Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306, USA.
J Biol Chem. 2011 Jan 14;286(2):1389-99. doi: 10.1074/jbc.M110.184077. Epub 2010 Nov 8.
Folding, assembly, and trafficking of ion channels are tightly controlled processes and are important for biological functions relevant to health and disease. Here, we report that functional expression of the Eag channel is temperature-sensitive by a mechanism that is independent of trafficking or surface targeting of the channel protein. Eag channels in cells grown at 37 °C exhibit voltage-evoked gating charge movements but fail to conduct K(+) ions. By mutagenesis and chimeric channel studies, we show that the N- and C-terminal regions are involved in controlling a step after movement of the voltage sensor, as well as in regulating biophysical properties of the Eag channel. Synthesis and assembly of Eag at high temperature disrupt the ability of these domains to carry out their function. These results suggest an important role of the intracellular regions in the generation of Eag currents.
离子通道的折叠、组装和运输是受到严格调控的过程，对于与健康和疾病相关的生物学功能至关重要。在这里，我们报告了 Eag 通道的功能表达是温度敏感的，其机制与通道蛋白的运输或表面靶向无关。在 37°C 下生长的细胞中的 Eag 通道表现出电压诱发的门控电荷运动，但不能传导 K(+)离子。通过突变和嵌合通道研究，我们表明 N 和 C 末端区域参与控制电压传感器运动后的步骤，以及调节 Eag 通道的生物物理特性。高温下 Eag 的合成和组装会破坏这些结构域执行其功能的能力。这些结果表明细胞内区域在产生 Eag 电流中起重要作用。
