A Role for the HSV Tegument Protein pUL16 in Modulating Cellular Energy Metabolism during HSV-2 Infection

The conserved, multifunctional tegument protein, pUL16, is implicated in several processes during Herpes simplex virus (HSV) infection, including virion morphogenesis and cell-to-cell spread of infection. Recent literature has also demonstrated that HSV-1 pUL16 localizes to distinct regions of mitochondria. Consistent with these findings, our proximity-dependent biotinylation experiments identified both mitochondrial-associated membrane and mitochondrial matrix components in proximity to HSV-2 pUL16 during virus infection. While the interaction between pUL16 and host cell mitochondria has been well-established, the implications have yet to be determined. We hypothesized that the interaction between pUL16 and mitochondrial components regulates mitochondrial physiology to promote viral replication. We characterized the influence of pUL16 on host cell energy metabolism by quantifying parameters of mitochondrial morphology, oxidative phosphorylation, glycolysis and ATP metabolism, in mock, HSV-2 WT and HSV-2 pUL16 null mutant (Δ16), infected human keratinocytes (HaCaT). Mitochondria in WT infected cells exhibited elongated morphology contributing to a more tubular mitochondrial network associated with promotion of mitochondrial function, while mitochondria in Δ16 infected cells exhibited punctate and bifurcated morphology resulting in a more fragmented mitochondrial network predicted to negatively impact mitochondrial function. Mitochondrial stress tests showed that WT infected cells exhibited a greater capacity to respond to increasing metabolic energy demands under stress via oxidative phosphorylation relative to mock and Δ16 infected cells. By contrast, we found an overall increase in glycolytic rate in Δ16 infected cells relative to WT infected cells. No significant differences in ATP metabolism between WT and Δ16 infected cells were observed, suggesting that enhanced glycolysis in Δ16 infected cells compensated for the reductions in oxidative phosphorylation observed. Importantly, uninfected HaCaT cells stably expressing pUL16 exhibited enhanced oxidative phosphorylation in comparison to parental HaCaT cells suggesting that pUL16 expression is sufficient to support mitochondrial function. Currently, there is no vaccine available to prevent HSV infection, and while good therapeutics exist, viral resistance has become problematic. Therefore, a thorough understanding of viral replication is required for the development of new targets for antiviral interventions.

Department dc:contributor.department

Biomedical and Molecular Sciences

Year dc:date.issued

2025

Author dc:creator

• Denniston, Nick

Advisor dc:contributor.supervisor

• Banfield, Bruce

• Herpes virus
• HSV-2
• pUL16
• Virology
• Metabolism
• HSV
• Tegument
• Mitochondria
• Oxidative phosphorylation
• Glycolysis

Statement dc:rights

• Attribution-NonCommercial-NoDerivatives 4.0 International

Licence dc:rights.uri

• http://creativecommons.org/licenses/by-nc-nd/4.0/

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1974/34828

OAI identifier oai:identifier

oai:queensu.scholaris.ca:1974/34828