HDAC4-mediated deacetylation of GSDMD prevents pyroptosis by inhibiting GSDMD ubiquitination

Gasdermin D (GSDMD) functions as a key pyroptotic executor and induces cytokine secretion after cleavage by inflammatory caspases. However, less is known about the role of posttranslational modifications (PTMs) in GSDMD-mediated pyroptosis. Here, we report that GSDMD can be acetylated at Lysine 248 residue and the acetylation of GSDMD promotes pyroptosis. We identified histone deacetylase 4 (HDAC4) as the specific deacetylase that mediates GSDMD deacetylation and subsequent pyroptosis inhibition in vitro and in vivo. GSDMD deacetylation impairs the ubiquitination of GSDMD, for which pyroptosis is inhibited. Interestingly, the phosphorylation of HDAC4 is important for its ability of deacetylating GSDMD and suppressing GSDMD-mediated pyroptosis. The Protein phosphatase 1 (PP1) catalytic subunits (PP1 and PP1{gamma}) mediate the dephosphorylation of HDAC4, thereby abrogating its deacetylase activity on GSDMD. Therefore, our work unravels a complex regulatory mechanism involving HDAC4, PP1 and GSDMD, and provides novel insights into the crosstalk among acetylation, ubiquitination and phosphorylation.