Import of sterols into mitochondria of the yeast Saccharomyces cerevisiae

Abstract

An in vitro assay was designed to study the import of radiolabeled ergosterol and cholesterol from unilameilar vesicles into isolated mitoehondria of the yeast Saccharomyces cerevisiae.Supply of ergosterol to the mitochondrial surface was enhanced by a cytosolic fraction containing a lipid transfer protein, whereas no such additive to the assay was required for cholesterol transport. Both sterols reached the inner mitochondrial membrane. During import, they were detected in contact sites between the outer and the inner mitochondrial membrane supporting the idea, that these zones are sites of intramitochondrial lipid translocation. Transport of ergosterol between the outer and the inner mitochondrial membrane was not affected by addition of ATP, depletion of ATP caused by treatment of mitochondria with apyrase and oligomycin, and incubation with the uncoupler CCCP, indicating that this process is energy-independent.

Anaerobiosis induces complex changes in sterol esterification pattern in the yeast Saccharomyces cerevisiae

“…A plausible explanation for variation in sterol ester levels could be in a di¡erent ability of externally supplied sterols to reach endoplasmic reticulum as the site of esteri¢cation. This idea is supported by results of Taller and Daum [12] showing that cholesterol and ergosterol were delivered to yeast mitochondria by di¡erent mechanisms in a reconstituted lipid transfer assay. In addition, Soustre et al [13] showed that exogenously supplied ergosterol was incapable to downregulate transcription of ERG2 gene controlled under normal conditions by levels of endogenously synthesized ergosterol.…”

Hormone‐induced changes in cardiolipin from leydog cells: Possible involvement in intramitochondrial cholesterol translocation

“…Several pieces of evidence suggest that the formation of contact sites between outer and inner mitochondrial membranes is a necessary component for cholesterol transfer (10). In support of this hypothesis, we and others have demonstrated that mitochondrial contact sites are not only sites of protein import but also enable phospholipid (11) and sterol (12) translocation between the outer and the inner mitochondrial membrane.…”

Lipid content disturbance in the arbuscular mycorrhizal, Glomus irregulare grown in monoxenic conditions under PAHs pollution

“…It is known that mitochondrial membranes contain a certain amount of sterols (Tuller & Daum 1995). A decrease in sterol levels in the inner mitochondrial membrane is likely to affect the mitochondrial electron transport leading to the formation of ROS.…”