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Structural-functional diversity of malaria parasite's PfHSP70-1 and PfHSP40 chaperone pair gives an edge over human orthologs in chaperone-assisted protein folding. Biochem J 2021; 477:3625-3643. [PMID: 32893851 DOI: 10.1042/bcj20200434] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/02/2020] [Accepted: 09/07/2020] [Indexed: 12/13/2022]
Abstract
Plasmodium falciparum, the human malaria parasite harbors a metastable proteome which is vulnerable to proteotoxic stress conditions encountered during its lifecycle. How parasite's chaperone machinery is able to maintain its aggregation-prone proteome in functional state, is poorly understood. As HSP70-40 system forms the central hub in cellular proteostasis, we investigated the protein folding capacity of PfHSP70-1 and PfHSP40 chaperone pair and compared it with human orthologs (HSPA1A and DNAJA1). Despite the structural similarity, we observed that parasite chaperones and their human orthologs exhibit striking differences in conformational dynamics. Comprehensive biochemical investigations revealed that PfHSP70-1 and PfHSP40 chaperone pair has better protein folding, aggregation inhibition, oligomer remodeling and disaggregase activities than their human orthologs. Chaperone-swapping experiments suggest that PfHSP40 can also efficiently cooperate with human HSP70 to facilitate the folding of client-substrate. SPR-derived kinetic parameters reveal that PfHSP40 has higher binding affinity towards unfolded substrate than DNAJA1. Interestingly, the observed slow dissociation rate of PfHSP40-substrate interaction allows PfHSP40 to maintain the substrate in folding-competent state to minimize its misfolding. Structural investigation through small angle x-ray scattering gave insights into the conformational architecture of PfHSP70-1 (monomer), PfHSP40 (dimer) and their complex. Overall, our data suggest that the parasite has evolved functionally diverged and efficient chaperone machinery which allows the human malaria parasite to survive in hostile conditions. The distinct allosteric landscapes and interaction kinetics of plasmodial chaperones open avenues for the exploration of small-molecule based antimalarial interventions.
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2
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Role of Heat Shock Proteins in Immune Modulation in Malaria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1340:169-186. [PMID: 34569025 DOI: 10.1007/978-3-030-78397-6_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Malaria is one of the major parasitic killer diseases worldwide. Severe cases of malaria are mostly in children under the age of 5 years due to their naïve immune system and in pregnant women with weakened immune responses. Inflammatory immune responses against the parasite involve complement activation as well as the antibody and effector cell-mediated immune system. However, after an infection with Plasmodium falciparum (P. falciparum), the most dangerous malaria species, the host-derived immunity is often insufficient to completely inhibit the infection cycles of the parasite in red blood cells for yet unknown reasons. In the present chapter we aim to elucidate the role of the host's and the parasite's heat shock proteins (HSPs) in the development of a novel anti-malaria therapeutic approach.
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Edkins AL, Boshoff A. General Structural and Functional Features of Molecular Chaperones. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1340:11-73. [PMID: 34569020 DOI: 10.1007/978-3-030-78397-6_2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Molecular chaperones are a group of structurally diverse and highly conserved ubiquitous proteins. They play crucial roles in facilitating the correct folding of proteins in vivo by preventing protein aggregation or facilitating the appropriate folding and assembly of proteins. Heat shock proteins form the major class of molecular chaperones that are responsible for protein folding events in the cell. This is achieved by ATP-dependent (folding machines) or ATP-independent mechanisms (holders). Heat shock proteins are induced by a variety of stresses, besides heat shock. The large and varied heat shock protein class is categorised into several subfamilies based on their sizes in kDa namely, small Hsps (HSPB), J domain proteins (Hsp40/DNAJ), Hsp60 (HSPD/E; Chaperonins), Hsp70 (HSPA), Hsp90 (HSPC), and Hsp100. Heat shock proteins are localised to different compartments in the cell to carry out tasks specific to their environment. Most heat shock proteins form large oligomeric structures, and their functions are usually regulated by a variety of cochaperones and cofactors. Heat shock proteins do not function in isolation but are rather part of the chaperone network in the cell. The general structural and functional features of the major heat shock protein families are discussed, including their roles in human disease. Their function is particularly important in disease due to increased stress in the cell. Vector-borne parasites affecting human health encounter stress during transmission between invertebrate vectors and mammalian hosts. Members of the main classes of heat shock proteins are all represented in Plasmodium falciparum, the causative agent of cerebral malaria, and they play specific functions in differentiation, cytoprotection, signal transduction, and virulence.
