Pathre Purnima, Shome Kuntala, Blumental-Perry Anna, Bielli Anna, Haney Charles J, Alber Sean, Watkins Simon C, Romero Guillermo, Aridor Meir
Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, 3500 Terrace Street, Pittsburgh, PA 15261, USA.
EMBO J. 2003 Aug 15;22(16):4059-69. doi: 10.1093/emboj/cdg390.
The small GTPase Sar1p controls the assembly of the cytosolic COPII coat that mediates export from the endoplasmic reticulum (ER). Here we demonstrate that phospholipase D (PLD) activation is required to support COPII-mediated ER export. PLD activity by itself does not lead to the recruitment of COPII to the membranes or ER export. However, PLD activity is required to support Sar1p-dependent membrane tubulation, the subsequent Sar1p-dependent recruitment of Sec23/24 and Sec13/31 COPII complexes to ER export sites and ER export. Sar1p recruitment to the membrane is PLD independent, yet activation of Sar1p is required to stimulate PLD activity on ER membranes, thus PLD is temporally regulated to support ER export. Regulated modification of membrane lipid composition is required to support the cooperative interactions that enable selective transport, as we demonstrate here for the mammalian COPII coat.
小GTP酶Sar1p控制着胞质COPII衣被的组装，该衣被介导从内质网（ER）输出。在此我们证明，磷脂酶D（PLD）的激活是支持COPII介导的ER输出所必需的。PLD活性本身不会导致COPII募集到膜上或ER输出。然而，PLD活性是支持Sar1p依赖性膜微管形成、随后Sar1p依赖性地将Sec23/24和Sec13/31 COPII复合物募集到ER输出位点以及ER输出所必需的。Sar1p募集到膜上不依赖于PLD，但需要激活Sar1p来刺激ER膜上的PLD活性，因此PLD在时间上受到调控以支持ER输出。正如我们在此针对哺乳动物COPII衣被所证明的，需要对膜脂质组成进行调控修饰以支持能够实现选择性转运的协同相互作用。
