The Saccharomyces cerevisiae YBR159w gene encodes the 3-ketoreductase of the microsomal fatty acid elongase
The Saccharomyces cerevisiae YBR159w gene encodes the 3-ketoreductase of the microsomal fatty acid elongase
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DOI：
10.1074/jbc.m205620200
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发表时间：
2002-09-20
影响因子：
4.8
通讯作者：
Dunn, TM
中科院分区：
文献类型：
--
作者：
Han, GS;Gable, K;Dunn, TM
YBR159w基因编码超长链脂肪酸(VLCFA)合成所需的延伸酶系统的主要3-酮还原酶活性。缺乏YBR159w基因的突变体表现出许多以前所描述的脂肪酸延长缺陷突变体的表型。这些表型包括VLCFA合成减少，高水平的二氢鞘氨醇和植鞘氨醇的积累，以及中链神经酰胺的积累。体外伸长实验证实，ybr159Delta突变体在脂肪酸伸长中间产物3-酮酰基的还原方面存在缺陷。Ybr159Delta突变体还表现出脂肪酸伸长的3-OH酰基中间体的脱水减少，这表明Ybr159p是伸长酶系统脱水酶活性稳定或发挥功能所必需的。绿色荧光蛋白标记的Ybrl59p与其他伸长酶Elo3p和Tsc13p共定位和共沉淀。虽然V-LCFA的合成是生存所必需的，但ybr159 Delta突变细胞是有活力的(尽管生长非常缓慢)，并确实合成了一些VLCFA。这表明Ybr159p存在一个功能同源基因，它负责剩余的3-酮还原酶活性。通过破坏ybr159 Delta突变体中Ybr159w的直系物，我们发现ybr159 Deltaayr1Delta双突变体是不活的，这表明Ayr1p负责剩余的3-酮还原酶活性。
The YBR159w gene encodes the major 3-ketoreductase activity of the elongase system of enzymes required for very long-chain fatty acid (VLCFA) synthesis. Mutants lacking the YBR159w gene display many of the phenotypes that have previously been described for mutants with defects in fatty acid elongation. These phenotypes include reduced VLCFA synthesis, accumulation of high levels of dihydrosphingosine and phytosphingosine, and accumulation of medium-chain ceramides. In vitro elongation assays confirm that the ybr159Delta mutant is deficient in the reduction of the 3-ketoacyl intermediates of fatty acid elongation. The ybr159Delta mutant also displays reduced dehydration of the 3-OH acyl intermediates of fatty acid elongation, suggesting that Ybr159p is required for the stability or function of the dehydratase activity of the elongase system. Green fluorescent protein-tagged Ybrl59p co-localizes and co-immunoprecipitates with other elongating enzymes, Elo3p and Tsc13p. Whereas V-LCFA synthesis is essential for viability, the ybr159Delta mutant cells are viable (albeit very slowly growing) and do synthesize some VLCFA. This suggested that a functional ortholog of Ybr159p exists that is responsible for the residual 3-ketoreductase activity. By disrupting the orthologs of Ybr159w in the ybr159Delta mutant we found that the ybr159Deltaayr1Delta double mutant was inviable, suggesting that Ayr1p is responsible for the residual 3-ketoreductase activity.