# The regulation of c-di-AMP homeostasis and signaling in bacteria

> **NIH NIH R35** · UNIVERSITY OF WISCONSIN-MADISON · 2024 · $388,750

## Abstract

PROJECT SUMMARY
 The small nucleotide c-di-AMP is a ubiquitous second messenger produced by thousands of bacterial and
archeal species. Many bacteria, especially those in the Firmicutes phylum, require c-di-AMP for growth in
standard laboratory media, and the mechanisms for c-di-AMP essentiality have been extensively studied.
However, in a wide range of c-di-AMP-producing bacteria, including those for which c-di-AMP is completely
dispensable, unregulated c-di-AMP accumulation is toxic, diminishing bacterial growth and stress response.
Thus, c-di-AMP homeostasis is critical for bacteria that produce it. Nevertheless, the mechanisms that regulate
c-di-AMP levels in the bacterial cell, and the mechanisms by which c-di-AMP regulates different cellular pathways
to achieve optimal physiology, are both poorly understood. My lab found that c-di-AMP levels are dynamic in the
bacterial cell, and c-di-AMP hydrolysis is a key mechanism to modulate c-di-AMP levels. Furthermore, we have
generated bacterial mutants lacking c-di-AMP phosphodiesterases, called pde mutants, and extensively studied
their phenotypic defects. In the next five years, we will investigate two major aspects of c-di-AMP signaling: i)
the signal detection and regulatory mechanisms of c-di-AMP phosphodiesterase, and ii) the mechanisms by
which c-di-AMP coordinates its molecular targets to achieve optimal physiology and stress response. For the
second theme, we will take two complementary approaches. One, we will elucidate the biological functions of c-
di-AMP molecular targets based on targeted phenotypic, genetic, and biochemical analyses. Two, we will identify
the molecular targets underlying the toxicity phenotypes of pde mutants, through genetic fitness assays. Our
findings will reveal fundamental mechanisms of c-di-AMP signaling, and these mechanisms will provide a
framework to understand the global regulatory roles of c-di-AMP in the physiology of different bacterial species.

## Key facts

- **NIH application ID:** 10914990
- **Project number:** 5R35GM147519-03
- **Recipient organization:** UNIVERSITY OF WISCONSIN-MADISON
- **Principal Investigator:** Tu Anh Huynh
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $388,750
- **Award type:** 5
- **Project period:** 2022-09-21 → 2027-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10914990

## Citation

> US National Institutes of Health, RePORTER application 10914990, The regulation of c-di-AMP homeostasis and signaling in bacteria (5R35GM147519-03). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10914990. Licensed CC0.

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