# Uncovering the Role of UFM1 in the Release of Arrested Peptides from Stalled Ribosomes at the Endoplasmic Reticulum (ER) Membrane

> **NIH NIH F32** · STANFORD UNIVERSITY · 2022 · $1

## Abstract

Abstract
Ribosome-associated quality control (RQC) is the process by which cells deal with prolonged translational stalls caused
by genetic errors, insufficient charged tRNA, or faulty mRNA which results in ribosome collisions and potentially
cytotoxic, incomplete, translation products. Ribosomes are split into a free 40S and 60S subunit with an incomplete
nascent chain (arrest product or AP) as a peptidyl tRNA adduct which obstructs the exit tunnel and P-site of the 60S. In
the cytosol, an intricate process has been defined for how cells remove the AP, recycle the 60S subunit, and degrade the
AP. However, corresponding research into how this process is managed for proteins produced at the endoplasmic
reticulum (ER) membrane is lacking. The key difference between cytosolic and ER-RQC is that at the ER membrane the
AP is integrated into the SEC61 translocon and thus separated from the cytosolic RQC and degradative machinery. How
cells manage this topological restraint is the focus of this proposal. The Kopito lab and others have shown that ER
localized ribosome collisions result in the conjugation of the small ubiquitin-like protein UFM1 to ribosomal protein L26
(RPL26) on the 60S subunit (UFMylation). UFM1 knockout cells (UFM1KO) prevent proteasomal degradation of ER
localized, but not cytosolic, APs suggesting a link between UFMylation and AP degradation in ER-RQC. I hypothesize
that UFMylation of RPL26 severs as mark to recruit proteins to stalled ER ribosomes necessary for resolving the 60S-AP-
translcoon complex so that the AP may be degraded. In Aim 1 and Aim 2 of this proposal I will identify the readers of
UFMylation using two complimentary approaches: proximity labeling via fusion of a biotin ligase to UFM1 and affinity
purification of UFM1 binding proteins. These experiments are designed such that I will identify proteins that interact with
conjugated UFM1 and not free UFM1. Preliminary results show that ER localized, translocon associated proteins, are
enriched in proximity labeling experiments which supports the model that UFMylation occurs at the ER membrane near
the translocon. Preliminary affinity purification experiments reveal that known cytosolic RQC proteins are enriched on
UFMylated ribosomes supporting the role of UFMylation in ER-RQC. In Aim 3 of this proposal, I will define the
mechanism by which UFMylation leads to AP degradation. I will first evaluate the role of UFMylation readers identified
in Aims 1 and 2 in AP stability via emetine chase and metabolic pulse/chase experiments. I will also test if UFMylation
facilitates release of the AP from the ribosome or translocon. The UFMylation pathway is conserved amongst most
eukaryotic species and is essential for hematopoietic and neurological development in metazoan cells. Mutations in this
pathway have been linked to a wide variety of human diseases. Despite its importance, we do not fully understand what
this pathway is doing. In this proposal, I will uncover the readers of...

## Key facts

- **NIH application ID:** 10462233
- **Project number:** 1F32GM146380-01
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** Justin Tyler Marinko
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $1
- **Award type:** 1
- **Project period:** 2022-05-01 → 2022-05-02

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10462233

## Citation

> US National Institutes of Health, RePORTER application 10462233, Uncovering the Role of UFM1 in the Release of Arrested Peptides from Stalled Ribosomes at the Endoplasmic Reticulum (ER) Membrane (1F32GM146380-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10462233. Licensed CC0.

---

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