TY - JOUR
T1 - Cryo-EM structures of STING reveal its mechanism of activation by cyclic GMP–AMP
AU - Shang, Guijun
AU - Zhang, Conggang
AU - Chen, Zhijian J.
AU - Bai, Xiao chen
AU - Zhang, Xuewu
N1 - Publisher Copyright:
© 2019, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2019/3/21
Y1 - 2019/3/21
N2 - Infections by pathogens that contain DNA trigger the production of type-I interferons and inflammatory cytokines through cyclic GMP–AMP synthase, which produces 2′3′-cyclic GMP–AMP (cGAMP) that binds to and activates stimulator of interferon genes (STING; also known as TMEM173, MITA, ERIS and MPYS)1–8. STING is an endoplasmic-reticulum membrane protein that contains four transmembrane helices followed by a cytoplasmic ligand-binding and signalling domain9–13. The cytoplasmic domain of STING forms a dimer, which undergoes a conformational change upon binding to cGAMP9,14. However, it remains unclear how this conformational change leads to STING activation. Here we present cryo-electron microscopy structures of full-length STING from human and chicken in the inactive dimeric state (about 80 kDa in size), as well as cGAMP-bound chicken STING in both the dimeric and tetrameric states. The structures show that the transmembrane and cytoplasmic regions interact to form an integrated, domain-swapped dimeric assembly. Closure of the ligand-binding domain, induced by cGAMP, leads to a 180° rotation of the ligand-binding domain relative to the transmembrane domain. This rotation is coupled to a conformational change in a loop on the side of the ligand-binding-domain dimer, which leads to the formation of the STING tetramer and higher-order oligomers through side-by-side packing. This model of STING oligomerization and activation is supported by our structure-based mutational analyses.
AB - Infections by pathogens that contain DNA trigger the production of type-I interferons and inflammatory cytokines through cyclic GMP–AMP synthase, which produces 2′3′-cyclic GMP–AMP (cGAMP) that binds to and activates stimulator of interferon genes (STING; also known as TMEM173, MITA, ERIS and MPYS)1–8. STING is an endoplasmic-reticulum membrane protein that contains four transmembrane helices followed by a cytoplasmic ligand-binding and signalling domain9–13. The cytoplasmic domain of STING forms a dimer, which undergoes a conformational change upon binding to cGAMP9,14. However, it remains unclear how this conformational change leads to STING activation. Here we present cryo-electron microscopy structures of full-length STING from human and chicken in the inactive dimeric state (about 80 kDa in size), as well as cGAMP-bound chicken STING in both the dimeric and tetrameric states. The structures show that the transmembrane and cytoplasmic regions interact to form an integrated, domain-swapped dimeric assembly. Closure of the ligand-binding domain, induced by cGAMP, leads to a 180° rotation of the ligand-binding domain relative to the transmembrane domain. This rotation is coupled to a conformational change in a loop on the side of the ligand-binding-domain dimer, which leads to the formation of the STING tetramer and higher-order oligomers through side-by-side packing. This model of STING oligomerization and activation is supported by our structure-based mutational analyses.
UR - http://www.scopus.com/inward/record.url?scp=85063003311&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85063003311&partnerID=8YFLogxK
U2 - 10.1038/s41586-019-0998-5
DO - 10.1038/s41586-019-0998-5
M3 - Article
C2 - 30842659
AN - SCOPUS:85063003311
SN - 0028-0836
VL - 567
SP - 389
EP - 393
JO - Nature
JF - Nature
IS - 7748
ER -