# Unraveling the link between serine/threonine protein kinase and two-component system regulation of environment-mediated Mycobacterium tuberculosis growth arrest

> **NIH NIH R21** · TUFTS UNIVERSITY BOSTON · 2022 · $245,550

## Abstract

PROJECT SUMMARY/ABSTRACT
A marked feature of Mycobacterium tuberculosis (Mtb) infection is heterogeneity that encompasses several
aspects, including in bacterial replication status and in the local microenvironment. This heterogeneity exists
not just temporally, but also spatially even within a single lesion, as revealed at the single bacterium level by an
integrated imaging system that combines the use of fluorescent reporter Mtb strains, a murine infection model
that recapitulates hallmark caseous necrotic lesions, and confocal imaging. While environmental signals such
as nitric oxide (NO) are known to be able to drive Mtb into growth arrest, how Mtb coordinates its replication
with environmental cue response remains largely unknown. Further, the interplay between the two key systems
that play central roles in Mtb signal transduction, namely serine/threonine protein kinases (STPKs) and two-
component systems (TCSs), is also poorly understood. To this end, we recently uncovered the essential
transcription factor PrrA, part of the PrrAB TCS, as (i) a regulator of Mtb response to multiple environmental
cues, including NO, and (ii) a TCS whose function is significantly modulated by STPK phosphorylation, with
consequent effects on Mtb replication status in response to NO. Aim 1 of this proposal thus seeks to elucidate
the global transcriptional impact of STPK regulation of PrrA on the adaptive entry of Mtb into a non-replicating
state upon extended NO exposure, utilizing a PrrA STPK phosphoablative mutant. A bacterial-two-hybrid
approach will further be undertaken to uncover the STPKs responsible for phosphorylation of PrrA. Aim 2
focuses on understanding the functional consequences of STPK regulation of PrrA on Mtb replication status
during infection in vivo, with single bacterium resolution. This will exploit the use of a replication reporter-
expressing STPK phosphoablative PrrA mutant with our integrated imaging system, to delineate how STPK
regulation of PrrA may differentially influence Mtb growth in disparate lesion sublocations, and reveal its
relation to local NO conditions. This project is conceptually innovative in its focus on the connection between
STPKs and TCSs in Mtb, and between Mtb environmental response and replication regulation. By laying the
groundwork for revealing key connecting nodes in these understudied concepts, these studies will provide
insight into facets of Mtb infection biology critical for bacterial colonization success, and open new avenues of
study targeted at understanding and exploiting these vital aspects for therapeutic purposes.

## Key facts

- **NIH application ID:** 10428709
- **Project number:** 1R21AI168597-01
- **Recipient organization:** TUFTS UNIVERSITY BOSTON
- **Principal Investigator:** Shumin Tan
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $245,550
- **Award type:** 1
- **Project period:** 2022-09-01 → 2024-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10428709

## Citation

> US National Institutes of Health, RePORTER application 10428709, Unraveling the link between serine/threonine protein kinase and two-component system regulation of environment-mediated Mycobacterium tuberculosis growth arrest (1R21AI168597-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10428709. Licensed CC0.

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