Lipid biosynthesis perturbation impairs endoplasmic reticulum-associated degradation

Area of Science:

• Cell Biology
• Biochemistry
• Genetics

Background:

• The interplay between lipid and protein homeostasis is intricate and not fully elucidated.
• Aberrant proteins in the endoplasmic reticulum (ER) require efficient degradation pathways for cellular health.

Purpose of the Study:

• To identify genes crucial for the degradation of aberrant translocon-associated substrates in yeast.
• To investigate the role of lipid biosynthesis pathways in maintaining protein homeostasis.

Main Methods:

• Conducted a genetic screen in Saccharomyces cerevisiae to identify genes involved in Deg1-Sec62 degradation.
• Utilized yeast strains with deletions in INO4 and genes related to phospholipid and sterol biosynthesis.
• Assessed the impact of INO4 deletion on the stability of various ER-associated protein degradation substrates.

Main Results:

• Identified INO4 as essential for the efficient degradation of the model substrate Deg1-Sec62.
• Demonstrated that impaired lipid biosynthesis, due to mutations in INO4 or related genes, leads to accumulation of aberrant ER proteins.
• Showed that INO4 deletion sensitizes yeast cells to proteotoxic stress, highlighting a broad role for lipid homeostasis in proteostasis.

Conclusions:

• Lipid homeostasis is fundamentally linked to endoplasmic reticulum protein quality control and overall proteostasis.
• Perturbations in lipid biosynthesis significantly impact the cell's ability to manage aberrant proteins.
• Understanding this lipid-proteostasis axis may offer insights into human diseases linked to altered lipid metabolism.