Fig. 4: GSNO induces S-nitrosylation of STING to inhibit cGAMP binding.

a, b Immunoblot assays of STING S-nitrosylation in PMs infected with HSV-1 or L. monocytogenes using the irreversible biotinylation procedure (IBP). c Immunoblot assays of STING S-nitrosylation in HEK293T cells transfected with STING-FLAG and treated with solvent (Ctrl) or GSNO. d Immunoblot assays of in vitro S-nitrosylation of recombinant human STING protein treated with GSNO. e Liquid chromatography-mass spectrometry (LC-MS) spectra of STING S-nitrosylation at residue C257. f Immunoblot assays of S-nitrosylation in HEK293T cells transfected with empty vector, wild-type (WT) STING, or STING mutants (C257S or C309S) using the IBP. g Co-immunoprecipitation analysis of cGAMP-biotin binding to STING in HEK293T cells transfected with empty vector, WT, or C257S STING mutant. h, i The binding pattern of cGAMP with WT STING or S-nitrosylation of STING at C257 (STING-C257-NO) after an 80–100 ns simulation. The dashed green lines represent hydrogen bonds, and the red gear represents hydrophobicity. j Immunoblot assays of S-nitrosylation in HEK293T cells transfected with empty vector, wild-type (WT) STING, or STING mutants (R238A/Y240A) using the IBP. Data are shown as one representative image from three independent experiments.