Department of Food and Animal Sciences, Alabama A&M University, Normal, AL 35762, USA.
Department of Food and Animal Sciences, Alabama A&M University, Normal, AL 35762, USA.
Biochim Biophys Acta Mol Cell Biol Lipids. 2024 Dec;1869(8):159544. doi: 10.1016/j.bbalip.2024.159544. Epub 2024 Jul 31.
Yarrowia lipolytica is a model oleaginous yeast with a strong capacity for lipid accumulation, yet its lipid metabolic pathways and regulatory mechanisms remain largely unexplored. The PAH1-encoded phosphatidate (PA) phosphatase governs lipid biosynthesis by its enzymatic activity and regulating the transcription of genes involved in phospholipid biosynthesis. In this work, we examined the effect of the loss of Pah1 (i.e., pah1Δ) on cell metabolism in cells growing in low- and high-glucose media. Multi-omics analyses revealed the global effect of the pah1Δ mutation on lipid and central carbon metabolism. Lipidomics analyses showed that the pah1Δ mutation caused a massive decrease in the masses of triacylglycerol (TAG) and diacylglycerol (DAG), and these effects were independent of glucose concentration in the media. Conversely, phospholipid levels declined in low-glucose media but increased in high-glucose media. The loss of Pah1 affected the expression of genes involved in key pathways of glucose metabolism, such as glycolysis, citric acid cycle, oxidative phosphorylation, and the pentose phosphate pathway, and these effects were more pronounced in high-glucose media. In lipid biosynthesis, the genes catalyzing phosphatidylcholine (PC) synthesis from phosphatidylethanolamine (PE) were upregulated within the CDP-DAG pathway. In contrast, PC synthesis through the Kennedy pathway was downregulated. The ethanolamine branch of the Kennedy pathway that synthesizes PE was also upregulated in pah1Δ. Interestingly, we noted a massive increase in the levels of lysophospholipids, consistent with the upregulation of genes involved in lipid turnover. Overall, this work identified novel regulatory roles of Pah1 in lipid biosynthesis and gene expression.
解脂耶氏酵母是一种具有很强油脂积累能力的模式油脂酵母，但它的油脂代谢途径和调控机制在很大程度上仍未被探索。编码磷酸酯酶（PA）的 PAH1 基因编码的磷酸酶通过其酶活性控制脂质生物合成，并调节参与磷脂生物合成的基因的转录。在这项工作中，我们研究了在低葡萄糖和高葡萄糖培养基中生长的细胞中失去 Pah1（即 pah1Δ）对细胞代谢的影响。多组学分析揭示了 pah1Δ突变对脂质和中心碳代谢的全局影响。脂质组学分析表明，pah1Δ突变导致三酰基甘油（TAG）和二酰基甘油（DAG）的质量大量减少，这些影响与培养基中葡萄糖浓度无关。相反，在低葡萄糖培养基中磷脂水平下降，但在高葡萄糖培养基中增加。Pah1 的缺失影响了参与葡萄糖代谢关键途径的基因的表达，如糖酵解、柠檬酸循环、氧化磷酸化和戊糖磷酸途径，这些影响在高葡萄糖培养基中更为明显。在脂质生物合成中，从磷脂酰乙醇胺（PE）合成磷脂酰胆碱（PC）的基因在 CDP-DAG 途径中被上调。相反，通过 Kennedy 途径合成 PC 的途径被下调。通过 Kennedy 途径合成 PE 的乙醇胺分支在 pah1Δ 中也被上调。有趣的是，我们注意到溶血磷脂的水平大量增加，这与参与脂质周转的基因上调一致。总的来说，这项工作确定了 Pah1 在脂质生物合成和基因表达中的新的调控作用。
