Ion permeation controlled by hydrophobic residues and proton binding in the proton-activated chloride channel.
Ion permeation controlled by hydrophobic residues and proton binding in the proton-activated chloride channel.
复制标题
质子激活氯离子通道中疏水残基和质子结合控制的离子渗透
DOI：
10.1016/j.isci.2021.103395
复制
发表时间：
2021-12-17
期刊：
影响因子：
5.8
通讯作者：
Chen XZ
中科院分区：
文献类型：
--
作者：
Cai R;Tang J;Chen XZ
最近发现的质子激活氯离子通道（PAC）包含两个跨膜螺旋（S1-S2），并参与溶酶体功能，缺氧适应，中风和致癌。虽然PAC结构最近得到解决，但其门控和激活机制在很大程度上仍然未知。通过对非洲爪蟾卵母细胞的双电极电压钳电生理研究，我们发现在pH7.5时，开孔处304位点的疏水性对维持PAC的封闭状态起着重要作用，而邻近位点的疏水性对维持PAC的封闭状态不起作用。当在酸性pH下活化时，PAC活性随着S2内307位点的亲水性而显著增加，但不随邻近位点的亲水性而增加，表明307充当活化门。我们确定了六个保守的质子化残基的关键质子诱导的激活，与结构研究一致。我们的研究描绘了一个方案，其中质子结合诱导构象变化从W304控制的封闭状态在开窗激活状态控制的激活门I307在螺旋S2。304位点的疏水性是维持PAC处于封闭状态的关键。激活的PAC的功能受307位点的亲水性调节。质子诱导的PAC激活中涉及六个可质子化的氨基酸。H+结合似乎将PAC从W304控制的封闭状态改变为I307门控的开放状态。分子生物学;细胞生物学;结构生物学
Recently identified proton-activated chloride channel (PAC) contains two transmembrane helices (S1–S2) and is involved in lysosome function, hypoxia adaption, stroke, and carcinogenesis. Although a PAC structure was recently resolved, its gating and activation mechanisms remained largely unknown. By the two-electrode voltage clamp electrophysiology in Xenopus oocytes, we found that the hydrophobicity of site 304 at fenestrations, but not that of neighbor sites, is important for maintaining PAC at a closed state at pH 7.5. When activated at acidic pH, PAC activity significantly increased with the hydrophilicity of site 307 within S2, but not with that of neighbor sites, suggesting that 307 acts as an activation gate. We identified six conserved protonatable residues critical for proton-induced activation, consistent with structural studies. Our study depicted a scheme in which proton binding induces conformational changes from the W304-controlled closed state at fenestrations to an activated state controlled by activation gate I307 in helix S2. The hydrophobicity of site 304 is critical for maintaining PAC at a closed state The function of activated PAC is modulated by the hydrophilicity of site 307 Six protonatable amino acids are involved in proton-induced PAC activation H+ binding seem to change PAC from W304-controlled closed to I307-gated open state Molecular biology; Cell biology; Structural biology
登录
查看更多内容
影响因子：
56.9
作者：
Yang, Junhua;Chen, Jianan;Qiu, Zhaozhu
通讯作者：
Qiu, Zhaozhu
影响因子：
64.8
作者：
Ruan Z;Osei-Owusu J;Du J;Qiu Z;Lü W
通讯作者：
Lü W
影响因子：
3.4
作者：
Rao S;Lynch CI;Klesse G;Oakley GE;Stansfeld PJ;Tucker SJ;Sansom MSP
通讯作者：
Sansom MSP
影响因子：
6.2
作者：
REHNCRONA, S
通讯作者：
REHNCRONA, S
影响因子：
4.8
作者：
Auzanneau, C;Thoreau, V;Becq, F
通讯作者：
Becq, F