PLD1 and ERK2 regulate cytosolic lipid droplet formation
PLD1 and ERK2 regulate cytosolic lipid droplet formation
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DOI：
10.1242/jcs.02941
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发表时间：
2006-06-01
影响因子：
4
通讯作者：
Olofsson, Sven-Olof
中科院分区：
文献类型：
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作者：
Andersson, Linda;Bostrom, Pontus;Olofsson, Sven-Olof
我们之前已经发现了磷脂酶D （PLD）和一种未知的细胞质蛋白在使用无细胞系统形成细胞质脂滴中的作用。在本报告中，PLD1被确定为相关亚型，细胞外信号调节激酶2 （ERK2）被确定为胞质蛋白。PLD1表达的增加增加了脂滴的形成，而使用siRNA敲低PLD1则具有抑制作用。ERK2在基础脂滴形成中的作用通过过表达或显微注射，以及siRNA敲低或药物抑制的消融被揭示。其他Map激酶如ERK1、JNK1或JNK2和p38 α或p38 β的类似操作没有效果。胰岛素刺激脂滴的形成，这种刺激被PLD1（通过siRNA）的敲低和ERK2（通过siRNA）的抑制或敲低所抑制。抑制ERK2消除了PLD1对脂滴形成的影响，而不影响PLD1的活性，这表明PLD1在ERK2的上游起作用。ERK2增加了动力蛋白的磷酸化，从而增加了含有adrp的脂滴上的蛋白量。微量注射动力蛋白抗体强烈抑制脂滴的形成，表明动力蛋白在脂滴形成中起核心作用。因此动力蛋白可能是ERK2的靶标。
We have previously uncovered roles for phospholipase D (PLD) and an unknown cytosolic protein in the formation of cytosolic lipid droplets using a cell-free system. In this report, PLD1 has been identified as the relevant isoform, and extracellular signal-regulated kinase 2 (ERK2) as the cytosolic protein. Increased expression of PLD1 increased lipid droplet formation whereas knockdown of PLD1 using siRNA was inhibitory. A role for ERK2 in basal lipid droplet formation was revealed by overexpression or microinjection, and ablation by siRNA knockdown or pharmacological inhibition. Similar manipulations of other Map kinases such as ERK1, JNK1 or JNK2 and p38 alpha or p38 beta were without effect. Insulin stimulated the formation of lipid droplets and this stimulation was inhibited by knockdown of PLD1 ( by siRNA) and by inhibition or knockdown ( by siRNA) of ERK2. Inhibition of ERK2 eliminated the effect of PLD1 on lipid droplet formation without affecting PLD1 activity, suggesting that PLD1 functions upstream of ERK2. ERK2 increased the phosphorylation of dynein which increased the amount of the protein on ADRP-containing lipid droplets. Microinjection of antibodies to dynein strongly inhibited the formation of lipid droplets, demonstrating that dynein has a central role in this formation. Thus dynein is a possible target for ERK2.