- Department of Bioscience and Biotechnology, Dalian University of Technology, 2 Linggong road, Dalian 116024, P. R. China
| | | | | | | |
Collapse
|
19
|
Prijatelj P, Vardjan N, Rowan EG, Krizaj I, Pungercar J. Binding to the high-affinity M-type receptor for secreted phospholipases A2 is not obligatory for the presynaptic neurotoxicity of ammodytoxin A. Biochimie 2006; 88:1425-33. [PMID: 16815622 DOI: 10.1016/j.biochi.2006.06.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Accepted: 06/05/2006] [Indexed: 01/19/2023]
Abstract
R180, isolated from porcine brain cortex, is a high-affinity membrane receptor for ammodytoxin A (AtxA), a secreted phospholipase A(2) (sPLA(2)) and presynaptically active neurotoxin from venom of the long-nosed viper (Vipera ammodytes ammodytes). As a member of the M-type sPLA(2) receptors, present on the mammalian plasma membrane, R180 has been proposed to be responsible for one of the first events in the process of presynaptic neurotoxicity, the binding of the toxin to the nerve cell. To test this hypothesis, we prepared and analyzed three N-terminal fusion proteins of AtxA possessing a 12 or 5 amino acid residue peptide. The presence of such an additional "propeptide" prevented interaction of the toxin with the M-type receptor but not its lethality in mouse and neurotoxic effects on a mouse phrenic nerve-hemidiaphragm preparation. In addition, antibodies raised against the sPLA(2)-binding C-type lectin-like domain 5 of the M-type sPLA(2) receptor were unable to abolish the neurotoxic action of AtxA on the neuromuscular preparation. The specific enymatic activities of the fusion AtxAs were two to three orders of magnitude lower from that of the wild type, yet resulting in a similar but less pronounced neurotoxic profile on the neuromuscular junction. This is in accordance with other data showing that a minimal enzymatic activity suffices for presynaptic toxicity of sPLA(2)s to occur. Our results indicate that the interaction of AtxA with the M-type sPLA(2) receptor at the plasma membrane is not essential for presynaptic activity of the toxin. Interaction of AtxA with two intracellular proteins, calmodulin and the R25 receptor, was affected but not prevented by the presence of the N-terminal fusion peptides, implying that these proteins may play a role in the sPLA(2) neurotoxicity.
Collapse
Affiliation(s)
- Petra Prijatelj
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, SI-1000 Ljubljana, Slovenia
| | | | | | | | | |
Collapse
|
20
|
Liou JC, Kang KH, Chang LS, Ho SY. Mechanism of β-bungarotoxin in facilitating spontaneous transmitter release at neuromuscular synapse. Neuropharmacology 2006; 51:671-80. [PMID: 16806309 DOI: 10.1016/j.neuropharm.2006.05.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2005] [Revised: 05/12/2006] [Accepted: 05/15/2006] [Indexed: 10/24/2022]
Abstract
The mechanism of the action of beta-bungarotoxin (beta-BuTx) in the facilitation of spontaneous transmitter release at neuromuscular synapse was investigated in Xenopus cell culture using whole-cell patch clamp recording. Exposure of the culture to beta-BuTx dose-dependently enhances the frequency of spontaneous synaptic currents (SSCs). Buffering the rise of intracellular Ca2+ with BAPTA-AM hampered the facilitation of SSC frequency induced by beta-BuTx. The beta-BuTx-enhanced SSC frequency was reduced when the pharmacological Ca2+ -ATPase inhibitor thapsigargin was used to deplete intracellular Ca2+ store. Application of membrane-permeable inhibitors of inositol 1,4,5-trisphosphate (IP3) but not ryanodine receptors effectively occluded the increase of SSC frequency elicited by beta-BuTx. Treating cells with either wortmannin or LY294002, two structurally different inhibitors of phosphatidylinositol 3-kinase (PI3K) and with phospholipase C (PLC) inhibitor U73122, abolished the beta-BuTx-induced facilitation of synaptic transmission. The beta-BuTx-induced synaptic facilitation was completely abolished while there was presynaptic loading of the motoneuron with GDPbetaS, a non-hydrolyzable GDP analogue and inhibitor of G protein. Taken collectively, these results suggest that beta-BuTx elicits Ca2+ release from the IP3 sensitive intracellular Ca2+ stores of the presynaptic nerve terminal. This is done via PI3K/PLC signaling cascades and G protein activation, leading to an enhancement of spontaneous transmitter release.
Collapse
Affiliation(s)
- Jau-Cheng Liou
- Department of Biological Sciences, National Sun Yat-sen University, No 70, Lein-Hai Rd., Kaohsiung 804, Taiwan.
