Studies on regulatory mechanisms of phospholipid-metabolizing enzymes

我们将编码二酰基甘油激酶（KGK）和磷脂酸磷酸酶（PAP9）的cdna转染到培养细胞中，并研究了它们在细胞内的定位和催化活性。我们发现dgk - δ通过其c端SAM结构域作为锚定信号与内质网结合。我们还注意到，市售的DGK抑制剂如R59022对钙依赖性DGK同工酶具有选择性，我们将其归类为I型同工酶。在PAP的情况下，我们发现在HEK293细胞中表达的PAP-2b作为胞外溶磷脂酸水解的外酶。我们目前正在研究PAP-2s在非空泡筏微域定位的生理意义。

We transfected into cultured cells cDNAs coding for diacylglycerol kinase(KGK) and phosphatidic acid phosphatase(PAP9, and investigated their intracellular localization and catalytic activities. We found that DGK-delta binds to the endoplasmic reticulum through its C-terminal SAM domain serving as an anchoring signal. We also noted that the commercially available DGK inhibitors such as R59022 are selective to calcium-dependent DGK isozymes classified by us as type I isozymes.In the case of PAP, we showed that PAP-2b expressed in HEK293 cells acts as an ectoenzyme hydrolyzing extracellular lyso-phosphatidic acid. We are currently studying the physiological implication of the localization of PAP-2s in non-caveolar raft microdomains.