The Vaccinia Virus (VACV) B1 and Cellular VRK2 Kinases Promote VACV Replication Factory Formation through Phosphorylation-Dependent Inhibition of VACV B12

Authors

Amber B. Rico, University of Nebraska-Lincoln
Zhigang Wang, University of Nebraska-Lincoln
Annabel T. Olson, University of Nebraska-Lincoln
Alexandria C. Linville, University of Nebraska-Lincoln
Brianna L. Bullard, University of Nebraska-LincolnFollow
Eric A. Weaver, University of Nebraska-LincolnFollow
Clinton Jones, Oklahoma State University - Main Campus
Matthew S. Wiebea, University of Nebraska-Lincoln

ORCID IDs

https://orcid.org/0000-0001-6337-6556

Document Type

Article

Date of this Version

10-2019

Citation

Rico AB, Wang Z, Olson AT, Linville AC, Bullard BL, Weaver EA, Jones C, Wiebe MS. 2019. The vaccinia virus (VACV) B1 and cellular VRK2 kinases promote VACV replication factory formation through phosphorylationdependent inhibition of VACV B12. J Virol 93:e00855-19. https://doi.org/10.1128/JVI .00855-19.

Comments

October 2019 Volume 93 Issue 20 e00855-19 Journal of Virology jvi.asm.org 1

Abstract

Comparative examination of viral and host protein homologs reveals novel mechanisms governing downstream signaling effectors of both cellular and viral origin. The vaccinia virus B1 protein kinase is involved in promoting multiple facets of the virus life cycle and is a homolog of three conserved cellular enzymes called vaccinia virus-related kinases (VRKs). Recent evidence indicates that B1 and VRK2 mediate a common pathway that is largely uncharacterized but appears independent of previous VRK substrates. Interestingly, separate studies described a novel role for B1 in inhibiting vaccinia virus protein B12, which otherwise impedes an early event in the viral lifecycle. Herein, we characterize the B1/VRK2 signaling axis to better understand their shared functions. First, we demonstrate that vaccinia virus uniquely requires VRK2 for viral replication in the absence of B1, unlike other DNA viruses. Employing loss-of-function analysis, we demonstrate that vaccinia virus’s dependence on VRK2 is only observed in the presence of B12, suggesting that B1 and VRK2 share a pathway controlling B12. Moreover, we substantiate a B1/VRK2/B12 signaling axis by examining coprecipitation of B12 by B1 and VRK2. Employing execution point analysis, we reveal that virus replication proceeds normally through early protein translation and uncoating but stalls at replication factory formation in the presence of B12 activity. Finally, structure/function analyses of B1 and VRK2 demonstrate that enzymatic activity is essential for B1 or VRK2 to inhibit B12. Together, these data provide novel insights into B1/VRK signaling coregulation and support a model in which these enzymes modulate B12 in a phosphorylation-dependent manner.