| | | | | | | |
Collapse
|
21
|
Triggiani M, Granata F, Frattini A, Marone G. Activation of human inflammatory cells by secreted phospholipases A2. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1289-300. [PMID: 16952481 DOI: 10.1016/j.bbalip.2006.07.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Revised: 07/07/2006] [Accepted: 07/17/2006] [Indexed: 10/24/2022]
Abstract
Secreted phospholipases A(2) (sPLA(2)s) are enzymes detected in serum and biological fluids of patients with various inflammatory, autoimmune and allergic disorders. Different isoforms of sPLA(2)s are expressed and released by human inflammatory cells, such as neutrophils, eosinophils, T cells, monocytes, macrophages and mast cells. sPLA(2)s generate arachidonic acid and lysophospholipids thus contributing to the production of bioactive lipid mediators in inflammatory cells. However, sPLA(2)s also activate human inflammatory cells by mechanisms unrelated to their enzymatic activity. Several human and non-human sPLA(2)s induce degranulation of mast cells, neutrophils and eosinophils and activate exocytosis in macrophages. In addition some, but not all, sPLA(2) isoforms promote cytokine and chemokine production from macrophages, neutrophils, eosinophils, monocytes and endothelial cells. These effects are primarily mediated by binding of sPLA(2)s to specific membrane targets (heparan sulfate proteoglycans, M-type, N-type or mannose receptors) expressed on effector cells. Thus, sPLA(2)s may play an important role in the initiation and amplification of inflammatory reactions by at least two mechanisms: production of lipid mediators and direct activation of inflammatory cells. Selective inhibitors of sPLA(2)-enzymatic activity and specific antagonists of sPLA(2) receptors are current being tested for pharmacological treatment of inflammatory and autoimmune diseases.
Collapse
Affiliation(s)
- Massimo Triggiani
- Division of Clinical Immunology and Allergy, Center for Basic and Clinical Immunology Research (CISI), University of Naples Federico II, 80131 Naples, Via Pansini 5, Italy.
| | | | | | | |
Collapse
|
22
|
Rouault M, Rash LD, Escoubas P, Boilard E, Bollinger J, Lomonte B, Maurin T, Guillaume C, Canaan S, Deregnaucourt C, Schrével J, Doglio A, Gutiérrez JM, Lazdunski M, Gelb MH, Lambeau G. Neurotoxicity and other pharmacological activities of the snake venom phospholipase A2 OS2: the N-terminal region is more important than enzymatic activity. Biochemistry 2006; 45:5800-16. [PMID: 16669624 PMCID: PMC2796912 DOI: 10.1021/bi060217r] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Several snake venom secreted phospholipases A2 (sPLA2s) including OS2 exert a variety of pharmacological effects ranging from central neurotoxicity to anti-HIV activity by mechanisms that are not yet fully understood. To conclusively address the role of enzymatic activity and map the key structural elements of OS2 responsible for its pharmacological properties, we have prepared single point OS2 mutants at the catalytic site and large chimeras between OS2 and OS1, a homologous but nontoxic sPLA2. Most importantly, we found that the enzymatic activity of the active site mutant H48Q is 500-fold lower than that of the wild-type protein, while central neurotoxicity is only 16-fold lower, providing convincing evidence that catalytic activity is at most a minor factor that determines central neurotoxicity. The chimera approach has identified the N-terminal region (residues 1-22) of OS2, but not the central one (residues 58-89), as crucial for both enzymatic activity and pharmacological effects. The C-terminal region of OS2 (residues 102-119) was found to be critical for enzymatic activity, but not for central neurotoxicity and anti-HIV activity, allowing us to further dissociate enzymatic activity and pharmacological effects. Finally, direct binding studies with the C-terminal chimera, which poorly binds to phospholipids while it is still neurotoxic, led to the identification of a subset of brain N-type receptors which may be directly involved in central neurotoxicity.
Collapse
Affiliation(s)
- Morgane Rouault
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
| | - Lachlan D. Rash
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
| | - Pierre Escoubas
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
| | - Eric Boilard
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
| | - James Bollinger
- Departments of Chemistry and Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Bruno Lomonte
- Universidad de Costa Rica, Faculdad de Microbiologia, Instituto Clodomiro Picado, San José, Costa Rica
| | - Thomas Maurin
- Laboratoire de Virologie, IFR50, Faculté de Médecine, 06107 Nice cedex 2, France
| | - Carole Guillaume
- USM 0504, Biologie Fonctionnelle des Protozoaires, Laboratoire de Biologie Parasitaire, Museum National d’Histoire Naturelle, 61 rue Buffon, 75231 Paris cedex 05, France
| | - Stéphane Canaan
- Laboratoire d'Enzymologie Interfaciale et de Physiologie de la Lipolyse, CNRS-UPR 9025, 31 Chemin Joseph-Aiguier, 13402 Marseille cedex 20, France
| | - Christiane Deregnaucourt
- USM 0504, Biologie Fonctionnelle des Protozoaires, Laboratoire de Biologie Parasitaire, Museum National d’Histoire Naturelle, 61 rue Buffon, 75231 Paris cedex 05, France
| | - Joseph Schrével
- USM 0504, Biologie Fonctionnelle des Protozoaires, Laboratoire de Biologie Parasitaire, Museum National d’Histoire Naturelle, 61 rue Buffon, 75231 Paris cedex 05, France
| | - Alain Doglio
- Laboratoire de Virologie, IFR50, Faculté de Médecine, 06107 Nice cedex 2, France
| | - José María Gutiérrez
- Universidad de Costa Rica, Faculdad de Microbiologia, Instituto Clodomiro Picado, San José, Costa Rica
| | - Michel Lazdunski
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
| | - Michael H. Gelb
- Departments of Chemistry and Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Gérard Lambeau
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
- Address correspondence to: Gérard Lambeau, Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France, Tel. +33 (0) 4 93 95 77 33; Fax. +33 (0) 4 93 95 77 08;
| |
Collapse
|
23
|
Petrovič U, Šribar J, Matis M, Anderluh G, Peter-Katalinić J, Križaj I, Gubenšek F. Ammodytoxin, a secretory phospholipase A2, inhibits G2 cell-cycle arrest in the yeast Saccharomyces cerevisiae. Biochem J 2006; 391:383-8. [PMID: 16008522 PMCID: PMC1276937 DOI: 10.1042/bj20050417] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Ammodytoxin (Atx), an sPLA2 (secretory phospholipase A2), binds to g and e isoforms of porcine 14-3-3 proteins in vitro. 14-3-3 proteins are evolutionarily conserved eukaryotic regulatory proteins involved in a variety of biological processes, including cell-cycle regulation. We have now shown that Atx binds to yeast 14-3-3 proteins with an affinity similar to that for the mammalian isoforms. Thus yeast Saccharomyces cerevisiae can be used as a model eukaryotic cell, which lacks endogenous phospholipases A2, to assess the in vivo relevance of this interaction. Atx was expressed in yeast cells and shown to be biologically active inside the cells. It inhibited G2 cell-cycle arrest in yeast, which is regulated by 14-3-3 proteins. Interference with the cell cycle indicates a possible mechanism by which sPLA2s are able to cause the opposing effects, proliferation and apoptosis, in mammalian cells.
