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Šribar J, Kovačič L, Oberčkal J, Ivanušec A, Petan T, Fox JW, Križaj I. The neurotoxic secreted phospholipase A 2 from the Vipera a. ammodytes venom targets cytochrome c oxidase in neuronal mitochondria. Sci Rep 2019; 9:283. [PMID: 30670719 PMCID: PMC6342964 DOI: 10.1038/s41598-018-36461-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 11/16/2018] [Indexed: 12/30/2022] Open
Abstract
The β-neurotoxic secreted phospholipases A2 (sPLA2s) block neuro-muscular transmission by poisoning nerve terminals. Damage inflicted by such sPLA2s (β-ntx) on neuronal mitochondria is characteristic, very similar to that induced by structurally homologous endogenous group IIA sPLA2 when its activity is elevated, as, for example, in the early phase of Alzheimer's disease. Using ammodytoxin (Atx), the β-ntx from the venom of the nose-horned viper (Vipera a. ammodytes), the sPLA2 receptor R25 has been detected in neuronal mitochondria. This receptor has been purified from porcine cerebral cortex mitochondria by a new Atx-affinity-based chromatographic procedure. Mass spectrometry analysis revealed R25 to be the subunit II of cytochrome c oxidase (CCOX), an essential constituent of the respiratory chain complex. CCOX was confirmed as being the first intracellular membrane receptor for sPLA2 by alternative Atx-affinity-labellings of purified CCOX, supported also by the encounter of Atx and CCOX in PC12 cells. This discovery suggests the explanation of the mechanism by which β-ntx hinders production of ATP in poisoned nerve endings. It also provides a new insight into the potential function and dysfunction of endogenous GIIA sPLA2 in mitochondria.
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Affiliation(s)
- Jernej Šribar
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia
| | - Lidija Kovačič
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia
| | - Jernej Oberčkal
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia
| | - Adrijan Ivanušec
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000, Ljubljana, Slovenia
| | - Toni Petan
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia
| | - Jay W Fox
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, 22908, USA
| | - Igor Križaj
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia.
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Oberčkal J, Kovačič L, Šribar J, Leonardi A, Dolinar K, Pucer Janež A, Križaj I. On the role of protein disulfide isomerase in the retrograde cell transport of secreted phospholipases A2. PLoS One 2015; 10:e0120692. [PMID: 25763817 PMCID: PMC4357439 DOI: 10.1371/journal.pone.0120692] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 01/25/2015] [Indexed: 11/29/2022] Open
Abstract
Following the finding that ammodytoxin (Atx), a neurotoxic secreted phospholipase A2 (sPLA2) in snake venom, binds specifically to protein disulfide isomerase (PDI) in vitro we show that these proteins also interact in living rat PC12 cells that are able to internalize this group IIA (GIIA) sPLA2. Atx and PDI co-localize in both differentiated and non-differentiated PC12 cells, as shown by fluorescence microscopy. Based on a model of the complex between Atx and yeast PDI (yPDI), a three-dimensional model of the complex between Atx and human PDI (hPDI) was constructed. The Atx binding site on hPDI is situated between domains b and b’. Atx interacts hPDI with an extensive area on its interfacial binding surface. The mammalian GIB, GIIA, GV and GX sPLA2s have the same fold as Atx. The first three sPLA2s have been detected intracellularly but not the last one. The models of their complexes with hPDI were constructed by replacement of Atx with the respective mammalian sPLA2 in the Atx—hPDI complex and molecular docking of the structures. According to the generated models, mammalian GIB, GIIA and GV sPLA2s form complexes with hPDI very similar to that with Atx. The contact area between GX sPLA2 and hPDI is however different from that of the other sPLA2s. Heterologous competition of Atx binding to hPDI with GV and GX sPLA2s confirmed the model-based expectation that GV sPLA2 was a more effective inhibitor than GX sPLA2, thus validating our model. The results suggest a role of hPDI in the (patho)physiology of some snake venom and mammalian sPLA2s by assisting the retrograde transport of these molecules from the cell surface. The sPLA2–hPDI model constitutes a valuable tool to facilitate further insights into this process and into the (patho)physiology of sPLA2s in relation to their action intracellularly.
