# Mechanism and Function of Stress Induced Protein Translation

> **NIH NIH R01** · UNIVERSITY OF ARIZONA · 2021 · $308,343

## Abstract

Oxidative stress is an important component of disease etiology and progression.
At the cellular level, while inhibition of overall protein synthesis is a measure of stress in
general, increasing evidence suggests that selective protein translation occurs and
determines cell fate. Many xenobiotics or disease states cause an increase in oxidative
stress. We have found that low to mild doses of oxidants trigger de novo translation of
Nrf2 protein, a transcription factor regulating a network of antioxidant and detoxification
genes. Deficiency of Nrf2 protein results in an increased sensitivity to a variety of
chemical and pathophysiological stresses. It is not known the components in the
translation machinery responsible for Nrf2 protein translation. Normally, initiation of
protein translation requires recognition of 7-methyl Guanine cap at the 5' end (5' m7G)
of an mRNA strand by eIF4E in the eIF4F complex, and recruitment of the 43S pre-
initiation complex. Human Nrf2 gene encodes an mRNA species containing a 555
nucleotide 5' Untranslated Region (5'UTR). Genes containing an Internal Ribosomal
Entry Site (IRES) in 5'UTR can bypass 5' m7G cap-dependent translation and undergo
stress-induced protein translation. Using LC-MS/MS based proteomics, we have
identified the La autoantigen as a binding partner of Nrf2 5'UTR. Oxidants induce La
protein to translocate from the nucleus to the cytoplasm, where it exhibits increased
binding to Nrf2 mRNA and ribosomes, resulting in Nrf2 protein translation. Nrf2 is
typically activated when modification of redox-sensitive cysteine residues in Keap1
renders it incapable of mediating Nrf2 ubiquitination. Whether or not de novo Nrf2
protein translation is sufficient for activating the Nrf2 transcription network has not been
addressed. We hypothesize that La facilitates the assembly of the 48S Initiation
Complex for de novo Nrf2 protein translation, and La-Nrf2 signaling is essential
for cytoprotection via controlling gene expression under oxidative stress. Aim 1
will test whether RNA recognition motifs of La protein form physical contact with a
specific region of Nrf2 5'UTR to mediate de novo Nrf2 protein translation. The region of
Nrf2 5'UTR for La binding will be mapped using an RNA Electrophoretic Mobility Shift
Assay (EMSA) in combination with RNase/Chemical probing. The motif of La protein
responsible for binding to Nrf2 5'UTR will be identified by deletion or mutation. Aim 2
will test whether La coordinates the assembly of the 48S Initiation Complex to drive new
protein translation under oxidative stress. The eIF4E, 4G, 4A, 4B, 4H, 1, 1A, 2, 3, 5,
5B, and PABP are essential elements of the 48S Initiation Complex (48S IC) and will be
examined for interactions with La and La/Nrf2 5'UTR complex under oxidative stress.
Proteins associated with the La or the La binding site of Nrf2 5'UTR will be revealed
using high resolution LC-MS/MS proteomics. The role of these proteins will be tested for
assembly of 48S IC and de...

## Key facts

- **NIH application ID:** 10104519
- **Project number:** 5R01GM125212-04
- **Recipient organization:** UNIVERSITY OF ARIZONA
- **Principal Investigator:** QIN M CHEN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $308,343
- **Award type:** 5
- **Project period:** 2018-05-01 → 2023-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10104519

## Citation

> US National Institutes of Health, RePORTER application 10104519, Mechanism and Function of Stress Induced Protein Translation (5R01GM125212-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10104519. Licensed CC0.

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