Inhibition of protein kinase C promotes dengue virus replication

Warobon Noppakunmongkolchai (1) , Teera Poyomtip (1) , Thichakorn Jittawuttipoka (1) , Natthanej Luplertlop (1) , Anavaj Sakuntabhai (2, 1) , Sarin Chimnaronk (1) , Siwanon Jirawatnotai (1, 3) , Rutaiwan Tohtong (1)

1 Mahidol University [Bangkok]
2 Génétique fonctionnelle des Maladies infectieuses - Functional Genetics of Infectious Diseases
3 Siriraj Hospital, Mahidol University

BACKGROUND: Dengue virus (DENV) is a member of the Flaviviridae family, transmitted to human via mosquito. DENV infection is common in tropical areas and occasionally causes life-threatening symptoms. DENV contains a relatively short positive-stranded RNA genome, which encodes ten viral proteins. Thus, the viral life cycle is necessarily rely on or regulated by host factors. METHODS: In silico analyses in conjunction with in vitro kinase assay were used to study kinases that potentially phosphorylate DENV NS5. Potential kinase was inhibited or activated by a specific inhibitor (or siRNA), or an activator. Results of the inhibition and activation on viral entry/replication and host cell survival were examined. RESULTS: Our in silico analyses indicated that the non-structural protein 5 (NS5), especially the RNA-dependent RNA polymerase (RdRp) domain, contains conserved phosphorylation sites for protein kinase C (PKC). Phosphorylation of NS5 RdRp was further verified by PKC in vitro kinase assay. Inhibitions of PKC by a PKC-specific chemical inhibitor or siRNA suppressed NS5 phosphorylation in vivo, increased viral replication and reduced viability of the DENV-infected cells. In contrary, activation of PKC effectively suppressed intracellular viral number. CONCLUSIONS: These results indicated that PKC may act as a restricting mechanism that modulates the DENV replication and represses the viral outburst in the host cells.

Keywords: Dengue virus (DENV); Protein kinase C (PKC); Phosphorylation; Non-structural protein 5 (NS5); viral replication; Flavivirus

Domains: Virology; Biochemistry, Molecular Biology

Warobon Noppakunmongkolchai, Teera Poyomtip, Thichakorn Jittawuttipoka, Natthanej Luplertlop, Anavaj Sakuntabhai, et al.. Inhibition of protein kinase C promotes dengue virus replication. Virology Journal, 2016, 13, pp.35. ⟨10.1186/s12985-016-0494-6⟩. ⟨pasteur-02082898⟩