1
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Zuo W, Tian M, Qi J, Zhang G, Hu J, Wang S, Bao Y. The functions of EF-hand proteins from host and zoonotic pathogens. Microbes Infect 2023:105276. [PMID: 38072184 DOI: 10.1016/j.micinf.2023.105276] [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: 11/08/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023]
Abstract
EF-hand proteins not only regulate biological processes, but also influence immunity and infection. In this review, we summarize EF-hand proteins' functions in host and zoonotic pathogens, with details in structures, Ca2+ affinity, downstream targets and functional mechanisms. Studies entitled as EF-hand-related but with less solid features were also discussed. We believe it could raise cautions and facilitate proper research strategy for researchers.
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Affiliation(s)
- Wei Zuo
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Mingxing Tian
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Jingjing Qi
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Guangdong Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Jiangang Hu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Shaohui Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China; Engineering Research Center for the Prevention and Control of Animal Original Zoonosis of Fujian Province University, College of Life Science, Longyan University, Longyan, 364012, Fujian, China.
| | - Yanqing Bao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China; Engineering Research Center for the Prevention and Control of Animal Original Zoonosis of Fujian Province University, College of Life Science, Longyan University, Longyan, 364012, Fujian, China.
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2
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Jhingan GD, Manich M, Olivo-Marin JC, Guillen N. Live Cells Imaging and Comparative Phosphoproteomics Uncover Proteins from the Mechanobiome in Entamoeba histolytica. Int J Mol Sci 2023; 24:ijms24108726. [PMID: 37240072 DOI: 10.3390/ijms24108726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/03/2023] [Accepted: 05/05/2023] [Indexed: 05/28/2023] Open
Abstract
Entamoeba histolytica is a protozoan parasite and the causative agent of amoebiasis in humans. This amoeba invades human tissues by taking advantage of its actin-rich cytoskeleton to move, enter the tissue matrix, kill and phagocyte the human cells. During tissue invasion, E. histolytica moves from the intestinal lumen across the mucus layer and enters the epithelial parenchyma. Faced with the chemical and physical constraints of these diverse environments, E. histolytica has developed sophisticated systems to integrate internal and external signals and to coordinate cell shape changes and motility. Cell signalling circuits are driven by interactions between the parasite and extracellular matrix, combined with rapid responses from the mechanobiome in which protein phosphorylation plays an important role. To understand the role of phosphorylation events and related signalling mechanisms, we targeted phosphatidylinositol 3-kinases followed by live cell imaging and phosphoproteomics. The results highlight 1150 proteins, out of the 7966 proteins within the amoebic proteome, as members of the phosphoproteome, including signalling and structural molecules involved in cytoskeletal activities. Inhibition of phosphatidylinositol 3-kinases alters phosphorylation in important members of these categories; a finding that correlates with changes in amoeba motility and morphology, as well as a decrease in actin-rich adhesive structures.
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Affiliation(s)
| | - Maria Manich
- Institut Pasteur, Cell Biology of Parasitism Unit, 75015 Paris, France
- Institut Pasteur, Biological Image Analysis Unit, 75015 Paris, France
- Centre National de la Recherche Scientifique, CNRS UMR3691, 75015 Paris, France
| | - Jean-Christophe Olivo-Marin
- Institut Pasteur, Biological Image Analysis Unit, 75015 Paris, France
- Centre National de la Recherche Scientifique, CNRS UMR3691, 75015 Paris, France
| | - Nancy Guillen
- Institut Pasteur, Cell Biology of Parasitism Unit, 75015 Paris, France
- Institut Pasteur, Biological Image Analysis Unit, 75015 Paris, France
- Centre National de la Recherche Scientifique, CNRS-ERL9195, 75015 Paris, France
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3
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Narooka AR, Apte A, Yadav P, Murillo JR, Goto-Silva L, Junqueira M, Datta S. EhRho6 mediated actin degradation in Entamoeba histolytica is associated with compromised pathogenicity. Mol Microbiol 2022; 117:1121-1137. [PMID: 35324049 DOI: 10.1111/mmi.14896] [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: 10/04/2021] [Revised: 02/14/2022] [Accepted: 03/16/2022] [Indexed: 11/27/2022]
Abstract
Entamoeba histolytica causes amoebiasis which is a major health concern in developing countries. E. histolytica pathogenicity has been implicated to a large repertoire of small GTPases which switch between the inactive GDP bound state and the active GTP bound state with the help of guanine nucleotide exchange factors (GEFs) and GTPase activating protein (GAPs). Rho family of small GTPases are well known to modulate the actin cytoskeletal dynamics which plays a major role in E. histolytica pathogenicity. Here we report an atypical amoebic RhoGEF, and its preferred substrate EhRho6, which, upon overexpression abrogated the pathogenic behavior of the amoeba such as adhesion to host cell, monolayer destruction, erythrophagocytosis, and formation of actin dots. A causative immunoblot analysis revealed actin degradation in the EhRho6 overexpressing trophozoites that could be inhibited by blocking the amoebic proteasomal pathway. A careful analysis of the results from a previously published transcriptomics study, in conjunction with our observations, led to the identification of a clade of Rho GTPases in this pathogenic amoeba which we hypothesize to have implications during the amoebic encystation.
