scholarly journals Molecular characterization of the conoid complex in Toxoplasma reveals its conservation in all apicomplexans, including Plasmodium species

PLoS Biology ◽  
2021 ◽  
Vol 19 (3) ◽  
pp. e3001081 ◽  
Author(s):  
Ludek Koreny ◽  
Mohammad Zeeshan ◽  
Konstantin Barylyuk ◽  
Eelco C. Tromer ◽  
Jolien J. E. van Hooff ◽  
...  
Keyword(s):  
Plasmodium Species ◽  
Mosquito Vector ◽  
Apicomplexan Parasites ◽  
Invasion Mechanisms ◽  
Molecular Differentiation ◽  
Associated Proteins ◽  
Molecular Conservation ◽  
Malaria Model ◽  
High Resolution Microscopy

The apical complex is the instrument of invasion used by apicomplexan parasites, and the conoid is a conspicuous feature of this apparatus found throughout this phylum. The conoid, however, is believed to be heavily reduced or missing fromPlasmodiumspecies and other members of the class Aconoidasida. Relatively few conoid proteins have previously been identified, making it difficult to address how conserved this feature is throughout the phylum, and whether it is genuinely missing from some major groups. Moreover, parasites such asPlasmodiumspecies cycle through 3 invasive forms, and there is the possibility of differential presence of the conoid between these stages. We have applied spatial proteomics and high-resolution microscopy to develop a more complete molecular inventory and understanding of the organisation of conoid-associated proteins in the model apicomplexanToxoplasma gondii. These data revealed molecular conservation of all conoid substructures throughout Apicomplexa, includingPlasmodium, and even in allied Myzozoa such asChromeraand dinoflagellates. We reporter-tagged and observed the expression and location of several conoid complex proteins in the malaria modelP.bergheiand revealed equivalent structures in all of its zoite forms, as well as evidence of molecular differentiation between blood-stage merozoites and the ookinetes and sporozoites of the mosquito vector. Collectively, we show that the conoid is a conserved apicomplexan element at the heart of the invasion mechanisms of these highly successful and often devastating parasites.

scholarly journals Conservation of the Toxoplasma conoid complex proteome reveals a cryptic conoid in Plasmodium that differentiates between blood- and vector-stage zoites

2020 ◽  
Author(s):  
Ludek Koreny ◽  
Mohammad Zeeshan ◽  
Konstantin Barylyuk ◽  
Eelco C. Tromer ◽  
Jolien J. E. van Hooff ◽  
...  
Keyword(s):  
High Resolution ◽  
Toxoplasma Gondii ◽  
Mosquito Vector ◽  
Apicomplexan Parasites ◽  
Invasion Mechanisms ◽  
Molecular Differentiation ◽  
Associated Proteins ◽  
Molecular Conservation ◽  
Malaria Model ◽  
High Resolution Microscopy

AbstractThe apical complex is the instrument of invasion used by apicomplexan parasites, and the conoid is a conspicuous feature of this apparatus found throughout this phylum. The conoid, however, is believed to be heavily reduced or missing from Plasmodium species and other members of the class Aconoidasida. Relatively few conoid proteins have previously been identified, making it difficult to address how conserved this feature is throughout the phylum, and whether it is genuinely missing from some major groups. Moreover, parasites such as Plasmodium species cycle through three invasive forms and there is the possibility of differential presence of the conoid between these stages. We have applied spatial proteomics and high-resolution microscopy to develop a more complete molecular inventory and understanding of the organisation of conoid-associated proteins in the model apicomplexan Toxoplasma gondii. These data revealed molecular conservation of all conoid substructures throughout Apicomplexa, including Plasmodium, and even in allied Myzozoa such as Chromera and dinoflagellates. We reporter-tagged and observed the expression and location of several conoid complex proteins in the malaria model P. berghei and revealed equivalent structures in all of its zoite forms, as well as evidence of molecular differentiation between blood-stage merozoites and the ookinetes and sporozoites of the mosquito vector. Collectively we show that the conoid is a conserved apicomplexan element at the heart of the invasion mechanisms of these highly successful and often devastating parasites.

