通过CASTOR1-GATOR2复合体进行mTORC1调节的结构基础
Research square
|June 5, 2025
概括
氨酸水平调节mTORC1,这是一个关键的新陈代谢控制器. 这项研究揭示了氨酸传感器CASTOR1与GATOR2结合如何抑制GATOR1,在低氨酸条件下激活mTORC1.
科学领域:
- 细胞代谢的细胞代谢.
- 分子生物学分子生物学
- 生物化学 生物化学
背景情况:
- 拉巴胺素复合体1 (mTORC1) 的机械标调节了对营养素的反应代谢.
- 氨基酸通过Rag GTPases控制mTORC1在溶酶体的定位和激活.
- 一个GTPase激活蛋白质复合体GATOR1在营养缺乏条件下通过促进Raga/B上的GTP水解来使mTORC1失活.
研究的目的:
- 阐明素传感器CASTOR1与GATOR2复合体相互作用的结构机制.
- 为了了解这种相互作用如何消毒GATOR1,从而在低细胞质氨酸的条件下激活mTORC1.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 来确定与apo-CASTOR1.1.结合的GATOR2的结构.
- 结构分析的重点是CASTOR1和GATOR2组件之间的接口.
主要成果:
- 冷-EM结构显示,GATOR2的两个MIOS WD40域β-螺旋与单个CASTOR1同位体结合.
- 每个GATOR2螺旋与CASTOR1上的一个独特的MIOS绑定接口 (MBI) 相互作用,该接口位于远离氨酸绑定口袋.
- 氨酸结合诱导了CASTOR1的结构变化,导致循环排序阻碍了MBI,破坏了GATOR2的结合并激活了mtORC1.1.
结论:
- 这项研究提供了一个结构基础,说明氨酸水平如何通过CASTOR1-GATOR2-GATOR1轴控制mTORC1信号传递.
- 这种机制突出了由营养的可用性来精确调节细胞代谢的分子调节.
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