Phosphatidic acid and phospholipid biosynthesis

All major phospholipid classes in yeast may trace their synthesis to a common precursor: cytidine diphosphate diacylglycerol (CDP-DAG). CDP-DAG is synthesized in a reaction catalyzed by CDP-DAG synthase, which converts phosphatidic acid (PA) to CDP-DAG using cytidine triphosphate (CTP) as the CDP donor. There are two distinct CDP-DAG synthases in S. cerevisiae: Cds1p, localized in the endoplasmic reticulum (ER), and Tam41p, localized in the mitochondrial matrix. In the ER, CDP-DAG generated by Cds1p can be converted to phosphatidylinositol (PI) or phosphatidylserine (PS) via PI synthase (Pis1p) or PS synthase (Cho1p), respectively. In the mitochondrion, CDP-DAG generated by Tam41p can be sequentially converted to phosphatidylglycerol (PG), which can be further converted to cardiolipin. Synthesis of PI, PG, and cardiolipin occurs through similar mechanisms in mammalian cells; however, unlike yeast, mammals primarily synthesize PS from other phospholipids and not from CDP-DAG. Source: https://pathway.yeastgenome.org/

在酵母中，所有主要的磷脂类群或许均可追溯其合成之源至一种共同的先体：胞嘧啶二磷酸二酰甘油（CDP-DAG）。CDP-DAG的合成通过CDP-DAG合成酶的催化作用完成，该酶以胞嘧啶三磷酸（CTP）作为CDP供体，将磷脂酸（PA）转化为CDP-DAG。在酿酒酵母（S. cerevisiae）中存在两种不同的CDP-DAG合成酶：Cds1p，定位于内质网（ER）中，以及Tam41p，定位于线粒体基质中。在内质网中，由Cds1p生成的CDP-DAG可通过PI合成酶（Pis1p）或PS合成酶（Cho1p）分别转化为磷脂酰肌醇（PI）或磷脂酰丝氨酸（PS）。在线粒体中，由Tam41p生成的CDP-DAG可依次转化为磷脂酰甘油（PG），进而转化为心磷脂。PI、PG及心磷脂的合成在哺乳动物细胞中通过类似的机制进行；然而，与酵母不同，哺乳动物主要从其他磷脂而非CDP-DAG合成磷脂酰丝氨酸。资料来源：https://pathway.yeastgenome.org/