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Affiliation(s)
- Jernej Oberčkal
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Lidija Kovačič
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Jernej Šribar
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Adrijana Leonardi
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Klemen Dolinar
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Anja Pucer Janež
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Igor Križaj
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
- * E-mail:
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Dreiling A, König S. Side reactions in protein cross-linking experiments using azide linkers. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:1887-1890. [PMID: 23857935 DOI: 10.1002/rcm.6641] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 05/27/2013] [Accepted: 05/28/2013] [Indexed: 06/02/2023]
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Kovačič L, Paulič N, Leonardi A, Hodnik V, Anderluh G, Podlesek Z, Žgur-Bertok D, Križaj I, Butala M. Structural insight into LexA-RecA* interaction. Nucleic Acids Res 2013; 41:9901-10. [PMID: 23965307 PMCID: PMC3834820 DOI: 10.1093/nar/gkt744] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
RecA protein is a hallmark for the bacterial response to insults inflicted on DNA. It catalyzes the strand exchange step of homologous recombination and stimulates self-inactivation of the LexA transcriptional repressor. Importantly, by these activities, RecA contributes to the antibiotic resistance of bacteria. An original way to decrease the acquisition of antibiotic resistance would be to block RecA association with LexA. To engineer inhibitors of LexA–RecA complex formation, we have mapped the interaction area between LexA and active RecA–ssDNA filament (RecA*) and generated a three-dimensional model of the complex. The model revealed that one subunit of the LexA dimer wedges into a deep helical groove of RecA*, forming multiple interaction sites along seven consecutive RecA protomers. Based on the model, we predicted that LexA in its DNA-binding conformation also forms a complex with RecA* and that the operator DNA sterically precludes interaction with RecA*, which guides the induction of SOS gene expression. Moreover, the model shows that besides the catalytic C-terminal domain of LexA, its N-terminal DNA-binding domain also interacts with RecA*. Because all the model-based predictions have been confirmed experimentally, the presented model offers a validated insight into the critical step of the bacterial DNA damage response.
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Affiliation(s)
- Lidija Kovačič
- Department of Molecular and Biomedical Sciences, JoŽef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia, Department of Biology, University of Ljubljana, Biotechnical Faculty, Večna pot 111, 1000 Ljubljana, Slovenia, National Institute of Chemistry, 1000 Ljubljana, Slovenia, Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana, Slovenia and Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins, Jamova 39, 1000 Ljubljana, Slovenia
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Puchulu-Campanella E, Chu H, Anstee DJ, Galan JA, Tao WA, Low PS. Identification of the components of a glycolytic enzyme metabolon on the human red blood cell membrane. J Biol Chem 2012; 288:848-58. [PMID: 23150667 DOI: 10.1074/jbc.m112.428573] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Glycolytic enzymes (GEs) have been shown to exist in multienzyme complexes on the inner surface of the human erythrocyte membrane. Because no protein other than band 3 has been found to interact with GEs, and because several GEs do not bind band 3, we decided to identify the additional membrane proteins that serve as docking sites for GE on the membrane. For this purpose, a method known as "label transfer" that employs a photoactivatable trifunctional cross-linking reagent to deliver a biotin from a derivatized GE to its binding partner on the membrane was used. Mass spectrometry analysis of membrane proteins that were biotinylated following rebinding and photoactivation of labeled GAPDH, aldolase, lactate dehydrogenase, and pyruvate kinase revealed not only the anticipated binding partner, band 3, but also the association of GEs with specific peptides in α- and β-spectrin, ankyrin, actin, p55, and protein 4.2. More importantly, the labeled GEs were also found to transfer biotin to other GEs in the complex, demonstrating for the first time that GEs also associate with each other in their membrane complexes. Surprisingly, a new GE binding site was repeatedly identified near the junction of the membrane-spanning and cytoplasmic domains of band 3, and this binding site was confirmed by direct binding studies. These results not only identify new components of the membrane-associated GE complexes but also provide molecular details on the specific peptides that form the interfacial contacts within each interaction.
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Križaj I. Ammodytoxin: a window into understanding presynaptic toxicity of secreted phospholipases A(2) and more. Toxicon 2011; 58:219-29. [PMID: 21726572 DOI: 10.1016/j.toxicon.2011.06.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 06/10/2011] [Accepted: 06/18/2011] [Indexed: 11/15/2022]
Affiliation(s)
- Igor Križaj
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia.
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Kovacic L, Novinec M, Petan T, Krizaj I. Structural basis of the significant calmodulin-induced increase in the enzymatic activity of secreted phospholipases A(2). Protein Eng Des Sel 2010; 23:479-87. [PMID: 20348188 DOI: 10.1093/protein/gzq019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Ammodytoxin (Atx), a neurotoxic secreted phospholipase A(2) (sPLA(2)), forms a high-affinity complex with calmodulin (CaM). The latter substantially increases the enzymatic activity of Atx under both non-reducing and reducing conditions, and the activity enhancement was accompanied, but not caused, by conformational stabilization of the enzyme. In this work, the energetically most favorable model of the complex was generated, making use of interaction site mapping, mutagenesis data and protein-docking algorithms. The model explains, in structural terms, the observed effects of stabilization and activity enhancement of the neurotoxic sPLA(2) by CaM. The structures of four mammalian sPLA(2) isoforms, groups IB, IIA, V and X, having the same fold as Atx, were superimposed on the structure of Atx in the complex with CaM. According to the generated models, the group V and X sPLA(2)s, but not the group IB and IIA enzymes, form stable complexes with CaM, which should also result in the augmentation of their enzymatic activity. By confirming the latter, the presented model is validated as a valuable tool to investigate the as yet unexplained role of CaM in the pathophysiology of snake venom and mammalian sPLA(2)s.