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Affiliation(s)
- Anil Raj Narooka
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Achala Apte
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Pooja Yadav
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Jimmy Rodriguez Murillo
- Division of Chemistry I, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Livia Goto-Silva
- D'Or Institute for Research and Education (IDOR), Rua Diniz Cordeiro, 30 - Botafogo, Rio de Janeiro, RJ, Brazil
| | - Magno Junqueira
- Laboratório de Espectrometria de Massa Biológica - LEMB, do Departamento de Bioquímica do Instituto de Química UFRJ, Rio de Janeiro, RJ, Brasil
| | - Sunando Datta
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
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4
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Kumar N, Rath PP, Aggarwal P, Maiti S, Bhavesh NS, Gourinath S. Unravelling the Biology of EhActo as the First Cofilin From Entamoeba histolytica. Front Cell Dev Biol 2022; 10:785680. [PMID: 35281106 PMCID: PMC8914023 DOI: 10.3389/fcell.2022.785680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
Actin-depolymerising factors (ADF) are a known family of proteins that regulate actin dynamics. Actin regulation is critical for primitive eukaryotes since it drives their key cellular processes. Entamoeba histolytica, a protist human pathogen harbours eleven proteins within this family, however, with no actin depolymerising protein reported to date. We present here the NMR model of EhActo, the first Cofilin from E. histolytica that severs actin filaments and also participates in cellular events like phagocytosis and pseudopod formation. The model typically represents the ADF-homology domain compared to other cofilins. Uniquely, EhActo lacks the critical Serine3 residue present in all known actophorins mediating its phospho-regulation. The second mode of regulation that cofilin’s are subjected to is via their interaction with 14-3-3 proteins through the phosphorylated Serine residue and a consensus binding motif. We found a unique interaction between EhActo and 14-3-3 without the presence of the consensus motif or the phosphorylated Serine. These interesting results present unexplored newer mechanisms functional in this pathogen to regulate actophorin. Through our structural and biochemical studies we have deciphered the mechanism of action of EhActo, implicating its role in amoebic biology.
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Affiliation(s)
- Nitesh Kumar
- Department of Pathology, Indira Gandhi Institute of Medical Sciences, Patna, India
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- *Correspondence: Nitesh Kumar, ; Samudrala Gourinath,
| | | | - Priyanka Aggarwal
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Sankar Maiti
- Indian Institute of Science, Education and Research, Kolkata, India
| | - Neel Sarovar Bhavesh
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Samudrala Gourinath
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
- *Correspondence: Nitesh Kumar, ; Samudrala Gourinath,
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5
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Saito-Nakano Y, Makiuchi T, Tochikura M, Gilchrist CA, Petri WA, Nozaki T. ArfX2 GTPase Regulates Trafficking From the Trans-Golgi to Lysosomes and Is Necessary for Liver Abscess Formation in the Protozoan Parasite Entamoeba histolytica. Front Cell Infect Microbiol 2022; 11:794152. [PMID: 34976870 PMCID: PMC8719317 DOI: 10.3389/fcimb.2021.794152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 11/24/2021] [Indexed: 02/03/2023] Open
Abstract
