Cyclic nucleotide permeability through unopposed connexin hemichannels.
Cyclic nucleotide permeability through unopposed connexin hemichannels.
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DOI：
10.3389/fphar.2013.00075
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发表时间：
2013
影响因子：
5.6
通讯作者：
Valiunas V
中科院分区：
文献类型：
--
作者：
Valiunas V
环磷酸腺苷（cAMP）是一种众所周知的细胞内和细胞间的第二信使。这些分子的膜渗透性对于自分泌样或旁分泌样递送具有潜在的重要性。在这里，实验已经被设计来证明是否间隙连接半通道，由连接蛋白，是一个可能的入口途径环核苷酸进入细胞内部。采用稳定表达缝隙连接蛋白43（Cx43）和缝隙连接蛋白26（Cx 26）的HeLa细胞研究缝隙连接半通道的环核苷酸通透性。为了检测cAMP摄取，使用来自海胆精子的环核苷酸调节通道（SpIH）作为cAMP传感器转染细胞。SpIH衍生电流（Im）记录在全细胞/穿孔膜片钳配置。将细胞灌注在含有500 μM cAMP且不含细胞外Ca ~（2+）的外部K ~+天冬氨酸（KAsp）溶液中，使Im电流水平增加5至7倍。SpIH电流增加与可检测的半通道电流活性相关。在含500 μM cAMP的无Ca ~（2+）NaCl灌流液中，细胞去极化也引起SpIH电流增加。升高细胞外Ca 2+至mM水平抑制半通道活性。用含有500 μM cAMP和2 mM Ca ~（2+）的去极化KAsp溶液灌注不增加SpIH电流。将差距连接阻断剂甘珀酸加入到外部溶液中抑制cAMP摄取。细胞去极化和细胞外Ca 2+降低都增加了非连接半通道的开放概率。因此，SpIH电流增强是通过在表达Cx43和Cx 26的细胞中经由开放的膜半通道摄取细胞外cAMP诱导的。本文提供的数据显示Cx43和Cx 26的半通道对cAMP是可渗透的，并且进一步的数据表明半通道实际上是cAMP介导的细胞间信号传导的潜在途径。
Cyclic adenosine monophosphate (cAMP) is a well-known intracellular and intercellular second messenger. The membrane permeability of such molecules has potential importance for autocrine-like or paracrine-like delivery. Here experiments have been designed to demonstrate whether gap junction hemichannels, composed of connexins, are a possible entrance pathway for cyclic nucleotides into the interior of cells. HeLa cells stably expressing connexin43 (Cx43) and connexin26 (Cx26) were used to study the cyclic nucleotide permeability of gap junction hemichannels. For the detection of cAMP uptake, the cells were transfected using the cyclic nucleotide-modulated channel from sea urchin sperm (SpIH) as the cAMP sensor. SpIH derived currents (Im) were recorded in whole-cell/perforated patch clamp configuration. Perfusion of the cells in an external K+ aspartate- (KAsp) solution containing 500 μM cAMP and no extracellular Ca2+, yielded a five to sevenfold increase in the Im current level. The SpIH current increase was associated with detectable hemichannel current activity. Depolarization of cells in Ca2+-free NaCl perfusate with 500 μM cAMP also induced a SpIH current increase. Elevating extracellular Ca2+ to mM levels inhibited hemichannel activity. Perfusion with a depolarizing KAsp solution containing 500 μM cAMP and 2 mM Ca2+ did not increase SpIH currents. The addition of the gap junction blocker carbenoxolone to the external solution inhibited cAMP uptake. Both cell depolarization and lowered extracellular Ca2+ increase the open probability of non-junctional hemichannels. Accordingly, the SpIH current augmentation was induced by the uptake of extracellular cAMP via open membrane hemichannels in Cx43 and Cx26 expressing cells. The data presented here show that hemichannels of Cx43 and Cx26 are permeable to cAMP, and further the data suggest that hemichannels are, in fact, a potential pathway for cAMP mediated cell-to-cell signaling.
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DOI：
10.1073/pnas.012589799
发表时间：
2002-01-08
影响因子：
11.1
作者：
Contreras, JE;Sánchez, HA;Sáez, JC
通讯作者：
Sáez, JC
影响因子：
4.8
作者：
Plotkin, LI;Manolagas, SC;Bellido, T
通讯作者：
Bellido, T
影响因子：
20.1
作者：
KLEBER, AG;JANSE, MJ;DURRER, D
通讯作者：
DURRER, D
影响因子：
64.8
作者：
Gauss, R;Seifert, R;Kaupp, UB
通讯作者：
Kaupp, UB
影响因子：
3.4
作者：
EBIHARA, L;BERTHOUD, VM;BEYER, EC
通讯作者：
BEYER, EC