# The roles of the UFM1 post-translational modification in cellular metabolism

> **NIH NIH K99** · UT SOUTHWESTERN MEDICAL CENTER · 2024 · $125,000

## Abstract

Project Summary
Cells use post-translational modifications (PTM) to modulate protein function by conjugating and deconjugating modifiers
to protein targets. Imbalance in these reactions leads to human disease. Conjugation of ubiquitin-fold modifier 1 (UFM1)
to protein targets (UFMylation) has been linked to many cellular processes at the endoplasmic reticulum (ER). In contrast,
much less is known about the roles of UFM1 deconjugation (de-UFMylation), the process of removing UFM1 from
UFMylated proteins. Defects in UFSP2, a de-UFMylation enzyme, were identified in patients with skeletal and
neurodevelopmental disorders. Notably, patient-derived fibroblasts harboring UFSP2 deficiency show excessive amounts
of UFMylation (hyper-UFMylation) and defects in mitochondrial respiration and nucleotide metabolism, indicating as-yet
undescribed roles of UFMylation in cellular metabolism. These findings suggest UFMylation as a novel regulator of
mitochondrial function and nucleotide metabolism. The long-term goal is to understand how UFMylation regulates cellular
metabolism. The overall objective is to understand the molecular mechanism by which UFMylation regulates mitochondrial
respiration and nucleotide metabolism, and the molecular mechanism of action of UFSP2-mediated de-UFMylation. The
central hypothesis is that UFSP2 deficiency causes (i) hyper-UFMylation of mitochondrial ribosomes (mitoribosomes) and
the electron transport chain (ETC) complex I which change protein localization and/or function, leading to decreased protein
abundance and/or loss-of-function of ETC complexes; and (ii) hyper-UFMylation of enzymes in nucleotide metabolic
pathways, leading to changes in enzyme activity and perturbation of nucleotide metabolism. The rationale is that probing
localization and measuring activity of the hyper-UFMylated mitoribosomes, the ETC Complex I and serine
hydroxymethyltransferase-2 (SHMT2), will reveal how UFMylation regulates mitochondrial respiration and nucleotide
metabolism. In addition, the structure of UFSP2 in complex with UFMylated targets will reveal the structural basis for
substrate recognition and de-UFMylation reaction. The central hypothesis will be tested by pursuing three specific aims: 1)
Determine how hyper-UFMylation of mitoribosomes and Complex I impairs mitochondrial respiration; 2) Investigate the
effect of hyper-UFMylation of SHMT2 on nucleotide metabolism; and 3) Determine the structural basis for substrate
recognition and deconjugation reaction of human UFSP2. For the first aim, protein abundance, localization and enzyme
activity of mitochondrial ribosomes and the ETC Complex I will be measured in patient-derived UFSP2-depleted versus
WT UFSP2 cells. For the second aim, isotope tracing will be used to evaluate metabolic rates of serine and nucleotide
synthesis, while the localization and enzyme activity of SHMT2 will be assessed in patient-derived UFSP2-depleted versus
WT UFSP2 cells. For the third aim, the UFSP2 in complex with...

## Key facts

- **NIH application ID:** 10873278
- **Project number:** 5K99GM151439-02
- **Recipient organization:** UT SOUTHWESTERN MEDICAL CENTER
- **Principal Investigator:** Phong Thanh Nguyen
- **Activity code:** K99 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $125,000
- **Award type:** 5
- **Project period:** 2023-07-01 → 2025-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10873278

## Citation

> US National Institutes of Health, RePORTER application 10873278, The roles of the UFM1 post-translational modification in cellular metabolism (5K99GM151439-02). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10873278. Licensed CC0.

---

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