Transport across the yeast peroxisomal membrane
Transport across the yeast peroxisomal membrane
The eukaryotic cell consists of multiple membrane-enclosed compartments, namely organelles. These organelles serve in numerous biological and chemical reactions. One of these organelles is the peroxisome, which is found in most cell types. In mammalian cells, defects in genes related to peroxisomes cause a spectrum of severe genetic disorders, often with devastating results. To investigate further, yeast is applied as a model organism for peroxisome research.
Proteins located in the yeast peroxisomal matrix are involved in the beta-oxidation breakdown of fatty acids, amino acids biosynthesis, hydrogen peroxide neutralization, redox balancing, and the glyoxylate cycle. All these biochemical reactions and pathways are known to require a substrate and produce a product.
However, only a few peroxisomal membrane transport proteins have been identified. Such transport proteins are required to facilitate the exchange of substrates and products between the cytosol and the peroxisomal matrix. This thesis aims to elucidate the mechanisms of transport across the yeast peroxisomal membrane.
This thesis provides an updated yeast peroxisomal metabolic map and the enzymes required to assist in catabolic conversions. From this map, we deduce a number of theoretical transport proteins required to facilitate exchange. Furthermore, the experimental part presents 3 previously known transport proteins to localize to the peroxisomal membrane. Namely, Mir1, a proton/phosphate symporter, and Mpc1/Mpc3 as pyruvate exporters across the peroxisomal membrane. Also, we provide evidence that the unfolded peptide domains of the protein Nsp1 can be imported to the peroxisomal matrix.