Identification and functional characterization of a voltage-gated chloride channel and its novel splice variant in taste bud cells
Identification and functional characterization of a voltage-gated chloride channel and its novel splice variant in taste bud cells
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DOI：
10.1074/jbc.m507706200
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发表时间：
2005-10-28
影响因子：
4.8
通讯作者：
Brand, JG
中科院分区：
文献类型：
--
作者：
Huang, LQ;Cao, J;Brand, JG
味蕾细胞是具有神经元特性的上皮细胞。在这些细胞中，电压依赖的离子通道已经被生理学地描述。在这里，我们报道了味蕾细胞电压门控氯通道(CLC-4)及其新的剪接变异体(CLC-4A)的分子鉴定和功能特性。CLC-4A在其5‘端附近跳过一个外显子，导致N端缺失60个氨基酸。原位杂交和免疫组织化学将这两个通道的转录本和蛋白质定位于味蕾细胞的一个子集。对非洲爪哇卵母细胞异源表达通道的电生理记录表明，ClC-4和ClC-4A对pH具有相反的敏感性和独特的离子选择性。氯离子通道阻断剂尼氟酸和5-硝基-2-(3-苯丙氨基)苯甲酸对CLC-4的电导有轻微的抑制作用，但这两种阻断剂都抑制CLC-4A，提示CLC-4A是酸诱导的5-硝基-2-(3-苯丙氨基)苯甲酸敏感电流的候选通道。此外，这两个通道可能通过调节递质摄取到突触小泡而在苦味、甜味和鲜味介导的味觉传递中发挥作用。
Taste bud cells are epithelial cells with neuronal properties. Voltage-dependent ion channels have been physiologically described in these cells. Here, we report the molecular identification and functional characterization of a voltage-gated chloride channel (ClC-4) and its novel splice variant (ClC-4A) from taste bud cells. ClC-4A skipped an exon near its 5'-end, incurring the loss of 60 amino acids at the N terminus. In situ hybridization and immunohistochemistry localized these two channels' transcripts and proteins to a subset of taste bud cells. Electrophysiological recordings of the heterologously expressed channels in Xenopus oocytes showed that ClC-4 and ClC-4A have opposite sensitivity to pH and unique ion selectivity. The chloride channel blockers niflumic acid and 5-nitro-2-(3-phenylpropylamino) benzoic acid had a slight or no inhibitory effect on the conductance of ClC-4, but both blockers inhibited ClC-4A, suggesting that ClC-4A is a candidate channel for an acid-induced 5-nitro-2-( 3-phenylpropylamino) benzoic acid-sensitive current. Furthermore, these two channels may play a role in bitter-, sweet-, and umami-mediated taste transmission by regulating transmitter uptake into synaptic vesicles.