# Activation of immune receptor signaling by a sulfated peptide

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2020 · $444,634

## Abstract

Tyrosine sulfation is an important post-translational modification that has been
shown to significantly influence receptor/ligand interactions and modulate disease
outcome in both plants and animals. Despite its importance, the precise role of tyrosine
sulfation in protein function, host receptor activation and infection is not well understood.
The long-term goal of this proposal is to elucidate the mechanisms with which tyrosine
sulfation influences receptor-ligand interactions and resistance to infection.
As a model for these studies, we will investigate the interaction of the rice XA21
immune receptor, a protein that is representative of a large class of plant and animal
immune receptors, with the sulfated microbial protein, RaxX-sY, which is able to trigger a
potent immune response in its host. We propose three complementary aims:
Aim 1. Identify key amino acids that govern the interaction of sulfated RaxX
with host receptors. Aim 2. Test if RaxB and CvaB are required for RaxX-sY
processing and secretion. Aim 3. Determine the biological function of the Pald1
gene in the innate immune response.
The proposed analyses will provide a framework for elucidating the critical role of
sulfotyrosine in RaxX-sY/Xa21 interactions. To accomplish our goals, we will employ
new experimental tools and approaches. These include using an expanded genetic code
approach to produced full-length sulfated recombinant proteins in E. coli, new assays to
assess receptor activation and ligand binding, and a liquid chromatography tandem
mass spectrometry coupled with ultraviolet photodissociation to facilitate the
characterization of sulfated tyrosine residues within peptides.
The proposed studies are expected to lead to new insights regarding sulfated
molecules and their interacting partners. The information gained from this research can
be used to develop peptide-based reagents capable of inhibiting or activating receptor-
ligand interactions with a high degree of affinity and specificity with potential applications
in research, agriculture and medicine. Because sulfation of receptors or ligands is
important in controlling the outcome of serious diseases and because innate immunity is
critical for plant and animal defense against pathogens, the expected results will be
broadly relevant to human health.

## Key facts

- **NIH application ID:** 9912789
- **Project number:** 5R01GM122968-04
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** PAMELA C RONALD
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $444,634
- **Award type:** 5
- **Project period:** 2017-07-01 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9912789

## Citation

> US National Institutes of Health, RePORTER application 9912789, Activation of immune receptor signaling by a sulfated peptide (5R01GM122968-04). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/9912789. Licensed CC0.

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