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Innate Immunity in Aquatic Vertebrates

Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Immunol. | doi: 10.3389/fimmu.2019.00582

The fish specific protein kinase containing Z-DNA binding domain (PKZ) initiates innate immune responses via IRF3- and ISGF3-like mediated pathways

  • 1Nanchang University, China

Protein kinase containing Zα domain (PKZ) is a fish specific protein kinase. PKZ can induce apoptosis through phosphorylating eIF2α, which is similar to PKR. However, its unique roles in recognition of pathogen remain to be fully elucidated. Herein, we identify PKZ acts as a fish special DNA sensor which can initiate IFN expression through IRF3- or ISGF3-like-mediated pathway. Firstly, the expression pattern of PKZ is similar to those of innate immune mediators under stimulation with poly (dA:dT) and poly (dG:dC). As a DNA sensor, PKZ can interact with DNA but not with ISD-PS (dsRNA analog), and expectedly, the DNA-PKZ interaction promotes the phosphorylation and dimerization of PKZ in vitro. These indicate that PKZ participates in cytoplasmic DNA-mediated signaling pathway. Besides, subcellular localization assays showed that PKZ is located in the cytoplasm, which suggests that PKZ acts as a cytoplasmic PRR. In addition, co-IP assays showed that PKZ can separately interact with IRF3, STING, ZDHHC1, eIF2α, IRF9 and STAT2. Further investigation revealed that PKZ can activate IRF3 and STAT2. Moreover, IRF3-dependent and ISGF3-like-dependent mediators are critical for PKZ initiated IFN expression. In a word, these results demonstrated that PKZ acts as a special DNA pattern-recognition receptor, and PKZ can initiate innate immune responses through IRF3-mediated or ISGF3-like mediated pathways in fish.

Keywords: PKZ, PRR, IRF3-mediated and ISGF3-like mediated pathways, innate immunity, teleost

Received: 06 Sep 2018; Accepted: 04 Mar 2019.

Edited by:

Stephanie DeWitte-Orr, Wilfrid Laurier University, Canada

Reviewed by:

Eduardo Gomez-Casado, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Spain
Maria Del Mar Ortega-Villaizan, Universidad Miguel Hernández de Elche, Spain  

Copyright: © 2019 Hu, Xu, Li, Wu, Jiang, Liu, Cheng and Mao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Chengyu Hu, Nanchang University, Nanchang, China, hucy2008@163.com