Novel Peroxisome–Vacuole Contacts in Yeast

Peroxisomes are important organelles and present in almost all eukaryotic cells. Close associations between peroxisomes and other cell compartments are known for several decades. The first molecular details of physical contacts between peroxisomes and various other organelles are now beginning to emerge. We recently described a novel contact between peroxisomes and vacuoles in the yeast Hansenula polymorpha, which develops during conditions of strong peroxisome proliferation. At such conditions, Pex3-GFP forms focal patches at the peroxisome–vacuole contacts, while overproduction of Pex3 promotes their formation. These results reveal a novel function for Pex3 in the formation of these contacts, where it might act as a tethering protein. We speculate that the peroxisome–vacuole contact is important for membrane lipid transfer at conditions of strong organellar expansion.