Collapse
Affiliation(s)
- Uroš Petrovič
- *Department of Biochemistry and Molecular Biology, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Jernej Šribar
- *Department of Biochemistry and Molecular Biology, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Maja Matis
- †Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA 30912-2620, U.S.A
- ‡Institute for Medical Physics and Biophysics, University of Münster, D-48189 Münster, Germany
| | - Gregor Anderluh
- §Department of Biology, Biotechnical Faculty, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Jasna Peter-Katalinić
- †Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA 30912-2620, U.S.A
- ‡Institute for Medical Physics and Biophysics, University of Münster, D-48189 Münster, Germany
| | - Igor Križaj
- *Department of Biochemistry and Molecular Biology, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
- To whom correspondence should be addressed (email )
| | - Franc Gubenšek
- *Department of Biochemistry and Molecular Biology, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
- ∥Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| |
Collapse
|
24
|
Prijatelj P, Charnay M, Ivanovski G, Jenko Z, Pungercar J, Krizaj I, Faure G. The C-terminal and β-wing regions of ammodytoxin A, a neurotoxic phospholipase A2 from Vipera ammodytes ammodytes, are critical for binding to factor Xa and for anticoagulant effect. Biochimie 2006; 88:69-76. [PMID: 16039772 DOI: 10.1016/j.biochi.2005.06.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Accepted: 06/21/2005] [Indexed: 11/25/2022]
Abstract
Ammodytoxin A (AtxA) from the venom of Vipera ammodytes ammodytes belongs to group IIA secreted phospholipase A2 (sPLA2), for which the major pathologic activity is presynaptic neurotoxicity. We show here that this toxin also affects hemostasis because it exhibits strong anticoagulant activity. AtxA binds directly to human coagulation factor Xa (FXa) with Kdapp of 32 nM, thus inhibiting the activity of the prothrombinase complex with an IC50 of 20 nM. To map the FXa-interaction site on AtxA, various mutants of AtxA produced by site-directed mutagenesis and expressed in Escherichia coli were tested in the study. In surface plasmon resonance (SPR) measurements, with FXa covalently attached to the sensor chip, we show that the FXa-binding site on AtxA includes several basic amino acid residues at the C-terminal and beta-wing regions of the molecule. Applying an in vitro biological test for inhibition of prothrombinase activity, we further demonstrate that the same residues are also very important for the anticoagulant activity of AtxA. We conclude that the anticoagulant site of AtxA is located in the C-terminal and beta-wing regions of this phospholipase A2. Synthetic peptides comprising residues of the deduced anticoagulant site of AtxA provide a basis to synthesize novel anticoagulant drugs.
Collapse
Affiliation(s)
- Petra Prijatelj
- Unité des Venins, Institut Pasteur, 25, rue du Dr. Roux, 75724 Paris cedex 15, France
| | | | | | | | | | | | | |
Collapse
|
25
|
Belo CAD, Leite GB, Toyama MH, Marangoni S, Corrado AP, Fontana MD, Southan A, Rowan EG, Hyslop S, Rodrigues-Simioni L. Pharmacological and structural characterization of a novel phospholipase A2 from Micrurus dumerilii carinicauda venom. Toxicon 2005; 46:736-50. [PMID: 16198388 DOI: 10.1016/j.toxicon.2005.07.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Accepted: 07/20/2005] [Indexed: 10/25/2022]
Abstract
We have isolated a new phospholipase A2 (MiDCA1) from the venom of the coral snake Micrurus dumerilii carinicauda. This toxin, which had a molecular mass of 15,552Da, shared high sequence homology with the PLA2 toxins MICNI A and B from Micrurus nigrocinctus venom (77.7% and 73.1%, respectively). In chick biventer cervicis preparations, MiDCA1 produced concentration- and time-dependent neuromuscular blockade that reached 100% after 120 min (2.4 microM, n = 6); contractures to exogenously applied carbachol (8 microM) and KCl (13 mM) were still seen after complete blockade. In mouse phrenic-nerve diaphragm preparations, MiDCA1 (2.4 microM; n = 6) caused triphasic changes followed by partial neuromuscular blockade. Intracellular recordings of end-plate potentials (EPPs) and miniature end-plate potentials (MEPPs) from mouse diaphragm preparations showed that MiDCA1 increased the quantal content by 386+/-12% after 10 min (n = 14; p<0.05) and caused a triphasic change in the frequency of MEPPs. MiDCA1 also decreased the resting membrane potential, an effect that was prevented by tetrodotoxin and/or low extracellular calcium, but not by d-tubocurarine. The toxin increased the amplitude of mouse sciatic-nerve compound action potentials by 30+/-9% (0.6 microM; p<0.05). Potassium currents elicited in freshly dissociated dorsal root ganglia neurones were blocked by 31+/-1% (n = 4; p<0.05) in the presence of 2.4 microM MiDCA1. These results show that MiDCA1 is a new presynaptic phospholipase A2 that produces neuromuscular blockade in vertebrate nerve-muscle preparations. The triphasic effects seen in mammalian preparations and the facilitatory response were probably caused mainly by the activation of sodium channels, complemented by the blockade of nerve terminal potassium channels. The inability of d-turocurarine to prevent the depolarization by MiDCA1 indicated that cholinergic nicotinic receptors were not involved in this phenomenon.