scholarly journals Identification and Characterization of the Rhoptry Neck Protein 2 in Babesia divergens and B. microti

2016 ◽  
Vol 84 (5) ◽  
pp. 1574-1584 ◽  
Author(s):  
Rosalynn L. Ord ◽  
Marilis Rodriguez ◽  
Jeny R. Cursino-Santos ◽  
Hyunryung Hong ◽  
Manpreet Singh ◽  
...  
Keyword(s):  
Direct Role ◽  
Parasite Invasion ◽  
Content Type ◽  
Apicomplexan Parasites ◽  
Babesia Divergens ◽  
Associated Proteins ◽  
Identification And Characterization

Apicomplexan parasites include those of the generaPlasmodium,Cryptosporidium, andToxoplasmaand those of the relatively understudied zoonotic genusBabesia. In humans, babesiosis, particularly transfusion-transmitted babesiosis, has been emerging as a major threat to public health. Like malaria, the disease pathology is a consequence of the parasitemia which develops through cyclical replication ofBabesiaparasites in host erythrocytes. However, there are no exoerythrocytic stages inBabesia, so targeting of the blood stage and associated proteins to directly prevent parasite invasion is the most desirable option for effective disease control. Especially promising among such molecules are the rhoptry neck proteins (RONs), whose homologs have been identified in many apicomplexan parasites. RONs are involved in the formation of the moving junction, along with AMA1, but no RON has been identified and characterized in anyBabesiaspp. Here we identify the RON2 proteins ofBabesia divergens(BdRON2) andB. microti(BmRON2) and show that they are localized apically and that anti-BdRON2 antibodies are significant inhibitors of parasite invasionin vitro. Neither protein is immunodominant, as both proteins react only marginally with sera from infected animals. Further characterization of the direct role of both BdRON2 and BmRON2 in parasite invasion is required, but knowledge of the level of conformity of RON2 proteins within the apicomplexan phylum, particularly that of the AMA1-RON2 complex at the moving junction, along with the availability of an animal model forB. microtistudies, provides a key to target this complex with a goal of preventing the erythrocytic invasion of these parasites and to further our understanding of the role of these conserved ligands in invasion.

scholarly journals Characterization of the Tubovesicular Network in Plasmodium vivax Liver Stage Hypnozoites and Schizonts

2021 ◽  
Vol 11 ◽  
Author(s):  
Kayla Sylvester ◽  
Steven P. Maher ◽  
Dora Posfai ◽  
Michael K. Tran ◽  
McKenna C. Crawford ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Molecular Mechanisms ◽  
Parasitophorous Vacuole ◽  
Clinical Relapse ◽  
Liver Stage ◽  
Apicomplexan Parasites ◽  
Stage Development ◽  
Host Parasite ◽  
High Resolution Microscopy

Plasmodium is a genus of apicomplexan parasites which replicate in the liver before causing malaria. Plasmodium vivax can also persist in the liver as dormant hypnozoites and cause clinical relapse upon activation, but the molecular mechanisms leading to activation have yet to be discovered. In this study, we use high-resolution microscopy to characterize temporal changes of the P. vivax liver stage tubovesicular network (TVN), a parasitophorous vacuole membrane (PVM)-derived network within the host cytosol. We observe extended membrane clusters, tubules, and TVN-derived vesicles present throughout P. vivax liver stage development. Additionally, we demonstrate an unexpected presence of the TVN in hypnozoites and observe some association of this network to host nuclei. We also reveal that the host water and solute channel aquaporin-3 (AQP3) associates with TVN-derived vesicles and extended membrane clusters. AQP3 has been previously shown to localize to the PVM of P. vivax hypnozoites and liver schizonts but has not yet been shown in association to the TVN. Our results highlight host-parasite interactions occur in both dormant and replicating liver stage P. vivax forms and implicate AQP3 function during this time. Together, these findings enhance our understanding of P. vivax liver stage biology through characterization of the TVN with an emphasis on the presence of this network in dormant hypnozoites.

