Bimodal effect of alkalization on the polycystin transient receptor potential channel, PKD2L1
Bimodal effect of alkalization on the polycystin transient receptor potential channel, PKD2L1
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DOI：
10.1007/s00424-011-0934-5
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发表时间：
2011-05-01
影响因子：
4.5
通讯作者：
Sakai, Hideki
中科院分区：
文献类型：
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作者：
Shimizu, Takahiro;Higuchi, Taiga;Sakai, Hideki
多囊肾病2-样蛋白1（PKD 2L 1），以前称为瞬时受体电位多囊蛋白3（TRPP 3），在质膜上形成组成性活性的电压依赖性非选择性阳离子通道。然而，PKD 2L 1通道的调节机制知之甚少。在本研究中，我们发现了一个钟形碱性pH依赖性的PKD 2L 1通道活性在单通道和全细胞水平的膜片钳记录在HEK 293 T细胞过表达小鼠PKD 2L 1：碱化至pH 8.0-9.0增加PKD 2L 1电流，但碱化至pH 10.0降低它们。单通道分析表明，碱化改变PKD 2L 1通道的开放概率，但不改变其单通道电导。此外，pH8.0 -9.0和pH10.0溶液分别使PKD 2L 1通道的电压依赖性负移和正移。这些结果表明，PKD 2L 1通道的电压依赖性门控通过两种不同的机制调节碱化。有趣的是，我们观察到PKD 2L 1通道在pH 10.0下抑制PKD 2L 1通道后，在碱性溶液洗脱时PKD 2L 1通道的反弹激活，表明碱化至pH 10.0通过使通道失活而降低PKD 2L 1电流。结果表明，碱化可使PKD 2L 1尾电流加快。这些结果表明，碱化是小鼠PKD 2L 1通道的双峰调制器。
Polycystic kidney disease 2-like 1(PKD2L1), previously called transient receptor potential polycystin 3 (TRPP3), forms constitutively active voltage-dependent nonselective cation channels in the plasma membrane. The mechanism of regulation of PKD2L1 channels, however, has been poorly understood. In the present study, we found a bell-shaped alkaline pH dependence of PKD2L1 channel activity at the single-channel and whole-cell levels in patch-clamp recordings in HEK293T cells overexpressing mouse PKD2L1: alkalization to pH 8.0-9.0 increased the PKD2L1 currents, but alkalization to pH 10.0 decreased them. Single-channel analysis revealed that alkalization changed the open probability of PKD2L1 channels, but not their single-channel conductance. In addition, the voltage dependence of PKD2L1 channels was negatively and positively shifted by treatment with solutions of pH 8.0-9.0 and pH 10.0, respectively. These results indicate that the voltage-dependent gating of PKD2L1 channels was modulated by alkalization through two different mechanisms. Interestingly, we observed rebound activation of the PKD2L1 channel on washout of the alkaline solution after PKD2L1 channel inhibition at pH 10.0, suggesting that alkalization to pH 10.0 decreased PKD2L1 currents by inactivating the channels. Consistently, the PKD2L1 tail currents were accelerated by alkalization. These results suggest that alkalization is a bimodal modulator of mouse PKD2L1 channels.