Entamoeba histolytica is the causative agent of amoebic dysentery and liver abscess in humans. The parasitic lifestyle and the virulence of the protist require elaborate biological processes, including vesicular traffic and stress management against a variety of reactive oxygen and nitrogen species produced by the host immune response. Although the mechanisms for intracellular traffic of representative virulence factors have been investigated at molecular levels, it remains poorly understood whether and how intracellular traffic is involved in the defense against reactive oxygen and nitrogen species. Here, we demonstrate that EhArfX2, one of the Arf family of GTPases known to be involved in the regulation of vesicular traffic, was identified by comparative transcriptomic analysis of two isogenic strains: an animal-passaged highly virulent HM-1:IMSS Cl6 and in vitro maintained attenuated avirulent strain. EhArfX2 was identified as one of the most highly upregulated genes in the highly virulent strain. EhArfX2 was localized to small vesicle-like structures and largely colocalized with the marker for the trans-Golgi network SNARE, EhYkt6, but neither with the endoplasmic reticulum (ER)-resident chaperon, EhBip, nor the cis-Golgi SNARE, EhSed5, and Golgi-luminal galactosyl transferase, EhGalT. Expression of the dominant-active mutant form of EhArfX2 caused an increase in the number of lysosomes, while expression of the dominant-negative mutant led to a defect in lysosome formation and cysteine protease transport to lysosomes. Expression of the dominant-negative mutant in the virulent E. histolytica strain caused a reduction of the size of liver abscesses in a hamster model. This defect in liver abscess formation was likely at least partially attributed to reduced resistance to nitrosative, but not oxidative stress in vitro. These results showed that the EhArfX2-mediated traffic is necessary for the nitrosative stress response and virulence in the host.
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Affiliation(s)
- Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
| | - Takashi Makiuchi
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Mami Tochikura
- Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
| | - Carol A Gilchrist
- Department of Medicine, University of Virginia, Charlottesville, VA, United States
| | - William A Petri
- Department of Medicine, University of Virginia, Charlottesville, VA, United States
| | - Tomoyoshi Nozaki
- Graduate School of Medicine, The University of Tokyo, Bunkyo, Tokyo, Japan
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6
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Bharadwaj R, Kushwaha T, Ahmad A, Inampudi KK, Nozaki T. An atypical EhGEF regulates phagocytosis in Entamoeba histolytica through EhRho1. PLoS Pathog 2021; 17:e1010030. [PMID: 34807955 PMCID: PMC8648123 DOI: 10.1371/journal.ppat.1010030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 12/06/2021] [Accepted: 10/13/2021] [Indexed: 01/09/2023] Open
Abstract
The parasite Entamoeba histolytica is the etiological agent of amoebiasis, a major cause of morbidity and mortality due to parasitic diseases in developing countries. Phagocytosis is an essential mode of obtaining nutrition and has been associated with the virulence behaviour of E. histolytica. Signalling pathways involved in activation of cytoskeletal dynamics required for phagocytosis remains to be elucidated in this parasite. Our group has been studying initiation of phagocytosis and formation of phagosomes in E. histolytica and have described some of the molecules that play key roles in the process. Here we showed the involvement of non-Dbl Rho Guanine Nucleotide Exchange Factor, EhGEF in regulation of amoebic phagocytosis by regulating activation of EhRho1. EhGEF was found in the phagocytic cups during the progression of cups, until closure of phagosomes, but not in the phagosomes themselves. Our observation from imaging, pull down experiments and down regulating expression of different molecules suggest that EhGEF interacts with EhRho1 and it is required during initiation of phagocytosis and phagosome formation. Also, biophysical, and computational analysis reveals that EhGEF mediates GTP exchange on EhRho1 via an unconventional pathway. In conclusion, we describe a non-Dbl EhGEF of EhRho1 which is involved in endocytic processes of E. histolytica.
