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Toxoplasma gondii virulence factor ROP18 inhibits the host NF-κB pathway by promoting p65 degradation.
Du, Jian; An, Ran; Chen, Lijian; Shen, Yuxian; Chen, Ying; Cheng, Li; Jiang, Zhongru; Zhang, Aimei; Yu, Li; Chu, Deyong; Shen, Yujun; Luo, Qingli; Chen, He; Wan, Lijuan; Li, Min; Xu, Xiucai; Shen, Jilong.
Afiliação
  • Du J; From the Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China.
J Biol Chem ; 289(18): 12578-92, 2014 05 02.
Article em En | MEDLINE | ID: mdl-24648522
ABSTRACT
The obligate intracellular parasite Toxoplasma gondii secretes effector molecules into the host cell to modulate host immunity. Previous studies have shown that T. gondii could interfere with host NF-κB signaling to promote their survival, but the effectors of type I strains remain unclear. The polymorphic rhoptry protein ROP18 is a key serine/threonine kinase that phosphorylates host proteins to modulate acute virulence. Our data demonstrated that the N-terminal portion of ROP18 is associated with the dimerization domain of p65. ROP18 phosphorylates p65 at Ser-468 and targets this protein to the ubiquitin-dependent degradation pathway. The kinase activity of ROP18 is required for p65 degradation and suppresses NF-κB activation. Consistently, compared with wild-type ROP18 strain, ROP18 kinase-deficient type I parasites displayed a severe inability to inhibit NF-κB, culminating in the enhanced production of IL-6, IL-12, and TNF-α in infected macrophages. In addition, studies have shown that transgenic parasites carrying kinase-deficient ROP18 induce M1-biased activation. These results demonstrate for the first time that the virulence factor ROP18 in T. gondii type I strains is responsible for inhibiting the host NF-κB pathway and for suppressing proinflammatory cytokine expression, thus providing a survival advantage to the infectious agent.
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Texto completo: 1 Base de dados: MEDLINE Assunto principal: Toxoplasma / Transdução de Sinais / Proteínas de Protozoários / NF-kappa B / Proteínas Serina-Treonina Quinases / Fator de Transcrição RelA Limite: Animals / Female / Humans Idioma: En Ano de publicação: 2014 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Toxoplasma / Transdução de Sinais / Proteínas de Protozoários / NF-kappa B / Proteínas Serina-Treonina Quinases / Fator de Transcrição RelA Limite: Animals / Female / Humans Idioma: En Ano de publicação: 2014 Tipo de documento: Article