Peroxi-ome – a near-complete compendium of yeast peroxisomal proteins

The peroxisome is an organelle that hosts a myriad of essential metabolic processes, such as the metabolism of fatty acids and the detoxification of Reactive Oxygen Species (ROS). Peroxisomal loss or even dysfunction leads to severe genetic diseases. Therefore, there is great significance in the characterization of the complete peroxisomal proteome- the peroxi-ome, as a basis for understanding the various functions and processes taking place in peroxisomes. Our lab has been developing and using imaging-based screens to identify additional peroxisomal proteins in the model organism Saccharomyces cerevisiae. We have already uncovered tens of peroxisomal proteins, yet it was clear that more proteins awaited discovery. In this work, we established and utilized a collection of strains, each expressing a C terminal fusion of one yeast protein and the fluorescent protein NeonGreen on the background of a genomically integrated peroxisomal marker (Pex3-mCherry). We imaged all strains to find cases of co-localization and uncovered 11 proteins that were not observed in peroxisomes before. By defining their sub-peroxisomal localization, we found that seven are peroxisomal membrane proteins, all of which are dually localized to peroxisomes and mitochondria.

This work, alongside our previous efforts, now enables us to define a near-complete peroxi-ome in yeast.