# Phosphorylation and ubiquitination of immune sensory complexes in innate immune signaling

> **NIH NIH R01** · TEXAS A&M AGRILIFE RESEARCH · 2020 · $171,870

## Abstract

Project title: Phosphorylation and ubiquitination of immune sensory complexes in innate immune
signaling
PI: Libo Shan
Grant number: R01GM097247
Duration: 07/01/2011-11/30/2021
Annual direct amount: $185,000
Project Summary
Plants and animals rely on pattern-recognition receptors (PRRs) to detect infection by recognizing microbe-
associated molecular patterns (MAMPs). FLS2, a structural and functional ortholog of mammalian Toll-like
receptors (TLRs) in plants, recognizes bacterial flagellin and initiates immune signaling by dimerizing with a co-
receptor BAK1. With the previous NIH support, we have identified a plasma membrane-tethered receptor-like
cytoplasmic kinase (RLCK) BIK1 as a convergent immune regulator by association with multiple PRR
complexes. MAMP perception induces rapid BIK1 phosphorylation by BAK1, and subsequent release from PRR
complexes to transduce diverse immune signaling. It remains unknown how PRR-associated BIK1 is activated
and then bifurcates intracellular PRR signaling. Our preliminary data indicate that MAMP perception triggers
rapid mono-ubiquitination of BIK1 and related RLCKs. A RING-type E3 ubiquitin ligase BMU1, that is
phosphorylated by BIK1, mediates MAMP-induced BIK1 ubiquitination. BIK1 interacts and phosphorylates a
diacylglycerol kinase DGK5 that regulates MAMP-induced phosphatidic acid (PA) production. Three over-
arching aims are proposed to test a central hypothesis that mono-ubiquitination of BIK1 by BMU1 triggers
release of BIK1 from PRR complexes, and subsequent endosomal trafficking and relaying intracellular
signaling events, including activation of DGK5 for PA production.
Three specific aims are
1. Ubiquitination of BIK1 by BIK1-phosphorylated BMU1 in plant immunity;
2. Ligand-induced BIK1 mono-ubiquitination in endosomal trafficking and plant immunity;
3. Dual phosphorylation of DGK5 by PRR-activated BIK1 and MAP kinase 4 in plant immunity.
Recent advance on the molecular architecture of nonself recognition has revealed remarkable conservation in the
mechanisms of microbial perception and innate immune signaling in multicellular eukaryotes. Phosphorylation
and ubiquitination are two key mechanisms in regulating diverse cellular and organismal processes. Our project
on pathogen-induced sequential and intertwined phosphorylation and ubiquitination orchestrating PRR complex
activation and signal transduction in plant immunity will generate conceptual advance in understanding the
biological functions of these two universal regulatory mechanisms at the whole organismal level. The proposed
research will also contribute to the general understanding of innate immune signaling and immune sensory
complex function.

## Key facts

- **NIH application ID:** 10135642
- **Project number:** 3R01GM097247-08S1
- **Recipient organization:** TEXAS A&M AGRILIFE RESEARCH
- **Principal Investigator:** Libo Shan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $171,870
- **Award type:** 3
- **Project period:** 2011-07-01 → 2021-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10135642

## Citation

> US National Institutes of Health, RePORTER application 10135642, Phosphorylation and ubiquitination of immune sensory complexes in innate immune signaling (3R01GM097247-08S1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10135642. Licensed CC0.

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