Distinct lipid bilayer compositions have general and protein-specific effects on K+ channel function.
Distinct lipid bilayer compositions have general and protein-specific effects on K+ channel function.
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DOI：
10.1085/jgp.202012731
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发表时间：
2021-02-01
期刊：
影响因子：
--
通讯作者：
Rauh O
中科院分区：
文献类型：
--
作者：
Winterstein LM;Kukovetz K;Hansen UP;Schroeder I;Van Etten JL;Moroni A;Thiel G;Rauh O
Winterstein等人利用小病毒K+通道的自然多样性来解决磷脂双分子层组成对通道功能的影响。单通道记录揭示了阴离子磷脂对通道电导的刺激作用和对门控的蛋白质特异性作用。细胞膜的脂质组成影响跨膜蛋白如离子通道的功能，这一点越来越明显。在这里，我们利用小病毒K+通道的结构和功能多样性，系统地研究了双层组成对单个K+通道孔模块的影响。体外合成的通道重组为磷脂酰胆碱双分子层±胆固醇或阴离子磷脂（apl）。单通道记录显示，饱和浓度30%的胆固醇对单一电导和门控只有轻微的和蛋白质特异性的影响。这表明通道具有有效的策略来避免蛋白质与周围双分子层之间疏水不匹配的结构影响。在所有测试的七个通道中，api增强了单一电导，这表明这是带负电荷的磷脂对通道功能的一般影响。对于一个通道，我们确定了15%磷脂酰丝氨酸的有效半最大浓度，该值在aPL浓度的生理范围内。两种通道蛋白对apl的不同敏感性可以解释为在脂质头基团和跨膜结构域之间的界面上存在/不存在阳离子氨基酸。api还影响某些通道的门控，表明电导和门控是不耦合的现象，并且api对门控的影响是蛋白质特异性的。在两个通道中，后者可以通过改变孔衬跨膜螺旋的方向来解释，这可以防止苯丙氨酸侧链翻转到离子渗透途径中，从而关闭长通道。不对称双分子层的实验表明，这种作用是小叶特异性的，并且在内小叶中最有效，其中api通常存在于质膜中。这些数据强调了原料药对K+通道电导率的普遍积极影响，以及它们的负头基与附近阳离子氨基酸的潜在相互作用。
Winterstein et al. use the natural diversity of small viral K+ channels to address the impact of phospholipid bilayer composition on channel function. Single-channel recordings reveal a stimulating effect of anionic phospholipids on channel conductance and protein-specific effects on gating. It has become increasingly apparent that the lipid composition of cell membranes affects the function of transmembrane proteins such as ion channels. Here, we leverage the structural and functional diversity of small viral K+ channels to systematically examine the impact of bilayer composition on the pore module of single K+ channels. In vitro–synthesized channels were reconstituted into phosphatidylcholine bilayers ± cholesterol or anionic phospholipids (aPLs). Single-channel recordings revealed that a saturating concentration of 30% cholesterol had only minor and protein-specific effects on unitary conductance and gating. This indicates that channels have effective strategies for avoiding structural impacts of hydrophobic mismatches between proteins and the surrounding bilayer. In all seven channels tested, aPLs augmented the unitary conductance, suggesting that this is a general effect of negatively charged phospholipids on channel function. For one channel, we determined an effective half-maximal concentration of 15% phosphatidylserine, a value within the physiological range of aPL concentrations. The different sensitivity of two channel proteins to aPLs could be explained by the presence/absence of cationic amino acids at the interface between the lipid headgroups and the transmembrane domains. aPLs also affected gating in some channels, indicating that conductance and gating are uncoupled phenomena and that the impact of aPLs on gating is protein specific. In two channels, the latter can be explained by the altered orientation of the pore-lining transmembrane helix that prevents flipping of a phenylalanine side chain into the ion permeation pathway for long channel closings. Experiments with asymmetrical bilayers showed that this effect is leaflet specific and most effective in the inner leaflet, in which aPLs are normally present in plasma membranes. The data underscore a general positive effect of aPLs on the conductance of K+ channels and a potential interaction of their negative headgroup with cationic amino acids in their vicinity.
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影响因子：
56.9
作者：
Doyle, DA;Cabral, JM;MacKinnon, R
通讯作者：
MacKinnon, R
影响因子：
--
作者：
Levitan, Irena;Fang, Yun;Rosenhouse-Dantsker, Avia;Romanenko, Victor
通讯作者：
Romanenko, Victor
影响因子：
4.7
作者：
Murry, Carter R.;Agarkova, Irina, V;Van Etten, James L.
通讯作者：
Van Etten, James L.
DOI：
10.1074/jbc.m111.224840
发表时间：
2012-01-06
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Jeffries O;Tian L;McClafferty H;Shipston MJ
通讯作者：
Shipston MJ
影响因子：
15
作者：
Rauh O;Urban M;Henkes LM;Winterstein T;Greiner T;Van Etten JL;Moroni A;Kast SM;Thiel G;Schroeder I
通讯作者：
Schroeder I