Identification and characterization of a novel Neospora caninum immune mapped protein 1

Parasitology ◽  
2012 ◽  
Vol 139 (8) ◽  
pp. 998-1004 ◽  
Author(s):  
X. CUI ◽  
T. LEI ◽  
D. Y. YANG ◽  
P. HAO ◽  
Q. LIU
Keyword(s):  
Neospora Caninum ◽  
Polyclonal Antibodies ◽  
Functional Protein ◽  
Reading Frame ◽  
Protein Motifs ◽  
Apicomplexan Parasites ◽  
Potential Vaccine ◽  
Palmitoylation Site

SUMMARYImmune mapped protein 1 (IMP1) is a newly discovered protein in Eimeria maxima. It is recognized as a potential vaccine candidate against E. maxima and a highly conserved protein in apicomplexan parasites. Although the Neospora caninum IMP1 (NcIMP1) orthologue of E. maxima IMP1 was predicted in the N. caninum genome, it was still not identified and characterized. In this study, cDNA sequence encoding NcIMP1 was cloned by RT-PCR from RNA isolated from Nc1 tachyzoites. NcIMP1 was encoded by an open reading frame of 1182 bp, which encoded a protein of 393 amino acids with a predicted molecular weight of 42·9 kDa. Sequence analysis showed that there was neither a signal peptide nor a transmembrane region present in the NcIMP1 amino acid sequence. However, several kinds of functional protein motifs, including an N-myristoylation site and a palmitoylation site were predicted. Recombinant NcIMP1 (rNcIMP1) was expressed in Escherichia coli and then purified rNcIMP1 was used to prepare specific antisera in mice. Mouse polyclonal antibodies raised against the rNcIMP1 recognized an approximate 43 kDa native IMP1 protein. Immunofluorescence analysis showed that NcIMP1 was localized on the membrane of N. caninum tachyzoites. The N-myristoylation site and the palmitoylation site were found to contribute to the localization of NcIMP1. Furthermore, the rNcIMP1-specific antibodies could inhibit cell invasion by N. caninum tachyzoites in vitro. All the results indicate that NcIMP1 is likely to be a membrane protein of N. caninum and may be involved in parasite invasion.

scholarly journals Identification and characterization of microtubule proteins from myxamoebae of Physarum polycephalum

1980 ◽  
Vol 189 (2) ◽  
pp. 305-312 ◽  
Author(s):  
A Roobol ◽  
C I Pogson ◽  
K Gull
Keyword(s):  
Physarum Polycephalum ◽  
Microtubule Assembly ◽  
Alpha Tubulin ◽  
Microtubule Associated Proteins ◽  
Cell Extracts ◽  
Microtubule Protein ◽  
Associated Proteins ◽  
Microtubule Formation

Cell extracts of myxamoebae of Physarum polycephalum have been prepared in such a way that they do not inhibit assembly of brain microtubule protein in vitro even at high extract-protein concentration. Co-polymers of these extracts and brain tubulin have been purified to constant stoichiometry and amoebal components identified by radiolabelling. Amoebal tubulin has been identified as having an alpha-subunit, mol.wt. 54 000, which co-migrates with brain alpha-tubulin and a beta-subunit, mol.wt. 50 000, which co-migrates with Tetrahymena ciliary beta-tubulin. Non-tubulin amoebal proteins that co-purify with tubulin during co-polymer formation have been shown to be essential for microtubule formation in the absence of glycerol and appear to be rather more effective than brain microtubule-associated proteins in stimulating assembly. The mitotic inhibitor griseofulvin (7-chloro-2′,4,6-trimethoxy-6′-methylspiro[benzofuran-2(3H),1′-cyclohex-2′-ene] −3,4′-dione), which binds to brain microtubule-associated proteins and inhibits brain microtubule assembly in vitro, affected co-polymer microtubule protein in a similar way, but to a slightly greater extent.

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