Kawasaki M, Suzuki M, Uchida S, Sasaki S, Marumo F
Second Department of Internal Medicine, School of Medicine, Tokyo Medical and Dental University, Japan.
Neuron. 1995 Jun;14(6):1285-91. doi: 10.1016/0896-6273(95)90275-9.
The CIC family is the superfamily of voltage-gated Cl- channels. Although the CIC channels expressed in Xenopus oocytes have been characterized, their channel properties are still poorly understood. We recently cloned a unique member of the CIC family, CIC-3, that is expressed abundantly in neurons. Its channel activity was regulated by phorbol esters. Now, we have established a stably transfected somatic cell line expressing functional CIC-3 channels and examined the CIC-3 single-channel current by patch-clamp techniques. In inside-out patches from the stably transfected cells, a rise of bath Ca2+ concentration in the physiological range of intracellular Ca2+ concentrations inhibited the CIC-3 single-channel currents. This inhibition by Ca2+ was independent of phosphorylation and ATP. Thus, the CIC-3 channel is a Ca(2+)-sensitive Cl- channel localized in neuronal cells, and its Ca2+ sensitivity implies a physiological role in neuronal functions.
CIC家族是电压门控氯离子通道的超家族。尽管在非洲爪蟾卵母细胞中表达的CIC通道已得到表征，但其通道特性仍知之甚少。我们最近克隆了CIC家族的一个独特成员CIC-3，它在神经元中大量表达。其通道活性受佛波酯调节。现在，我们建立了一个稳定转染的体细胞系，该细胞系表达功能性CIC-3通道，并通过膜片钳技术检测了CIC-3单通道电流。在稳定转染细胞的内面向外膜片中，在细胞内钙离子浓度的生理范围内，胞外钙离子浓度的升高抑制了CIC-3单通道电流。钙离子的这种抑制作用与磷酸化和ATP无关。因此，CIC-3通道是一种定位于神经细胞的钙敏感氯离子通道，其对钙离子的敏感性暗示了其在神经功能中的生理作用。
