Palmitoylation restricts SQSTM1/p62-mediated autophagic degradation of NOD2 to modulate inflammation.

Abstract

The nucleotide-binding oligomerization domain protein 2 (NOD2) senses bacterial peptidoglycan to induce proinflammatory and antimicrobial responses. Dysregulation of NOD2 signaling is involved in multiple inflammatory disorders. Recently, S-palmitoylation, a novel type of post-translational modification, is reported to play a crucial role in membrane association and ligand-induced signaling of NOD2, yet its influence on the stability of NOD2 is unclear. Here we show that inhibition of S-palmitoylation facilitates the SQSTM1/p62-mediated autophagic degradation of NOD2, while S-palmitoylation of NOD2 by ZDHHC5 promotes the stability of NOD2. Furthermore, we identify a gain-of-function R444C variant of NOD2 short isoform (NOD2s-R444C) in autoinflammatory disease, which induces excessive inflammation through its high S-palmitoylation level. Mechanistically, the NOD2s-R444C variant possesses a stronger binding ability to ZDHHC5, which promotes its S-palmitoylation, and restricts its autophagic degradation by reducing its interaction with SQSTM1/p62. Taken together, our study reveals the regulatory role of S-palmitoylation in controlling NOD2 stability through the crosstalk with autophagy, and provides insights into the association between dysfunctional S-palmitoylation and the occurrence of inflammatory diseases.