7A08

CryoEM Structure of cGAS Nucleosome complex


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.11 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structural basis for sequestration and autoinhibition of cGAS by chromatin.

Michalski, S.de Oliveira Mann, C.C.Stafford, C.A.Witte, G.Bartho, J.Lammens, K.Hornung, V.Hopfner, K.P.

(2020) Nature 587: 678-682

  • DOI: 10.1038/s41586-020-2748-0
  • Primary Citation of Related Structures:  
    7A08

  • PubMed Abstract: 
  • Cyclic GMP-AMP synthase (cGAS) is an innate immune sensor for cytosolic microbial DNA 1 . After binding DNA, cGAS synthesizes the messenger 2'3'-cyclic GMP-AMP (cGAMP) 2-4 , which triggers cell-autonomous defence and the production of type I interferons and pro-inflammatory cytokines via the activation of STING 5 ...

    Cyclic GMP-AMP synthase (cGAS) is an innate immune sensor for cytosolic microbial DNA 1 . After binding DNA, cGAS synthesizes the messenger 2'3'-cyclic GMP-AMP (cGAMP) 2-4 , which triggers cell-autonomous defence and the production of type I interferons and pro-inflammatory cytokines via the activation of STING 5 . In addition to responding to cytosolic microbial DNA, cGAS also recognizes mislocalized cytosolic self-DNA and has been implicated in autoimmunity and sterile inflammation 6,7 . Specificity towards pathogen- or damage-associated DNA was thought to be caused by cytosolic confinement. However, recent findings place cGAS robustly in the nucleus 8-10 , where tight tethering of chromatin is important to prevent autoreactivity to self-DNA 8 . Here we show how cGAS is sequestered and inhibited by chromatin. We provide a cryo-electron microscopy structure of the cGAS catalytic domain bound to a nucleosome, which shows that cGAS does not interact with the nucleosomal DNA, but instead interacts with histone 2A-histone 2B, and is tightly anchored to the 'acidic patch'. The interaction buries the cGAS DNA-binding site B, and blocks the formation of active cGAS dimers. The acidic patch robustly outcompetes agonistic DNA for binding to cGAS, which suggests that nucleosome sequestration can efficiently inhibit cGAS, even when accessible DNA is nearby, such as in actively transcribed genomic regions. Our results show how nuclear cGAS is sequestered by chromatin and provides a mechanism for preventing autoreactivity to nuclear self-DNA.


    Organizational Affiliation

    Department of Biochemistry, Ludwig-Maximilians-Universität, Munich, Germany. hopfner@genzentrum.lmu.de.



Macromolecules

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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Cyclic GMP-AMP synthaseA [auth a]370Mus musculusMutation(s): 0 
Gene Names: Mb21d1Cgas
EC: 2.7.7.86
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Find proteins for Q8C6L5 (Mus musculus)
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Go to UniProtKB:  Q8C6L5
IMPC:  MGI:2442261
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Entity ID: 4
MoleculeChainsSequence LengthOrganismDetailsImage
Histone H2A type 1-CD [auth b], H [auth f]129Homo sapiensMutation(s): 0 
Gene Names: H2AC6H2AFLHIST1H2AC
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Find proteins for Q93077 (Homo sapiens)
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PHAROS:  Q93077
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Entity ID: 5
MoleculeChainsSequence LengthOrganismDetailsImage
Histone H2B type 1-C/E/F/G/IE [auth c], I [auth g]125Homo sapiensMutation(s): 0 
Gene Names: 
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Find proteins for P62807 (Homo sapiens)
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PHAROS:  P62807
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Entity ID: 6
MoleculeChainsSequence LengthOrganismDetailsImage
Histone H3.3F [auth d], J [auth h]135Homo sapiensMutation(s): 0 
Gene Names: H3-3AH3.3AH3F3H3F3APP781H3-3BH3.3BH3F3B
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Find proteins for P84243 (Homo sapiens)
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PHAROS:  P84243
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Entity ID: 7
MoleculeChainsSequence LengthOrganismDetailsImage
Histone H4G [auth e], K [auth i]102Homo sapiensMutation(s): 0 
Gene Names: 
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Find proteins for P62805 (Homo sapiens)
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PHAROS:  P62805
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Entity ID: 2
MoleculeChainsLengthOrganismImage
Nucleosomal DNA strand 1B [auth I]147synthetic construct
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Entity ID: 3
MoleculeChainsLengthOrganismImage
Nucleosomal DNA strand 2C [auth J]147synthetic construct
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Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download Ideal Coordinates CCD File 
L [auth a]ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.11 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
German Research Foundation (DFG)GermanyCRC/TRR237

Revision History  (Full details and data files)

  • Version 1.0: 2020-09-23
    Type: Initial release
  • Version 1.1: 2020-12-09
    Changes: Database references
  • Version 1.2: 2021-02-10
    Changes: Source and taxonomy