Their expression and function are regulated via numerous mechanisms, from transcriptional regulation to the regulation of gating (for reviews on distribution, regulation and roles of glial gap junctions and hemichannels see for reviews on pannexin channels, see ). They are involved in multiple aspects of CNS physiology. In the mammalian CNS, connexin gap junctions and hemichannels, as well as pannexin channels, display a complex distribution among various cell types and each has a unique developmental pattern of expression. They, however, exist solely as unopposed cell membrane channels and do not form gap junctions. Pannexins, which are vertebrate homologues of invertebrate gap junction proteins (innexins) also are expressed in glial cells and neurons. Different types of connexins may form the hemichannels, presumably including neuronal Cx36. In addition to gap junctions, unopposed hemichannels are also found in the nervous system. In addition to gap junctions, unopposed connexin hemichannels and pannexin channels (which, however, do not form gap junctions) also can be expressed by neurons. Also shown are some of the molecules and ions that pass through gap junctions. Connexins forming the gap junction channels in neurons are indicated on the figure. The gap junction channels are made of two hemichannels (one in each apposed membrane) and each hemichannel consists of six connexin subunits. Schematic drawing of connexin gap junctions, connexin hemichannels and pannexin channels
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |