Specific permeability and selective formation of gap junction channels in connexin-transfected HeLa cells.
Specific permeability and selective formation of gap junction channels in connexin-transfected HeLa cells.
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DOI：
10.1083/jcb.129.3.805
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发表时间：
1995-05
期刊：
影响因子：
--
通讯作者：
Willecke K
中科院分区：
文献类型：
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作者：
Elfgang C;Eckert R;Lichtenberg-Fraté H;Butterweck A;Traub O;Klein RA;Hülser DF;Willecke K
编码7种小鼠连接蛋白（Cx） （Cx26、Cx31、Cx32、Cx37、Cx40、Cx43和Cx45）的dna在缺乏间隙连接通讯的人HeLa细胞中功能性表达。我们比较了由不同连接蛋白组成的间隙连接与离子电泳注入的示踪分子的通透性。我们的结果表明，路西法黄可以通过所有分析的连接蛋白通道。另一方面，碘化丙啶和溴化乙啶分别通过Cx31和Cx32通道的渗透能力很差或根本不通过，而通过其他连接蛋白的通道。4,6二氨基-2-苯基吲哚（DAPI）二盐酸盐在Cx31和Cx43之间转移较少。神经生物素在Cx31转染物中转移较弱。Cx31或Cx45转染细胞的总结电导率仅为分析的其他连接蛋白转染细胞的一半左右，并且与任何示踪剂通透性不完全相关。通过不同连接蛋白通道的渗透性似乎取决于每种示踪剂的分子结构，即大小、电荷和可能的刚性。这支持了一个假设，即不同的连接蛋白通道对第二信使分子和代谢物具有不同的渗透性，并可能以这种方式实现它们在细胞类型的生长控制和分化中的特定作用。此外，我们还研究了两种不同连接蛋白共培养后的异型间隙连接的功能，其中一种连接蛋白用荧光葡聚糖珠预标记。对路西法黄转移的分析表明，表达Cx31 （β型连接蛋白）的HeLa细胞不与任何其他连接蛋白转染物进行通信，而只与自己进行通信。另外两种β型连接蛋白，HeLa-Cx26和-Cx32，不会将路西法黄传递给任何α型连接蛋白。在alpha型连接蛋白中，Cx40不与Cx43通信。因此，连接蛋白在哺乳动物细胞之间形成功能性异型间隙连接的能力是不同的。
DNAs coding for seven murine connexins (Cx) (Cx26, Cx31, Cx32, Cx37, Cx40, Cx43, and Cx45) are functionally expressed in human HeLa cells that were deficient in gap junctional communication. We compare the permeabilities of gap junctions comprised of different connexins to iontophoretically injected tracer molecules. Our results show that Lucifer yellow can pass through all connexin channels analyzed. On the other hand, propidium iodide and ethidium bromide penetrate very poorly or not at all through Cx31 and Cx32 channels, respectively, but pass through channels of other connexins. 4,6 Diamidino-2-phenylindole (DAPI) dihydrochloride shows less transfer among Cx31 or Cx43 transfectants. Neurobiotin is weakly transferred among Cx31 transfectants. Total junctional conductance in Cx31 or Cx45 transfected cells is only about half as high as in other connexin transfectants analyzed and does not correlate exactly with any of the tracer permeabilities. Permeability through different connexin channels appears to be dependent on the molecular structure of each tracer, i.e. size, charge and possibly rigidity. This supports the hypothesis that different connexin channels show different permeabilities to second messenger molecules as well as metabolites and may fulfill in this way their specific role in growth control and differentiation of cell types. In addition, we have investigated the function of heterotypic gap junctions after co-cultivation of two different connexin transfectants, one of which had been prelabeled with fluorescent dextran beads. Analysis of Lucifer yellow transfer reveals that HeLa cells expressing Cx31 (beta-type connexin) do not communicate with any other connexin transfectant tested but only with themselves. Two other beta-type connexin transfectants, HeLa-Cx26 and -Cx32, do not transmit Lucifer yellow to any of the alpha-type connexins analyzed. Among alpha- type connexins, Cx40 does not communicate with Cx43. Thus, connexins differ in their ability to form functional heterotypic gap junctions among mammalian cells.