Collapse
Affiliation(s)
- Cháriston André Dal Belo
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), P.O. Box 6111, 13083-970 Campinas, SP, Brazil
| | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Kini RM. Structure–function relationships and mechanism of anticoagulant phospholipase A2 enzymes from snake venoms. Toxicon 2005; 45:1147-61. [PMID: 15922780 DOI: 10.1016/j.toxicon.2005.02.018] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Phospholipase A(2) (PLA(2)) enzymes from snake venom are toxic and induce a wide spectrum of pharmacological effects, despite similarity in primary, secondary and tertiary structures and common catalytic properties. Thus, the structure-function relationships and the mechanism of this group of small proteins are subtle, complex and intriguing challenges. This review, taking the PLA(2) enzymes from spitting cobra (Naja nigricollis) venom as examples, describes the mechanism of anticoagulant effects. The strongly anticoagulant CM-IV inhibits both the extrinsic tenase and prothrombinase complexes, whereas the weakly anticoagulant PLA(2) enzymes (CM-I and CM-II) inhibit only the extrinsic tenase complex. CM-IV binds to factor Xa and interferes in its interaction with factor Va and the formation of prothrombinase complex. In contrast, CM-I and CM-II do not affect the formation of prothrombinase complex. In addition, CM-IV inhibits the extrinsic tenase complex by a combination of enzymatic and nonenzymatic mechanisms, while CM-I and CM-II inhibit by only enzymatic mechanism. These functional differences explain the disparity in the anticoagulant potency of N. nigricollis PLA(2) enzymes. Similarly, human secretory enzyme binds to factor Xa and inhibits the prothrombinase complex. We predicted the anticoagulant region of PLA(2) enzymes using a systematic and direct comparison of amino acid sequences. This region between 54 and 77 residues is basic in the strongly anticoagulant PLA(2) enzymes and neutral or negatively charged in weakly and non-anticoagulant enzymes. The prediction is validated independently by us and others using both site directed mutagenesis and synthetic peptides. Thus, strongly anticoagulant CM-IV binds to factor Xa (its target protein) through the specific anticoagulant site on its surface. In contrast, weakly anticoagulant enzymes, which lack the anticoagulant region fail to bind specifically to the target protein, factor Xa in the coagulation cascade. Thus, these studies strongly support the target model which suggests that protein-protein interaction rather than protein-phospholipid interaction determines the pharmacological specificity of PLA(2) enzymes.
Collapse
Affiliation(s)
- R Manjunatha Kini
- Protein Science Laboratory, Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
| |
Collapse
|
27
|
Sribar J, Anderluh G, Fox JW, Krizaj I. Protein disulphide isomerase binds ammodytoxin strongly: Possible implications for toxin trafficking. Biochem Biophys Res Commun 2005; 329:733-7. [PMID: 15737647 DOI: 10.1016/j.bbrc.2005.02.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2005] [Indexed: 11/19/2022]
Abstract
Ammodytoxin, a group IIA secreted phospholipase A(2) from the venom of the long-nosed viper (Vipera ammodytes ammodytes), is a potent presynaptically acting neurotoxin. It blocks the secretion of neurotransmitter from the nerve cell, thus hindering the communication with the neighbouring neuron or muscle cell. To express the neurotoxicity, ammodytoxin should interact with specific receptors in the axon terminal and express phospholipase activity. Our previous results indicate that, following the association with a receptor on the external side of the presynaptic membrane, the toxin penetrates into the cytosol of the nerve cell. Here, we show that the toxin associates specifically with protein disulphide isomerase, a protein in the lumen of endoplasmic reticulum, which may be crucial for the retention and concentration of the toxin in this cellular compartment and for its subsequent transport across the membrane of endoplasmic reticulum into the cytosol of the nerve cell.
