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

Yeast Saccharomyces cervisiae is auxotrophic for ergosterol in the absence of oxygen. We showed that complex changes in esterification of exogenously supplied sterols were also induced by anaerobiosis. Utilization of oleic ac id for sterol esterification was significantly impaired in aerobic cells. F urthermore, anerobic cells fed different sterols exhibited striking variati on in esterification efficiency (high levels of sterol esters for cholester ol and sitosterol, low levels for ergosterol, lanosterol or stigmasterol). Relative activities of two yeast acylCoA:sterol acyltransferases (Are1p and Are2p) changed in response to anaerobiosis: while Are2p was dominant under aerobic conditions Are1p provided the major activity in the absence of oxy gen. Our results indicate that sterol esters may fulfil different roles in aerobic and anaerobic cells. (C) 2001 Federation of European Microbiologica l Societies. Published by Elsevier Science B.V. All rights reserved.