scholarly journals Apical membrane antigen 1 mediates apicomplexan parasite attachment but is dispensable for host cell invasion

2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Daniel Y. Bargieri ◽  
Nicole Andenmatten ◽  
Vanessa Lagal ◽  
Sabine Thiberge ◽  
Jamie A. Whitelaw ◽  
...  
Keyword(s):  
Host Cell ◽  
Cell Invasion ◽  
Apical Membrane ◽  
Apicomplexan Parasite ◽  
Host Cell Invasion ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen

scholarly journals Conditional Expression of Toxoplasma gondii Apical Membrane Antigen-1 (TgAMA1) Demonstrates That TgAMA1 Plays a Critical Role in Host Cell Invasion

2005 ◽  
Vol 16 (9) ◽  
pp. 4341-4349 ◽  
Author(s):  
Jeffrey Mital ◽  
Markus Meissner ◽  
Dominique Soldati ◽  
Gary E. Ward
Keyword(s):  
Toxoplasma Gondii ◽  
Host Cell ◽  
Cell Invasion ◽  
Apical Membrane ◽  
Conditional Knockout ◽  
Host Cell Invasion ◽  
Apical Membrane Antigen 1 ◽  
Apicomplexan Parasites ◽  
Apical Membrane Antigen ◽  
Conditional Expression

Toxoplasma gondii is an obligate intracellular parasite and an important human pathogen. Relatively little is known about the proteins that orchestrate host cell invasion by T. gondii or related apicomplexan parasites (including Plasmodium spp., which cause malaria), due to the difficulty of studying essential genes in these organisms. We have used a recently developed regulatable promoter to create a conditional knockout of T. gondii apical membrane antigen-1 (TgAMA1). TgAMA1 is a transmembrane protein that localizes to the parasite's micronemes, secretory organelles that discharge during invasion. AMA1 proteins are conserved among apicomplexan parasites and are of intense interest as malaria vaccine candidates. We show here that T. gondii tachyzoites depleted of TgAMA1 are severely compromised in their ability to invade host cells, providing direct genetic evidence that AMA1 functions during invasion. The TgAMA1 deficiency has no effect on microneme secretion or initial attachment of the parasite to the host cell, but it does inhibit secretion of the rhoptries, organelles whose discharge is coupled to active host cell penetration. The data suggest a model in which attachment of the parasite to the host cell occurs in two distinct stages, the second of which requires TgAMA1 and is involved in regulating rhoptry secretion.

scholarly journals Independent Roles of Apical Membrane Antigen 1 and Rhoptry Neck Proteins during Host Cell Invasion by Apicomplexa

2011 ◽  
Vol 10 (6) ◽  
pp. 591-602 ◽  
Author(s):  
Donatella Giovannini ◽  
Stephan Späth ◽  
Céline Lacroix ◽  
Audrey Perazzi ◽  
Daniel Bargieri ◽  
...  
Keyword(s):  
Host Cell ◽  
Cell Invasion ◽  
Apical Membrane ◽  
Host Cell Invasion ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen

scholarly journals Eimeria tenella Eimeria-specific protein that interacts with apical membrane antigen 1 (EtAMA1) is involved in host cell invasion

2019 ◽  
Author(s):  
Cong Li ◽  
Qiping Zhao ◽  
Shunhai Zhu ◽  
Qingjie Wang ◽  
Haixia Wang ◽  
...  
Keyword(s):  
Host Cell ◽  
Cell Invasion ◽  
Apical Membrane ◽  
Specific Protein ◽  
Host Cells ◽  
Bimolecular Fluorescence Complementation ◽  
Host Cell Invasion ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen

Abstract Apical membrane antigen 1 (AMA1), which is released from micronemes and is conserved across all apicomplexans, plays a central role in the host cell invasion. In this study, we characterized one putative Et AMA1-interacting protein, E. tenella Eimeria -specific protein ( Et Esp). The interaction between Et AMA1 and Et Esp was confirmed with bimolecular fluorescence complementation (BiFC) in vivo and by glutathione S-transferase (GST) fusion protein pull-down (GST pull-down) in vitro . We showed that Et Esp is differentially expressed during distinct phases of the parasite life cycle by using qPCR and western blotting. Immunofluorescence analysis showed that the Et Esp protein is mainly distributed on the parasite surface, and that the expression of this protein increases during the development of the parasite in the host cells. Using staurosporine, we showed that Et Esp is a micronemal protein secreted by sporozoites. In inhibition tests, a polyclonal anti-r Et Esp antibody attenuated the capacity of E. tenella to invade host cells in vitro . These data have implications for the use of Et AMA1 or Et AMA1-interacting proteins as targets in intervention strategies against avian coccidiosis.

scholarly journals Eimeria tenella Eimeria-specific protein that interacts with apical membrane antigen 1 (EtAMA1) is involved in host cell invasion

2020 ◽  
Author(s):  
Cong Li ◽  
Qiping Zhao ◽  
Shunhai Zhu ◽  
Qingjie Wang ◽  
Haixia Wang ◽  
...  
Keyword(s):  
Cell Invasion ◽  
Apical Membrane ◽  
Specific Protein ◽  
Host Cells ◽  
Host Cell Invasion ◽  
Secreted Protein ◽  
Interacting Proteins ◽  
Apical Membrane Antigen 1

Abstract Background: Avian coccidiosis is a widespread, economically significant disease of poultry, caused by several species of the protozoan parasite Eimeria. Among these species, E. tenella causes hemorrhagic pathologies and high mortality. These parasites have complex and diverse lifestyles that require the invasion of their host cells. This is mediated by various proteins secreted from apical secretory organelles. Apical membrane antigen 1 (AMA1), which is released from micronemes and is conserved across all apicomplexans, plays a central role in the host cell invasion. In a previous study, some putative EtAMA1-interacting proteins of E. tenella were screened. In this study, we characterized one putative EtAMA1-interacting protein, E. tenella Eimeria -specific protein (EtEsp).Methods: Bimolecular fluorescence complementation (BiFC) and glutathione S-transferase (GST) fusion protein pull-down (GST pull-down) were used to confirm the interaction between EtAMA1 and EtEsp in vivo and in vitro. The expression of EtEsp was analyzed in different developmental stages of E. tenella with quantitative PCR and western blotting. The secretion of EtEsp protein was tested with staurosporine when sporozoites were incubated in complete medium at 41 °C.The localization of EtEsp was analyzed with an immunofluorescence assay. An in vitro invasion inhibition assay was conducted to assess the ability of antibodies against EtEsp to inhibit cell invasion by E. tenella sporozoites.Results: The interaction between EtAMA1 and EtEsp was confirmed with BiFC in vivo and by GST pull-down in vitro. Our results show that EtEsp is differentially expressed during distinct phases of the parasite life cycle. An immunofluorescence analysis showed that the EtEsp protein is mainly distributed on the parasite surface, and that the expression of this protein increases during the development of the parasite in the host cells. Using staurosporine, we showed that EtEsp is a secreted protein, but not from micronemes. In inhibition tests, a polyclonal anti-rEtEsp antibody attenuated the capacity of E. tenella to invade host cells in vitro. Conclusion: In this study, we show that EtEsp interacts with EtAMA1 and that the protein is secreted protein, but not from micronemes. The protein participates in the sporozoite invasion of host cells and maybe involved in the growth of the parasite in the host. These data have implications for the use of EtAMA1 or EtAMA1-interacting proteins as targets in intervention strategies against avian coccidiosis.

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