Collapse
Affiliation(s)
- Jernej Sribar
- Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Ljubljana, Slovenia
| | | | | | | |
Collapse
|
28
|
Gao W, Starkov VG, Tsetlin VI, Utkin YN, Lin ZJ, Bi RC. Isolation and preliminary crystallographic studies of two new phospholipases A2 from Vipera nikolskii venom. Acta Crystallogr Sect F Struct Biol Cryst Commun 2005; 61:189-92. [PMID: 16510990 PMCID: PMC1952264 DOI: 10.1107/s1744309104033688] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Accepted: 12/20/2004] [Indexed: 11/10/2022]
Abstract
Snake-venom phospholipases A2 (PLA2s) represent a good model for studies of structure-function relationships, mainly because of their small size and diverse pharmacological and toxicological activities. To obtain new members of the abundant PLA2 family, the venom of the viper Vipera nikolskii was fractionated for the first time and two new proteins, VN5-3 and VN4-3, were isolated. Both proteins show phospholipase A2 activity and may possess neurotoxic activity. Based on the determined partial amino-acid sequences, the new proteins can be classified as basic Asp49 phospholipases A2. They were crystallized using the hanging-drop vapour-diffusion method and crystals of both proteins belong to space group R32, with similar unit-cell parameters: a = b = 76.29, c = 303.35 A for protein VN5-3 and a = b = 76.28, c = 304.39 A for protein VN4-3. Diffraction data sets to 3.0 and 2.2 A resolution were collected and processed for the VN5-3 and VN4-3 crystals, respectively. Preliminary analysis indicates that there are two molecules in the asymmetric unit for both crystals. Further crystallographic studies will help in understanding the structural basis for the multiple functions of snake-venom PLA2s.
Collapse
Affiliation(s)
- Wei Gao
- Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, People’s Republic of China
| | - Vladislav G. Starkov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Victor I. Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Yuri N. Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Zheng-jiong Lin
- Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, People’s Republic of China
| | - Ru-chang Bi
- Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, People’s Republic of China
| |
Collapse
|
29
|
Angulo Y, Lomonte B. Differential susceptibility of C2C12 myoblasts and myotubes to group II phospholipase A2 myotoxins from crotalid snake venoms. Cell Biochem Funct 2005; 23:307-13. [PMID: 15657942 DOI: 10.1002/cbf.1208] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Group II phospholipase A(2) (PLA(2)) myotoxins isolated from Viperidae/Crotalidae snake venoms induce a rapid cytolytic effect upon diverse cell types in vitro. Previous studies suggested that this effect could be more pronounced on skeletal muscle myotubes than on other cell types, including undifferentiated myoblasts. This study utilized the murine skeletal muscle C2C12 cell line to investigate whether differentiated myotubes are more susceptible than myoblasts, and if this characteristic is specific for the group II myotoxic PLA(2)s. The release of lactic dehydrogenase was quantified as a measure of cytolysis, 3 h after cell exposure to different group II PLA(2)s purified from Bothrops asper, Atropoides nummifer, Cerrophidion godmani, and Bothriechis schlegelii venoms. In addition, susceptibility to lysis induced by synthetic melittin and group III PLA(2) from bee (Apis mellifera) venom, as well as by anionic, cationic, and neutral detergents, was comparatively evaluated on the two cultures. Myotubes were significantly more susceptible to group II PLA(2) myotoxins, but not to the other agents tested, under the same conditions. Moreover, the increased susceptibility of myotubes over myoblasts was also demonstrated with two cytolytic synthetic peptides, derived from the C-terminal region of Lys49 PLA(2) myotoxins, that reproduce the action of their parent proteins. These results indicate that fusion and differentiation of myoblasts into myotubes induce changes that render these cells more susceptible to the toxic mechanism of group II PLA(2) myotoxins, but not to general perturbations of membrane homeostasis. Such changes are likely to involve myotoxin acceptor site(s), which remain(s) to be identified.
Collapse
Affiliation(s)
- Yamileth Angulo
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | | |
Collapse
|
30
|
Ivanovski G, Petan T, Krizaj I, Gelb MH, Gubensek F, Pungercar J. Basic amino acid residues in the β-structure region contribute, but not critically, to presynaptic neurotoxicity of ammodytoxin A. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2004; 1702:217-25. [PMID: 15488774 DOI: 10.1016/j.bbapap.2004.09.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2004] [Revised: 08/30/2004] [Accepted: 09/01/2004] [Indexed: 11/26/2022]
Abstract
The molecular mechanism of action of presynaptically toxic secreted phospholipases A2 (sPLA2s) isolated from snake venoms is not completely understood. It has been proposed that the positive charge in the beta-structure region is important for their toxic activity. To test this hypothesis, we characterised several mutants of ammodytoxin A (AtxA) possessing substitution of all five basic residues in this region. The mutations had relatively little influence on the catalytic activity of AtxA, either on charge-neutral or anionic phospholipid vesicles. An exception was R72 when replaced by a hydrophobic (higher activity) or an acidic (lower activity) residue. Lethal potencies of the eight single site mutants were up to four times lower than that of the wild-type, whereas the triple mutant (K74S/H76S/R77L) was 13-fold less toxic. The substitutions also lowered the affinity of the toxin, slightly to moderately, for the neuronal receptors R25 and R180. Interaction with calmodulin was only slightly affected by substitutions of K86, more by those of the K74/H76/R77 cluster and most by those of R72 (up to 11-fold lower binding affinity). The results clearly indicate that the basic amino acid residues in the beta-region of AtxA contribute to, but are not necessary for, its neurotoxic effect.
