Role of connexin 26 hemichannels in the regulatión of purinergic calcium signaling under physiólogical and pathological conditións
Gap junction channels (GJCs) are intercellular channels that connect the cytoplasm of two neighboring cells. They allow the exchange of cytoplasmic molecules up to about 1 kD, including metabolites, second messengers and ions (Goldberg et al., 2004). Thus, they allow to a group of cells to display c...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2012 |
| País: | Chile |
| Idioma: | inglés |
| OAI Identifier: | oai:repositorio.anid.cl:10533/180482 |
| Acceso en línea: | http://creativecommons.org/licenses/by-nc-nd/3.0/cl/ https://hdl.handle.net/10533/180482 |
| Access Level: | acceso abierto |
| Sumario: | Gap junction channels (GJCs) are intercellular channels that connect the cytoplasm of two neighboring cells. They allow the exchange of cytoplasmic molecules up to about 1 kD, including metabolites, second messengers and ions (Goldberg et al., 2004). Thus, they allow to a group of cells to display coordinated responses to a given stimulus of physiological or pathophysiological nature, through direct transfer of chemical and electrical signals. Each GJC is made by the docking of a two hemichannels (HCs) or connexons each one contributed by an adjacent cell (Fig. 1). In turn, each hemichannel (HC) is composed of six protein subunits called connexins (Cxs) (Sáez et al., 2003). Cxs are integral membrane proteins encoded by a multigene family corresponding to 21 genes in humans and 20 in mice (Sohl and Willecke; 2004). By convention, these proteins are referred to the Cx prefix followed by a number indicating its molecular weight (Beyer et al., 1987). Cxs share a common membrane topology (Fig. 1), which has been determined through their sensitivity to proteases and predicted by hydropathy analysis. Thus, Cxs present four hydrophobic transmembrane regions (M1-M4), two extracellular loops (E1 and E2) and three cytoplasmatic regions, corresponding to the amino terminus (NT), the carboxyl-terminus (CT) and one intracellular loop (IL). The latter two are the most variable regions in length and amino acid composition between Cxs (Bruzzone et al 1996). Cellular coupling through GJCs occurs in various cell types, including hepatocytes, cardiac cells, neurons, astrocytes, oligodendrocytes and cochlea support cells, among others (Sáez et al., 1989, Taimor, 2000., Santos-Sacchi, 2000; Bennett and Zukin, 2004; Orthmann-Murphy et al.; 2008). |
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