Innexin hemichannel activation by Microplitis bicoloratus ecSOD monopolymer reduces ROS.

The extracellular superoxide dismutases (ecSODs) secreted by Microplitis bicoloratus reduce the reactive oxygen species (ROS) stimulated by the Microplitis bicoloratus bracovirus. Here, we demonstrate that the bacterial transferase hexapeptide (hexapep) motif and bacterial-immunoglobulin-like (BIg-like) domain of ecSODs bind to the cell membrane and transiently open hemichannels, facilitating ROS reductions. RNAi-mediated ecSOD silencing in vivo elevated ROS in host hemocytes, impairing parasitoid larva development. In vitro, the ecSOD-monopolymer needed to be membrane bound to open hemichannels. Furthermore, the hexapep motif in the beta-sandwich of ecSOD49 and ecSOD58, and BIg-like domain in the signal peptides of ecSOD67 were required for cell membrane binding. Hexapep motif and BIg-like domain deletions induced ecSODs loss of adhesion and ROS reduction failure. The hexapep motif and BIg-like domain mediated ecSOD binding via upregulating innexins and stabilizing the opened hemichannels. Our findings reveal a mechanism through which ecSOD reduces ROS, which may aid in developing anti-redox therapy. © 2024 The Authors.

Citation

Jiang-Hui Meng, Yong-Biao Huang, Jin Long, Qiu-Chen Cai, Xin Qiao, Qiong-Li Zhang, Li-Dan Zhang, Xiang Yan, Rui Jing, Xing-Shan Liu, Sai-Jun Zhou, Yong-Sheng Yuan, Yin-Chen Ma, Li-Xiang Zhou, Nan-Nan Peng, Xing-Cheng Li, Cheng-Hui Cai, Hong-Mei Tang, André F Martins, Jean X Jiang, Kai-Jun Luo. Innexin hemichannel activation by Microplitis bicoloratus ecSOD monopolymer reduces ROS. iScience. 2024 Apr 19;27(4):109469

PMID: 38577101

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