Vacuolar transport and function of <i>Saccharomyces cerevisiae</i> sterol ester hydrolase Tgl1

Sterol ester hydrolases (SEHs) play an important role in the quantitative regulation of sterols. Mammalian cells are known to possess SEHs both on the surface of lipid droplets and inside lysosomes. However, to date, no studies on the yeast Saccharomyces cerevisiae have identified active SEHs in the vacuole, which is the corresponding organelle to the mammalian lysosome. Here, we show that S. cerevisiae Tgl1 functions as the major SEH in the vacuole after being transported into the organelle lumen, in addition to its role in the cytoplasm. The transport of Tgl1 into the vacuole was independent of macroautophagy and ESCRT (endosomal sorting complex required for transport) complex-0 component Vps27 but dependent on ESCRT-I-III components. This study also revealed the mechanism of formation of vacuolar membrane microdomains supported by the SEHs.