CARTS biogenesis requires VAP-lipid transfer protein complexes functioning at the endoplasmic reticulum-Golgi interface.
CARTS biogenesis requires VAP-lipid transfer protein complexes functioning at the endoplasmic reticulum-Golgi interface.
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DOI：
10.1091/mbc.e15-08-0599
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发表时间：
2015-12-15
影响因子：
3.3
通讯作者：
Tagaya M
中科院分区：
文献类型：
--
作者：
Wakana Y;Kotake R;Oyama N;Murate M;Kobayashi T;Arasaki K;Inoue H;Tagaya M
tgn衍生转运载体cart的生物发生需要内质网蛋白VAP和高尔基脂质转移蛋白、神经酰胺转移蛋白和OSBP。Sac1脂质磷酸酶被募集到与反式高尔基/TGN密切相关的ER亚结构域形成的VAP-OSBP复合体上。er -高尔基接触的缔合-离解动力学对cart的形成至关重要。囊泡相关膜蛋白相关蛋白（VAP）是一种驻留在内质网（ER）的整体膜蛋白，通过分别与神经酰胺转移蛋白和氧甾醇结合蛋白（OSBP）相互作用，控制神经酰胺和胆固醇从内质网转移到高尔基复合体的非囊泡模式。我们报道VAP及其相互作用蛋白是胰腺腺癌上调因子的加工和分泌所必需的，其从反式高尔基网络（TGN）转运到细胞表面是由称为“反式高尔基网络转运载体”（cart）的转运载体介导的。在vap缺失的细胞中，TGN的二酰基甘油水平降低，cart的形成受损。我们发现VAP不仅与OSBP，还与Sac1磷酸肌肽磷酸酶在与反式高尔基/TGN密切相关的特殊ER亚域上形成复合物，很可能反映了膜接触位点。固定化er -高尔基接触显著减少了cart的产生，表明两种膜的结合-解离动力学是重要的。基于这些发现，我们提出er -高尔基接触在脂质代谢中起关键作用，从而控制TGN转运载体的生物发生。
Biogenesis of the TGN-derived transport carriers CARTS requires the ER protein VAP and Golgi lipid transfer proteins, ceramide transfer protein and OSBP. Sac1 lipid phosphatase is recruited to a VAP–OSBP complex formed at an ER subdomain closely apposed to the trans-Golgi/TGN. Association–dissociation dynamics of ER–Golgi contacts are important for CARTS formation. Vesicle-associated membrane protein–associated protein (VAP) is an endoplasmic reticulum (ER)-resident integral membrane protein that controls a nonvesicular mode of ceramide and cholesterol transfer from the ER to the Golgi complex by interacting with ceramide transfer protein and oxysterol-binding protein (OSBP), respectively. We report that VAP and its interacting proteins are required for the processing and secretion of pancreatic adenocarcinoma up-regulated factor, whose transport from the trans-Golgi network (TGN) to the cell surface is mediated by transport carriers called “carriers of the trans-Golgi network to the cell surface” (CARTS). In VAP-depleted cells, diacylglycerol level at the TGN was decreased and CARTS formation was impaired. We found that VAP forms a complex with not only OSBP but also Sac1 phosphoinositide phosphatase at specialized ER subdomains that are closely apposed to the trans-Golgi/TGN, most likely reflecting membrane contact sites. Immobilization of ER–Golgi contacts dramatically reduced CARTS production, indicating that association–dissociation dynamics of the two membranes are important. On the basis of these findings, we propose that the ER–Golgi contacts play a pivotal role in lipid metabolism to control the biogenesis of transport carriers from the TGN.