The peroxisome proliferation machinery in yeast

PhD ceremony: mw. S. Nagotu, 13.15 uur, Academiegebouw, Broerstraat 5, Groningen

Thesis: The peroxisome proliferation machinery in yeast

Promotor(s): mw. prof.dr. I.J. van der Klei

Faculty: Mathematics and Natural Sciences

Contact: Shirisha Nagotu, tel. 050-363 23177, e-mail: s.nagotu@rug.nl

Cell organelles are membrane bound structures that are present in eukaryotic cells (e.g. yeast, plant or mammalian cells). These organelles perform highly specialized functions, such as the generation of energy or the recycling of waste material. Peroxisomes are cell organelles that are capable to perform various chemical reactions. In man they are involved in the degradation of specific fatty acids as well as in the production of certain lipids. The importance of these pathways is stressed by the observation that several human disorders exist due to defects in the formation of these organelles.

The topic of this thesis is to answer the question how peroxisomes are formed in a cell. Are they formed by fission of pre-existing ones or can they be derived from another type of organelle, the endoplasmic reticulum? And what are the proteins involved in these processes?

The main conclusion from this work is that the bulk of the peroxisomes are formed by division of pre-existing ones. The proteins required for this process in yeast are identified in this study. Cells which lack any of these proteins are blocked in division of peroxisomes and hence have only one single enlarged peroxisome per cell. The results also show that two different organelles in a cell the peroxisome and the mitochondrion have the same fission machinery. This finding provides novel leads to studies on peroxisome formation in different organisms.