Cx40 and Cx43 expression ratio influences heteromeric/heterotypic gap junction channel properties
Cx40 and Cx43 expression ratio influences heteromeric/heterotypic gap junction channel properties
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DOI：
10.1152/ajpcell.00484.2001
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发表时间：
2002-06-01
影响因子：
5.5
通讯作者：
Burt, JM
中科院分区：
文献类型：
--
作者：
Cottrell, GT;Wu, Y;Burt, JM
在共表达连接蛋白（Cx）40和Cx43的细胞中，表达的比率可以根据细胞环境而变化。我们研究了改变Cx40：Cx43表达比例对功能性间隙连接特性的影响。将转染有Cx40或Cx43的Rin细胞（Rin 40，Rin 43）与6 B5 n，A7 r5，A7 r540 C1或A7 r540 C3细胞共培养，用于电生理学和染料偶联分析。Cx40：Cx43在6 B5 n、A7 r5、A7 r540 C1和A7 r540 C3细胞中的表达比例分别为1：1、3：1、5：1和10：1。当Rin 43细胞与共表达细胞配对时，随着Cx40：Cx43比率在共表达细胞中的增加，电压依赖性门控的不对称性增加，并且朝向较小的电导事件转变。这些观察结果不能通过Cx40和Cx43特性与两个Cx的表达比率成比例的线性组合来预测。当Rin 40细胞与共表达细胞配对时，净电压门控和单通道电导行为与Rin 40/Rin 40细胞对相似。细胞单层的染料渗透性特性表明，随着共表达细胞中Cx40：Cx43表达比例的增加，染料转移的电荷和尺寸选择性反映了Rin 40细胞的电荷和尺寸选择性，正如所预测的那样。这些数据表明，异聚体/异型通道的电生理特性不直接相关的Cx成分在细胞中表达的比例，但是，这些相同的通道的染料渗透性可以预测的相对Cx的贡献。
In cells that coexpress connexin (Cx)40 and Cx43, the ratio of expression can vary depending on the cellular environment. We examined the effect of changing Cx40:Cx43 expression ratio on functional gap junction properties. Rin cells transfected with Cx40 or Cx43 (Rin40, Rin43) were cocultured with 6B5n, A7r5, A7r540C1, or A7r540C3 cells for electrophysiological and dye coupling analysis. Cx40: Cx43 expression ratio in 6B5n, A7r5, A7r540C1, and A7r540C3 cells was similar to1:1, 3:1, 5:1, and 10:1, respectively. When Rin43 cells were paired with coexpressing cells, there was an increasing asymmetry of voltage-dependent gating and a shift toward smaller conductance events as Cx40: Cx43 ratio increased in the coexpressing cell. These observations could not be predicted by linear combinations of Cx40 and Cx43 properties in proportion to the expressed ratios of the two Cxs. When Rin40 cells were paired with coexpressing cells, the net voltage gating and single-channel conductance behavior were similar to those of Rin40/Rin40 cell pairs. Dye permeability properties of cell monolayers demonstrated that as Cx40: Cx43 expression ratio increased in coexpressing cells the charge and size selectivity of dye transfer reflected that of Rin40 cells, as would be predicted. These data indicate that the electrophysiological properties of heteromeric/heterotypic channels are not directly related to the proportions of Cx constituents expressed in the cell; however, the dye permeability of these same channels can be predicted by the relative Cx contributions.