Cyclic [G(2′,5′)pA(3′,5′)p] Is the Metazoan Second Messenger Produced by DNA-Activated Cyclic GMP-AMP Synthase
By P. Gao, M. Ascano, Yang Wu, W. Barchet, B. Gaffney, T. Zillinger, A. Serganov, Yizhou Liu, Roger A. Jones, G. Hartmann and 2 more. Cell, 2013
1,011 citations recorded by the source corpus.
SUMMARY Recent studies identified cyclic GMP-AMP (cGAMP) as a metazoan second messenger triggering an interferon response. cGAMP is generated from GTP and ATP by cytoplasmic dsDNA sensor cGAMP synthase (cGAS). We combined structural, chemical, biochemical, and cellular assays to demonstrate that this second messenger contains G(2′,5′)pA and A(3′,5′)pG phosphodiester linkages, designated c[G(2′,5′) pA(3′,5′)p]. We show that, upon dsDNA binding, cGAS is activated through conformational transitions, resulting in formation of a catalytically competent and accessible nucleotide-binding pocket for generation of c[G(2′,5′)pA(3′,5′)p]. We demonstrate that cyclization occurs in a stepwise manner through initial generation of 5′-pppG(2′,5′)pA prior to cyclization to c[G(2′,5′)pA(3′,5′)p], with the latter positioned precisely in the catalytic pocket. Mutants of cGAS dsDNA-binding or catalytic pocket residues exhibit reduced or abrogated activity. Our studies have identified c[G(2′,5′)pA(3′,5′)p] as a founding member of a family of metazoan 2′,5′-containing cyclic heterodinucleotide second messengers distinct from bacterial 3′,5′ cyclic dinucleotides.
Subfields: Immunology, Molecular Biology
View Paper: https://www.semanticscholar.org/paper/1c92e7e18d88cda615b24236ac4659cdfbdb0480
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In Immunology
In Molecular Biology
Citations in the corpus
- Innate immune sensing of cytosolic chromatin fragments through cGAS promotes senescence (2017, neutral): “Upon activation, cGAS synthesizes the second messenger molecule 2`3`cyclic GMP-AMP (cGAMP), which engages STING, thereby leading to the production of inflammatory cytokines, chemokines and type I interferons (IFNs) 19 20 21 22, 23 24 25.”
- The innate immune DNA sensor cGAS produces a non-canonical cyclic-di-nucleotide that activates human STING (2013, background): “A recently published crystallographic and enzymatic study of cGAS independently identified this non- canonical CDN as the product of cGAS (Gao et al., 2013) but did not address its unique signaling properties.”