Collapse
Affiliation(s)
- Gabriela Ivanovski
- Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | | | | | | | | | | |
Collapse
|
31
|
Rigoni M, Schiavo G, Weston AE, Caccin P, Allegrini F, Pennuto M, Valtorta F, Montecucco C, Rossetto O. Snake presynaptic neurotoxins with phospholipase A2 activity induce punctate swellings of neurites and exocytosis of synaptic vesicles. J Cell Sci 2004; 117:3561-70. [PMID: 15226375 DOI: 10.1242/jcs.01218] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mechanisms of action of four snake presynaptic phospholipase A2 neurotoxins were investigated in cultured neurons isolated from various parts of the rat brain. Strikingly, physiological concentrations of notexin, beta-bungarotoxin, taipoxin or textilotoxin induced a dose-dependent formation of discrete bulges at various sites of neuronal projections. Neuronal bulging was paralleled by the redistribution of the two synaptic vesicle markers synaptophysin I (SypI) and vesicle-attached membrane protein 2 (VAMP2) to the bulges, and by the exposure of the luminal domain of synaptotagmin on the cell surface. These neurotoxins induced glutamate release from cultured neurons similarly to the known evoked release of acetylcholine from neuromuscular junctions. In addition, partial fragmentation of F-actin and neurofilaments was observed in neurons, but not in astrocytes. These findings indicate that these snake presynaptic neurotoxins act with by same mechanism and that the observed phenotype results from the fusion of synaptic vesicles with the plasma membrane not balanced by an adequate membrane retrieval. These changes closely resemble those occurring at neuromuscular junctions of intoxicated animals and fully qualify these primary neuronal cultures as pertinent models for studying the molecular mode of action of these neurotoxins.
Collapse
Affiliation(s)
- Michela Rigoni
- Department of Biomedical Sciences and CNR Institute of Neuroscience, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Abstract
Venom phospholipase A2 (PLA2) enzymes share similarity in structure and catalytic function with mammalian enzymes. However, in contrast to mammalian enzymes, many are toxic and induce a wide spectrum of pharmacological effects. Thus structure-function relationship of this group of small proteins is subtle, but complex puzzle to protein biochemists, molecular biologists, toxinologists, pharmacologists and physiologists. This review describes the present status of our understanding of their structure, function and mechanism. It was proposed that their unique ability to 'target' themselves to a specific organ or tissue is due to their high affinity binding to specific proteins which act as receptors (more precisely, acceptors). This specific binding of PLA2 is conferred by the presence of a 'pharmacological site' on its surface which is independent of the catalytic site. The high affinity interaction of PLA2 with its acceptor (or target protein) is probably due to the complementarity, in terms of charges, hydrophobicity and van der Waal's contact surfaces, between the pharmacological site and the binding site on the surface of the acceptor protein. Upon binding to the target, the PLA2 can induce its pharmacological effects by mechanisms either dependent on or independent of its catalytic activity. Because of the unprecedented wide spectrum of specific targeting to various tissues and organs, identification of the pharmacological sites has potential for exploitation in development of novel systems useful for 'delivering' specific proteins to a particular target tissue or organ. Thus research in this field will provide a lot of exciting opportunities.
Collapse
Affiliation(s)
- R Manjunatha Kini
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543.
| |
Collapse
|
33
|
Prijatelj P, Sribar J, Ivanovski G, Krizaj I, Gubensek F, Pungercar J. Identification of a novel binding site for calmodulin in ammodytoxin A, a neurotoxic group IIA phospholipase A2. EUROPEAN JOURNAL OF BIOCHEMISTRY 2003; 270:3018-25. [PMID: 12846835 DOI: 10.1046/j.1432-1033.2003.03679.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The molecular mechanism of the presynaptic neurotoxicity of snake venom phospholipases A2 (PLA2s) is not yet fully elucidated. Recently, new high-affinity binding proteins for PLA2 toxins have been discovered, including the important intracellular Ca2+ sensor, calmodulin (CaM). In the present study, the mode of interaction of group IIA PLA2s with the Ca2+-bound form of CaM was investigated by mutational analysis of ammodytoxin A (AtxA) from the long-nosed viper (Vipera ammodytes ammodytes). Several residues in the C-terminal part of AtxA were found to be important in this interaction, particularly those in the region 115-119. In support of this finding, introduction of Y115, I116, R118 and N119, present in AtxA, into a weakly neurotoxic PLA2 from Russell's viper (Daboia russellii russellii) increased by sevenfold its binding affinity for CaM. Furthermore, two out of four peptides deduced from different regions of AtxA were able to compete with the toxin in binding to CaM. The nonapeptide showing the strongest inhibition was that comprising the AtxA region 115-119. This stretch contributes to a distinct hydrophobic patch within the region 107-125 in the C-terminal part of the molecule. This lacks any substantial helical structure and is surrounded by several basic residues, which may form a novel binding motif for CaM on the molecular surface of the PLA2 toxin.
