# Mechanisms of action for the IBD-risk gene INAVA: an epithelial guard receptor for inflammation and integrity of the intestinal barrier

> **NIH NIH R01** · BOSTON CHILDREN'S HOSPITAL · 2020 · $532,404

## Abstract

Our goal is to elucidate how the IBD-risk gene INAVA (previously C1ORF106) acts in human intestinal epithelia
to manage environmentally-induced cell stress, inflammation, and the integrity of mucosal surfaces.
We recently found that INAVA exhibits dual activities that mechanistically link epithelial barrier function and
inflammatory signaling by IL1β (eLife 2018). This is driven by INAVA’s signature Domain of Unknown Function
DUF3338, which we newly define as an enhancer of TRAF6-dependent polyubiquitination. DUF3338 also stably
binds the GTP-exchange factor (GEF) cytohesin-2 (ARNO), in one case blocking INAVA activity in protein
ubiquitination, and in another case acting at lateral membranes where the INAVA-ARNO complex affects cortical
F-actin dynamics and epithelial barrier function. We now know INAVA acts in multiple stress pathways by forming
cytosolic puncta to enhance protein ubiquitination in signal transduction and affecting cellular proteostasis.
As such, we have proposed that INAVA acts as a guard receptor to innately sense dysfunction in the intestinal
epithelium and restore intestinal homeostasis in response to danger. Elucidating the function of INAVA will be
informative for how barrier epithelial cells interact with the lumenal and sub-epithelial microenvironment, and the
biology of mucosal host defense.
In Aim 1 we will explain how INAVA functions in protein ubiquitination induced by extracellular ROS (H2O2) and
IL1b, focusing first on the ROS-sensing E3-ligases KEAP-1 and SCF complex. The composition of the different
stress-induced puncta will be tested by hypothesis-driven studies based upon our own and two previously
published studies (Monahan Science 2018 and Huttlin Nature 2017), and by unbiased proteomic analysis of
ubiquitin-modified proteins that will identify effectors and substrates of INAVA action - and blocked by ARNO to
confirm specificity. Key results will be studied mechanistically as in our eLife 2018 paper and confirmed in primary
human intestinal enteroids (as for all Aims).
In Aim2 we will elucidate the structure of the INAVA puncta, it’s mechanism of assembly as a molecular
condensate, and if polysomes or ubiquitin chains form the initiating scaffold. We will also investigate puncta
disassembly by activation of the proteasome or autophagy, thus delineating mechanism(s) of INAVA puncta
down-regulation.
In Aim 3 we will test structure-function of the INAVA C-terminal and CUPID domains, including the IBD-SNP
Y33F, to define lateral membrane and puncta targeting and effects on epithelial barrier assemblies and function.
To further elucidate physiologic stimuli inducing these events, we will follow up on top “hits” of our chemical
screen for INAVA puncta formation and lateral membrane targeting (HSP90 and ROCK inhibitors respectively)

## Key facts

- **NIH application ID:** 10050303
- **Project number:** 1R01DK122953-01A1
- **Recipient organization:** BOSTON CHILDREN'S HOSPITAL
- **Principal Investigator:** WAYNE I LENCER
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $532,404
- **Award type:** 1
- **Project period:** 2020-07-01 → 2024-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10050303

## Citation

> US National Institutes of Health, RePORTER application 10050303, Mechanisms of action for the IBD-risk gene INAVA: an epithelial guard receptor for inflammation and integrity of the intestinal barrier (1R01DK122953-01A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10050303. Licensed CC0.

---

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