果糖-1,6-双酸和阿尔多酶通过AMPK传感葡萄糖
Chen-Song Zhang1, Simon A Hawley2, Yue Zong1
1State Key Laboratory for Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Fujian 361102, China.
Nature
|July 21, 2017
概括
阿尔多酶感知葡萄糖水平以激活AMP激活蛋白激酶 (AMPK) 独立于AMP/ADP. 这种机制涉及果糖-1,6-双酸盐 (FBP) 与阿尔多酶结合,调节葡萄糖剥夺期间的AMPK激活.
科学领域:
- 细胞代谢
- 信号传输
- 生物化学
背景情况:
- 葡萄糖是细胞的主要能量来源,通过糖解和氧化代谢推动ATP的产生.
- 传统上归因于AMP或ADP水平的变化,AMP激活蛋白激酶 (AMPK) 被葡萄糖剥夺激活.
- 在葡萄糖稀缺期间AMPK激活的精确机制,除了AMP/ADP信号外,仍然不完全理解.
研究的目的:
- 阐明在缺乏葡萄糖期间调节AMPK激活的AMP/ADP独立机制.
- 确定参与AMPK信号的新型葡萄糖可用性传感器.
- 调查果糖-1,6-双酸盐 (FBP) 和酶在AMPK激活中的作用.
主要方法:
- 研究了AMPK激活在不同葡萄糖度和FBP度的反应.
- 利用酶倒置和催化缺陷突变物 (D34S) 来评估它们对AMPK激活的影响.
- 使用无细胞复合试验来检查蛋白质复合体的形成和破坏.
- 在葡萄糖饥饿条件下测量AMP/ATP和ADP/ATP比率.
主要成果:
- 在葡萄糖剥夺过程中,AMPK的激活通过检测果糖-1,6-双酸盐 (FBP) 缺失的AMP/ADP独立途径发生.
- 细胞外葡萄糖和细胞内FBP的降低逐渐激活AMPK.
- 不被占用的阿尔多拉斯促进了包括v-ATPase,Ragulator,Axin,LKB1和AMPK在内的溶酶复合物的形成.
- 即使有足够的葡萄糖,也会激活AMPK,而FBP结合突变体则会阻止激活.
- FBP与阿尔多酶的结合破坏了轴素和LKB1与 lysosomal复合物的结合.
- 在急性葡萄糖饥饿期间,AMP/ATP和ADP/ATP的比率保持不变,AMPK上完整的AMP结合位点对激活不必.
结论:
- 阿尔多酶不仅作为一种糖解酶,而且也是细胞葡萄糖可用性的关键传感器.
- 通过AMP/ADP独立的机制调节AMPK的激活.
- 这一途径为细胞如何适应新陈代谢压力和调节能量平衡提供了新的理解.
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