Depletion of phosphatidylcholine in yeast induces shortening and increased saturation of the lipid acyl chains: Evidence for regulation of intrinsic membrane curvature in a eukaryote
Depletion of phosphatidylcholine in yeast induces shortening and increased saturation of the lipid acyl chains: Evidence for regulation of intrinsic membrane curvature in a eukaryote
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DOI：
10.1091/mbc.e05-04-0344
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发表时间：
2006-02-01
影响因子：
3.3
通讯作者：
de Kroon, AIPM
中科院分区：
文献类型：
--
作者：
Boumann, HA;Gubbens, J;de Kroon, AIPM
为了研究耗尽主要膜磷脂磷脂酰胆碱（PC）的后果，将酵母cho2opi3双缺失突变体的指数生长细胞从含胆碱的培养基转移到无胆碱的培养基中。4 ~ 5代后，PC水平降至总磷脂的2%以下，细胞生长才停止。增加的磷脂酰乙醇胺（PE）和磷脂酰肌醇含量弥补了PC的损失。质谱分析显示，在PC耗竭过程中，剩余的PC发生酰基链重塑，单不饱和物种取代了双不饱和物种。PC的重塑不需要spo14编码的磷脂酶d的转换。发现PC物种谱的变化反映了细胞酰基链组成的整体变化，C16比C18酰基链的比例增加了40%，饱和程度增加了10%。这种变化在磷脂中比在中性脂类中更强烈，在PE的物种剖面中最强。聚乙烯酰基链的缩短和饱和度的增加降低了聚乙烯的非双分子层倾向。结果指出酵母的调节机制，维持内在的膜曲率在最佳范围内。
To study the consequences of depleting the major membrane phospholipid phosphatidylcholine (PC), exponentially growing cells of a yeast cho2opi3 double deletion mutant were transferred from medium containing choline to choline-free medium. Cell growth did not cease until the PC level had dropped below 2% of total phospholipids after four to five generations. Increasing contents of phosphatidylethanolamine (PE) and phosphatidylinositol made up for the loss of PC. During PC depletion, the remaining PC was subject to acyl chain remodeling with monounsaturated species replacing diunsaturated species, as shown by mass spectrometry. The remodeling of PC did not require turnover by the SPO14-encoded phospholipase D. The changes in the PC species profile were found to reflect an overall shift in the cellular acyl chain composition that exhibited a 40% increase in the ratio of C16 over C18 acyl chains, and a 10% increase in the degree of saturation. The shift was stronger in the phospholipid than in the neutral lipid fraction and strongest in the species profile of PE. The shortening and increased saturation of the PE acyl chains were shown to decrease the nonbilayer propensity of PE. The results point to a regulatory mechanism in yeast that maintains intrinsic membrane curvature in an optimal range.