Institut Jacques Monod, CNRS UMR 7592, Bâtiment Buffon, Paris, France.
Mol Cell Proteomics. 2011 Jun;10(6):M110.006478. doi: 10.1074/mcp.M110.006478. Epub 2011 Mar 31.
The presence of multiple membrane-bound intracellular compartments is a major feature of eukaryotic cells. Many of the proteins required for formation and maintenance of these compartments share an evolutionary history. Here, we identify the SEA (Seh1-associated) protein complex in yeast that contains the nucleoporin Seh1 and Sec13, the latter subunit of both the nuclear pore complex and the COPII coating complex. The SEA complex also contains Npr2 and Npr3 proteins (upstream regulators of TORC1 kinase) and four previously uncharacterized proteins (Sea1-Sea4). Combined computational and biochemical approaches indicate that the SEA complex proteins possess structural characteristics similar to the membrane coating complexes COPI, COPII, the nuclear pore complex, and, in particular, the related Vps class C vesicle tethering complexes HOPS and CORVET. The SEA complex dynamically associates with the vacuole in vivo. Genetic assays indicate a role for the SEA complex in intracellular trafficking, amino acid biogenesis, and response to nitrogen starvation. These data demonstrate that the SEA complex is an additional member of a family of membrane coating and vesicle tethering assemblies, extending the repertoire of protocoatomer-related complexes.
多种膜结合的细胞内隔室的存在是真核细胞的主要特征。许多形成和维持这些隔室所需的蛋白质具有共同的进化历史。在这里，我们在酵母中鉴定了 SEA（Seh1 相关）蛋白复合物，该复合物包含核孔蛋白 Seh1 和 Sec13，后者是核孔复合物和 COPII 涂层复合物的亚基。SEA 复合物还包含 Npr2 和 Npr3 蛋白（TORC1 激酶的上游调节剂）和四个以前未被表征的蛋白（Sea1-Sea4）。组合的计算和生化方法表明，SEA 复合物蛋白具有与膜涂层复合物 COPI、COPII、核孔复合物相似的结构特征，特别是与相关的 Vps 类 C 囊泡连接复合物 HOPS 和 CORVET。SEA 复合物在体内与液泡动态相关。遗传分析表明，SEA 复合物在细胞内运输、氨基酸生物发生和对氮饥饿的反应中起作用。这些数据表明，SEA 复合物是膜涂层和囊泡连接组装的另一个成员，扩展了原核蛋白相关复合物的范围。