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Affiliation(s)
- Ravi Bharadwaj
- Division of Infectious Diseases, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Tushar Kushwaha
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India
| | - Azhar Ahmad
- Multidisciplinary Centre for Advanced Research and Studies, Jamia Millia Islamia, New Delhi, India
| | - Krishna K. Inampudi
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- * E-mail: (TN); , (S)
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7
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Saito-Nakano Y, Wahyuni R, Nakada-Tsukui K, Tomii K, Nozaki T. Rab7D small GTPase is involved in phago-, trogocytosis and cytoskeletal reorganization in the enteric protozoan Entamoeba histolytica. Cell Microbiol 2020; 23:e13267. [PMID: 32975360 PMCID: PMC7757265 DOI: 10.1111/cmi.13267] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/21/2020] [Accepted: 09/18/2020] [Indexed: 12/12/2022]
Abstract
Rab small GTPases regulate membrane traffic between distinct cellular compartments of all eukaryotes in a tempo‐spatially specific fashion. Rab small GTPases are also involved in the regulation of cytoskeleton and signalling. Membrane traffic and cytoskeletal regulation play pivotal role in the pathogenesis of Entamoeba histolytica, which is a protozoan parasite responsible for human amebiasis. E. histolytica is unique in that its genome encodes over 100 Rab proteins, containing multiple isotypes of conserved members (e.g., Rab7) and Entamoeba‐specific subgroups (e.g., RabA, B, and X). Among them, E. histolytica Rab7 is the most diversified group consisting of nine isotypes. While it was previously demonstrated that EhRab7A and EhRab7B are involved in lysosome and phagosome biogenesis, the individual roles of other Rab7 members and their coordination remain elusive. In this study, we characterised the third member of Rab7, Rab7D, to better understand the significance of the multiplicity of Rab7 isotypes in E. histolytica. Overexpression of EhRab7D caused reduction in phagocytosis of erythrocytes, trogocytosis (meaning nibbling or chewing of a portion) of live mammalian cells, and phagosome acidification and maturation. Conversely, transcriptional gene silencing of EhRab7D gene caused opposite phenotypes in phago/trogocytosis and phagosome maturation. Furthermore, EhRab7D gene silencing caused reduction in the attachment to and the motility on the collagen‐coated surface. Image analysis showed that EhRab7D was occasionally associated with lysosomes and prephagosomal vacuoles, but not with mature phagosomes and trogosomes. Finally, in silico prediction of structural organisation of EhRab7 isotypes identified unique amino acid changes on the effector binding surface of EhRab7D. Taken together, our data suggest that EhRab7D plays coordinated counteracting roles: a inhibitory role in phago/trogocytosis and lyso/phago/trogosome biogenesis, and an stimulatory role in adherence and motility, presumably via interaction with unique effectors. Finally, we propose the model in which three EhRab7 isotypes are sequentially involved in phago/trogocytosis.
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Affiliation(s)
- Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Ratna Wahyuni
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Institute of Tropical Disease, Universitas Airlangga, Surabaya, Indonesia.,Department of Health, Faculty of Vocational Studies, Universitas Airlangga, Surabaya, Indonesia
| | - Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kentaro Tomii
- Artificial Intelligence Research Center (AIRC) and Real World Big-Data Computation Open Innovation Laboratory (RWBC-OIL), National Institute of Advance Industrial Science and Technology (AIST), Tokyo, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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Kumar S, Mishra S, Gourinath S. Structural and functional diversity of Entamoeba histolytica calcium-binding proteins. Biophys Rev 2020; 12:10.1007/s12551-020-00766-6. [PMID: 33063237 PMCID: PMC7755952 DOI: 10.1007/s12551-020-00766-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 10/09/2020] [Indexed: 12/20/2022] Open
Abstract
Entamoeba histolytica (E. histolytica) is an etiological agent of human amoebic colitis, and it causes a high level of morbidity and mortality worldwide, particularly in developing countries. Ca2+ plays a pivotal role in amoebic pathogenesis, and Ca2+-binding proteins (CaBPs) of E. histolytica appear to be a major determinant in this process. E. histolytica has 27-EF-hand containing CaBPs, suggesting that this organism has complex Ca2+ signaling cascade. E. histolytica CaBPs share (29-47%) sequence identity with ubiquitous Ca2+-binding protein calmodulin (CaM); however, they do not show any significant structural similarity, indicating lack of a typical CaM in this organism. Structurally, these CaBPs are very diverse among themselves, and perhaps such diversity allows them to recognize different cellular targets, thereby enabling them to perform a range of cellular functions. The presence of such varied signaling molecules helps parasites to invade host cells and advance in disease progression. In the past two decades, tremendous progress has been made in understanding the structure of E. histolytica CaBPs by using the X-ray or NMR method. To gain greater insight into the structural and functional diversity of these amoebic CaBPs, we analyzed and compiled all the available literature. Most of the CaBPs has about 150 amino acids with 4-EF hand or EF-hand-like sequences, similar to CaM. In a few cases, all the EF-hand motifs are not capable of binding Ca2+, suggesting them to be pseudo EF-hand motifs. The CaBPs perform diverse cellular signaling that includes cytoskeleton remodeling, phagocytosis, cell proliferation, migration of trophozoites, and GTPase activity. Overall, the structural and functional diversity of E. histolytica CaBPs compiled here may offer a basis to develop an efficient drug to counter its pathogenesis.
