Functional analysis and regulation of purified connexin hemichannels.
Functional analysis and regulation of purified connexin hemichannels.
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DOI：
10.3389/fphys.2014.00071
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发表时间：
2014
影响因子：
4
通讯作者：
Altenberg GA
中科院分区：
文献类型：
--
作者：
Fiori MC;Reuss L;Cuello LG;Altenberg GA
间隙连接通道（GJCs）是连接相邻细胞的水通道。它们是由两个半通道（hc）头对头连接形成的，每个半通道来自相邻的细胞。功能性hc是由一种或多种连接蛋白异构体组成的连接蛋白六聚体。耳聋是最常见的感觉神经疾病，而Cx26的突变是遗传性耳聋最常见的原因。Cx43是最普遍存在的连接蛋白，在许多器官、组织和细胞类型中表达，包括心脏、大脑和肾脏。其表达和功能的改变在非常常见的医学问题（如与心脏和脑缺血有关的疾病）的病理生理中起着重要作用。在正常和病理条件下的细胞和器官实验中，有大量关于磷酸化和Cx43靶向、定位和功能之间关系的信息。然而，在复杂的系统中，通过磷酸化调控Cx43的分子机制很难解决。在这里，我们提出使用纯化的hc作为功能和结构研究的模型。Cx26和Cx43是唯一被纯化、重组并进行功能和结构分析的同工异构体。纯化的Cx26和Cx43 hcc具有与细胞中证实的性质相容的特性，并且提出了在脂质体中重组纯化hcc的功能分析方法。我们发现PKC对丝氨酸368的磷酸化产生了Cx43 hc的部分关闭，改变了溶质选择性。我们还提供证据表明，磷酸化的作用是高度协同的，需要修饰几个连接蛋白亚基，丝氨酸368的磷酸化引起纯化的hc的构象变化。纯化hcc的使用开始为理解hcc在分子水平上的调控提供关键数据。
Gap-junction channels (GJCs) are aqueous channels that communicate adjacent cells. They are formed by head-to-head association of two hemichannels (HCs), one from each of the adjacent cells. Functional HCs are connexin hexamers composed of one or more connexin isoforms. Deafness is the most frequent sensineural disorder, and mutations of Cx26 are the most common cause of genetic deafness. Cx43 is the most ubiquitous connexin, expressed in many organs, tissues, and cell types, including heart, brain, and kidney. Alterations in its expression and function play important roles in the pathophysiology of very frequent medical problems such as those related to cardiac and brain ischemia. There is extensive information on the relationship between phosphorylation and Cx43 targeting, location, and function from experiments in cells and organs in normal and pathological conditions. However, the molecular mechanisms of Cx43 regulation by phosphorylation are hard to tackle in complex systems. Here, we present the use of purified HCs as a model for functional and structural studies. Cx26 and Cx43 are the only isoforms that have been purified, reconstituted, and subjected to functional and structural analysis. Purified Cx26 and Cx43 HCs have properties compatible with those demonstrated in cells, and present methodologies for the functional analysis of purified HCs reconstituted in liposomes. We show that phosphorylation of serine 368 by PKC produces a partial closure of the Cx43 HCs, changing solute selectivity. We also present evidence that the effect of phosphorylation is highly cooperative, requiring modification of several connexin subunits, and that phosphorylation of serine 368 elicits conformational changes in the purified HCs. The use of purified HCs is starting to provide critical data to understand the regulation of HCs at the molecular level.
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影响因子：
2.4
作者：
Agullo-Pascual, Esperanza;Delmar, Mario
通讯作者：
Delmar, Mario
影响因子：
3.3
作者：
Cherian, PP;Siller-Jackson, AJ;Jiang, JX
通讯作者：
Jiang, JX
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：
Bevans, CG;Kordel, M;Harris, AL
通讯作者：
Harris, AL
影响因子：
--
作者：
Cheng, A;Schweissinger, D;Yeager, M
通讯作者：
Yeager, M