Crystal structure of the clathrin adaptor protein 1 core
Crystal structure of the clathrin adaptor protein 1 core
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DOI：
10.1073/pnas.0406102101
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发表时间：
2004-09-28
影响因子：
11.1
通讯作者：
Harrison, SC
中科院分区：
文献类型：
--
作者：
Heldwein, EE;Macia, E;Harrison, SC
异四聚体接头蛋白（AP复合物）将网格蛋白包被的囊泡的外晶格与膜锚定的货物分子连接起来。我们报道了AP-1复合物核心的晶体结构，它在反式高尔基网络（TGN）中起作用。在晶体中填充配合物会产生异常长的（1135埃）单胞轴，但6倍的非晶体冗余产生了4埃分辨率的优秀图。AP-1核心包括两条大链beta1和gamma的n端片段，以及完整的中、小链mu1和sigma1。它的分子结构与AP-2的核心非常相似，AP-2是一种质膜特异性适配器，其结构已经确定。这两种结构都代表了一种“非活性”构象，与基于酪氨酸的分类信号的货物结合有关。AP-1的TGN定位取决于小GTPase Arf1和磷酸肌苷PI-4-P。我们表明，伽马链特定角落残基的定向突变阻止了细胞中TGN的募集，并减少了pi -4- p依赖的脂质体结合，但不是arf1依赖的。
The heterotetrameric adaptor proteins (AP complexes) link the outer lattice of clathrin-coated vesicles with membrane-anchored cargo molecules. We report the crystal structure of the core of the AP-1 complex, which functions in the trans-Golgi network (TGN). Packing of complexes in the crystal generates an exceptionally long (1,135-Angstrom) unit-cell axis, but the 6-fold noncrystallographic redundancy yields an excellent map at 4-Angstrom resolution. The AP-1 core comprises N-terminal fragments of the two large chains, beta1 and gamma, and the intact medium and small chains, mu1 and sigma1. Its molecular architecture closely resembles that of the core of AP-2, the plasma-membrane-specific adaptor, for which a structure has been determined. Both structures represent an "inactive" conformation with respect to binding of cargo with a tyrosine-based sorting signal. TGN localization of AP-1 depends on the small GTPase, Arf1, and the phosphoinositide, PI-4-P. We show that directed mutations of residues at a particular corner of the gamma chain prevent recruitment to the TGN in cells and diminish PI-4-P-dependent, but not Arf1-dependent, liposome binding in vitro.