TMEM16A活性化化通道的冷EM结构
Shangyu Dang1, Shengjie Feng2, Jason Tien2
1Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158, USA.
Nature
|December 14, 2017
概括
这项研究介绍了TMEM16A活性化化通道 (CaCC) 的新原子结构,揭示了其离子透孔和功能状态. 这些发现确定了控制阴离子导电和通道封闭的关键残留物,这对于理解CaCC的生理作用至关重要.
科学领域:
- 结构生物学 结构生物学
- 分子生理学分子生理学
- 离子通道功能的功能
背景情况:
- 由TMEM16A编码的激活化通道 (CaCC) 对许多生理过程至关重要,包括神经元信号传递和光滑肌肉收缩.
- 了解TMEM16A的结构对于阐明其透机制及其在各种生物功能中的作用至关重要.
- 之前对CaCC的结构洞察力有限,依赖于同质模型和低分辨率技术.
研究的目的:
- 为了确定小鼠TMEM16A.的跨膜域的de novo原子结构.
- 为了识别离子透孔和残留物,对道封闭和离子选择性至关重要.
- 阐明CaCC离子导电的结构基础及其不同的功能状态.
主要方法:
- 单颗粒电子冷显微镜 (cryo-EM) 用于确定纳米光盘中的TMEM16A和劳瑞尔马尔新醇的原子结构.
- 进行了突变和电生理学研究以验证结构发现.
- 在不同的环境 (纳米盘,洗剂) 中分析结构,以捕捉不同的功能状态.
主要成果:
- 解析了TMEM16A跨膜域的两个不同的原子结构,揭示了离子透孔.
- 这些结构捕获了不同的功能状态,包括一个可能的闭合状态,其中有已解脱的Ca2+离子和狭窄的孔.
- 突变和电生理学确定了10种影响阴离子相互作用和选择性的孔外残留物,以及7种调节通道门的残留物.
结论:
- 该研究提供了TMEM16A的高分辨率结构,澄清了离子透通路的结构.
- 已经确定了涉及离子导电,选择性和门的关键残留物,提供了机械的洞察力.
- 这些发现有助于我们更好地理解TMEM16A在各种生理过程中的功能.
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