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Affiliation(s)
- Sanjeev Kumar
- Present Address: Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425 USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824 USA
| | - Shalini Mishra
- School of Life Science Jawaharlal Nehru University, New Delhi, 110067 India
| | - S. Gourinath
- School of Life Science Jawaharlal Nehru University, New Delhi, 110067 India
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9
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Agarwal S, Rath PP, Anand G, Gourinath S. Uncovering the Cyclic AMP Signaling Pathway of the Protozoan Parasite Entamoeba histolytica and Understanding Its Role in Phagocytosis. Front Cell Infect Microbiol 2020; 10:566726. [PMID: 33102254 PMCID: PMC7546249 DOI: 10.3389/fcimb.2020.566726] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/17/2020] [Indexed: 01/13/2023] Open
Abstract
Second messenger signaling controls a surprisingly diverse range of processes in several eukaryotic pathogens. Molecular machinery and pathways involving these messengers thus hold tremendous opportunities for therapeutic interventions. Relative to Ca2+ signaling, the knowledge of a crucial second messenger cyclic AMP (cAMP) and its signaling pathway is very scant in the intestinal parasite Entamoeba histolytica. In the current study, mining the available genomic resources, we have for the first time identified the cAMP signal transduction pathway of E. histolytica. Three heptahelical proteins with variable G-protein-coupled receptor domains, heterotrimeric G-proteins (Gα, Gβ, and Gγ subunits), soluble adenylyl cyclase, cyclase-associated protein, and enzyme carbonic anhydrase were identified in its genome. We could also identify several putative candidate genes for cAMP downstream effectors such as protein kinase A, A-kinase anchoring proteins, and exchange protein directly activated by the cAMP pathway. Using specific inhibitors against key identified targets, we could observe changes in the intracellular cAMP levels as well as defect in the rate of phagocytosis of red blood cells by the parasite E. histolytica. We thus strongly believe that characterization of some of these unexplored crucial signaling determinants will provide a paradigm shift in understanding the pathogenicity of this organism.
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Affiliation(s)
- Shalini Agarwal
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | | | - Gaurav Anand
- International Center for Genetic Engineering and Biotechnology, New Delhi, India
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10
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Calcium modulates the domain flexibility and function of an α-actinin similar to the ancestral α-actinin. Proc Natl Acad Sci U S A 2020; 117:22101-22112. [PMID: 32848067 DOI: 10.1073/pnas.1917269117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The actin cytoskeleton, a dynamic network of actin filaments and associated F-actin-binding proteins, is fundamentally important in eukaryotes. α-Actinins are major F-actin bundlers that are inhibited by Ca2+ in nonmuscle cells. Here we report the mechanism of Ca2+-mediated regulation of Entamoeba histolytica α-actinin-2 (EhActn2) with features expected for the common ancestor of Entamoeba and higher eukaryotic α-actinins. Crystal structures of Ca2+-free and Ca2+-bound EhActn2 reveal a calmodulin-like domain (CaMD) uniquely inserted within the rod domain. Integrative studies reveal an exceptionally high affinity of the EhActn2 CaMD for Ca2+, binding of which can only be regulated in the presence of physiological concentrations of Mg2+ Ca2+ binding triggers an increase in protein multidomain rigidity, reducing conformational flexibility of F-actin-binding domains via interdomain cross-talk and consequently inhibiting F-actin bundling. In vivo studies uncover that EhActn2 plays an important role in phagocytic cup formation and might constitute a new drug target for amoebic dysentery.