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Affiliation(s)
- Adrienne Lesley Edkins
- Biomedical Biotechnology Research Unit (BioBRU), Department of Biochemistry and Microbiology, Rhodes University, Makhanda/Grahamstown, South Africa.
- Rhodes University, Makhanda/Grahamstown, South Africa.
| | - Aileen Boshoff
- Rhodes University, Makhanda/Grahamstown, South Africa.
- Biotechnology Innovation Centre, Rhodes University, Makhanda/Grahamstown, South Africa.
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Das D, Krishnan SR, Roy A, Bulusu G. A network-based approach reveals novel invasion and Maurer's clefts-related proteins in Plasmodium falciparum. Mol Omics 2019; 15:431-441. [PMID: 31631203 DOI: 10.1039/c9mo00124g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Malaria continues to be a major concern in developing countries despite continuous efforts to find a cure for the disease. Understanding the pathogenesis mechanism is necessary to identify more effective drug targets against malaria. Many years of experimental research have generated a large amount of data for the malarial parasite, Plasmodium falciparum. These data are useful to understand the importance of certain parasite proteins, but it often remains unclear how these proteins come together, interact with other proteins and carry out their function. Identification of all proteins involved in pathogenesis is an important step towards understanding the molecular mechanism of pathogenesis. In this study, dynamic stage-specific protein-protein interaction networks were created based on gene expression data during the parasite's intra-erythrocytic stages and static protein-protein interaction data. Using previously known proteins of a biological event as seed proteins, the random walk with restart (RWR) method was used on the dynamic protein-protein interaction networks to identify novel proteins related to that event. Two screening procedures namely, permutation test and GO enrichment test were performed to increase the reliability of the RWR predictions. The proposed method was first validated on Plasmodium falciparum proteins related to invasion, where it could reproduce the existing knowledge from a small set of seed proteins. It was then used to identify novel Maurer's clefts resident proteins, where it could identify 152 parasite proteins. We show that the current approach can annotate conserved proteins with unknown function. The predicted proteins can help build a mechanistic model for disease pathogenesis, which will be useful in identifying new drug targets.
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Affiliation(s)
- Dibyajyoti Das
- TCS Innovation Labs - Hyderabad (Life Sciences Division), Tata Consultancy Services Limited, Hyderabad, India.
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5
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Grijalva-Mañay R, Dorca-Fornell C, Enríquez-Villacreses W, Miño-Castro G, Oliva R, Ochoa V, Proaño-Tuma K, Armijos-Jaramillo V. DnaJ molecules as potential effectors in Meloidogyne arenaria. An unexplored group of proteins in plant parasitic nematodes. Commun Integr Biol 2019; 12:151-161. [PMID: 31666916 PMCID: PMC6802931 DOI: 10.1080/19420889.2019.1676138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 09/16/2019] [Indexed: 01/09/2023] Open
Abstract
Plant pathogenic organisms secrete proteins called effectors that recognize, infect and promote disease within host cells. Bacteria, like Pseudomona syringae, use effectors with DnaJ function to disrupt plant defenses. DnaJ proteins (also called Hsp40) are a group of co-chaperone molecules, which assist in the folding of proteins. Despite the described role of DnaJs as effectors in several groups of pathogens, this group of proteins has never been correlated with the infection process in plant parasitic nematodes. In this study, we analyze the importance of DnaJ for plant parasitic nematodes. To do that, we compare the number of DnaJ proteins in nematodes with different lifestyles. Then, we predict the secreted DnaJ proteins in order to detect effector candidates. We found that Meloidogyne species have more secreted DnaJs than the rest of the nematodes analyzed in the study. Particularly, M. arenaria possess the highest proportion of secreted DnaJ sequences in comparison to total DnaJ proteins. Furthermore, we found in this species at least five sequences with a putative nuclear localization signal, three of them with a serine rich region with an unknown function. Then, we chose one of these sequences (MG599854) to perform an expression analysis. We found that MG599854 is over-expressed from 3 days post inoculation onwards in tomato plants. Moreover, MG599854 seems to be enough to produce cell death in Nicotiana benthamiana under transient expression conditions. In concordance with our results, we propose that DnaJ proteins are a potential source of effector proteins in plant parasitic nematodes.
