Department of Physiology, University College Cork, Western Gateway Building, Western Road, Cork, Ireland.
Adv Exp Med Biol. 2012;740:159-82. doi: 10.1007/978-94-007-2888-2_7.
Ryanodine receptors (RyRs), along with the related inositol 1,4,5-trisphosphate receptors (IP(3)Rs), mediate the release of Ca(2+) from intracellular organelles of eukaryotes. As discussed in other chapters, such increases in intracellular Ca(2+) levels act a fundamental second messenger, regulating a diverse array of cellular processes. For over two decades, it has been reported that vertebrates express multiple RYR genes, whereas non-vertebrate multicellular organisms possess a single homologue within their genomes. Recently, the existence of RyR-like channels in unicellular organisms has also been reported. This chapter exploits recent expansions in available genome data to generate an overview of the expression of RyR-like genes in organisms representing a broad range of viral, archaeal, bacterial and eukaryotic taxa. Analyses of the multidomain structures and phylogenetic relationships of these proteins has lead to a model in which, early during eukaryotic evolution, IP(3)R-like ancestral Ca(2+) release channels were converted to RyR proteins via the addition of promiscuous protein domains, possibly via horizontal gene transfer mechanisms.
Ryanodine 受体（RyRs）与相关的肌醇 1,4,5-三磷酸受体（IP3Rs）一起，介导真核生物细胞内细胞器中 Ca2+的释放。正如其他章节所讨论的，细胞内 Ca2+水平的这种增加充当基本的第二信使，调节各种细胞过程。二十多年来，据报道脊椎动物表达多种 RYR 基因，而无脊椎多细胞生物在其基因组中仅具有一个同源物。最近，还报道了单细胞生物中存在 RyR 样通道。本章利用现有基因组数据的最新扩展，概述了代表广泛病毒、古细菌、细菌和真核生物类群的生物体中 RyR 样基因的表达。对这些蛋白质的多结构域结构和系统发育关系的分析提出了一个模型，即在真核生物进化的早期，通过添加混杂的蛋白质结构域，可能通过水平基因转移机制，将 IP3R 样祖先 Ca2+释放通道转化为 RyR 蛋白。