Collapse
Affiliation(s)
- Petra Prijatelj
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | | | | | | | | | | |
Collapse
|
34
|
Sribar J, Sherman NE, Prijatelj P, Faure G, Gubensek F, Fox JW, Aitken A, Pungercar J, Krizaj I. The neurotoxic phospholipase A2 associates, through a non-phosphorylated binding motif, with 14-3-3 protein gamma and epsilon isoforms. Biochem Biophys Res Commun 2003; 302:691-6. [PMID: 12646224 DOI: 10.1016/s0006-291x(03)00228-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two novel acceptors for ammodytoxin C, a presynaptically neurotoxic phospholipase A(2) from snake venom, have been purified from porcine cerebral cortex by a toxin-affinity-based procedure. Using tandem mass spectrometry, the isolated acceptors were identified as 14-3-3 gamma and epsilon isoforms, highly conserved cytoplasmic proteins involved in the regulation of numerous physiological processes. The interaction between ammodytoxin C and 14-3-3 proteins is direct and not mediated by calmodulin, a high-affinity acceptor for both ammodytoxin C and 14-3-3 proteins, as demonstrated in pull-down experiments and by surface plasmon resonance. The latter technique gave an apparent dissociation constant of 1.0+/-0.2 microM for the interaction between chip-immobilized 14-3-3 and ammodytoxin C. 14-3-3 usually interacts with proteins through specific phospho-Ser/Thr motifs. Ammodytoxin C is not a phospho-protein, therefore the interaction must occur through a non-phosphorylated binding site, most probably the KEESEK sequence at its C-terminal end. The interaction we describe suggests an explanation for the pathophysiological effects evoked by some secreted phospholipases A(2), such as the inhibition of protein phosphorylation, of terminal ion currents, and of neurotransmission, as well as the initiation of neuronal cell death, all processes regulated by 14-3-3 proteins.
Collapse
Affiliation(s)
- Jernej Sribar
- Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Ljubljana, Slovenia
| | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Faure G, Copic A, Le Porrier S, Gubensek F, Bon C, Krizaj I. Crotoxin acceptor protein isolated from Torpedo electric organ: binding properties to crotoxin by surface plasmon resonance. Toxicon 2003; 41:509-17. [PMID: 12657321 DOI: 10.1016/s0041-0101(02)00394-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Crotoxin, a potent neurotoxin from the South American rattlesnake Crotalus durissus terrificus, is a heterodimeric phospholipase A(2) (EC 3.1.1.4), which blocks the release of acetylcholine from peripheral neurons. We previously have suggested the existence of a 48 kDa crotoxin-binding protein in the presynaptic membranes of the electric organ of Torpedo marmorata. Here, we report the purification and characterization of this protein that we called the crotoxin acceptor protein from Torpedo (CAPT). The membranes of electric organs from Torpedo were solubilized with a detergent (4% (w/v) Triton X-100) and CAPT was isolated by affinity chromatography on a crotoxin column. SDS-PAGE showed that the purified protein was homogeneous and cross-linking studies with radioiodinated crotoxin confirmed that it had retained its toxin-binding properties. The purified CAPT has similar molecular mass as crocalbin, a crotoxin-binding protein isolated from porcine brains, yet anti-crocalbin antiserum failed to recognize CAPT. Surface plasmon resonance biosensor technology was used to measure the specific interaction between crotoxin and solubilized CAPT. Using this method, it was possible to follow CAPT throughout the purification procedure. As well, an apparent dissociation constant (K(d)(app)) of 3.4 nM was calculated for the interaction of pure CAPT and crotoxin from the dissociation rate constant (k(off)=1.2 x 10(-2)s(-1)) and the association rate constant (k(on)=3.5 x 10(6)M(-1)s(-1)).
Collapse
Affiliation(s)
- Grazyna Faure
- Unité des Venins, Institut Pasteur, 25 rue du Dr Roux, 75724, Paris Cedex 15 France.
| | | | | | | | | | | |
Collapse
|
36
|
Prijatelj P, Krizaj I, Kralj B, Gubensek F, Pungercar J. The C-terminal region of ammodytoxins is important but not sufficient for neurotoxicity. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:5759-64. [PMID: 12444963 DOI: 10.1046/j.1432-1033.2002.03301.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Ammodytoxins (Atxs) are presynaptically acting snake venom phospholipase A2 (PLA2) toxins the molecular mechanism of whose neurotoxicity is not completely understood. Two chimeric PLA2s were prepared by replacing the C-terminal part of a nontoxic venom PLA2, ammodytin I2, with that of AtxA(K108N). The chimeras were not toxic, but were able to bind strongly to an Atxs-specific neuronal receptor, R25. They also showed an increased affinity for calmodulin, a recently identified high-affinity binding protein for Atxs, whereas affinity for a neuronal M-type PLA2 receptor remained largely unchanged. The results show that the C-terminal region of Atxs, which is known to be involved in neurotoxicity, is critical for their interaction with specific binding proteins, but that some other part of the molecule also contributes to toxicity.
Collapse
Affiliation(s)
- Petra Prijatelj
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | | | | | | | | |
Collapse
|
37
|
Hanasaki K, Arita H. Phospholipase A2 receptor: a regulator of biological functions of secretory phospholipase A2. Prostaglandins Other Lipid Mediat 2002; 68-69:71-82. [PMID: 12432910 DOI: 10.1016/s0090-6980(02)00022-9] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The phospholipase A2 receptor (PLA2R) is a type I transmembrane glycoprotein related to the C-type animal lectin family that includes the mannose receptor. PLA2R regulates a variety of biological responses elicited by specific types of secretory PLA2s (sPLA2s). Group IB sPLA2 (sPLA2-IB) acts as an endogenous PLA2R ligand to induce cell proliferation, cell migration, and lipid mediator production. Analysis of PLA2R-deficient mice has suggested a potential role of the sPLA2-IB/PLA2R pathway in the production of pro-inflammatory cytokines in endotoxic shock. PLA2R is also involved in the clearance of sPLA2s, including group X sPLA2 (sPLA2-X) and a particular type of snake venom sPLA2, and clearance suppresses their potent enzymatic activities. In the circulation, the soluble form of PLA2R is constitutively present as anendogenous inhibitor of sPLA2s. This review will focus on recent findings on the roles of PLA2R in regulating sPLA2 functions and summarize what is known about the otherbinding proteins for mammalian and snake venom sPLA2s.
