Pex3-mediated peroxisomal membrane contact sites in yeast

Abstract

Cell organelles are compartments that occur in eukaryotic cells (for instance plant, animal or fungal cells). Recent studies indicated that cell organelles do not function in isolation, but extensively communicate and collaborate with each other. For these processes membrane contact sites are very important. Membrane contact sites are regions where two membranes form tight physical associations. These contact sites play roles in multiple important cellular processes, such as transport of various molecules like lipids, organelle formation and fission, organelle positioning and degradation. Peroxisomes are cell organelles that occur in almost all eukaryotic cells. Peroxisomes have been implicated in multiple functions including the detoxification of hydrogen peroxide and cellular lipid metabolism. In human, defects in peroxisome formation or function cause various symptoms and often are lethal. The research described in this thesis focuses on peroxisomal contact sites, using yeast as model organism. The research resulted in the identification of two novel contact sites, namely peroxisome-vacuole and peroxisome-plasma membrane contact sites. These contacts are important for peroxisomal membrane expansion and peroxisomal anchoring, respectively. The formation of both contacts require the peroxisomal membrane protein Pex3.