TitleHerpes simplex virus 1 infection activates poly(ADP-ribose) polymerase and triggers the degradation of poly(ADP-ribose) glycohydrolase.
Publication TypeJournal Article
Year of Publication2012
AuthorsGrady, SL, Hwang, J, Vastag, L, Rabinowitz, JD, Shenk, T
JournalJ Virol
Volume86
Issue15
Pagination8259-68
Date Published2012 Aug
KeywordsCells, Cultured, DNA Replication, DNA, Viral, Glycoside Hydrolases, Herpes Simplex, Herpesvirus 1, Human, Humans, Immediate-Early Proteins, NAD, Poly(ADP-ribose) Polymerases, Proteolysis, Ubiquitin-Protein Ligases
Abstract

Herpes simplex virus 1 infection triggers multiple changes in the metabolism of host cells, including a dramatic decrease in the levels of NAD(+). In addition to its role as a cofactor in reduction-oxidation reactions, NAD(+) is required for certain posttranslational modifications. Members of the poly(ADP-ribose) polymerase (PARP) family of enzymes are major consumers of NAD(+), which they utilize to form poly(ADP-ribose) (PAR) chains on protein substrates in response to DNA damage. PAR chains can subsequently be removed by the enzyme poly(ADP-ribose) glycohydrolase (PARG). We report here that the HSV-1 infection-induced drop in NAD(+) levels required viral DNA replication, was associated with an increase in protein poly(ADP-ribosyl)ation (PARylation), and was blocked by pharmacological inhibition of PARP-1/PARP-2 (PARP-1/2). Neither virus yield nor the cellular metabolic reprogramming observed during HSV-1 infection was altered by the rescue or further depletion of NAD(+) levels. Expression of the viral protein ICP0, which possesses E3 ubiquitin ligase activity, was both necessary and sufficient for the degradation of the 111-kDa PARG isoform. This work demonstrates that HSV-1 infection results in changes to NAD(+) metabolism by PARP-1/2 and PARG, and as PAR chain accumulation can induce caspase-independent apoptosis, we speculate that the decrease in PARG levels enhances the auto-PARylation-mediated inhibition of PARP, thereby avoiding premature death of the infected cell.

Alternate JournalJ. Virol.