# Regulation of mitochondrial signaling by protein AMPylation

> **NIH NIH R01** · UT SOUTHWESTERN MEDICAL CENTER · 2024 · $349,915

## Abstract

ABSTRACT
Mitochondria are essential organelles that serve as the cellular hub for metabolism, ATP production, and redox
signaling. We identified a novel mechanism of signaling in the mitochondria mediated by a post translational
modification known as AMPylation, the covalent addition of adenosine monophosphate (AMP) to protein
substrates. Our previous studies revealed that Selenoprotein O catalyzes AMPylation of multiple mitochondrial
proteins involved in redox homeostasis and cellular metabolism. There are several critical gaps in our current
knowledge of AMPylation including the functional importance of AMPylation, as well as the enzymes that reverse
AMPylation. To gain a mechanistic understanding of AMPylation, we developed an enrichment strategy for
AMPylated proteins and identified RNase Z as a deAMPylase that catalyzes the removal of AMP from AMPylated
substrates. RNase Z was previously shown to be a conserved endoribonuclease that cleaves the 3’ trailer of
precursor tRNAs to generate mature tRNAs.
Our studies establish RNase Z as a multifunctional protein with previously unrecognized functional roles beyond
tRNA processing. Thus, the goal of this proposal is to determine the biochemical and molecular mechanisms of
RNase Z-mediated deAMPylation. Mutations in RNase Z result in severe hypertrophic cardiomyopathy and
increased prostate cancer susceptibility. We hypothesize that the deAMPylation activity, in addition to the
endoribonuclease activity, contributes to the functional importance of RNase Z in the mitochondria. However,
our understanding of mitochondrial AMPylation is in its infancy due to the lack of tools to study the AMPylated
proteins. Thus, we developed a novel enrichment strategy for the identification and functional characterization
of AMPylated proteins. We anticipate these studies will reveal previously undocumented roles for AMPylation in
cellular signaling and the molecular mechanisms of RNase Z-associated diseases.

## Key facts

- **NIH application ID:** 10940082
- **Project number:** 1R01GM154887-01
- **Recipient organization:** UT SOUTHWESTERN MEDICAL CENTER
- **Principal Investigator:** Anju Sreelatha
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $349,915
- **Award type:** 1
- **Project period:** 2024-09-01 → 2029-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10940082

## Citation

> US National Institutes of Health, RePORTER application 10940082, Regulation of mitochondrial signaling by protein AMPylation (1R01GM154887-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10940082. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*