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11
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Abstract
Calcium signaling plays a key role in many essential processes in almost all eukaryotic systems. It is believed that it may also be an important signaling system of the protist parasite Entamoeba histolytica. Motility, adhesion, cytolysis, and phagocytosis/trogocytosis are important steps in invasion and pathogenesis of E. histolytica, and Ca2+ signaling is thought to be associated with these processes leading to tissue invasion. There are a large number of Ca2+-binding proteins (CaBPs) in E. histolytica, and a number of these proteins appear to be associated with different steps in pathogenesis. The genome encodes 27 EF-hand–containing CaBPs in addition to a number of other Ca2+-binding domain/motif-containing proteins, which suggest intricate calcium signaling network in this parasite. Unlike other eukaryotes, a typical calmodulin-like protein has not been seen in E. histolytica. Though none of the CaBPs display sequence similarity with a typical calmodulin, extensive structural similarity has been seen in spite of lack of significant functional overlap with that of typical calmodulins. One of the unique features observed in E. histolytica is the identification of CaBPs (EhCaBP1, EhCaBP3) that have the ability to directly bind actin and modulate actin dynamics. Direct interaction of CaBPs with actin has not been seen in any other system. Pseudopod formation and phagocytosis are some of the processes that require actin dynamics, and some of the amoebic CaBPs (EhC2Pk, EhCaBP1, EhCaBP3, EhCaBP5) participate in this process. None of these E. histolytica CaBPs have any homolog in organisms other than different species of Entamoeba, suggesting a novel Ca2+ signaling pathway that has evolved in this genus.
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Affiliation(s)
- Mrigya Babuta
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Sudha Bhattacharya
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Alok Bhattacharya
- Department of Biology, Ashoka University, Sonepat, Haryana, India
- * E-mail:
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12
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Tripathi A, Jain M, Chandra M, Parveen S, Yadav R, Collins BM, Maiti S, Datta S. EhC2B, a C2 domain-containing protein, promotes erythrophagocytosis in Entamoeba histolytica via actin nucleation. PLoS Pathog 2020; 16:e1008489. [PMID: 32365140 PMCID: PMC7197785 DOI: 10.1371/journal.ppat.1008489] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/23/2020] [Indexed: 12/17/2022] Open
Abstract
Remodelling of the actin cytoskeleton in response to external stimuli is obligatory for many cellular processes in the amoebic cell. A rapid and local rearrangement of the actin cytoskeleton is required for the development of the cellular protrusions during phagocytosis, trogocytosis, migration, and invasion. Here, we demonstrated that EhC2B, a C2 domain-containing protein, is an actin modulator. EhC2B was first identified as an effector of EhRab21 from E. histolytica. In vitro interaction studies including GST pull-down, fluorescence-based assay and ITC also corroborated with our observation. In the amoebic trophozoites, EhC2B accumulates at the pseudopods and the tips of phagocytic cups. FRAP based studies confirmed the recruitment and dynamics of EhC2B at the phagocytic cup. Moreover, we have shown the role of EhC2B in erythrophagocytosis. It is well known that calcium-dependent signal transduction is essential for the cytoskeletal dynamics during phagocytosis in the amoebic parasite. Using liposome pelleting assay, we demonstrated that EhC2B preferentially binds to the phosphatidylserine in the presence of calcium. The EhC2B mutants defective in calcium or lipid-binding failed to localise beneath the plasma membrane. The cells overexpressing these mutants have also shown a significant reduction in erythrophagocytosis. The role of EhC2B in erythrophagocytosis and pseudopod formation was also validated by siRNA-based gene knockdown approach. Finally, with the help of in vitro nucleation assay using fluorescence spectroscopy and total internal reflection fluorescence microscopy, we have established that EhC2B is an actin nucleator. Collectively, based on the results from the study, we propose that EhC2B acts like a molecular bridge which promotes membrane deformation via its actin nucleation activity during the progression of the phagocytic cup in a calcium-dependent manner.