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Affiliation(s)
- Rosita Grijalva-Mañay
- Department of Life Sciences, Laboratory of Plant Biotechnology, Armed Forces University ESPE, Sangolquí, Ecuador
| | - Carmen Dorca-Fornell
- Department of Life Sciences, Laboratory of Plant Biotechnology, Armed Forces University ESPE, Sangolquí, Ecuador
| | | | - Gabriela Miño-Castro
- Department of Life Sciences, Laboratory of Plant Biotechnology, Armed Forces University ESPE, Sangolquí, Ecuador
| | - Ricardo Oliva
- Genetics and Biotechnology, International Rice Research Institute (IRRI), 4031 Laguna, Philippines
| | - Valeria Ochoa
- Department of Life Sciences, Laboratory of Plant Biotechnology, Armed Forces University ESPE, Sangolquí, Ecuador
| | - Karina Proaño-Tuma
- Department of Life Sciences, Laboratory of Plant Biotechnology, Armed Forces University ESPE, Sangolquí, Ecuador
| | - Vinicio Armijos-Jaramillo
- Carrera de Ingeniería en Biotecnología, Facultad de Ingeniería y Ciencias Aplicadas, Universidad de Las Américas, Quito, Ecuador.,Grupo de Bio-Quimioinformática, Universidad de Las Américas, Quito, Ecuador
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6
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Chisholm SA, Kalanon M, Nebl T, Sanders PR, Matthews KM, Dickerman BK, Gilson PR, de Koning-Ward TF. The malaria PTEX component PTEX88 interacts most closely with HSP101 at the host-parasite interface. FEBS J 2018; 285:2037-2055. [PMID: 29637707 DOI: 10.1111/febs.14463] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 03/08/2018] [Accepted: 04/03/2018] [Indexed: 12/28/2022]
Abstract
The pathogenic nature of malaria infections is due in part to the export of hundreds of effector proteins that actively remodel the host erythrocyte. The Plasmodium translocon of exported proteins (PTEX) has been shown to facilitate the trafficking of proteins into the host cell, a process that is essential for the survival of the parasite. The role of the auxiliary PTEX component PTEX88 remains unclear, as previous attempts to elucidate its function through reverse genetic approaches showed that in contrast to the core components PTEX150 and HSP101, knockdown of PTEX88 did not give rise to an export phenotype. Here, we have used biochemical approaches to understand how PTEX88 assembles within the translocation machinery. Proteomic analysis of the PTEX88 interactome showed that PTEX88 interacts closely with HSP101 but has a weaker affinity with the other core constituents of PTEX. PTEX88 was also found to associate with other PV-resident proteins, including chaperones and members of the exported protein-interacting complex that interacts with the major virulence factor PfEMP1, the latter contributing to cytoadherence and parasite virulence. Despite being expressed for the duration of the blood-stage life cycle, PTEX88 was only discretely observed at the parasitophorous vacuole membrane during ring stages and could not always be detected in the major high molecular weight complex that contains the other core components of PTEX, suggesting that its interaction with the PTEX complex may be dynamic. Together, these data have enabled the generation of an updated model of PTEX that now includes how PTEX88 assembles within the complex.
