Integrated proteome and lipidome analyses place OCIAD1 at the mitochondria-peroxisome intersection balancing lipid...

Area of Science:

• Cell Biology
• Biochemistry
• Molecular Biology

Background:

• Ovarian cancer immunoreactive antigen domain-containing 1 (OCIAD1) is a membrane protein with largely unknown functions, primarily localized to mitochondria.
• Understanding OCIAD1's role is critical for elucidating its involvement in cellular processes and disease.

Purpose of the Study:

• To comprehensively characterize the molecular consequences of OCIAD1 deficiency.
• To investigate the function of OCIAD1 in cellular lipid metabolism and organelle crosstalk.

Main Methods:

• Mass spectrometry was employed to analyze the mitochondrial and cellular proteome and lipidome in OCIAD1 knockout (KO) cells.
• Comparative analysis of lipid profiles, protein expression, peroxisomal morphology, and proximity labeling data.
• Bioinformatic analysis including meta-analysis of existing datasets.

Main Results:

• OCIAD1 deficiency led to extensive lipidome rearrangement, notably decreased ether phospholipids and odd-carbon chain phospholipids.
• Significant increase in proteins involved in mitochondrial fatty acid β-oxidation observed.
• Global loss of peroxisomal proteins, aberrant peroxisomal morphology, and altered peroxisomal lipid metabolism were identified.

Conclusions:

• OCIAD1 plays a significant role in balancing mitochondrial and peroxisomal lipid metabolism.
• The findings suggest OCIAD1 directly impacts key enzymes FAR1 and ABCD3, linking it to peroxisomal function.
• OCIAD1's function extends beyond mitochondria to include peroxisomal regulation and lipid homeostasis.