# Regulation and Function of Nuclear cGAS

> **NIH NIH R01** · UNIVERSITY OF WASHINGTON · 2022 · $625,254

## Abstract

Project Summary/Abstract
Detection of intracellular DNA by the cGAS-STING pathway mediates host defense against DNA viruses,
contributes to specific human autoimmune diseases, and can be harnessed to promote anti-tumor immunity.
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. We have found 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, revealing a fundamental mechanism that controls the resting
state of cGAS.
 In this grant application, we have developed innovative new tools to define the cGAS nuclear tethering
compartment, quantitate changes in cGAS disposition during DNA virus infection, and explore cGAS-
associated nucleic acids before and after its activation in the context of infection and autoimmune disease. Our
studies will uncover fundamental new aspects of cGAS biology, will identify new targets for therapeutic
modulation of cGAS activity, and will provide new insights into the principles of self/non-self discrimination by
intracellular nucleic acid sensors.

## Key facts

- **NIH application ID:** 10454990
- **Project number:** 5R01AI150716-03
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** Daniel B Stetson
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $625,254
- **Award type:** 5
- **Project period:** 2020-09-22 → 2025-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10454990

## Citation

> US National Institutes of Health, RePORTER application 10454990, Regulation and Function of Nuclear cGAS (5R01AI150716-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10454990. Licensed CC0.

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