Characterization of the Neospora caninum NcROP40 and NcROP2Fam-1 rhoptry proteins during the tachyzoite lytic cycle

Pastor-Fernández, I., Regidor-Cerrillo, J., Jiménez-Ruiz, E. , Álvarez-García, G., Marugán-Hernández, V., Hemphill, A. and Ortega-Mora, L. M. (2016) Characterization of the Neospora caninum NcROP40 and NcROP2Fam-1 rhoptry proteins during the tachyzoite lytic cycle. Parasitology, 143(1), pp. 97-113. (doi: 10.1017/S0031182015001511) (PMID:26521890)

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Abstract

Virulence factors from the ROP2-family have been extensively studied in Toxoplasma gondii, but in the closely related Neospora caninum only NcROP2Fam-1 has been partially characterized to date. NcROP40 is a member of this family and was found to be more abundantly expressed in virulent isolates. Both NcROP2Fam-1 and NcROP40 were evaluated as vaccine candidates and exerted a synergistic effect in terms of protection against vertical transmission in mouse models, which suggests that they may be relevant for parasite pathogenicity. NcROP40 is localized in the rhoptry bulbs of tachyzoites and bradyzoites, but in contrast to NcROP2Fam-1, the protein does not associate with the parasitophorous vacuole membrane due to the lack of arginine-rich amphipathic helix in its sequence. Similarly to NcROP2Fam-1, NcROP40 mRNA levels are highly increased during tachyzoite egress and invasion. However, NcROP40 up-regulation does not appear to be linked to the mechanisms triggering egress. In contrast to NcROP2Fam-1, phosphorylation of NcROP40 was not observed during egress. Besides, NcROP40 secretion into the host cell was not successfully detected by immunofluorescence techniques. These findings indicate that NcROP40 and NcROP2Fam-1 carry out different functions, and highlight the need to elucidate the role of NcROP40 within the lytic cycle and to explain its relative abundance in tachyzoites.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Jimenez Ruiz, Dr Elena
Authors: Pastor-Fernández, I., Regidor-Cerrillo, J., Jiménez-Ruiz, E., Álvarez-García, G., Marugán-Hernández, V., Hemphill, A., and Ortega-Mora, L. M.
College/School:College of Medical Veterinary and Life Sciences > School of Infection & Immunity
Journal Name:Parasitology
Publisher:Cambridge University Press
ISSN:0031-1820
ISSN (Online):1469-8161
Published Online:02 November 2015
Copyright Holders:Copyright © 2015 Cambridge University Press
First Published:First published in Parasitology 143(1): 97-113
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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