Dysferlin-containing proteins and peroxisome proliferation

The research goals of the proposed project aim to better understand biological systems at the level of organelle function and proliferation. Compartmentalization of biochemical pathways is an essential property of eukaryotic cells. This structural differentiation, however, requires orchestration and constant remodeling of the cellular content during various physiological conditions. Throughout these changes organelles vary in shape, proliferate, generate or degrade metabolites and ultimately contribute to the cellular response to the environment providing the necessary structural framework. Hence, organelles participate in the establishment of tolerance to various deleterious assaults. Consequently, defects in the function of sub-cellular organelles are the cause of lethal disorders. In this project we propose to move on from identification of novel components of a system to a full understanding of the macromolecular architecture of this system. Peroxisomes are vital organelles. Their function mostly comprises lipid metabolism and they enclose the hydrogen peroxide degrading enzyme catalase making them essential for cellular detoxification. Although their biochemical function has been documented, information on their proliferation mechanism is still limited. To tackle this problem we chose to concentrate on peroxisomal membrane proteins containing among functionally uncharacterized domains a dysferlin domain usually involved in membrane partitioning processes, especially on Peroxin 30. Resolving the structural and functional domains of integral membrane proteins takes a significant step ahead within post-genomic research. Here we wish to establish the function and spatiotemporal dynamics of Peroxin 30 both in yeast and human cells. For this we will pinpoint its interaction partners, characterize its functional motifs and identify components of protein complexes via mass spectrometry. To understand the exact function of Peroxin 30 in peroxisome proliferation its dynamics will be followed using biochemical as well as live imaging techniques upon optimal growth conditions and oxidative stress assaults. We anticipate the results of our study to provide a better comprehension of the formation of membranes in eukaryotic cells and novel insights on their vulnerability to oxidative insults.