Biology:Cyclic GMP-AMP synthase
 cGAS complexed with dsDNA (based on PDB 4O6A) | |||||||||
| Identifiers | |||||||||
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| EC number | 2.7.7.86 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
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Cyclic GMP-AMP synthase (cGAS, cGAMP synthase), belonging to the nucleotidyltransferase family, is a cytosolic DNA sensor that activates a type-I interferon response. It is part of the cGAS-STING DNA sensing pathway. It binds to microbial DNA as well as self DNA that invades the cytoplasm, and catalyzes cGAMP synthesis.[1] cGAMP then functions as a second messenger that binds to and activates the endoplasmic reticulum protein STING to trigger type-I IFNs production.[2][3][4] Mice lacking cGAS are more vulnerable to lethal infection by DNA viruses and RNA viruses.[5][6] In addition, cGAS has been shown to be an innate immune sensor of retroviruses including HIV.[7][8] The human gene encoding cGAS is MB21D1 on chromosome 6.
Human cGAS has been shown to produce less 2'3' cGAMP than mouse cGAS [1][9]. This difference can be explained by the structural differences between mcGAS and hcGAS. Human cGAS is activated in a strongly DNA length-dependent manner [10]. Indeed, human cGAS exhibits a higher affinity for DNA fragments of over 45 bp, whereas mouse cGAS is preferentially activated by shorter DNA sequences. Two amino acids, K187 and L195 in the N-terminus of hcGAS, have been shown to be responsible for human-specific control of 2'3' cGAMP synthesis [9]. The opposing responses of hcGAS and mcGAS to short DNA are completely reversed by the human-specific K187/L195 substitution [9].
References
- ↑ 1.0 1.1 "Cyclic GMP-AMP synthase is a cytosolic DNA sensor that activates the type I interferon pathway". Science 339 (6121): 786–91. February 2013. doi:10.1126/science.1232458. PMID 23258413. Bibcode: 2013Sci...339..786S.
- ↑ "Cyclic GMP-AMP is an endogenous second messenger in innate immune signaling by cytosolic DNA". Science 339 (6121): 826–30. February 2013. doi:10.1126/science.1229963. PMID 23258412. Bibcode: 2013Sci...339..826W.
- ↑ "Cyclic [G(2',5')pA(3',5')p is the metazoan second messenger produced by DNA-activated cyclic GMP-AMP synthase"]. Cell 153 (5): 1094–107. May 2013. doi:10.1016/j.cell.2013.04.046. PMID 23647843.
- ↑ "Cyclic GMP-AMP containing mixed phosphodiester linkages is an endogenous high-affinity ligand for STING". Molecular Cell 51 (2): 226–35. July 2013. doi:10.1016/j.molcel.2013.05.022. PMID 23747010.
- ↑ "Pivotal roles of cGAS-cGAMP signaling in antiviral defense and immune adjuvant effects". Science 341 (6152): 1390–4. September 2013. doi:10.1126/science.1244040. PMID 23989956. Bibcode: 2013Sci...341.1390L.
- ↑ "cGAS-STING effectively restricts murine norovirus infection but antagonizes the antiviral action of N-terminus of RIG-I in mouse macrophages.". Gut Microbes 13 (1). January 2021. doi:10.1080/19490976.2021.1959839. PMID 34347572.
- ↑ "Cyclic GMP-AMP synthase is an innate immune sensor of HIV and other retroviruses". Science 341 (6148): 903–6. August 2013. doi:10.1126/science.1240933. PMID 23929945. Bibcode: 2013Sci...341..903G.
- ↑ "The capsids of HIV-1 and HIV-2 determine immune detection of the viral cDNA by the innate sensor cGAS in dendritic cells". Immunity 39 (6): 1132–42. December 2013. doi:10.1016/j.immuni.2013.11.002. PMID 24269171.
- ↑ 9.0 9.1 9.2 Zhou, Wen; Whiteley, Aaron T.; de Oliveira Mann, Carina C.; Morehouse, Benjamin R.; Nowak, Radosław P.; Fischer, Eric S.; Gray, Nathanael S.; Mekalanos, John J. et al. (July 2018). "Structure of the Human cGAS–DNA Complex Reveals Enhanced Control of Immune Surveillance" (in en). Cell 174 (2): 300–311.e11. doi:10.1016/j.cell.2018.06.026. PMID 30007416. PMC 6084792. https://linkinghub.elsevier.com/retrieve/pii/S0092867418307943.
- ↑ Andreeva, Liudmila; Hiller, Björn; Kostrewa, Dirk; Lässig, Charlotte; de Oliveira Mann, Carina C.; Jan Drexler, David; Maiser, Andreas; Gaidt, Moritz et al. (September 2017). "cGAS senses long and HMGB/TFAM-bound U-turn DNA by forming protein–DNA ladders" (in en). Nature 549 (7672): 394–398. doi:10.1038/nature23890. ISSN 0028-0836. https://www.nature.com/articles/nature23890.
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