| Abstract |
Changes in plasma membrane permeability caused by H(2)O(2) were recently found to be involved in the adaptation to H(2)O(2), but the mechanism responsible for this change remains largely unknown. Here this mechanism was addressed and two lines of evidence showed for the first time that fatty acid synthase (Fas) plays a key role during the cellular response of Saccharomyces cerevisiae to H(2)O(2): (1) adaptation was associated with a decrease in both Fas expression and activity; (2) more importantly, decreasing Fas activity by 50\% through deletion of one of the FAS alleles increased the resistance to lethal doses of H(2)O(2). The mechanism by which a decrease of Fas expression causes a higher resistance to H(2)O(2) was not fully elucidated. However, the fas1 Delta strain plasma membrane had large increases in the levels of lignoceric acid (C24:0) (40\%) and cerotic acid (C26:0) (50\%), suggesting that alterations in the plasma membrane composition are involved. Very-long-chain fatty acids (VLCFA) through interdigitation or by modulating fort-nation of lipid rafts may decrease the overall or localized plasma membrane permeability to H(2)O(2), respectively, thus conferring a higher resistance to H(2)O(2). (C) 2007 Elsevier Inc. All rights reserved. |
