# Reversible protein acetylation and sirtuin function

> **NIH NIH R01** · UNIVERSITY OF WISCONSIN-MADISON · 2020 · $448,373

## Abstract

Protein-lysine acetylation is a major post-translational modification, where acetyl-proteomic studies have
catalogued thousands of acetylation sites, representing proteins in diverse cellular pathways. Mechanistic
studies have revealed diverse consequences of specific protein acetylation, but such functional studies
have lagged behind protein cataloguing. Deacetylases and acetyl-CoA (AcCoA) dependent transferases are
implicated in controlling the acetylation state of target proteins, though the dynamics and the mechanisms
that lead to cellular compartment-specific acetylation is unclear. While evidence of enzyme-catalyzed
acetylation exits in the cytoplasm, nucleus and ER, most mitochondrial protein acetylation is thought to be
uncatalyzed. We recently described rapid cellular protein acetylation in response to growth factor
stimulation, which remarkably includes a subset of mitochondrial proteins, indicative of enzyme-catalyzed
acetylation. Thus, the contribution of non-enzymatic acetylation, driven by AcCoA flux/levels, and of
enzyme-catalyzed acetylation remains poorly understood. With strategic use of cultured cell lines and
mouse models, a major portion of this proposal investigates the mechanisms that control specific and
proteome-wide acetylation in both acute cellular responses and chronic energy-depleted conditions.
 In addition to cellular mechanisms that promote acetylation, regulation of deacetylases drive
functional consequences in various organelles. The NAD+-dependent protein deacetylases (SIRT1-7) are a
major family of enzymes found in diverse sub-cellular compartments. Mitochondrial SIRT3 and nuclear
SIRT6 and SIRT7 are the subject of this proposal. SIRT3 deacetylates and increases the catalytic efficiency
of enzymes involved in oxidative metabolism. SIRT6 and SIRT7 are chromatin bound proteins that can
remove specific lysine acetylations on histones. The mechanisms by which SIRT6 and SIRT7 catalyze the
deacetylation of nucleosomes are completely unknown, yet the genetic and biological importance of these
proteins is advancing rapidly. Loss-of-function (deacetylation) mutants of SIRT6 cause cancer and perinatal
lethality. Our recent data on SIRT6 provides unprecedented insight into the molecular functions of SIRT6
and reveal the therapeutic potential of small-molecule activation. Our preliminary data on SIRT7 indicates
novel activities related to nucleosome binding.
 To address these major gaps in our understanding of sirtuin biology and of the mechanisms that
drive functionally relevant protein acetylation in a compartment-specific manner, the following aims are
proposed: Aim 1, Determine the mechanisms of nucleosomal deacetylation by SIRT6 and SIRT7; Aim 2,
Elucidate the mechanisms of compartment-specific protein acetylation under acute stimulation and chronic
metabolic stress; and Aim 3, Reveal pathway-level and site-specific functional roles of protein acetylation in
energy metabolism and mitochondrial proteostasis.

## Key facts

- **NIH application ID:** 9963232
- **Project number:** 5R01GM065386-19
- **Recipient organization:** UNIVERSITY OF WISCONSIN-MADISON
- **Principal Investigator:** JOHN M DENU
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $448,373
- **Award type:** 5
- **Project period:** 2003-05-01 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9963232

## Citation

> US National Institutes of Health, RePORTER application 9963232, Reversible protein acetylation and sirtuin function (5R01GM065386-19). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9963232. Licensed CC0.

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