对胆汁酸敏感的离子通道被超膜域的Ca2+依赖的构造变化所封闭
Makayla M Freitas1, Eric Gouaux2,3
1Vollum Institute, Oregon Health and Science University, 3232 SW Research Drive, Portland, OR, USA.
Nature communications
|July 22, 2025
概括
细胞外离子通过诱导形状变化来调节胆酸敏感离子通道 (BASIC). 人类BASIC蛋白中的这些变化改变了离子流,揭示了对离子通道封闭机制的新见解.
科学领域:
- 分子生物学分子生物学
- 生物物理学的生物物理.
- 结构生物学是结构生物学.
背景情况:
- 胆酸敏感离子通道 (BASIC) 是表皮Na+通道/脱原素 (ENaC/DEG) 超级家族的一部分.
- 细胞外 (Ca2+o) 抑制BASIC,但其机制尚不清楚.
研究的目的:
- 为了阐明人类BASIC (hBASIC) 中Ca2+调制的分子机制.
- 揭示Ca2+结合的结构基础及其对hBASIC功能的影响.
主要方法:
- 单粒子冷电子显微镜 (cryo-EM) 用于确定hBASIC结构,含有和没有Ca2+.
- 电生理学实验以评估通道功能和Ca2+结合部位.
主要成果:
- 在hBASIC的跨膜域和β-链接体中确定了Ca2+依赖的构造变化.
- 在细胞外孔前门中定位了一种谷氨酸残留物,作为Ca2+结合部位.
- 证明Ca2+结合会改变孔隙构造,调节离子流.
结论:
- Ca2+离子通过形状变化调节hBASIC功能,而不仅仅是孔隙阻断.
- 揭示了管理BASIC网关和Ca2+调节的分子原理.
- 提供了一个结构基础,以理解通过双价离子的离子通道调制.
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