Tight nuclear tethering of cGAS is essential for preventing autoreactivity

Abstract
Data availability
Article and author information
Metrics

Abstract

cGAS is an intracellular innate immune sensor that detects double-stranded DNA. The presence of billions of base pairs of genomic DNA in all nucleated cells raises the question of how cGAS is not constitutively activated. A widely accepted explanation for this is the sequestration of cGAS in the cytosol, which is thought to prevent cGAS from accessing nuclear DNA. Here, we demonstrate that endogenous cGAS is predominantly a nuclear protein, regardless of cell cycle phase or cGAS activation status. We show that nuclear cGAS is tethered tightly by a salt-resistant interaction. This tight tethering is independent of the domains required for cGAS activation, and it requires intact nuclear chromatin. We identify the evolutionarily conserved tethering surface on cGAS and we show that mutation of single amino acids within this surface renders cGAS massively and constitutively active against self-DNA. Thus, tight nuclear tethering maintains the resting state of cGAS and prevents autoreactivity.

Data availability

All data generated or analyzed during this study are included in the manuscript and supporting files.

Article and author information

Author details

Hannah E Volkman

Department of Immunology, University of Washington, Seattle, United States

Competing interests
The authors declare that no competing interests exist.
Stephanie Cambier

Department of Immunology, University of Washington, Seattle, United States

Competing interests
The authors declare that no competing interests exist.
Elizabeth E Gray

Department of Immunology, University of Washington, Seattle, United States

Competing interests
The authors declare that no competing interests exist.
Daniel B Stetson

Department of Immunology, University of Washington, Seattle, United States

For correspondence
stetson@uw.edu

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-5936-1113

Funding

National Institutes of Health (AI084914)

Daniel B Stetson

Jane Coffin Childs Memorial Fund for Medical Research

Hannah E Volkman

Burroughs Wellcome Fund (1013540)

Daniel B Stetson

Howard Hughes Medical Institute (55108572)

Daniel B Stetson

Bill and Melinda Gates Foundation (OPP1156262)

Daniel B Stetson

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.