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Affiliation(s)
| | - Ming Kalanon
- School of Medicine, Deakin University, Waurn Ponds, Australia
| | - Thomas Nebl
- The Walter and Eliza Hall Institute, Parkville, Australia
| | - Paul R Sanders
- Burnet Institute, Prahran, Australia.,Monash University, Melbourne, Australia
| | | | | | - Paul R Gilson
- Burnet Institute, Prahran, Australia.,Monash University, Melbourne, Australia
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Eichenberger RM, Ramakrishnan C, Russo G, Deplazes P, Hehl AB. Genome-wide analysis of gene expression and protein secretion of Babesia canis during virulent infection identifies potential pathogenicity factors. Sci Rep 2017; 7:3357. [PMID: 28611446 PMCID: PMC5469757 DOI: 10.1038/s41598-017-03445-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 04/27/2017] [Indexed: 12/14/2022] Open
Abstract
Infections of dogs with virulent strains of Babesia canis are characterized by rapid onset and high mortality, comparable to complicated human malaria. As in other apicomplexan parasites, most Babesia virulence factors responsible for survival and pathogenicity are secreted to the host cell surface and beyond where they remodel and biochemically modify the infected cell interacting with host proteins in a very specific manner. Here, we investigated factors secreted by B. canis during acute infections in dogs and report on in silico predictions and experimental analysis of the parasite’s exportome. As a backdrop, we generated a fully annotated B. canis genome sequence of a virulent Hungarian field isolate (strain BcH-CHIPZ) underpinned by extensive genome-wide RNA-seq analysis. We find evidence for conserved factors in apicomplexan hemoparasites involved in immune-evasion (e.g. VESA-protein family), proteins secreted across the iRBC membrane into the host bloodstream (e.g. SA- and Bc28 protein families), potential moonlighting proteins (e.g. profilin and histones), and uncharacterized antigens present during acute crisis in dogs. The combined data provides a first predicted and partially validated set of potential virulence factors exported during fatal infections, which can be exploited for urgently needed innovative intervention strategies aimed at facilitating diagnosis and management of canine babesiosis.
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Affiliation(s)
| | | | | | - Peter Deplazes
- Institute of Parasitology, University of Zurich, Zurich, Switzerland
| | - Adrian B Hehl
- Institute of Parasitology, University of Zurich, Zurich, Switzerland.
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Plasmodium Helical Interspersed Subtelomeric (PHIST) Proteins, at the Center of Host Cell Remodeling. Microbiol Mol Biol Rev 2016; 80:905-27. [PMID: 27582258 DOI: 10.1128/mmbr.00014-16] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During the asexual cycle, Plasmodium falciparum extensively remodels the human erythrocyte to make it a suitable host cell. A large number of exported proteins facilitate this remodeling process, which causes erythrocytes to become more rigid, cytoadherent, and permeable for nutrients and metabolic products. Among the exported proteins, a family of 89 proteins, called the Plasmodium helical interspersed subtelomeric (PHIST) protein family, has been identified. While also found in other Plasmodium species, the PHIST family is greatly expanded in P. falciparum. Although a decade has passed since their first description, to date, most PHIST proteins remain uncharacterized and are of unknown function and localization within the host cell, and there are few data on their interactions with other host or parasite proteins. However, over the past few years, PHIST proteins have been mentioned in the literature at an increasing rate owing to their presence at various localizations within the infected erythrocyte. Expression of PHIST proteins has been implicated in molecular and cellular processes such as the surface display of PfEMP1, gametocytogenesis, changes in cell rigidity, and also cerebral and pregnancy-associated malaria. Thus, we conclude that PHIST proteins are central to host cell remodeling, but despite their obvious importance in pathology, PHIST proteins seem to be understudied. Here we review current knowledge, shed light on the definition of PHIST proteins, and discuss these proteins with respect to their localization and probable function. We take into consideration interaction studies, microarray analyses, or data from blood samples from naturally infected patients to combine all available information on this protein family.
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9
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Yeo SJ, Liu DX, Park H. Potential Interaction of Plasmodium falciparum Hsp60 and Calpain. THE KOREAN JOURNAL OF PARASITOLOGY 2015; 53:665-73. [PMID: 26797432 PMCID: PMC4725232 DOI: 10.3347/kjp.2015.53.6.665] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 12/19/2015] [Accepted: 12/19/2015] [Indexed: 11/23/2022]
Abstract
After invasion of red blood cells, malaria matures within the cell by degrading hemoglobin avidly. For enormous protein breakdown in trophozoite stage, many efficient and ordered proteolysis networks have been postulated and exploited. In this study, a potential interaction of a 60-kDa Plasmodium falciparum (Pf)-heat shock protein (Hsp60) and Pf-calpain, a cysteine protease, was explored. Pf-infected RBC was isolated and the endogenous Pf-Hsp60 and Pf-calpain were determined by western blot analysis and similar antigenicity of GroEL and Pf-Hsp60 was determined with anti-Pf-Hsp60. Potential interaction of Pf-calpain and Pf-Hsp60 was determined by immunoprecipitation and immunofluorescence assay. Mizoribine, a well-known inhibitor of Hsp60, attenuated both Pf-calpain enzyme activity as well as P. falciparum growth. The presented data suggest that the Pf-Hsp60 may function on Pf-calpain in a part of networks during malaria growth.
