Related Experiment Videos
(DEAD)-box RNA helicase 3 modulates NF-κB signal pathway by controlling the phosphorylation of PP2A-C subunit
Xin Wang1, Rui Wang1, Miao Luo1
1College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, 210095, China.
Abstract:
Asp-Glu-Ala-Asp (DEAD)-box RNA helicase 3 (DDX3), an ATP-dependent RNA helicase, is associated with RNA splicing, mRNA export, transcription, translation, and RNA decay. Recent studies revealed that DDX3 participates in innate immune response during virus infection by interacting with TBK1 and regulating the production of IFN-β. In our studies, we demonstrated that DDX3 regulated NF-κB signal pathway. We found that DDX3 knockdown reduced the phosphorylation of p65 and IKK-β and ultimately attenuated the production of inflammatory cytokines induced by poly(I:C) or TNF-α stimulation. The regulatory effect of DDX3 on NF-κB signal pathway was not affected by the loss of its ATPase or helicase activity. We further identified PP2A C subunit (PP2A-C) as an interaction partner of DDX3 by co-immunoprecipitation and mass spectrum analysis. We confirmed that DDX3 formed the complex with PP2A-C/IKK-β and regulated the interaction between IKK-β and PP2A-C. Furthermore, we demonstrated that DDX3 modulated the activity of PP2A by controlling the phosphorylation of PP2A-C, which might enable PP2A-C to regulate NF-κB signal pathway by dephosphorylating IKK-β. All these findings suggested DDX3 plays multiple roles in modulating innate immune system.
Insights
DEAD-box RNA helicase 3 (DDX3) regulates the NF-κB innate immune pathway by interacting with PP2A-C and IKK-β. This interaction modulates inflammatory cytokine production, independent of DDX3
Area of Science:
- Immunology
- Molecular Biology
- Cellular Biology
Background:
- DEAD-box RNA helicase 3 (DDX3) is an ATP-dependent RNA helicase involved in various cellular processes including RNA metabolism.
- Emerging evidence suggests DDX3 plays a role in innate immunity, notably in antiviral responses through interactions with kinases like TBK1.
- The precise mechanisms by which DDX3 influences inflammatory signaling pathways remain incompletely understood.
Purpose of the Study:
- To elucidate the role of DDX3 in regulating the NF-κB signaling pathway.
- To identify novel interaction partners of DDX3 involved in innate immune responses.
- To investigate the functional impact of DDX3 on inflammatory cytokine production.
Main Methods:
- DDX3 knockdown was performed to assess its effect on NF-κB pathway components.
- Co-immunoprecipitation and mass spectrometry were used to identify DDX3 interaction partners.
- Western blotting was employed to analyze protein phosphorylation levels (p65, IKK-β, PP2A-C).
- Stimulation with poly(I:C) and TNF-α was used to induce inflammatory responses.
Main Results:
- DDX3 knockdown significantly reduced the phosphorylation of p65 and IKK-β, attenuating inflammatory cytokine production.
- The regulatory function of DDX3 on NF-κB was independent of its ATPase and helicase activities.
- Protein phosphatase 2A catalytic subunit (PP2A-C) was identified as a novel interaction partner of DDX3.
- DDX3 forms a complex with PP2A-C and IKK-β, modulating their interaction and PP2A-C phosphorylation.
- DDX3 controls PP2A-C activity, which in turn dephosphorylates IKK-β, thereby regulating the NF-κB pathway.
Conclusions:
- DDX3 plays a critical role in modulating the NF-κB innate immune signaling pathway.
- DDX3 interacts with PP2A-C and influences its activity to regulate IKK-β phosphorylation and downstream inflammatory responses.
- These findings reveal a novel mechanism by which DDX3 contributes to innate immunity beyond its canonical RNA helicase functions.