Fig. 4 |. Structure of STING tetramer.

a, Tetramer structure of cGAMP-bound chicken STING in the side and top views. The right panel shows an expanded view of the LBDα2–LBDα3 loop at the tetramer interface. b, Clashes at the LBDα2–LBDα3 loop in the tetramer model of inactive chicken STING, as constructed in Extended Data Fig. 6b. c, Tetramer of the human STING LBD bound to cGAMP. Two symmetry-related human STING LBD dimers in the structure (PDB code 4KSY) form the tetramer, which is similar to the chicken STING tetramer. d, Effects of mutations in the STING tetramer interface on cGAMP-induced formation of STING cellular puncta. Representative confocal images with or without cGAMP stimulation are shown. Scale bar, 10 μm. The experiments and analyses were conducted as in Fig. 2e. Data are mean ± s.d. and representative of three biological replicates. e, Cartoon model of cGAMP-induced conformational changes and oligomerization of STING.