Millar C A, Jess T J, Saqib K M, Wakelam M J, Gould G W
Division of Biochemistry and Molecular Biology, Davidson Building, Glasgow, G12 8QQ, Scotland.
Biochem Biophys Res Commun. 1999 Jan 27;254(3):734-8. doi: 10.1006/bbrc.1998.0110.
Phospholipase D has been implicated as an important enzyme in a range of cellular responses, including regulated secretion and the formation of secretory vesicles, cell proliferation and control of cell morphology. As insulin treatment of adipocytes has been shown to stimulate a phosphatidylcholine-specific phospholipase D and also modulates membrane trafficking, we wished to determine which isoform(s) of phospholipase D were present within adipocytes, to identify their subcellular distribution, and examine how this distribution may change in response to insulin. Using RT-PCR, 3T3-L1 adipocytes were found to express two isoforms of phospholipase D, specifically PLD1b and PLD2a. Using isoform-specific antibodies, PLD1 and PLD2 were found to be present predominantly in intracellular membranes, unlike the situation reported in other cells. Detailed analysis of the intracellular localisation of PLD1 and PLD2 revealed that these isoforms are differentially localised within adipocytes, implying functionally distinct roles for PLD activity in distinct subcellular compartments.
磷脂酶D被认为是一系列细胞反应中的一种重要酶，这些反应包括调节性分泌和分泌小泡的形成、细胞增殖以及细胞形态的控制。由于已证明胰岛素处理脂肪细胞可刺激一种磷脂酰胆碱特异性磷脂酶D，并且还可调节膜运输，我们希望确定脂肪细胞内存在哪些磷脂酶D同工型，以识别它们的亚细胞分布，并研究这种分布如何响应胰岛素而发生变化。使用逆转录聚合酶链反应（RT-PCR），发现3T3-L1脂肪细胞表达两种磷脂酶D同工型，即PLD1b和PLD2a。使用同工型特异性抗体，发现PLD1和PLD2主要存在于细胞内膜中，这与其他细胞中报道的情况不同。对PLD1和PLD2细胞内定位的详细分析表明，这些同工型在脂肪细胞内的定位不同，这意味着PLD活性在不同亚细胞区室中具有功能上不同的作用。
