Brucella melitensis UGPase inhibits the activation of NF-κB by modulating the ubiquitination of NEMO

BMC Veterinary Research

Linzhu Ren¹  Jing Qian²  Zhaoyang Bu³  Xinglong Wang³  Sen Yang⁴  Yanling Yang⁴  Yuening Cheng⁴  Yucheng Zhou⁴  Lianjiang Qiao⁴  Shipeng Cheng⁴ 

[1]College of Animal Sciences, Jilin University, 130062, Changchun, China

[2]Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, 210014, Nanjing, China

[3]Military Veterinary Institute, Academy of Military Medical Sciences, 130112, Changchun, China

[4]State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, 130112, Changchun, China

关键词: Brucella melitensis;    UTP-glucose-1-phosphate uridylyltransferase (UGPase);    Nuclear factor-kappa enhancer-binding protein (NF-κB);    Ubiquitination;   

DOI  :  10.1186/s12917-021-02993-9

来源: Springer

【 摘 要 】

BackgroundUTP-glucose-1-phosphoryl transferase (UGPase) catalyzes the synthesis of UDP-glucose, which is essential for generating the glycogen needed for the synthesis of bacterial lipopolysaccharide (LPS) and capsular polysaccharide, which play important roles in bacterial virulence. However, the molecular function of UGPase in Brucella is still unknown.ResultsIn this study, the ubiquitination modification of host immune-related protein in cells infected with UGPase-deleted or wild-type Brucella was analyzed using ubiquitination proteomics technology. The ubiquitination modification level and type of NF-κB Essential Modulator (NEMO or Ikbkg), a molecule necessary for NF-κB signal activation, was evaluated using Coimmunoprecipitation, Western blot, and dual-Luciferase Assay. We found 80 ubiquitin proteins were upregulated and 203 ubiquitin proteins were downregulated in cells infected with B. melitensis 16 M compared with those of B. melitensis UGPase-deleted strain (16 M-UGPase−). Moreover, the ubiquitin-modified proteins were mostly enriched in the categories of regulation of kinase/NF-κB signaling and response to a bacterium, suggesting Brucella UGPase inhibits ubiquitin modification of related proteins in the host NF-κB signaling pathway. Further analysis showed that the ubiquitination levels of NEMO K63 (K63-Ub) and Met1 (Met1-Ub) were significantly increased in the 16 M-UGPase−-infected cells compared with that of the 16 M-infected cells, further confirming that the ubiquitination levels of NF-κB signaling-related proteins were regulated by the bacterial UGPase. Besides, the expression level of IκBα was decreased, but the level of p-P65 was significantly increased in the 16 M-UGPase−-infected cells compared with that of the 16 M- and mock-infected cells, demonstrating that B. melitensis UGPase can significantly inhibit the degradation of IκBα and the phosphorylation of p65, and thus suppressing the NF-κB pathway.ConclusionsThe results of this study showed that Brucella melitensis UGPase inhibits the activation of NF-κB by modulating the ubiquitination of NEMO, which will provide a new scientific basis for the study of immune mechanisms induced by Brucella.

【 授权许可】

CC BY