PARP10 condensation inhibits viral replication via targeting NAD+ homeostasis

Although diphtheria toxin-like ADP-ribosyltransferases (ARTDs) are implicated in host-virus interactions, the specific antiviral mechanisms of certain family members remain largely undefined. Here, we reveal that mono-ADP-ribosyltransferase PARP10 restricts viral replication by forming biomolecular condensates via multivalent interactions among its structured domains. PARP10 condensates enhance enzymatic activity, resulting in increased NAD⁺ consumption that ultimately inhibits viral replication. The antiviral effects of PARP10 are shown to require both its catalytic activity and NAD⁺ regulation, as catalytic mutants and PARP10 inhibitors abrogate these effects, while reduction of NAD⁺ potently restricts viral replication. Furthermore, we identify auto-ADP-ribosylation as an intrinsic negative feedback mechanism modulating PARP10 condensation. These findings establish PARP10 condensation as a compartmentalization strategy that amplifies local NAD⁺ consumption to safeguard host antiviral immunity. While specific antiviral mechanisms of certain ADP-ribosyltransferases remain unclear, this study uses vesicular stomatitis virus to reveal that PARP10 forms condensates to amplify enzyme activity. This in turn decreases local NAD+ levels to block viral replication.