Structural basis for the inhibition of cGAS by nucleosomes.
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Embargo End Date
ICR Authors
Authors
Kujirai, T
Zierhut, C
Takizawa, Y
Kim, R
Negishi, L
Uruma, N
Hirai, S
Funabiki, H
Kurumizaka, H
Zierhut, C
Takizawa, Y
Kim, R
Negishi, L
Uruma, N
Hirai, S
Funabiki, H
Kurumizaka, H
Document Type
Journal Article
Date
2020-10-23
Date Accepted
2020-08-28
Abstract
The cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) senses invasion of pathogenic DNA and stimulates inflammatory signaling, autophagy, and apoptosis. Organization of host DNA into nucleosomes was proposed to limit cGAS autoinduction, but the underlying mechanism was unknown. Here, we report the structural basis for this inhibition. In the cryo-electron microscopy structure of the human cGAS-nucleosome core particle (NCP) complex, two cGAS monomers bridge two NCPs by binding the acidic patch of the histone H2A-H2B dimer and nucleosomal DNA. In this configuration, all three known cGAS DNA binding sites, required for cGAS activation, are repurposed or become inaccessible, and cGAS dimerization, another prerequisite for activation, is inhibited. Mutating key residues linking cGAS and the acidic patch alleviates nucleosomal inhibition. This study establishes a structural framework for why cGAS is silenced on chromatinized self-DNA.
Citation
Science (New York, N.Y.), 2020, 370 (6515), pp. 455 - 458
Source Title
Publisher
AMER ASSOC ADVANCEMENT SCIENCE
ISSN
0036-8075
eISSN
1095-9203
Collections
Research Team
Epigenetics and Genome Stability