High-copy suppressor analysis reveals a physical interaction between Sec34p and Sec35p, a protein implicated in vesicle docking
High-copy suppressor analysis reveals a physical interaction between Sec34p and Sec35p, a protein implicated in vesicle docking
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DOI：
10.1091/mbc.10.10.3317
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发表时间：
1999-10-01
影响因子：
3.3
通讯作者：
Ferro-Novick, S
中科院分区：
文献类型：
--
作者：
Kim, DW;Sacher, M;Ferro-Novick, S
温度敏感突变体 sec34-2 在内质网 (ER) 到高尔基体运输的后期阶段存在缺陷。使用 sec34-2 突变体的高拷贝抑制筛选已鉴定出 SEC34 结构基因和称为 GRP1 的新基因。 GRP1 编码一种先前未鉴定的亲水性酵母蛋白，该蛋白与哺乳动物高尔基体蛋白 golgin-160 相关。尽管 GRP1 对于生长不是必需的，但 grp1 Delta 突变显示出与几种突变的合成致死相互作用，这些突变导致 ER 积累并阻碍 ER 到高尔基体运输的后期阶段，但不会与那些阻碍 ER 囊泡出芽的突变相互作用。我们的研究结果表明，Grp1p 可能通过维持高尔基体功能来间接促进膜交通。为了鉴定其产物与 Sec34p 发生物理相互作用的基因，我们还测试了过表达的 SEC34 抑制已知分泌突变（阻止 ER 和高尔基体之间的囊泡运输）的能力。该屏幕显示 SEC34 专门抑制 sec35-1。 SEC34 编码类似于 100 kDa 的亲水蛋白。与 Sec35p（与内质网来源的囊泡与高尔基体的束缚有关）一样，Sec34p 主要是可溶的。 Sec34p 和 Sec35p 彼此稳定结合，形成类似于 480 kDa 的多蛋白复合物。这些数据表明 Sec34p 与 Sec35p 协同作用以介导囊泡交通中的共同步骤。
A temperature-sensitive mutant, sec34-2, is defective in the late stages of endoplasmic reticulum (ER)-to-Golgi transport. A high-copy suppressor screen that uses the sec34-2 mutant has resulted in the identification of the SEC34 structural gene and a novel gene called GRP1. GRP1 encodes a previously unidentified hydrophilic yeast protein related to the mammalian Golgi protein golgin-160. Although GRP1 is not essential for growth, the grp1 Delta mutation displays synthetic lethal interactions with several mutations that result in ER accumulation and a block in the late stages of ER-to-Golgi transport, but not with those that block the budding of vesicles from the ER. Our findings suggest that Grp1p may facilitate membrane traffic indirectly, possibly by maintaining Golgi function. Ln an effort to identify genes whose products physically interact with Sec34p, we also tested the ability of overexpressed SEC34 to suppress known secretory mutations that block vesicular traffic between the ER and the Golgi. This screen revealed that SEC34 specifically suppresses sec35-1. SEC34 encodes a hydrophilic protein of similar to 100 kDa. Like Sec35p, which has been implicated in the tethering of ER-derived vesicles to the Golgi, Sec34p is predominantly soluble. Sec34p and Sec35p stably associate with each other to form a multiprotein complex of similar to 480 kDa. These data indicate that Sec34p acts in conjunction with Sec35p to mediate a common step in vesicular traffic.