A Pichia pastoris VPS15 homologue is required in selective peroxisome autophagy

Methylotrophic yeasts contain large peroxisomes during growth on methanol. Upon exposure to excess glucose or ethanol these organelles are selectively degraded by autophagy, Here we describe the cloning of a Pichia pastoris g ene (PpVPS15) involved ill peroxisome degradation, which is homologous to S accharomyces cerevisiae VPS15. In methanol-grown cells of a P. pastoris VPS 15 deletion strain, the levels of peroxisomal marker enzymes remained high after addition of excess glucose or ethanol. Electron microscopic studies r evealed that the organelles were not taken up by vacuoles, suggesting that PpVPS15 is required at an early stage in peroxisome degradation.