The study shows that a cellular process called palmitoylation boosts immune signaling against malaria in mice. It identifies specific proteins that add or remove a fatty tag on TBK1, affecting how well the immune system works, and suggests that blocking the removal step can improve survival in infected mice.

Precise regulation of type I interferon signaling is crucial for effective immune defense against infectious diseases. However, the molecular mechanisms governing this pathway are not fully understood. Here, we show a function for palmitoylation in enhancing anti-malarial immune responses. Our findings reveal that ZDHHC9 enhances the type I interferon signaling by palmitoylating TBK1 at cysteine 292. Following infection with Plasmodium yoelii N67, the delicate balance between palmitoylation and depalmitoylation of TBK1 is disrupted. Specifically, upregulation of APT2 promotes persistent depalmitoylation of TBK1 and triggers its selective autophagic degradation via K48-linked polyubiquitination at lysine 251/372 by E3 ligase TRIM27. This process acts as a recognition signal for the cargo receptor NDP52, resulting in inhibition of the type I interferon pathway. Notably, inhibition of APT2 using ML349 elevates type I interferon levels and improves survival rates against N67 infection. Here, we show that targeting APT2-mediated TBK1 depalmitoylation is a potential therapeutic strategy for malaria and may also be applicable to other diseases driven by dysregulated type I interferon signaling.