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Affiliation(s)
- Seon-Ju Yeo
- Zoonosis Research Center, Department of Infection Biology, School of Medicine, Wonkwang University, Iksan 54538, Korea
| | - Dong-Xu Liu
- Zoonosis Research Center, Department of Infection Biology, School of Medicine, Wonkwang University, Iksan 54538, Korea
| | - Hyun Park
- Zoonosis Research Center, Department of Infection Biology, School of Medicine, Wonkwang University, Iksan 54538, Korea
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Park CJ, Seo YS. Heat Shock Proteins: A Review of the Molecular Chaperones for Plant Immunity. THE PLANT PATHOLOGY JOURNAL 2015; 31:323-33. [PMID: 26676169 PMCID: PMC4677741 DOI: 10.5423/ppj.rw.08.2015.0150] [Citation(s) in RCA: 288] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 09/14/2015] [Accepted: 09/14/2015] [Indexed: 05/19/2023]
Abstract
As sessile organisms, plants are exposed to persistently changing stresses and have to be able to interpret and respond to them. The stresses, drought, salinity, chemicals, cold and hot temperatures, and various pathogen attacks have interconnected effects on plants, resulting in the disruption of protein homeostasis. Maintenance of proteins in their functional native conformations and preventing aggregation of non-native proteins are important for cell survival under stress. Heat shock proteins (HSPs) functioning as molecular chaperones are the key components responsible for protein folding, assembly, translocation, and degradation under stress conditions and in many normal cellular processes. Plants respond to pathogen invasion using two different innate immune responses mediated by pattern recognition receptors (PRRs) or resistance (R) proteins. HSPs play an indispensable role as molecular chaperones in the quality control of plasma membrane-resident PRRs and intracellular R proteins against potential invaders. Here, we specifically discuss the functional involvement of cytosolic and endoplasmic reticulum (ER) HSPs/chaperones in plant immunity to obtain an integrated understanding of the immune responses in plant cells.
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Affiliation(s)
- Chang-Jin Park
- Department of Plant Biotechnology and PERI, Sejong University, Seoul 143-747,
Korea
- Corresponding author. C.-J. Park, Phone) +82-2-3408-4378, FAX) +82-2-3408-4318, E-mail) . Y.-S. Seo, Phone) +82-51-510-2267, FAX) +82-51-514-1778, E-mail:) , ORCID, Young-Su Seo, http://orcid.org/0000-0001-9191-1405, Chang-Jin Park, http://orcid.org/0000-0002-2586-8856
| | - Young-Su Seo
- Department of Microbiology, Pusan National University, Busan 609-735,
Korea
- Corresponding author. C.-J. Park, Phone) +82-2-3408-4378, FAX) +82-2-3408-4318, E-mail) . Y.-S. Seo, Phone) +82-51-510-2267, FAX) +82-51-514-1778, E-mail:) , ORCID, Young-Su Seo, http://orcid.org/0000-0001-9191-1405, Chang-Jin Park, http://orcid.org/0000-0002-2586-8856
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11
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Mongkol W, Arunyawat U, Surat W, Kubera A. Active Compounds Against Anopheles minimus Carboxypeptidase B for Malaria Transmission-Blocking Strategy. JOURNAL OF MEDICAL ENTOMOLOGY 2015; 52:1322-1332. [PMID: 26352934 DOI: 10.1093/jme/tjv133] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 08/13/2015] [Indexed: 06/05/2023]
Abstract
Malaria transmission-blocking compounds have been studied to block the transmission of malaria parasites, especially the drug-resistant Plasmodium. Carboxypeptidase B (CPB) in the midgut of Anopheline mosquitoes has been demonstrated to be essential for the sexual development of Plasmodium in the mosquito. Thus, the CPB is a potential target for blocking compounds. The aim of this research was to screen compounds from the National Cancer Institute (NCI) diversity dataset and U.S. Food and Drug Administration (FDA)-approved drugs that could reduce the Anopheles CPB activity. The cDNA fragment of cpb gene from An. minimus (cpbAmi) was amplified and sequenced. The three-dimensional structure of CPB was predicted from the deduced amino acid sequence. The virtual screening of the compounds from NCI diversity set IV and FDA-approved drugs was performed against CPBAmi. The inhibition activity against CPBAmi of the top-scoring molecules was characterized in vitro. Three compounds-NSC-1014, NSC-332670, and aminopterin with IC50 at 0.99 mM, 1.55 mM, and 0.062 mM, respectively-were found to significantly reduce the CPBAmi activity.
