在酵母ER膜的翻译后蛋白质运输中识别信号序列
K Plath1, W Mothes, B M Wilkinson
1Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Cell
|September 30, 1998
概括
研究人员发现,pre-pro-alpha-factor信号序列在酵母体内等离子网中与Sec61p结合. 这种独立于Kar2p和ATP的相互作用,涉及到跨膜域的插入,表明开放蛋白质运输通道的一般机制.
科学领域:
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
- 蛋白质的运输方式
背景情况:
- 翻译后的蛋白质输送到内质网膜 (ER) 对于细胞功能至关重要.
- 前体蛋白的信号序列将它们引导到ER膜.
- 了解信号序列识别是阐明蛋白质转位机制的关键.
研究的目的:
- 为了研究蛋白质输送到酵母中的信号序列识别的分子机制.
- 为了确定在这个初步步骤中涉及的特定蛋白质相互作用.
- 提出信号序列介导通道开通的一般模型.
主要方法:
- 交叉链接研究被用来绘制蛋白质与蛋白质相互作用的地图.
- 分析的重点是预先阿尔法因子信号序列和蛋白质导通通道的组件之间的相互作用.
- 生物化学分析评估了Kar2p和ATP的作用.
主要成果:
- 预先阿尔法因子的信号序列直接与Sec61p相互作用,Sec61p是蛋白质导电通道的核心组成部分.
- 这种相互作用发生在Sec61p的跨膜域2和7的间隙中.
- 绑定的信号序列形成了一个螺旋,在道-脂质双层接口上与Sec62p和Sec71p接触.
- 相互作用是独立于Kar2p和ATP的.
结论:
- 通过Sec61p进行信号序列识别是独立于ATP和Kar2p的过程.
- 在通道膜接口的结合部位有助于信号序列的插入.
- 这种机制可能是启动跨ER膜的多转位的一般途径,可能打开通道.
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