ε-COP is a structural component of coatomer that functions to stabilize α-COP
ε-COP is a structural component of coatomer that functions to stabilize α-COP
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DOI：
10.1093/emboj/17.4.985
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发表时间：
1998-02-16
期刊：
影响因子：
11.4
通讯作者：
Schekman, R
中科院分区：
文献类型：
--
作者：
Duden, R;Kajikawa, L;Schekman, R
我们分离了一种新的酵母α - cop突变体ret1-3，其中α - cop在细胞转移到限制性温度后被降解，ret1-3细胞在28℃时停止生长并积累羧基肽酶Y （p1 CPY）的ER前体，在筛选这些缺陷的高拷贝抑制因子时，我们分离了以前未识别的酵母epsilon-COP基因。epsilon-COP （Sec28p）的过量产生通过稳定α - cop水平抑制ret1-3细胞在34℃以下的缺陷。令人惊讶的是，缺乏epsilon-COP （sec28 Delta）的细胞在34℃下生长良好，并在允许的温度下显示羧基肽酶Y和kkx标记蛋白的正常运输，因此epsilon-COP对酵母细胞生长不是必需的，但sec28 Delta细胞是热敏感的。在sec28 Delta细胞转移到37℃时，野生型α - cop （Ret1p）水平迅速下降，细胞积累p1 CPY，这些缺陷可以被α - cop过量产生抑制。sec28 Delta突变体与α - cop突变体表现出等位基因特异性的合成致死性相互作用：sec28 Delta ret1-3双突变体在所有温度下都不存活，而sec28 Delta ret1-1双突变体在30℃下生长良好。我们的研究结果表明，epsilon-COP的一个功能是稳定α - cop和涂层复合物。
We isolated a novel yeast alpha-COP mutant, ret1-3, in which alpha-COP is degraded after cells are shifted to a restrictive temperature, ret1-3 cells cease growth at 28 degrees C and accumulate the ER precursor of carboxypeptidase Y (p1 CPY), In a screen for high copy suppressors of these defects, me isolated the previously unidentified yeast epsilon-COP gene. epsilon-COP (Sec28p) overproduction suppresses the defects of ret1-3 cells up to 34 degrees C, through stabilizing levels of alpha-COP. Surprisingly, cells lacking epsilon-COP (sec28 Delta) grow well up to 34 degrees C and display normal trafficking of carboxypeptidase Y and KKXX-tagged proteins at a permissive temperature, epsilon-COP is thus non-essential for yeast cell growth, but sec28 Delta cells are thermosensitive, In sec28 Delta cells shifted to 37 degrees C, wild-type alpha-COP (Ret1p) levels diminish rapidly and cells accumulate p1 CPY these defects can be suppressed by alpha-COP overproduction. Mutant coatomer from sec28 Delta cells behaves as an unusually large protein complex in gel filtration experiments, The sec28 Delta mutation displays allele-specific synthetic-lethal interactions with alpha-COP mutations: sec28 Delta ret1-3 double mutants are unviable at all temperatures, whereas sec28 Delta ret1-1 double mutants grow well up to 30 degrees C, Our results suggest that a function of epsilon-COP is to stabilize alpha-COP and the coatomer complex.