Structure-Function Analysis of STING Activation by c[G(2',5')pA(3',5')p] and Targeting by Antiviral DMXAA.Gao, P., Ascano, M., Zillinger, T., Wang, W., Dai, P., Serganov, A.A., Gaffney, B.L., Shuman, S., Jones, R.A., Deng, L., Hartmann, G., Barchet, W., Tuschl, T., Patel, D.J.
(2013) Cell 154: 748-762
- PubMed: 23910378
- DOI: https://doi.org/10.1016/j.cell.2013.07.023
- Primary Citation of Related Structures:
4LOH, 4LOI, 4LOJ, 4LOK, 4LOL
- PubMed Abstract:
Binding of dsDNA by cyclic GMP-AMP (cGAMP) synthase (cGAS) triggers formation of the metazoan second messenger c[G(2',5')pA(3',5')p], which binds the signaling protein STING with subsequent activation of the interferon (IFN) pathway. We show that human hSTING(H232) adopts a "closed" conformation upon binding c[G(2',5')pA(3',5')p] and its linkage isomer c[G(2',5')pA(2',5')p], as does mouse mSting(R231) on binding c[G(2',5')pA(3',5')p], c[G(3',5')pA(3',5')p] and the antiviral agent DMXAA, leading to similar "closed" conformations. Comparing hSTING to mSting, 2',5'-linkage-containing cGAMP isomers were more specific triggers of the IFN pathway compared to the all-3',5'-linkage isomer. Guided by structural information, we identified a unique point mutation (S162A) placed within the cyclic-dinucleotide-binding site of hSTING that rendered it sensitive to the otherwise mouse-specific drug DMXAA, a conclusion validated by binding studies. Our structural and functional analysis highlights the unexpected versatility of STING in the recognition of natural and synthetic ligands within a small-molecule pocket created by the dimerization of STING.
Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.