Cx30 exhibits unique characteristics including a long half-life when assembled into gap junctions
Cx30 exhibits unique characteristics including a long half-life when assembled into gap junctions
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DOI：
10.1242/jcs.174698
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发表时间：
2015-11-01
影响因子：
4
通讯作者：
Laird, Dale W.
中科院分区：
文献类型：
--
作者：
Kelly, John J.;Shao, Qing;Laird, Dale W.
在本研究中，我们研究了连接蛋白家族成员连接蛋白30 （Cx30，也称为GJB6）的生命周期、运输、组装和细胞表面动力学，它在皮肤健康和听力中起着至关重要的作用。出乎意料的是，Cx30在细胞表面的定位和间隙连接细胞间的通讯不受内质网(ER)-高尔基转运抑制剂brefeldin A或蛋白质合成抑制剂环已酰亚胺的长时间处理的影响，而Cx43（也称为GJA1）被迅速清除。光漂白后的荧光恢复显示，Cx30斑块是从外缘重建的，与位于斑块内芯的旧通道保持一致。Sar1 GTPase的显性阴性形式的表达导致内质网内Cx30的积累，这与Cx30通过高尔基非依赖性途径转运的报道相反。Cx30与Cx43的共表达表明，这些连接蛋白在共同的间隙连接斑块中分离到不同的区域，这表明它们的组装受不同机制的控制。综上所述，我们发现Cx30是一种异常稳定、寿命长的连接蛋白（半衰期约为12h），这可能是其在表皮和耳蜗中的特殊作用的基础。
In the present study we investigated the life cycle, trafficking, assembly and cell surface dynamics of a poorly characterized connexin family member, connexin 30 (Cx30; also known as GJB6), which plays a critical role in skin health and hearing. Unexpectedly, Cx30 localization at the cell surface and gap junctional intercellular communication was not affected by prolonged treatments with the endoplasmic reticulum (ER)-Golgi transport inhibitor brefeldin A or the protein synthesis inhibitor cycloheximide, whereas Cx43 (also known as GJA1) was rapidly cleared. Fluorescent recovery after photobleaching revealed that Cx30 plaques were rebuilt from the outer edges in keeping with older channels residing in the inner core of the plaque. Expression of a dominant-negative form of Sar1 GTPase led to the accumulation of Cx30 within the ER, in contrast to a report that Cx30 traffics via a Golgi-independent pathway. Co-expression of Cx30 with Cx43 revealed that these connexins segregate into distinct domains within common gap junction plaques, suggesting that their assembly is governed by different mechanisms. In summary, Cx30 was found to be an unusually stable, long-lived connexin (half-life >12 h), which may underlie its specific role in the epidermis and cochlea.