A Newly Discovered Dense Granule Protein 3 in Neospora caninum

The obligate intracellular apicomplexan parasiteNeospora caninum (N. caninum)is closely related toToxoplasma gondii (T. gondii). The dense granules, which are present in all apicomplexan parasites, are important secretory organelles. Dense granule (GRA) proteins are released into the parasitophorous vacuole (PV) following host cell invasion and are known to play important roles in the maintenance of the host-parasite relationship and in the acquisition of nutrients. Here, we provide a detailed characterization of theN. caninumdense granule protein NcGRA9. The in silico genomic organization and key protein characteristics are described. Immunofluorescence-based localization studies revealed that NcGRA9 is located in the dense granules and is released into the interior of the PV following host cell invasion. Immunogold-electron microscopy confirmed the dense granule localization and showed that NcGRA9 is associated with the intravacuolar network. In addition, NcGRA9 is found in the “excreted secreted antigen” (ESA) fraction ofN. caninum. Furthermore, by analysing the distribution of truncated versions of NcGRA9, we provide evidence that the C-terminal region of this protein is essential for the targeting of NcGRA9 into the dense granules ofN. caninum, and the truncated proteins show reduced secretion.

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Identification of the antigenic region of Neospora caninum dense granule protein 7 using ELISA

Parasitology International ◽

10.1016/j.parint.2018.06.012 ◽

2018 ◽

Vol 67 (6) ◽

pp. 675-678 ◽

Cited By ~ 5

Author(s):

Hanan H. Abdelbaky ◽

Ragab M. Fereig ◽

Yoshifumi Nishikawa

Keyword(s):

Neospora Caninum ◽

Dense Granule ◽

Granule Protein ◽

Antigenic Region

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The tandemly repeated NTPase (NTPDase) from Neospora caninum is a canonical dense granule protein whose RNA expression, protein secretion and phosphorylation coincides with the tachyzoite egress

Parasites & Vectors ◽

10.1186/s13071-016-1620-4 ◽

2016 ◽

Vol 9 (1) ◽

Cited By ~ 9

Author(s):

Iván Pastor-Fernández ◽

Javier Regidor-Cerrillo ◽

Gema Álvarez-García ◽

Virginia Marugán-Hernández ◽

Paula García-Lunar ◽

...

Keyword(s):

Protein Secretion ◽

Neospora Caninum ◽

Dense Granule ◽

Rna Expression ◽

Granule Protein

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Toxoplasma gondii dense granule protein 3 (GRA3) is a type I transmembrane protein that possesses a cytoplasmic dilysine (KKXX) endoplasmic reticulum (ER) retrieval motif

Parasitology ◽

10.1017/s0031182005007559 ◽

2005 ◽

Vol 131 (2) ◽

pp. 169-179 ◽

Cited By ~ 22

Author(s):

F. L. HENRIQUEZ ◽

M. B. NICKDEL ◽

R. MCLEOD ◽

R. E. LYONS ◽

K. LYONS ◽

...

Keyword(s):

Molecular Weight ◽

Endoplasmic Reticulum ◽

Toxoplasma Gondii ◽

Transmembrane Domain ◽

Neospora Caninum ◽

Parasitophorous Vacuole ◽

Dense Granule ◽

Type I ◽

Dense Granules ◽

Granule Protein

Studies using antibodies to immunolocalize the Toxoplasma gondii dense granule protein GRA3, have shown that this protein associates strongly with the parasitophorous vacuole membrane (PVM). However, as there was no predicted membrane-spanning domain this highlighted an unanswered paradox. We demonstrate that the previously published sequence for GRA3 is actually an artificial chimera of 2 proteins. One protein, of molecular weight 65 kDa, shares the C-terminus with published GRA3 and possesses no significant sequence similarity with any protein thus far deposited in Genbank. The second, with a predicted molecular weight of 24 kDa shares the N-terminal region, is recognized by the monoclonal antibody 2H11 known to react with the dense granules of T. gondii and is therefore the authentic GRA3. The corrected GRA3 has an N-terminal secretory signal sequence and a transmembrane domain consistent with its insertion into the PVM. Antibodies to recombinant GRA3 recognize a protein of 24 kDa in T. gondii excretory–secretory antigen preparations. The signal peptide is necessary and sufficient to target GFP to the dense granules and parasitophorous vacuole. A homologue was identified in Neospora caninum. Finally, GRA3 possesses a dilysine ‘KKXX’ endoplasmic reticulum (ER) retrieval motif that rationalizes its association with PVM and possibly the host cell ER.

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Dense-Granule Protein NcGRA7, a New Marker for the Serodiagnosis of Neospora caninum Infection in Aborting Cows

Clinical and Vaccine Immunology ◽

10.1128/cvi.00251-07 ◽

2007 ◽

Vol 14 (12) ◽

pp. 1640-1643 ◽

Cited By ~ 27

Author(s):

Penglong Huang ◽

Min Liao ◽

Houshuang Zhang ◽

Eung-goo Lee ◽

Yoshifumi Nishikawa ◽

...

Keyword(s):

Immunosorbent Assay ◽

Specific Antibody ◽

Neospora Caninum ◽

Dense Granule ◽

Enzyme Linked Immunosorbent Assay ◽

Serum Samples ◽

Caninum Infection ◽

Recombinant Antigens ◽

Granule Protein ◽

Bovine Abortion

ABSTRACT To investigate whether the production of an antigen-specific antibody is associated with Neospora caninum-induced bovine abortion, 62 serum samples were tested with an enzyme-linked immunosorbent assay using the recombinant antigens NcSAG1, NcSRS2, and NcGRA7. Our study suggested that NcGRA7 would be a new marker for the serodiagnosis of N. caninum infection resulting in abortion.

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Immunization with Oligomannose-Coated Liposome-Entrapped Dense Granule Protein 7 Protects Dams and Offspring from Neospora caninum Infection in Mice

Clinical and Vaccine Immunology ◽

10.1128/cvi.00032-09 ◽

2009 ◽

Vol 16 (6) ◽

pp. 792-797 ◽

Cited By ~ 43

Author(s):

Yoshifumi Nishikawa ◽

Houshuang Zhang ◽

Yuzuru Ikehara ◽

Naoya Kojima ◽

Xuenan Xuan ◽

...

Keyword(s):

Neospora Caninum ◽

Subcutaneous Administration ◽

Dense Granule ◽

Effective Vaccine ◽

T Helper ◽

Infection Rates ◽

Caninum Infection ◽

Granule Protein ◽

New Type

ABSTRACT The present study demonstrates that the subcutaneous administration of Neospora caninum dense granule protein 7 (NcGRA7) entrapped in liposomes coated with mannotriose strongly induces the parasite-specific T-helper type 1 immune response and humoral antibody in mice. Although anti-NcGRA7 immunoglobulin G1 antibody production was induced in mice injected with NcGRA7 alone, the dams and offspring were never protected from N. caninum infection. The immunization of mice with liposome-entrapped NcGRA7 before pregnancy resulted in increased offspring survival and decreased the infection rates in the brains of dams after parasite infection at 6 to 9 days of gestation. In conclusion, oligomannose-coated liposome-entrapped NcGRA7 can be used as a new type of effective vaccine to control neosporosis.

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