Sequential actions of phospholipase D and phosphatidic acid phosphohydrolase 2b generate diglyceride in mammalian cells
Sequential actions of phospholipase D and phosphatidic acid phosphohydrolase 2b generate diglyceride in mammalian cells
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DOI：
10.1091/mbc.10.11.3863
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发表时间：
1999-11-01
影响因子：
3.3
通讯作者：
Morris, AJ
中科院分区：
文献类型：
--
作者：
Sciorra, VA;Morris, AJ
磷脂酰胆碱（PC）是脂质衍生的第二信使分子的主要来源，作为细胞内和细胞外的信号。pc特异性磷脂酶D （PLD）和磷脂酸磷酸水解酶（PAP）是该信号系统中的两个关键酶，它们串联作用产生具有生物活性的脂质磷脂酸（PA）和二甘油酯。参与pld介导的信号转导的PAP酶的身份尚不清楚。我们为2型PAP （PAP2b）在pld产生的PA代谢中的功能作用提供了第一个证据。我们的数据表明，PAP2b定位于PLD水解PC的细胞区域。利用新开发的PAP2b特异性抗体，我们鉴定了内源性PAP2b的表达、翻译后修饰和定位。PAP2b的糖基化和定位似乎具有细胞类型和组织特异性。生化分离和免疫沉淀分析显示，PAP2b和PLD2活性存在于富含小窝蛋白-1的耐洗涤剂膜微域中。我们发现PLD2和PAP2b在这个特殊的膜室中依次产生双甘油酯。这些膜的独特脂质组成可能为通过PC水解参与信号传导的酶的调节和作用提供了一个选择性的环境。
Phosphatidylcholine (PC) is a major source of lipid-derived second messenger molecules that function as both intracellular and extracellular signals. PC-specific phospholipase D (PLD) and phosphatidic acid phosphohydrolase (PAP) are two pivotal enzymes in this signaling system, and they act in series to generate the biologically active lipids phosphatidic acid (PA) and diglyceride. The identity of the PAP enzyme involved in PLD-mediated signal transduction is unclear. We provide the first evidence for a functional role of a type 2 PAP, PAP2b, in the metabolism of PLD-generated PA. Our data indicate that PAP2b localizes to regions of the cell in which PC hydrolysis by PLD is taking place. Using a newly developed PAP2b-specific antibody, we have characterized the expression, posttranslational modification, and localization of endogenous PAP2b. Glycosylation and localization of PAP2b appear to be cell type and tissue specific. Biochemical fractionation and immunoprecipitation analyses revealed that PAP2b and PLD2 activities are present in caveolin-1-enriched detergent-resistant membrane microdomains. We found that PLD2 and PAP2b act sequentially to generate diglyceride within this specialized membrane compartment. The unique lipid composition of these membranes may provide a selective environment for the regulation and actions of enzymes involved in signaling through PC hydrolysis.