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Affiliation(s)
- Lidija Kovacic
- Department of Molecular and Biomedical Sciences, Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia
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Sun GY, Shelat PB, Jensen MB, He Y, Sun AY, Simonyi A. Phospholipases A2 and inflammatory responses in the central nervous system. Neuromolecular Med 2009; 12:133-48. [PMID: 19855947 DOI: 10.1007/s12017-009-8092-z] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Accepted: 09/25/2009] [Indexed: 12/21/2022]
Abstract
Phospholipases A2 (PLA2s) belong to a superfamily of enzymes responsible for hydrolyzing the sn-2 fatty acids of membrane phospholipids. These enzymes are known to play multiple roles for maintenance of membrane phospholipid homeostasis and for production of a variety of lipid mediators. Over 20 different types of PLA2s are present in the mammalian cells, and in snake and bee venom. Despite their common function in hydrolyzing fatty acids of phospholipids, they are diversely encoded by a number of genes and express proteins that are regulated by different mechanisms. Recent studies have focused on the group IV calcium-dependent cytosolic cPLA2, the group VI calcium-independent iPLA2, and the group II small molecule secretory sPLA2. In the central nervous system (CNS), these PLA2s are distributed among neurons and glial cells. Although the physiological role of these PLA2s in regulating neural cell function has not yet been clearly elucidated, there is increasing evidence for their involvement in receptor signaling and transcriptional pathways that link oxidative events to inflammatory responses that underline many neurodegenerative diseases. Recent studies also reveal an important role of cPLA2 in modulating neuronal excitatory functions, sPLA2 in the inflammatory responses, and iPLA2 with childhood neurologic disorders associated with brain iron accumulation. The goal for this review is to better understand the structure and function of these PLA2s and to highlight specific types of PLA2s and their cross-talk mechanisms in these inflammatory responses under physiological and pathological conditions in the CNS.
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Affiliation(s)
- Grace Y Sun
- Department of Biochemistry, University of Missouri, 117 Schweitzer Hall, Columbia, MO 65211, USA.
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Recombinant human SMOCs produced by in vitro refolding: Calcium-binding properties and interactions with serum proteins. Protein Expr Purif 2008; 62:75-82. [DOI: 10.1016/j.pep.2008.07.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 07/18/2008] [Accepted: 07/21/2008] [Indexed: 11/18/2022]
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10
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Lambeau G, Gelb MH. Biochemistry and physiology of mammalian secreted phospholipases A2. Annu Rev Biochem 2008; 77:495-520. [PMID: 18405237 DOI: 10.1146/annurev.biochem.76.062405.154007] [Citation(s) in RCA: 406] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Phospholipases A(2) (PLA2s) are esterases that hydrolyze the sn-2 ester of glycerophospholipids and constitute one of the largest families of lipid hydrolyzing enzymes. The mammalian genome contains 10 enzymatically active secreted PLA2s (sPLA2s) and two sPLA2-related proteins devoid of lipolytic enzymatic activity. In addition to the well-established functions of one of these enzymes in digestion of dietary phospholipids and another in host defense against bacterial infections, accumulating evidence shows that some of these sPLA2s are involved in arachidonic acid release from cellular phospholipids for the biosynthesis of eicosanoids, especially during inflammation. More speculative results suggest the involvement of one or more sPLA2s in promoting atherosclerosis and cancer. In addition, the mammalian genome encodes several types of sPLA2-binding proteins, and mounting evidence shows that sPLA2s may have functions related to binding to cellular target proteins in a manner independent of their lipolytic enzymatic activity.
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Affiliation(s)
- Gérard Lambeau
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université de Nice-Sophia-Antipolis, 06560 Valbonne, France.
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Pražnikar ZJ, Kovačič L, Rowan EG, Romih R, Rusmini P, Poletti A, Križaj I, Pungerčar J. A presynaptically toxic secreted phospholipase A2 is internalized into motoneuron-like cells where it is rapidly translocated into the cytosol. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1129-39. [DOI: 10.1016/j.bbamcr.2008.01.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Revised: 01/07/2008] [Accepted: 01/08/2008] [Indexed: 10/22/2022]
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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]
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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.
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Affiliation(s)
- Joze Pungercar
- Department of Molecular and Biomedical Sciences, Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia
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