Sec2 protein contains a coiled-coil domain essential for vesicular transport and a dispensable carboxy terminal domain.
Sec2 protein contains a coiled-coil domain essential for vesicular transport and a dispensable carboxy terminal domain.
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DOI：
10.1083/jcb.110.6.1897
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发表时间：
1990-06
影响因子：
7.8
通讯作者：
Novick, P
中科院分区：
文献类型：
--
作者：
Nair, J;Muller, H;Peterson, M;Novick, P
SEC2功能在酵母分泌途径的高尔基体后阶段是必需的。SEC2序列编码一个由759个氨基酸组成的蛋白质产物，含有一个氨基末端区域，该区域被预测为α螺旋螺旋卷曲构象。两个温度敏感等位基因sec2-41和sec2-59编码被蛋白石终止密码子截断的蛋白质，并可被蛋白石tRNA抑制子抑制。缺失分析表明，去掉251个氨基酸的羧基没有明显的表型，而截短368个氨基酸会引起温度敏感性。蛋白质的氨基末端的一半，包含假定的盘绕结构域，在任何温度下都是必不可少的。Sec2蛋白主要存在于可溶性部分，其天然相对分子质量大于500kD。温度敏感的sec2等位基因的所有表型都被SEC4基因的复制部分抑制，但sec2中断的致命性并未被抑制。Sec2-41突变表现出合成致死性，与sec4-8和sec15-1具有相同的晚期作用sec突变子集。Sec2蛋白可能与Sec4和Sec15蛋白一起发挥控制囊泡运输的功能。
SEC2 function is required at the post-Golgi apparatus stage of the yeast secretory pathway. The SEC2 sequence encodes a protein product of 759 amino acids containing an amino terminal region that is predicted to be in an alpha-helical, coiled-coil conformation. Two temperature- sensitive alleles, sec2-41 and sec2-59, encode proteins truncated by opal stop codons and are suppressible by an opal tRNA suppressor. Deletion analysis indicates that removal of the carboxyl terminal 251 amino acids has no apparent phenotype, while truncation of 368 amino acids causes temperature sensitivity. The amino terminal half of the protein, containing the putative coiled-coil domain, is essential at all temperatures. Sec2 protein is found predominantly in the soluble fraction and displays a native molecular mass of greater than 500 kD. All phenotypes of the temperature-sensitive sec2 alleles are partially suppressed by duplication of the SEC4 gene, but the lethality of a sec2 disruption is not suppressed. The sec2-41 mutation exhibits synthetic lethality with the same subset of the late acting sec mutants as does sec4-8 and sec15-1. The Sec2 protein may function in conjunction with the Sec4 and Sec15 proteins to control vesicular traffic.