Publication Date:
2013-06-01
Description:
Detection of cytoplasmic DNA represents one of the most fundamental mechanisms of the innate immune system to sense the presence of microbial pathogens. Moreover, erroneous detection of endogenous DNA by the same sensing mechanisms has an important pathophysiological role in certain sterile inflammatory conditions. The endoplasmic-reticulum-resident protein STING is critically required for the initiation of type I interferon signalling upon detection of cytosolic DNA of both exogenous and endogenous origin. Next to its pivotal role in DNA sensing, STING also serves as a direct receptor for the detection of cyclic dinucleotides, which function as second messenger molecules in bacteria. DNA recognition, however, is triggered in an indirect fashion that depends on a recently characterized cytoplasmic nucleotidyl transferase, termed cGAMP synthase (cGAS), which upon interaction with DNA synthesizes a dinucleotide molecule that in turn binds to and activates STING. We here show in vivo and in vitro that the cGAS-catalysed reaction product is distinct from previously characterized cyclic dinucleotides. Using a combinatorial approach based on mass spectrometry, enzymatic digestion, NMR analysis and chemical synthesis we demonstrate that cGAS produces a cyclic GMP-AMP dinucleotide, which comprises a 2'-5' and a 3'-5' phosphodiester linkage 〉Gp(2'-5')Ap(3'-5')〉. We found that the presence of this 2'-5' linkage was required to exert potent activation of human STING. Moreover, we show that cGAS first catalyses the synthesis of a linear 2'-5'-linked dinucleotide, which is then subject to cGAS-dependent cyclization in a second step through a 3'-5' phosphodiester linkage. This 13-membered ring structure defines a novel class of second messenger molecules, extending the family of 2'-5'-linked antiviral biomolecules.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4143541/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4143541/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ablasser, Andrea -- Goldeck, Marion -- Cavlar, Taner -- Deimling, Tobias -- Witte, Gregor -- Rohl, Ingo -- Hopfner, Karl-Peter -- Ludwig, Janos -- Hornung, Veit -- 243046/European Research Council/International -- U19AI083025/AI/NIAID NIH HHS/ -- England -- Nature. 2013 Jun 20;498(7454):380-4. doi: 10.1038/nature12306. Epub 2013 May 30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute for Clinical Chemistry and Clinical Pharmacology, University Hospital, University of Bonn, 53127 Bonn, Germany. andrea.ablasser@uni-bonn.de〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23722158" target="_blank"〉PubMed〈/a〉
Keywords:
Adenosine Monophosphate/chemistry
;
Animals
;
Biocatalysis
;
Cell Line
;
Cyclic GMP/chemistry
;
Cyclization
;
HEK293 Cells
;
Humans
;
Magnetic Resonance Spectroscopy
;
Membrane Proteins/*metabolism
;
Mice
;
Models, Molecular
;
Molecular Structure
;
Nucleotidyltransferases/genetics/*metabolism
;
Oligoribonucleotides/biosynthesis/chemistry/*metabolism
;
Second Messenger Systems/*physiology
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
