在ASIC1 β11-12链接器中,氨酸替代物缓慢降低敏感度
Rutambhara Purohit1, Tyler Couch1, Matthew L Rook1
1Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York.
Biophysical journal
|August 25, 2024
概括
在酸感应离子通道 (ASIC) 中引入普罗林,通过改变链接体构造,显著减缓了脱敏. 一个单个修改的子单元足以使整个三元体ASIC通道变得不敏感.
科学领域:
- 神经科学是一个神经科学.
- 分子生物学分子生物学
- 生物物理学的生物物理.
背景情况:
- 脱敏是联结离子通道的关键特征,包括酸感应离子通道 (ASIC).
- 由于细胞外β11-12链接器的结构变化,ASIC脱敏发生在细胞外酸化后迅速发生.
- 对于ASIC无敏化所需的子单元的精确固体测量仍然不清楚.
研究的目的:
- 为了研究cis-trans异构化在ASIC脱敏化中的作用.
- 探索proline替代在β11-12链接器中的潜力,以调节ASIC无敏化动力学.
- 为了确定三聚体ASIC通道中脱敏的功能性静脉测量.
主要方法:
- 在 ASIC1 β11-12 链接器中引入proline替代物 (L414P,Y416P) 的部位定向突变发生.
- 电生理学记录 (切除的补丁) 来测量脱敏率和稳定状态脱敏曲线.
- 构建和功能分析的ASIC1 concatemers与不同数量的proline替代品.
主要成果:
- 氨酸替代剂 (L414P,Y416P) 极大地减缓了ASIC1的脱敏 (100-至1000倍).
- 这些替代物将稳定状态脱敏曲线转移到更酸的pH值,而不会显著改变激活或离子选择性.
- 引入一个或两个proline替代品在concatemers足以引起接近野生类型的无敏化,表明单个修改的子单元可以使通道无敏化.
结论:
- 在ASIC脱敏过程中,在β11-12链接器中存在一种不寻常的cis-trans异构化机制.
- 氨酸替代物有效地将链接器陷入非无敏化的形状中,作为一种有价值的研究工具.
- 单个子单元的构造变化足以触发整个三元体ASIC通道中的脱敏.
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