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Affiliation(s)
- Aashutosh Tripathi
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Megha Jain
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Mintu Chandra
- Institute for Molecular Biosciences, University of Queensland, St Lucia, Australia
| | - Sameena Parveen
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Rupali Yadav
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Brett M. Collins
- Institute for Molecular Biosciences, University of Queensland, St Lucia, Australia
| | - Sankar Maiti
- Department of Biological Sciences, Indian Institute of Science Education and Research, Kolkata, India
| | - Sunando Datta
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
- * E-mail:
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13
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Betanzos A, Bañuelos C, Orozco E. Host Invasion by Pathogenic Amoebae: Epithelial Disruption by Parasite Proteins. Genes (Basel) 2019; 10:E618. [PMID: 31416298 PMCID: PMC6723116 DOI: 10.3390/genes10080618] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 04/25/2019] [Accepted: 04/29/2019] [Indexed: 02/07/2023] Open
Abstract
The epithelium represents the first and most extensive line of defence against pathogens, toxins and pollutant agents in humans. In general, pathogens have developed strategies to overcome this barrier and use it as an entrance to the organism. Entamoeba histolytica, Naegleriafowleri and Acanthamoeba spp. are amoebae mainly responsible for intestinal dysentery, meningoencephalitis and keratitis, respectively. These amoebae cause significant morbidity and mortality rates. Thus, the identification, characterization and validation of molecules participating in host-parasite interactions can provide attractive targets to timely intervene disease progress. In this work, we present a compendium of the parasite adhesins, lectins, proteases, hydrolases, kinases, and others, that participate in key pathogenic events. Special focus is made for the analysis of assorted molecules and mechanisms involved in the interaction of the parasites with epithelial surface receptors, changes in epithelial junctional markers, implications on the barrier function, among others. This review allows the assessment of initial host-pathogen interaction, to correlate it to the potential of parasite invasion.
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Affiliation(s)
- Abigail Betanzos
- Consejo Nacional de Ciencia y Tecnología (CONACYT), Mexico City 03940, Mexico
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City 07360, Mexico
| | - Cecilia Bañuelos
- Coordinación General de Programas de Posgrado Multidisciplinarios, Programa de Doctorado Transdisciplinario en Desarrollo Científico y Tecnológico para la Sociedad, CINVESTAV-IPN, Mexico City 07360, Mexico
| | - Esther Orozco
- Departamento de Infectómica y Patogénesis Molecular, CINVESTAV-IPN, Mexico City 07360, Mexico.
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14
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Sharma S, Agarwal S, Bharadwaj R, Somlata, Bhattacharya S, Bhattacharya A. Novel regulatory roles of PtdIns(4,5)P2generating enzyme EhPIPKI in actin dynamics and phagocytosis ofEntamoeba histolytica. Cell Microbiol 2019; 21:e13087. [DOI: 10.1111/cmi.13087] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 07/03/2019] [Indexed: 02/06/2023]
Affiliation(s)
- Shalini Sharma
- School of Life SciencesJawaharlal Nehru University New Delhi India
| | - Shalini Agarwal
- School of Life SciencesJawaharlal Nehru University New Delhi India
| | - Ravi Bharadwaj
- School of MedicineUMASS Medical School Worcester Massachusetts USA
| | - Somlata
- Multidisciplinary Centre for Advance Research and StudiesJamia Milia Islamia New Delhi India
| | - Sudha Bhattacharya
- School of Environmental SciencesJawaharlal Nehru University New Delhi India
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15
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Agarwal S, Anand G, Sharma S, Parimita Rath P, Gourinath S, Bhattacharya A. EhP3, a homolog of 14-3-3 family of protein participates in actin reorganization and phagocytosis in Entamoeba histolytica. PLoS Pathog 2019; 15:e1007789. [PMID: 31095644 PMCID: PMC6541287 DOI: 10.1371/journal.ppat.1007789] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 05/29/2019] [Accepted: 04/24/2019] [Indexed: 11/19/2022] Open
Abstract
The highly conserved proteins of the 14-3-3 family are universal adaptors known to regulate an enormous range of cellular processes in eukaryotes. However, their biological functions remain largely uncharacterized in pathogenic protists comprising of several 14-3-3 protein isoforms. In this study, we report the role of 14-3-3 in coordinating cytoskeletal dynamics during phagocytosis in a professional phagocytic protist Entamoeba histolytica, the etiological agent of human amebiasis. There are three isoforms of 14-3-3 protein in amoeba and here we have investigated Eh14-3-3 Protein 3 (EhP3). Live and fixed cell imaging studies revealed the presence of this protein throughout the parasite phagocytosis process, with high rate of accumulation at the phagocytic cups and closed phagosomes. Conditional suppression of EhP3 expression caused significant defects in phagocytosis accompanied by extensive diminution of F-actin at the site of cup formation. Downregulated cells also exhibited defective recruitment of an F-actin stabilizing protein, EhCoactosin at the phagocytic cups. In addition, mass