相关实验视频
Updated: Jul 23, 2025

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In Vitro Analysis of E3 Ubiquitin Ligase Function
Published on: May 14, 2021
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通过KCTD5/Cullin3 E3结合酶对G蛋白βγ子单元的无处不在的结构基础
Wentong Jiang1,2, Wei Wang2,3, Yinfei Kong4
1Graduate School of Peking Union Medical College, Beijing 100730, China.
Science advances
|July 14, 2023
概括
一种新型的 pentameric E3 酶,KCTD5,通过无处不在的 Gβγ 子单元调节 G 蛋白结合受体 (GPCR) 信号传递. 这种机制微调循环腺单酸盐 (cAMP) 信号,揭示了 KCTD 蛋白质作为关键的 GPCR 调节器.
科学领域:
- 分子生物学分子生物学
- 结构生物学 结构生物学
- 细胞信号传递 细胞信号传递
背景情况:
- 需要精确调节G蛋白结合受体 (GPCR) 信号,以防止有害的过度刺激.
- 作为GPCR路径的一个组成部分的Gβγ信号传递,由依赖于Cullin3 (Cul3) 的E3酶KCTD5.5负面控制.
- KCTD5针对自由的Gβγ进行无处不在和随后的降解.
研究的目的:
- 阐明KCTD5-介导的Gβγ调节的结构基础.
- 研究KCTD5/Cul3 E3结合酶复合体对基质识别和无处不在的机制.
- 了解KCTD5在微调GPCR信号通路中的作用.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 确定了KCTD5-Gβγ融合复合体和KCTD7-Cul3复合体的结构.
- 结构分析的重点是KCTD5的米组合及其与Gβγ子单元的相互作用.
- 功能性测试评估了KCTD5介导的泛基化对Gβγ和循环腺3′,5′-单酸盐 (cAMP) 信号传递的影响.
主要成果:
- 冷-EM结构揭示了一个米KCTD5,通过其C端域对称地与五个Gβγ子单元交互.
- 独特的 pentameric E3 酶组件促进了无素结合酶 (E2) 和 Gβγ 修饰位点之间的接近.
- 通过KCTD5观察到多个Gβγ亚单元的同时无处不在,影响GPCR介导的cAMP信号传递.
结论:
- KCTD5作为 pentameric E3 酶起作用,独特地识别并使多个 Gβγ 子单元无处不在.
- 这种机制提供了对Gβγ信号传递的精确控制和微调GPCR介导的cAMP反应.
- KCTD家族成为GPCR信号的重要调节者,KCTD5提供了对不寻常的E3结合酶组合和基质识别的见解.
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