Yeast cells accumulate excess endogenous palmitate in phosphatidylcholine by acyl chain remodeling involving the phospholipase B Plb1p
Yeast cells accumulate excess endogenous palmitate in phosphatidylcholine by acyl chain remodeling involving the phospholipase B Plb1p
复制标题
DOI：
10.1016/j.bbalip.2013.03.002
复制
发表时间：
2013-06-01
影响因子：
4.8
通讯作者：
de Kroon, Anton I. P. M.
中科院分区：
文献类型：
--
作者：
De Smet, Cedric H.;Cox, Ruud;de Kroon, Anton I. P. M.
在酿酒酵母中，主要膜甘油磷脂磷脂酰胆碱（PC）的分子种类分布是由生物合成途径的分子种类选择性和酰基链重塑决定的。甘油-3-磷酸酰基转移酶Sct 1 p的过表达最近被证明诱导棕榈酸酯（C16：0）的细胞含量的强烈增加。使用稳定同位素标记和质谱，本研究表明，野生型酵母过度表达Sct 1 p通过PE的甲基化，CDP-胆碱途径和合成后酰基链重塑将过量的C16：0并入PC。Sct 1 p的过表达增加了PE衍生PC的重塑程度，为PC酰基链交换机制的研究提供了一种新的工具。酰基链的交换发生在PC的甘油骨架的sn-1和sn-2位置处，并且需要磷脂酶B Plb 1 p以获得最佳效率。Sct 1 p催化的酰基链交换，酰基辅酶A结合蛋白Acb 1 p，Plb 1 p同系物Plb 2 p，和甘油磷脂：三酰甘油转酰酶Lro 1 p是不需要PC重塑。结果表明，PC可作为过量细胞C16：0的缓冲剂。(C)2013爱思唯尔有限公司版权所有。
In the yeast Saccharomyces cerevisiae, the molecular species profile of the major membrane glycerophospholipid phosphatidylcholine (PC) is determined by the molecular species-selectivity of the biosynthesis routes and by acyl chain remodeling. Overexpression of the glycerol-3-phosphate acyltransferase Sct1p was recently shown to induce a strong increase in the cellular content of palmitate (C16:0). Using stable isotope labeling and mass spectrometry, the present study shows that wild type yeast overexpressing Sct1p incorporates excess C16:0 into PC via the methylation of PE, the CDP-choline route, and post-synthetic acyl chain remodeling. Overexpression of Sct1p increased the extent of remodeling of PE-derived PC, providing a novel tool to perform mechanistic studies on PC acyl chain exchange. The exchange of acyl chains occurred at both the sn-1 and sn-2 positions of the glycerol backbone of PC, and required the phospholipase B Plb1p for optimal efficiency. Sct1p-catalyzed acyl chain exchange, the acyl-CoA binding protein Acb1p, the Plb1p homologue Plb2p, and the glycerophospholipid:triacylglycerol transacylase Lro1p were not required for PC remodeling. The results indicate that PC serves as a buffer for excess cellular C16:0. (C) 2013 Elsevier B.V. All rights reserved.