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Affiliation(s)
- Watcharakorn Mongkol
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand
| | - Uraiwan Arunyawat
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand. Centre for Advanced Studies in Tropical Natural Resources, Kasetsart University, Bangkok, 10900, Thailand
| | - Wunrada Surat
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand. Centre for Advanced Studies in Tropical Natural Resources, Kasetsart University, Bangkok, 10900, Thailand
| | - Anchanee Kubera
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand. Centre for Advanced Studies in Tropical Natural Resources, Kasetsart University, Bangkok, 10900, Thailand.
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JPPRED: Prediction of Types of J-Proteins from Imbalanced Data Using an Ensemble Learning Method. BIOMED RESEARCH INTERNATIONAL 2015; 2015:705156. [PMID: 26587542 PMCID: PMC4637456 DOI: 10.1155/2015/705156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 10/05/2015] [Accepted: 10/11/2015] [Indexed: 11/17/2022]
Abstract
Different types of J-proteins perform distinct functions in chaperone processes and diseases development. Accurate identification of types of J-proteins will provide significant clues to reveal the mechanism of J-proteins and contribute to developing drugs for diseases. In this study, an ensemble predictor called JPPRED for J-protein prediction is proposed with hybrid features, including split amino acid composition (SAAC), pseudo amino acid composition (PseAAC), and position specific scoring matrix (PSSM). To deal with the imbalanced benchmark dataset, the synthetic minority oversampling technique (SMOTE) and undersampling technique are applied. The average sensitivity of JPPRED based on above-mentioned individual feature spaces lies in the range of 0.744–0.851, indicating the discriminative power of these features. In addition, JPPRED yields the highest average sensitivity of 0.875 using the hybrid feature spaces of SAAC, PseAAC, and PSSM. Compared to individual base classifiers, JPPRED obtains more balanced and better performance for each type of J-proteins. To evaluate the prediction performance objectively, JPPRED is compared with previous study. Encouragingly, JPPRED obtains balanced performance for each type of J-proteins, which is significantly superior to that of the existing method. It is anticipated that JPPRED can be a potential candidate for J-protein prediction.
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Molecular Chaperones of Leishmania: Central Players in Many Stress-Related and -Unrelated Physiological Processes. BIOMED RESEARCH INTERNATIONAL 2015; 2015:301326. [PMID: 26167482 PMCID: PMC4488524 DOI: 10.1155/2015/301326] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 05/24/2015] [Indexed: 12/12/2022]
Abstract
Molecular chaperones are key components in the maintenance of cellular homeostasis and survival, not only during stress but also under optimal growth conditions. Folding of nascent polypeptides is supported by molecular chaperones, which avoid the formation of aggregates by preventing nonspecific interactions and aid, when necessary, the translocation of proteins to their correct intracellular localization. Furthermore, when proteins are damaged, molecular chaperones may also facilitate their refolding or, in the case of irreparable proteins, their removal by the protein degradation machinery of the cell. During their digenetic lifestyle, Leishmania parasites encounter and adapt to harsh environmental conditions, such as nutrient deficiency, hypoxia, oxidative stress, changing pH, and shifts in temperature; all these factors are potential triggers of cellular stress. We summarize here our current knowledge on the main types of molecular chaperones in Leishmania and their functions. Among them, heat shock proteins play important roles in adaptation and survival of this parasite against temperature changes associated with its passage from the poikilothermic insect vector to the warm-blooded vertebrate host. The study of structural features and the function of chaperones in Leishmania biology is providing opportunities (and challenges) for drug discovery and improving of current treatments against leishmaniasis.
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Pesce ER, Blatch GL, Edkins AL. Hsp40 Co-chaperones as Drug Targets: Towards the Development of Specific Inhibitors. TOPICS IN MEDICINAL CHEMISTRY 2015. [DOI: 10.1007/7355_2015_92] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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