Oleaginous yeasts have the ability to store greater than 20% of their mass as neutral lipids, in the form of triacylglycerides. The ATP citrate lyase is thought to play a key role in triacylglyceride synthesis, but the relationship between expression levels of this and other related enzymes is not well understood in the role of total lipid accumulation conferring the oleaginous phenotype. We conducted comparative proteomic analyses with the oleaginous yeast, Yarrowia lipolytica, grown in either nitrogen-sufficient rich media or nitrogen-limited minimal media. Total proteins extracted from cells collected during logarithmic and late stationary growth phases were analyzed by 1D liquid chromatography, followed by mass spectroscopy. The ATP citrate lyase enzyme was expressed at similar concentrations in both conditions, in both logarithmic and stationary phase, but many upstream and downstream enzymes showed drastically different expression levels. In non-lipogenic conditions, several pyruvate enzymes were expressed at higher concentration. These enzymes, especially the pyruvate decarboxylase and pyruvate dehydrogenase, may be regulating carbon flux away from central metabolism and reducing the amount of citrate being produced in the mitochondria. While crucial for the oleaginous phenotype, the constitutively expressed ATP citrate lyase appears to cleave citrate in response to carbon flux upstream from other enzymes creating the oleaginous phenotype.

中文翻译：

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解脂耶氏酵母蛋白质组的分析揭示了脂肪生成和非脂肪生成条件之间表达水平的细微变化

产油酵母能够以甘油三酯的形式将其质量的 20% 以上作为中性脂质储存。ATP柠檬酸裂解酶被认为在甘油三酯合成中起关键作用，但在总脂质积累赋予含油表型的作用中，这种酶和其他相关酶的表达水平之间的关系尚不清楚。我们对产油酵母 Yarrowia lipolytica 进行了比较蛋白质组学分析，该酵母在氮充足的富培养基或氮限制的基本培养基中生长。通过一维液相色谱分析从对数和晚期静止生长期收集的细胞中提取的总蛋白质，然后进行质谱分析。ATP柠檬酸裂解酶在两种条件下的表达浓度相似，在对数和静止期，但许多上游和下游酶显示出截然不同的表达水平。在非脂肪生成条件下，几种丙酮酸酶以较高浓度表达。这些酶，尤其是丙酮酸脱羧酶和丙酮酸脱氢酶，可能正在调节远离中心代谢的碳通量，并减少线粒体中产生的柠檬酸盐的量。虽然对含油表型至关重要，但组成型表达的 ATP 柠檬酸裂合酶似乎响应于其他酶上游的碳通量而裂解柠檬酸，从而产生含油表型。尤其是丙酮酸脱羧酶和丙酮酸脱氢酶，可能正在调节远离中心代谢的碳通量并减少线粒体中产生的柠檬酸盐的量。虽然对含油表型至关重要，但组成型表达的 ATP 柠檬酸裂合酶似乎响应于其他酶上游的碳通量而裂解柠檬酸，从而产生含油表型。尤其是丙酮酸脱羧酶和丙酮酸脱氢酶，可能正在调节远离中心代谢的碳通量并减少线粒体中产生的柠檬酸盐的量。虽然对含油表型至关重要，但组成型表达的 ATP 柠檬酸裂合酶似乎响应于其他酶上游的碳通量而裂解柠檬酸，从而产生含油表型。