Use of Pichia pastoris as a Model Eukaryotic System: Peroxisome Biogenesis

Many subcellular processes present in multicellular eukaryotes have been shown to reside in yeast as well. The ease with which yeasts are genetically manipulated and analyzed by biochemical and ultrastructural techniques has greatly contributed to the present knowledge of these processes. In particular, the biogenesis, maintenance, and functions of the different subcellular organelles have been intensively studied in yeast. Saccharomyces cerevisiae has been the yeast of choice when the organelles under study are constitutively present in the cell, such as mitochondria, nucleus, Golgi, and the endoplasmic reticulum. In contrast, peroxisome biogenesis is studied in a variety of yeast species, mainly because the abundance of this organelle is highly inducible by external factors. Several nonconventional yeast species show a much more pronounced peroxisome proliferation than does S. cerevisiae (1 –6 ).