Collapse
Affiliation(s)
- Kohji Hanasaki
- Shionogi Research Laboratories, Shionogi and Co., Ltd., Osaka, Japan.
| | | |
Collapse
|
38
|
Leonardi A, Gubensek F, Krizaj I. Purification and characterisation of two hemorrhagic metalloproteinases from the venom of the long-nosed viper, Vipera ammodytes ammodytes. Toxicon 2002; 40:55-62. [PMID: 11602279 DOI: 10.1016/s0041-0101(01)00188-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Two hemorrhagic proteins, VaH1 and VaH2, have been purified from Vipera ammodytes ammodytes venom. They are monomeric glycoproteins of an apparent molecular mass of 70kDa and multiple isoelectric points around pH 5.5. Both molecules are proteolytically active against azocasein as substrate. VaH1, which was characterised in detail, showed maximum activity at pH 7.5. Ethylenediaminetetraacetic acid eliminated the proteolytic as well as the hemorrhagic activity of VaH1 while iodoacetamide, phenylmethylsulfonyl fluoride and pepstatin A, inhibitors of cysteine, serine and aspartic proteinases respectively, had no effect. VaH1 is therefore a metalloproteinase whose hemorrhagic activity is very likely the result of its proteolytic activity. VaH1 is a fibrinogenase, hydrolysing exclusively the Aalpha-chain of fibrinogen. In the B-chain of insulin it cleaved with a high preference the bond between Ala(14) and Leu(15). Based on its molecular mass, VaH1 (as well as VaH2) is a Class P-III metalloproteinase. Partial amino acid sequences of its CNBr fragments demonstrated a high level of identity with the reprolysin subfamily of zinc-metalloproteinases.
Collapse
Affiliation(s)
- Adrijana Leonardi
- Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, 1000, Ljubljana, Slovenia
| | | | | |
Collapse
|
39
|
Vardjan N, Sherman NE, Pungercar J, Fox JW, Gubensek F, Krizaj I. High-molecular-mass receptors for ammodytoxin in pig are tissue-specific isoforms of M-type phospholipase A(2) receptor. Biochem Biophys Res Commun 2001; 289:143-9. [PMID: 11708791 DOI: 10.1006/bbrc.2001.5940] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Studying the molecular basis of presynaptic neurotoxicity of ammodytoxin C, a secretory phospholipase A(2) from the venom of Vipera a. ammodytes snake, we demonstrated the existence of two high-molecular-mass ammodytoxin C-binding proteins in porcine tissues, one in cerebral cortex and the other in liver. These proteins differ considerably in stability and Western blotting properties. However, as shown by immunological analysis and tandem mass spectrometry sequencing of several internal peptides derived from the purified receptors, both belong to secretory phospholipase A(2) receptors of the M type, which are Ca(2+)-dependent multilectins homologous to the macrophage mannose receptor. Based on Southern blot analysis of genomic DNA and deglycosylation of the receptors, the difference between the two proteins most likely stems from the different posttranscriptional and posttranslational modifications of a single gene product. Our findings raise the possibility that the M-type receptors for secretory phospholipases A(2) may display different physiological properties in different tissues.
Collapse
Affiliation(s)
- N Vardjan
- Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | | | | | | | | | | |
Collapse
|
40
|
Sribar J, Copic A, Paris A, Sherman NE, Gubensek F, Fox JW, Krizaj I. A high affinity acceptor for phospholipase A2 with neurotoxic activity is a calmodulin. J Biol Chem 2001; 276:12493-6. [PMID: 11278260 DOI: 10.1074/jbc.c100048200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
One of the high affinity binding proteins for ammodytoxin C, a snake venom presynaptically neurotoxic phospholipase A(2), has been purified from porcine cerebral cortex and characterized. After extraction from the membranes, the toxin-binding protein was isolated in a homogenous form using wheat germ lectin-Sepharose, Q-Sepharose, and ammodytoxin-CH-Sepharose chromatography. The specific binding of (125)I-ammodytoxin C to the isolated acceptor was inhibited to different extents by some neurotoxic phospholipases A(2), ammodytoxins, bee venom phospholipase A(2), agkistrodotoxin, and crotoxin; but not by nontoxic phospholipases A(2), ammodytin I(2), porcine pancreatic phospholipase A(2), and human type IIA phospholipase A(2); suggesting the significance of the acceptor in the mechanism of phospholipase A(2) neurotoxicity. The isolated acceptor was identified as calmodulin by tandem mass spectrometry. Since calmodulin is generally considered as an intracellular protein, the identity of this acceptor supports the view that secretory phospholipase A(2) neurotoxins have to be internalized to exert their toxic effect. Moreover, since ammodytoxin is known to block synaptic transmission, its interaction with calmodulin as an acceptor may constitute a valuable probe for further investigation of the role of the latter in this Ca(2+)-regulated process.
Collapse
Affiliation(s)
- J Sribar
- Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Jamova 39, Slovenia
| | | | | | | | | | | | | |
Collapse
|