Molecular characterization of serine/threonine protein phosphatase of Eimeria tenella

Abstract

Avian coccidiosis is a widespread and economically significant poultry disease caused by several Eimeria species, including Eimeria tenella. Previously, E. tenella serine/threonine protein phosphatase (EtSTP) was found to be differentially expressed in drug‐sensitive (DS) and drug‐resistant strains using RNA‐seq. In the present study, we found that transcription and translation levels of EtSTP were higher in diclazuril‐resistant (DZR) strains and maduramicin‐resistant (MRR) strains than in DS strains using quantitative real‐time PCR (qPCR) and Western blotting. Enzyme activity results indicated that the catalytic activity of EtSTP was higher in the two drug‐resistant strains than in DS strains. Western blot and qPCR analysis also showed that expression levels of EtSTP were higher in unsporulated oocysts (UO) and second‐generation merozoites (SM). Indirect immunofluorescence localization showed that EtSTP was located in most areas of the parasite with the exception of refractile bodies, and fluorescence intensity was enhanced during development. In vitro inhibition experiments showed that the ability of sporozoites (SZ) to invade cells was significantly decreased after treatment with anti‐rEtSTP antibody. These results indicated that EtSTP acted mainly during the developmental and reproductive stages of the parasite and may be related to the resistance of coccidia to external drug pressure.

Exploration of the Mechanism of the Control of Coccidiosis in Chickens Based on Network Pharmacology and Molecular Docking With the Addition of Modified Gegen Qinlian Decoction

“…While in E. tenella infection or EtROP1 overexpression affects p53 interactions and phosphorylation, ultimately leading to host cell apoptosis and inhibition of G0/G1 cell cycle arrest ( 34 ). Dexing Ma realized that specific L peptides, competing with E. tenella rhotryneck protein 2 (EtRON2) to bind EtAMA1 located on the surface of ascospores, inhibited the parasite's invasion of cells ( 35 ). It was shown that EtSTP protein acts mainly in the developmental and reproductive stages of the parasite and that the ability of ascospores to invade cells was significantly reduced by anti-rEtSTP antibody treatment ( 36 ).…”

Eimeria proteins: order amidst disorder

“…2 ). Also, heat, cold, chemical factors and nutrition may cause changes in MIC expression [ 84 ]. After secretion, MICs persistently appear on parasite membrane and host cell surfaces [ 85 , 86 ] to enable Eimeria sporozoites to bind a diverse range of host cell glycan epitopes [ 87 ].…”

“…Western blot and qPCR analyses have demonstrated that E. tenella serine/threonine phosphatase (STP) was highly expressed in drug-resistant compared with drug-sensitive strains. The association of STP with drug resistance may possibly be linked to mutation with contiguous genes encoding proteins that interact with STP [ 84 ]. Of the enzymes secreted via E. tenella apicoplast, enoyl reductase is important in the formation of fatty acid synthase and synthesis of type 1 and 11 fatty acids [ 40 ] but multiple pathways for fatty acid synthase geared toward various organelles [ 74 ] need further elucidation.…”

“…Identification of protease-mediated processes would facilitate better understand of host cell lysis and immune evasion [ 131 ]. Factors influencing changes in amino acid sequences such as single nucleotide polymorphisms [ 101 ], mutation and antigenic variation [ 84 ] and trypsinic hydrolysis [ 112 ] need to be completely defined. Identifying when and why these changes occur will be essential to explain some mechanisms of antigenic variation, drug resistance and immune subversion.…”