spectrometry based analysis further revealed a large group of EhP3-associated proteins, many of these proteins are known to regulate cytoskeletal architecture in E histolytica. The dynamics of these proteins may also be controlled by EhP3. Taken together, our findings strongly suggest that EhP3 is a novel and a key regulatory element of actin dynamics and phagocytosis in E. histolytica. Phagocytosis of host cells is central to pathogenesis of protist parasite Entamoeba histolytica, the etiological agent of human amebiasis. It is a complex and multistep process that requires dynamic remodelling of the actin cytoskeleton by a large number of scaffolding, signaling and actin-binding proteins (ABPs). Although several parasite ligands such as EhC2PK, EhCaBP1, EhCaBP3, EhAK1, Arp2/3 complex and EhCoactosin that participate in the phagocytic machinery have been identified, the mechanistic insights to their regulation process remain largely elusive. We have in this study identified and characterized the important role of scaffolding protein EhP3 in modulating cytoskeletal dynamics and regulating phagocytosis in E. histolytica. Expression knockdown, imaging and interaction studies suggest that EhP3 function as an adaptor molecule that controls the localization of an F-actin stabilizing protein EhCoactosin and thus the dynamics of F-actin rearrangement during phagocytosis. EhP3 also interact with other actin dynamics regulating proteins that may in coordination regulate cytoskeletal dynamics and thereby phagocytosis in Entamoeba.
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Affiliation(s)
- Shalini Agarwal
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
- * E-mail:
| | - Gaurav Anand
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Shalini Sharma
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | | | | | - Alok Bhattacharya
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
- Ashoka University, P.O. Rai, Sonepat, Haryana, India
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16
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Naiyer S, Kaur D, Ahamad J, Singh SS, Singh YP, Thakur V, Bhattacharya A, Bhattacharya S. Transcriptomic analysis reveals novel downstream regulatory motifs and highly transcribed virulence factor genes of Entamoeba histolytica. BMC Genomics 2019; 20:206. [PMID: 30866809 PMCID: PMC6416950 DOI: 10.1186/s12864-019-5570-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/27/2019] [Indexed: 11/16/2022] Open
Abstract
Background Promoter motifs in Entamoeba histolytica were earlier analysed using microarray data with lower dynamic range of gene expression. Additionally, previous transcriptomic studies did not provide information on the nature of highly transcribed genes, and downstream promoter motifs important for gene expression. To address these issues we generated RNA-Seq data and identified the high and low expressing genes, especially with respect to virulence potential. We analysed sequences both upstream and downstream of start site for important motifs. Results We used RNA-Seq data to classify genes according to expression levels, which ranged six orders of magnitude. Data were validated by reporter gene expression. Virulence-related genes (except AIG1) were amongst the highly expressed, while some kinases and BspA family genes were poorly expressed. We looked for conserved motifs in sequences upstream and downstream of the initiation codon. Following enrichment by AME we found seven motifs significantly enriched in high expression- and three in low expression-classes. Two of these motifs (M4 and M6) were located downstream of AUG, were exclusively enriched in high expression class, and were mostly found in ribosomal protein, and translation-related genes. Motif deletion resulted in drastic down regulation of reporter gene expression, showing functional relevance. Distribution of core promoter motifs (TATA, GAAC, and Inr) in all genes revealed that genes with downstream motifs were not preferentially associated with TATA-less promoters. We looked at gene expression changes in cells subjected to growth stress by serum starvation, and experimentally validated the data. Genes showing maximum up regulation belonged to the low or medium expression class, and included genes in signalling pathways, lipid metabolism, DNA repair, Myb transcription factors, BspA, and heat shock. Genes showing maximum down regulation belonged to the high or medium expression class. They included genes for signalling factors, actin, Ariel family, and ribosome biogenesis factors. Conclusion Our analysis has added important new information about the E. histolytica transcriptome. We report for the first time two downstream motifs required for gene expression, which could be used for over expression of E. histolytica genes. Most of the virulence-related genes in this parasite are highly expressed in culture. Electronic supplementary material The online version of this article (10.1186/s12864-019-5570-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sarah Naiyer
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Devinder Kaur
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Jamaluddin Ahamad
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | | | | | - Vivek Thakur
- Centre for Systems Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Alok Bhattacharya
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Sudha Bhattacharya
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India.
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