Cryo-EM structures of mouse bestrophin 1 channel in closed and partially open conformations

IF 3.7 3区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Molecules and Cells Pub Date : 2025-03-03 DOI:10.1016/j.mocell.2025.100208

Kwon-Woo Kim , Euna Lee , Ara Ko , Junmo Hwang , Kunwoong Park , Byoung-Cheol Lee , Ki Woo Kim , Won-Jong Oh , Kyuhyung Kim , Hyun-Ho Lim

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引用次数: 0

Abstract

Bestrophin 1 (BEST1) channels are calcium-activated Cl⁻ channels involved in diverse physiological processes, including gliotransmitter release in astrocytes. Although human and chicken BEST1 orthologs have been extensively studied, the structural and functional properties of mouse BEST1 (mBEST1) remain poorly understood. In this study, we characterized the structure-function of mBEST1-BF, a C–terminally tagged variant, using whole-cell patch-clamp recordings, surface biotinylation assays, and single-particle cryo-electron microscopy. Cryo-electron microscopy structural analysis of mBEST1-BF revealed closed and partially open conformations. Comparative analysis with human and chicken BEST1 orthologs highlighted conserved calcium-binding and gating mechanisms, with distinct features in mBEST1, including a wider aperture sufficient to accommodate dehydrated Cl⁻ ions and potential anion-binding sites near Val205 and Gln208 residues. The disordered C-terminal region of mBEST1 remains unresolved, suggesting it may require stabilizing factors for structural determination. Additionally, the autoinhibitory domain, which includes Ser354, likely plays a key role in regulating gating, with Ser354 potentially serving as a phosphorylation site that modulates channel activity. Our findings provide structural and functional insights into mBEST1 and suggest mechanisms underlying its unique gating and ion permeation properties.

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小鼠strophin - 1通道封闭和部分开放构象的低温电镜结构。

besstrophin -1 （BEST1）通道是钙激活的Cl-通道，参与多种生理过程，包括星形胶质细胞中的胶质递质释放。尽管人类和鸡的BEST1同源基因已被广泛研究，但小鼠BEST1 （mBEST1）的结构和功能特性仍然知之甚少。在这项研究中，我们利用全细胞膜片钳记录、表面生物素化测定和单粒子冷冻电镜（cro - em）表征了mBEST1-BF的结构-功能，这是一种c末端标记的变体。mBEST1-BF的Cryo-EM结构分析显示为封闭和部分开放构象。与人类和鸡BEST1同源物的比较分析强调了保守的钙结合和门控机制，mBEST1具有明显的特征，包括足够大的孔径以容纳脱水Cl-离子和靠近Val205和Gln208残基的潜在阴离子结合位点。mBEST1的紊乱c端区域仍未得到解决，这表明可能需要稳定因子来确定其结构。此外，包括Ser354在内的自抑制结构域可能在调节门控中起关键作用，Ser354可能作为调节通道活性的磷酸化位点。我们的研究结果提供了mBEST1的结构和功能见解，并提出了其独特的门控和离子渗透特性的机制。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Molecules and Cells 生物-生化与分子生物学

CiteScore

6.60

自引率

10.50%

发文量

审稿时长

2.3 months

期刊介绍： Molecules and Cells is an international on-line open-access journal devoted to the advancement and dissemination of fundamental knowledge in molecular and cellular biology. It was launched in 1990 and ISO abbreviation is "Mol. Cells". Reports on a broad range of topics of general interest to molecular and cell biologists are published. It is published on the last day of each month by the Korean Society for Molecular and Cellular Biology.