A clathrin-binding site in the hinge of the beta 2 chain of mammalian AP-2 complexes
A clathrin-binding site in the hinge of the beta 2 chain of mammalian AP-2 complexes
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DOI：
10.1074/jbc.270.52.31083
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发表时间：
1995-12-29
影响因子：
4.8
通讯作者：
Kirchhausen, T
中科院分区：
文献类型：
--
作者：
Shih, W;Gallusser, A;Kirchhausen, T
组装的胞质网格蛋白到细胞质面的包被坑和包被囊泡似乎是由网格蛋白相关蛋白（AP）复合物。我们以前已经表明，AP复合物的大链之一，β链，足以在体外驱动涂层组装。该链由两个结构域组成，氨基末端主干和羧基末端耳，通过"铰链“连接。我们在此报道，重组β主干或重组β耳片段中铰链的存在对于驱动网格蛋白体外组装成被膜是必不可少的。我们还使用了结合试验来映射网格蛋白结合位点的嵌套删除铰链序列的铰链中心的50个残基的区域。该序列在来自多细胞生物的所有已知β序列中是保守的。一个单一的β铰链与网格蛋白三聚体离子的相互作用是弱的，我们建议，招聘的胞质网格蛋白形成涂层坑涉及同时接触的腿之间的单一网格蛋白三聚体和β铰链的两个或三个膜结合的AP复合物。剥离涂层可能需要中断这些接触。
The assembly of cytosolic clathrin into the cytoplasmic face of coated pits and coated vesicles appears to be driven by the clathrin-associated protein (AP) complexes. We have previously shown that one of the large chains of the AP complexes, the beta chain, is sufficient to drive coat assembly in vitro. This chain consists of two domains, the amino-terminal trunk and the carboxyl-terminal ear, linked by a ''hinge.'' We report here that presence of the hinge in recombinant beta trunk or in recombinant beta ear fragments is essential for driving in vitro assembly of clathrin into coats. We have also used a binding assay to map the clathrin-binding site by nested deletion of hinge sequences to a 50-residue region in the center of the hinge. This sequence is conserved in all known beta sequences from multicellular organisms. The interaction of a single beta hinge with a clathrin triskelion is weak, and we propose that recruitment of cytosolic clathrin to a forming coated pit involves simultaneous contacts between the legs of single clathrin trimers and the beta hinges of two or three membrane-bound AP complexes. Uncoating is likely to require interruption of these contacts.