在光受体G蛋白α子单元的N端的脂质修饰
K Kokame1, Y Fukada, T Yoshizawa
1Department of Biophysics, Faculty of Science, Kyoto University, Japan.
Nature
|October 22, 1992
概括
脂肪酸改变了转化素α子单元,影响视觉信号传递. 不同的脂肪酸会改变子单元的相互作用,这表明它们在快速视觉刺激中起作用.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 细胞信号传输 细胞信号传输
背景情况:
- 米里斯酸 (C14:0) 是一种常见的脂肪酸修饰蛋白质的N终端甘氨酸.
- 异构G蛋白,如转录素 (Tα/Tβ-玛),在信号转录中至关重要.
- 转化素 (Tα) 的α子单元在光受体信号传递中起着关键作用.
研究的目的:
- 为了研究光受体G蛋白转化素α子单元 (Tαα) 上的新型N端脂肪酸修饰.
- 为了确定这些异质脂肪酸修饰对Tα/Tβ玛相互作用和活性的功能影响.
- 探索改变子单元相互作用在视觉刺激中的作用.
主要方法:
- 对T.alpha的N端脂肪酸组成的分析.
- 合成和测试的N端 (lauroylated和myristoylated) 的T.阿尔法.
- 测试测量Tαα/Tββ gamma的GTPase活性.
- 评估由百日咳毒素催化Tαα的Tβ马依赖ADP-核糖化.
主要成果:
- α被异质脂肪酸修饰,包括劳拉酸 (C12:0),不和C14:2,C14:1,以及少量氨酸.
- 劳罗基化和米里斯基化N端Tαα都抑制了GTPase活性和ADP-ribosylation.
- 基酸比基酸具有显著更高的抑制功效,表明改变了Tα/Tβ gamma相互作用强度.
结论:
- α的N端脂肪酸组成显著影响与β gamma的相互作用强度.
- 一个较宽松的子单元相互作用,可能是由于非米里酸脂肪酸,可能有利于在视觉刺激中的快速周转和催化.
- 这表明通过脂肪酸修改调节视觉信号效率的调节机制.
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