Clathrin light chain: importance of the conserved carboxy terminal domain to function in living cells.
Clathrin light chain: importance of the conserved carboxy terminal domain to function in living cells.
复制标题
网格蛋白轻链：保守的羧基末端结构域在活细胞中发挥作用的重要性。
DOI：
10.1111/j.1600-0854.2006.00438.x
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
O'Halloran,TheresaJ
中科院分区：
文献类型：
--
作者：
Wang,Jingshan;Wang,Yanqin;O'Halloran,TheresaJ
笼状蛋白三离子组装成能够包装膜和受体的外套，以便运输到细胞内目的地。三条重链与三条轻链捆绑在一起，形成一个三棱柱。所有的笼状蛋白轻链(CLC)都含有一个酸性氨基末端结构域、一个中心卷曲段和一个氨基酸序列保守的羧基末端结构域。为了评估它们在体内的功能贡献，我们在CLC缺失的Dictyostelium(CLC空)细胞中表达了DictyosteliumclcA的标记片段。我们检测了这些CLCA片段修复clathrin表型缺陷，聚集成膜上的小点，并与重链结合的能力。当在CLC缺失细胞中表达时，含有氨基末端结构域和中心卷曲结构域的CLCA片段结合了重链，但对clathrin功能是必不可少的。相反，CLCA的羧基末端结构域是与点状蛋白结合、网状蛋白功能和与重链牢固结合的关键决定因素。70个氨基酸的羧基末端片段是充分发挥功能和定位到细胞内膜上的点状结构所必需的和充分的。一个较短的49个氨基酸的羧基末端片段可以分布到点状突起，但不能挽救发育缺陷。这些结果揭示了轻链的羧基末端结构域在体内的重要性。
Clathrin triskelions assemble into coats capable of packaging membrane and receptors for transport to intracellular destinations. A triskelion is formed from three heavy chains bound to three light chains. All clathrin light chains (clc) contain an acidic amino terminal domain, a central coiled segment, and a carboxy terminal domain conserved in amino acid sequence. To assess their functional contributionin vivo, we expressed tagged segments of theDictyosteliumclcA in clc‐minusDictyostelium(clc null) cells. We examined the ability of these clcA fragments to rescue clathrin phenotypic deficiencies, to cluster into punctae on membranes, and to bind to the heavy chain. When expressed in clc null cells, a clcA fragment containing the amino terminal domain and the central coiled domain bound heavy chain but was dispensable for clathrin function. Instead, the carboxy terminal domain of clcA was a critical determinant for association with punctae, for clathrin function and for robust binding to the heavy chain. A 70 amino acid carboxy terminal fragment was necessary and sufficient for full function, and for localization into punctae on intracellular membranes. A shorter 49 amino acid carboxy terminal fragment could distribute into punctae but failed to rescue developmental deficiencies. These results reveal the importance of the carboxy terminal domain of the light chainin vivo.