# Regulation of Signaling by Histidine Protein Methylation

> **NIH NIH R01** · STANFORD UNIVERSITY · 2020 · $315,781

## Abstract

Abstract
Covalent post-translational protein modifications (PTMs) contribute to all aspects of cell physiology and are a
primary source of protein functional diversity in mammalian cells. Our overarching goal is to better understand
the role of protein methylation signaling in the regulation of diverse biological functions and how disruption in
these mechanisms contributes to cancer and other disease pathologies. While the most commonly studied
methylation events occur on lysine and arginine residues – glutamine, cysteine, and histidine residues are also
methylated – though these modification events are thought to occur on only a limited number of proteins and
relatively little is known about the enzymes that catalyze these chemical reactions. In particular, while
modification of histidine residues by methylation is thought to be a rare event on proteins, the methylation of
actin at histidine 73 (actin-H73me) is a canonical modification in mammals that was identified more than fifty
years ago. However, the function of actin-H73me is enigmatic and the enzyme/s generating this abundant
modification event are not known. In preliminary work we have identified SETD3 as the first known metazoan
protein histidine methyltransferase (PHMT). SETD3, a little studied cytoplasmic protein that belongs to the SET
domain family of enzymes, is implicated in processes involved in muscle function and cancer. However, a clear
function for SETD3 is not known. Our initial data identified SETD3 as a critical host factor required for infection
by a broad class of enteroviruses. We also have evidence for SETD3 regulation of smooth muscle physiology
in cells and in vivo. In humans, beyond actin, virtually nothing is known about the molecular, signaling and
biological consequences associated with histidine methylation. Our central hypothesis is that histidine
methylation of actin and other proteins by enzymes such as SETD3 have an underappreciated and significant
role in signal transduction, cell biology, and disease pathogenesis.
We propose to use biochemical, cellular, genetic, and proteomic approaches to elucidate the molecular,
biological and pathological functions of histidine methylation, with a focus on the biology surrounding SETD3
and SETD3-catalyzed modification of actin. In Aim 1 we will perform experiments to gain a molecular level
understanding of the consequence of actin H73 methylation by SETD3. The goal of Aim 2 is to investigate
SETD3 cellular functions. Experiments are planned to identify the role of SETD3’s enzymatic activity in actin-
related cellular functions and cancer cell phenotypes. We will also explore the molecular mechanisms by which
actin is paired with SETD3 for methylation. The goal of Aim 3 is to expand our knowledge of histidine
methylation signaling in humans beyond that of SETD3 and actin. We will use computational, proteomic, and
biochemical strategies to identify and validate novel human histidine methylated proteins and to discover ne...

## Key facts

- **NIH application ID:** 9974541
- **Project number:** 5R01GM133051-02
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** Or P. Gozani
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $315,781
- **Award type:** 5
- **Project period:** 2019-07-15 → 2021-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9974541

## Citation

> US National Institutes of Health, RePORTER application 9974541, Regulation of Signaling by Histidine Protein Methylation (5R01GM133051-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9974541. Licensed CC0.

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