Eimeria tenella ROP kinase EtROP1 induces G0/G1 cell cycle arrest and inhibits host cell apoptosis.

Mamadou Amadou Diallo,Yves Le Vern,Aurélien Brionne,Alix Sausset,Adeline Ribeiro E Silva,Sonia Lacroix‐Lamandé,Audrey Gnahoui‐David,Fabrice Laurent,Julie Tottey,Françoise I Bussière,Anne Silvestre

doi:10.1111/cmi.13027

Abstract

Coccidia are obligate intracellular protozoan parasites responsible for human and veterinary diseases. Eimeria tenella, the aetiologic agent of caecal coccidiosis, is a major pathogen of chickens. In Toxoplasma gondii, some kinases from the rhoptry compartment (ROP) are key virulence factors. ROP kinases hijack and modulate many cellular functions and pathways, allowing T. gondii survival and development. E. tenella's kinome comprises 28 putative members of the ROP kinase family; most of them are predicted, as pseudokinases and their functions have never been characterised. One of the predicted kinase, EtROP1, was identified in the rhoptry proteome of E. tenella sporozoites. Here, we demonstrated that EtROP1 is active, and the N‐terminal extension is necessary for its catalytic kinase activity. Ectopic expression of EtROP1 followed by co‐immunoprecipitation identified cellular p53 as EtROP1 partner. Further characterisation confirmed the interaction and the phosphorylation of p53 by EtROP1. E. tenella infection or overexpression of EtROP1 resulted both in inhibition of host cell apoptosis and G0/G1 cell cycle arrest. This work functionally described the first ROP kinase from E. tenella and its noncanonical structure. Our study provides the first mechanistic insight into host cell apoptosis inhibition by E. tenella. EtROP1 appears as a new candidate for coccidiosis control.

Highlights

Apicomplexa are protozoan parasites that cause significant human diseases (Plasmodium, Toxoplasma, Cryptosporidium) and are of major agricultural importance (Cryptosporidium, Eimeria, Neospora, Theileria)
We describe the identification and functional characterisation of the first rhoptry compartment (ROP) kinase from Eimeria tenella, a putative virulence factor
Using actinomycin D, which blocks mRNA synthesis and induces apoptosis, we showed that EtROP1 prevents apoptosis in a manner that is independent of its kinase activity

Summary

| INTRODUCTION

Apicomplexa are protozoan parasites that cause significant human diseases (Plasmodium, Toxoplasma, Cryptosporidium) and are of major agricultural importance (Cryptosporidium, Eimeria, Neospora, Theileria). To develop efficient and sustainable control strategies of coccidiosis, it is a priority to identify new therapeutic targets or virulence factors expressed by E. tenella. In this context, we focused on kinases from E. tenella that may represent interesting targets for anticoccidial control. The phylogenetic analysis of ROPK sequences from T. gondii and E. tenella allowed the identification of four distinct subclades among them the N‐terminal extension (NTE)‐bearing clade containing Toxoplasma's ROPKs with homology to the TgROP2 NTE. This clade comprises the E. tenella ROP kinase encoded by the locus ETH_00005190. We identified the host p53 protein as a substrate for this parasite kinase

| RESULTS

| DISCUSSION

| EXPERIMENTAL PROCEDURES

Findings

4.21 | Ethics approval