Cation permeation through connexin 43 hemichannels is cooperative, competitive and saturable with parameters depending on the permeant species.
Cation permeation through connexin 43 hemichannels is cooperative, competitive and saturable with parameters depending on the permeant species.
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阳离子通过连接蛋白 43 半通道的渗透是合作性的、竞争性的和可饱和的，其参数取决于渗透物的种类。
DOI：
10.1016/j.bbrc.2011.05.031
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发表时间：
2011-06-17
影响因子：
3.1
通讯作者：
Sáez JC
中科院分区：
文献类型：
--
作者：
Orellana JA;Díaz E;Schalper KA;Vargas AA;Bennett MV;Sáez JC
通过连接蛋白43-EGFP半通道（Cx43-EGFP HC）的渗透动力学在二价无阳离子溶液中进行了评估，这提高了HC的打开概率，因此可以在初始速度期间进行测量。使用三种与细胞内核酸结合后荧光的阳离子[乙啶（Etd），丙啶（Prd）和4'，6-二氨基-2-苯基吲哚（DAPI）]和Cx43- egfp或Cx43野生型HeLa细胞转染物（分别为Cx43- egfp -和Cx43- wt -HeLa细胞）。细胞外周Cx43-EGFP水平与染料摄取率直接相关。每种染料的吸收速率达到饱和，与促进运输机制一致。饱和前，各染料的吸收率与浓度呈s型关系，希尔系数为>.1，表明在低浓度下，各染料的运输具有正协同性。Etd的最大摄取速率不受DAPI存在的影响，反之亦然，但在每种情况下，主要渗透分子的表观亲和力常数都显著增加，这与通道内竞争性抑制或结合位点竞争一致。此外，Cx43-EGFP和Cx43- wt hc具有相似的渗透性，这表明EGFP结合到Cx43的c端不会显著改变Cx43 hc对带正电分子的渗透性。
Kinetics of permeation through connexin 43-EGFP hemichannels (Cx43-EGFP HCs) were evaluated in divalent cation-free solutions, which enhance HC open probability and thus, allow measurements during initial velocity. Three cations that become fluorescent upon binding to intracellular nucleic acids [ethidium (Etd), propidium (Prd) and 4',6-diamidino-2-phenylindole (DAPI)] and Cx43-EGFP or Cx43 wild type HeLa cell transfectants (Cx43-EGFP- and Cx43-WT-HeLa cells, respectively) were used. Levels of Cx43-EGFP at the cell periphery and rate of dye uptake were directly related. The rate of uptake of each dye reached saturation consistent with a facilitated transport mechanism. Before saturation, the relation between rate of uptake and concentration of each dye was sigmoidal with Hill coefficients >1, indicating positive cooperativity of transport at low concentrations. The maximal rate of Etd uptake was not affected by the presence of DAPI and vice versa, but under each condition the apparent affinity constant of the main permeant molecule increased significantly consistent with competitive inhibition or competition for binding sites within the channel. Moreover, Cx43-EGFP and Cx43-WT HCs had similar permeability properties, indicating that EGFP bound to the C-terminal of Cx43 does not significantly alter the permeability of Cx43 HCs to positively charged molecules.
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DOI：
10.1083/jcb.129.3.805
发表时间：
1995-05
期刊：
The Journal of cell biology
影响因子：
--
作者：
Elfgang C;Eckert R;Lichtenberg-Fraté H;Butterweck A;Traub O;Klein RA;Hülser DF;Willecke K
通讯作者：
Willecke K
影响因子：
64.8
作者：
NICHOLSON, B;DERMIETZEL, R;REVEL, JP
通讯作者：
REVEL, JP
影响因子：
--
作者：
Schalper, Kurt A.;Palacios-Prado, Nicolas;Saez, Juan C.
通讯作者：
Saez, Juan C.
影响因子：
6.6
作者：
Orellana JA;Sáez PJ;Shoji KF;Schalper KA;Palacios-Prado N;Velarde V;Giaume C;Bennett MV;Sáez JC
通讯作者：
Sáez JC
DOI：
10.1085/jgp.119.2.171
发表时间：
2002-02
期刊：
The Journal of general physiology
影响因子：
--
作者：
Bukauskas FF;Bukauskiene A;Verselis VK
通讯作者：
Verselis VK