Peroxisomes are tiny enzyme filled vesicles found in all cells, with high concentrations in the liver. They play vital roles in breaking down fatty acids, forming membranes like the myelin sheath, and detoxifying cells by degrading hydrogen peroxide. Malfunctioning or absent peroxisomes can lead to severe disorders, such as Zellweger spectrum diseases, which affect multiple organs and can be fatal in infancy.

Despite decades of research, key aspects of peroxisome function remain unclear. Professor Bettina Warscheid and her team at the University of Würzburg, along with partners in the USA and Portugal, have now discovered a new piece of the puzzle: a previously uncharacterized protein called PEX39. This peroxin is crucial for transporting enzymes into peroxisomes an essential step in fatty acid metabolism.

Although PEX39's gene has been known since the human genome was mapped, its function was unknown. Using mass spectrometry and yeast models, the team showed that without PEX39, cells struggle to metabolize oleic acid a task performed only in peroxisomes. Further studies in human cells confirmed its role.

The researchers compare PEX39 to a relay runner, carrying enzymes to the peroxisome and handing them off at the membrane. Warscheid’s team now plans to study PEX39’s mechanism in detail using advanced structural and proteomic methods, aiming to shed light on poorly understood peroxisomal diseases.

Source: https://www.uni-wuerzburg.de/en/news-and-events/news/detail/news/peroxinpex39/