National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA, USA.
Channels (Austin). 2011 May-Jun;5(3):193-7. doi: 10.4161/chan.5.3.15765. Epub 2011 May 1.
Pannexins, a class of membrane channels, bear significant sequence homology with the invertebrate gap junction proteins, innexins and more distant similarities in their membrane topologies and pharmacological sensitivities with the gap junction proteins, connexins. However, the functional role for the pannexin oligomers, or pannexons, is different from connexin oligomers, the connexons. Many pannexin publications have used the term "hemichannels" to describe pannexin oligomers while others use the term "channels" instead. This has led to confusion within the literature about the function of pannexins that promotes the idea that pannexons serve as gap junction hemichannels and thus have an assembly and functional state as gap junctional intercellular channels. Here we present the case that unlike the connexin gap junction intercellular channels, so far, pannexin oligomers have repeatedly been shown to be channels that are functional in single membranes, but not as intercellular channel in appositional membranes. Hence, they should be referred to as channels and not hemichannels. Thus, we advocate that in the absence of firm evidence that pannexins form gap junctions, the use of the term "hemichannel" be discontinued within the pannexin literature.
Pannexins 是一类膜通道，与无脊椎动物间隙连接蛋白 innexin 具有显著的序列同源性，在膜拓扑结构和药理学敏感性方面与间隙连接蛋白 connexin 也有更远的相似性。然而，多聚体 pannexin 或 pannexons 的功能作用与 connexin 多聚体 connexons 不同。许多 pannexin 的出版物使用术语“半通道”来描述 pannexin 多聚体，而其他出版物则使用术语“通道”来代替。这导致文献中对 pannexin 功能的混淆，从而产生了 pannexons 充当间隙连接半通道的观点，因此具有作为间隙连接细胞间通道的组装和功能状态。在这里，我们提出这样的观点，与 connexin 间隙连接细胞间通道不同，到目前为止，多聚体 pannexin 已反复被证明是在单膜中具有功能的通道，但不能作为贴壁膜中的细胞间通道。因此，它们应该被称为通道而不是半通道。因此，我们主张，在没有确凿证据表明 pannexin 形成间隙连接的情况下，在 pannexin 文献中应停止使用“半通道”一词。
