PDF(Pubmed)
Abstract：
G protein-coupled receptors (GPCRs) constitute the largest family of transmembrane proteins in metazoans that mediate the regulation of various physiological responses to discrete ligands through heterotrimeric G protein subunits. The existence of GPCRs in plant is contentious, but their comparable crucial role in various signaling pathways necessitates the identification of novel remote GPCR-like proteins that essentially interact with the plant G protein α subunit and facilitate the transduction of various stimuli. In this study, we identified three putative GPCR-like proteins (OsGPCRLPs) (LOC_Os06g09930.1, LOC_Os04g36630.1, and LOC_Os01g54784.1) in the rice proteome using a stringent bioinformatics workflow. The identified OsGPCRLPs exhibited a canonical GPCR \'type I\' 7TM topology, patterns, and biologically significant sites for membrane anchorage and desensitization. Cluster-based interactome mapping revealed that the identified proteins interact with the G protein α subunit which is a characteristic feature of GPCRs. Computational results showing the interaction of identified GPCR-like proteins with G protein α subunit and its further validation by the membrane yeast-two-hybrid assay strongly suggest the presence of GPCR-like 7TM proteins in the rice proteome. The absence of a regulator of G protein signaling (RGS) box in the C- terminal domain, and the presence of signature motifs of canonical GPCR in the identified OsGPCRLPs strongly suggest that the rice proteome contains GPCR-like proteins that might be involved in signal transduction.
摘要：
G蛋白偶联受体（GPCRs）构成了后生动物中最大的跨膜蛋白家族，它们通过异源三聚体G蛋白亚基介导对离散配体的各种生理反应的调节。植物中GPCRs的存在是有争议的，但是它们在各种信号传导途径中的可比关键作用需要鉴定新型的远程GPCR样蛋白，这些蛋白基本上与植物G蛋白α亚基相互作用并促进各种刺激的转导。在这项研究中,我们使用严格的生物信息学工作流程在水稻蛋白质组中鉴定了三种推定的GPCR样蛋白（OsGPCRLPs）（LOC_Os06g09930.1，LOC_Os04g36630.1和LOC_Os01g54784.1）。鉴定的OsGPCRLPs表现出规范的GPCR\'I型\'7TM拓扑，模式,以及膜锚定和脱敏的生物学重要部位。基于簇的相互作用组作图表明，已鉴定的蛋白质与G蛋白α亚基相互作用，这是GPCRs的特征。计算结果表明已鉴定的GPCR样蛋白与G蛋白α亚基的相互作用，并通过膜酵母双杂交测定法进一步验证，强烈表明水稻蛋白质组中存在GPCR样7TM蛋白。C端结构域中不存在G蛋白信号传导（RGS）盒的调节剂，并且在鉴定的OsGPCRLPs中存在规范GPCR的特征基序，这强烈表明水稻蛋白质组含有可能参与信号转导的GPCR样蛋白。
