P4HB UFMylation regulates mitochondrial function and oxidative stress

Area of Science:

• Biochemistry
• Cell Biology
• Molecular Biology

Background:

• UFMylation is a ubiquitin-like post-translational modification.
• Few UFMylation targets have been identified to date.
• P4HB protein possesses oxidoreductase, chaperone, and isomerase functions.

Purpose of the Study:

• To identify new UFMylation targets.
• To investigate the role of P4HB UFMylation in hepatocellular cells.
• To explore the link between P4HB UFMylation and non-alcoholic fatty liver disease (NAFLD).

Main Methods:

• Identification of P4HB as a novel UFMylation target.
• Generation of a stable HepG2 cell line with defective P4HB UFMylation.
• Analysis of cellular responses to P4HB UFMylation defects, including protein degradation, mitochondrial function, and stress responses.

Main Results:

• P4HB is mono-UFMylated at three lysine residues.
• Defective P4HB UFMylation promotes protein degradation via the ubiquitin-proteasome pathway.
• Impaired P4HB UFMylation leads to mitochondrial dysfunction, oxidative stress, and ER stress in HepG2 cells, exacerbated by palmitic acid treatment.

Conclusions:

• UFMylation is essential for maintaining P4HB stability and function in HepG2 cells.
• P4HB UFMylation is a critical factor in cellular homeostasis.
• P4HB UFMylation represents a potential therapeutic target for NAFLD.