# Mechanistic Studies of cytosolic double-stranded DNA sensing pathways.

> **NIH NIH R35** · JOHNS HOPKINS UNIVERSITY · 2024 · $409,393

## Abstract

Project summary
In metazoan, the presence of double-stranded (ds)DNA in the cytosol signals serious problems, which range
from radiation damage to pathogen invasion. The innate immune system acts as the first line of defense
against cytosolic dsDNA by initiating inflammatory signaling pathways. Cytosolic dsDNA sensing pathways are
integral to host defense against numerous pathogens, and their malfunctions also result in various human
maladies.
Our research program is poised to resolve several long-standing mechanistic questions in understanding how
cytosolic dsDNA sensing pathways are activated and regulated at the molecular level. We will also test new
concepts as to how these sensors might be stigmatized as autoantigens, and explore the mechanical forces
that drive and regulate their higher order assemblies. Our approaches include X-ray crystallography, rigorous
biochemical measurements, cell-based assays, electron microscopy, and single molecule methods.
Here, we will determine how cGAS coordinates different nucleotide substrates and metal co-factors at the
active site to specifically generate 2'-5'/3'-5' linked cyclic G/AMP. We will also investigate how dimerization is
allosterically coupled to activation. We will then determine how cGAS and ALR sensors selectively recognize
and signal through dsDNA. Next, we will test the role of phase-separation/transition in the normal and aberrant
activities of cytosolic dsDNA sensors. Finally, we will delineate mechanical forces and structural mechanisms
that underpin the activation and regulation of cytosolic dsDNA sensors. The molecular insights resulting from
the proposed studies will provide a foundation for developing new therapeutic strategies that target various
human diseases caused by dysregulated cytosolic dsDNA sensing pathways.

## Key facts

- **NIH application ID:** 10865033
- **Project number:** 5R35GM145363-03
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** JUNGSAN SOHN
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $409,393
- **Award type:** 5
- **Project period:** 2022-09-01 → 2027-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10865033

## Citation

> US National Institutes of Health, RePORTER application 10865033, Mechanistic Studies of cytosolic double-stranded DNA sensing pathways. (5R35GM145363-03). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10865033. Licensed CC0.

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