Sorting of furin at the trans-Golgi network -: Interaction of the cytoplasmic tail sorting signals with AP-1 Golgi-specific assembly proteins
Sorting of furin at the trans-Golgi network -: Interaction of the cytoplasmic tail sorting signals with AP-1 Golgi-specific assembly proteins
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DOI：
10.1074/jbc.274.12.8199
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发表时间：
1999-03-19
影响因子：
4.8
通讯作者：
Garten, W
中科院分区：
文献类型：
--
作者：
Teuchert, M;Schäfer, W;Garten, W
真核枯草杆菌蛋白酶样内切蛋白酶弗林蛋白酶主要存在于跨高尔基体网络 (TGN) 中，并在该区室、细胞表面和内涵体之间循环。有实验证据表明质膜的内吞作用和从内体到 TGN 的运输，但通过网格蛋白包被的囊泡从 TGN 直接退出到内体仅被讨论过，但迄今为止尚未直接显示。在这里，我们提供的数据显示，弗林蛋白酶的表达促进 TGN 处网格蛋白外壳组装的第一步，即高尔基体膜上高尔基体特异性组装蛋白 AP-I 的募集。此外，我们报告弗林蛋白酶确实存在于分离的网格蛋白包被的囊泡中，包装到网格蛋白包被的囊泡中需要弗林蛋白酶胞质结构域中的信号成分，该信号成分可以被AP-1组装蛋白识别。我们发现，除了取决于酪蛋白激酶 II 位点的磷酸化状态外，弗林蛋白酶尾部与 AP-1 及其 mu 1 亚基的相互作用还由酪氨酸基序介导，并在较小程度上由亮氨酸-异亮氨酸信号介导，而单苯丙氨酸基序仅参与与完整 AP-1 复合物的结合。这项研究表明 AP-1 或 mu 1 与弗林蛋白酶细胞质尾部的高亲和力相互作用需要信号成分的复杂相互作用，而不是一个独特的信号。
The eukaryotic subtilisin-like endoprotease furin is found predominantly in the trans-Golgi network (TGN) and cycles between this compartment, the cell surface, and the endosomes. There is experimental evidence for endocytosis from the plasma membrane and transport from endosomes to the TGN, but direct exit from the TGN to endosomes via clathrin-coated vesicles has only been discussed but not directly shown so far. Here we present data showing that expression of furin promotes the first step of clathrin-coat assembly at the TGN, the recruitment of the Golgis-specific assembly protein AP-I on Golgi membranes. Further, we report that furin indeed is present in isolated clathrin-coated vesicles, packaging into clathrin-coated vesicles requires signal components in the furin cytoplasmic domain which can be recognized by AP-1 assembly proteins. We found that besides depending on the phosphorylation state of a casein kinase II site, interaction of the furin tail with AP-1 and its mu 1subunit is mediated by a tyrosine motif and to less extent by a leucine-isoleucine signal, whereas a monophenylalanine motif is only involved in binding to the intact AP-1 complex. This study implies that high affinity interaction of AP-1 or mu 1 with the cytoplasmic tail of furin needs a complex interplay of signal components rather than one distinct signal.