Poxvirus A51R Proteins Directly Bind to Microtubules to Antagonize Microtubule Dynamics, Intracellular Transport, and a Cell-intrinsic Antiviral Response

Viruses often manipulate the microtubule (MT) network to facilitate their replication inside host cells. Poxvirus A51R proteins have been shown to colocalize with, and bundle, MTs, but the mechanisms of their MT interactions remained unclear. Additionally, vaccinia virus (VV), a model poxvirus, utilizes kinesin motor proteins on MTs to transport newly formed virions, yet how VV regulates this virion transport was previously unknown. Here, I demonstrate that poxvirus A51R proteins directly bind to MTs, establishing them as bona fide MT-associated proteins (MAPs). Notably, VV A51R not only binds to MTs but also actively promotes MT polymerization, prevents MT depolymerization, and regulates MT-dependent transport--functions akin to cellular MAPs. To assess the impact of A51R-MT interaction on poxvirus replication and pathogenesis, I generated a VV strain encoding a MT binding-deficient A51R mutant, called a "Triple" mutant. This mutant virus was significantly attenuated in mice compared to the wild-type (WT) virus, suggesting A51R-MT interactions are critical for poxvirus replication and pathogenesis in vivo. Further investigation of VV replication revealed that the Triple mutant virus replicated just as well as the WT in epithelial cells but failed to replicate in macrophages. Triple mutant virus infection led to an increase in reactive oxygen species (ROS) in macrophages, and inhibition of ROS partially rescued mutant virus replication, highlighting the role of A51R-MT interactions in the suppression of ROS-dependent responses in this cell type. While exploring the impact of A51R-MT interactions on MT functions, I discovered that WT A51R, but not the Triple mutant A51R, negatively regulates kinesin-1 function. Therefore, to my knowledge, this study presents the first instance of an animal virus-encoded MAP negatively regulating kinesin motility, providing novel insights into viral host manipulation strategies. In summary, my research demonstrates that poxvirus A51R proteins directly bind to MTs to antagonize MT dynamics, intracellular transport, and a cell-intrinsic ROS-dependent antiviral response.

Author dc:creator

• Seo, Da Hee

Contributors dc:contributor

• Pfeiffer, Julie K.
• Gammon, Don B.
• Alto, Neal
• Rice, Luke M.

• Host Microbial Interactions
• Macrophages
• Microtubule-Associated Proteins
• Microtubules
• Poxviridae
• Virus Replication

Language dc:language

en

Identifier

1596185291

OAI identifier oai:identifier

oai:utswmed-ir.tdl.org:2152.5/10809