Identification of G protein-coupled receptor signaling pathway proteins in marine diatoms using comparative genomics.
Identification of G protein-coupled receptor signaling pathway proteins in marine diatoms using comparative genomics.
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DOI：
10.1186/1471-2164-14-503
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发表时间：
2013-07-24
期刊：
影响因子：
4.4
通讯作者：
Faustman EM
中科院分区：
文献类型：
--
作者：
Port JA;Parker MS;Kodner RB;Wallace JC;Armbrust EV;Faustman EM
G蛋白偶联受体信号通路在哺乳动物细胞的信号传递和对外界刺激的反应中起着重要的作用。该途径的蛋白质组分已经在植物和酵母等较简单的真核生物中得到了表征，但它们在单细胞光合作用真核生物中的存在和作用尚未确定。我们使用比较基因组学的方法，利用四种硅藻(假多系列尼氏藻、伪海链藻、三角褐指藻和圆柱藻)的全基因组序列和基因表达文库来寻找与已知的GPCR途径蛋白共享序列保守的GPCR信号途径蛋白的证据。4种硅藻中GPCRs信号的大部分核心成分都保存得很好，蛋白质序列与GPCRs、人G蛋白α-和β-亚基及下游效应物相似。有证据表明，只有在假单胞菌中才存在Gγ-亚基，从而存在完整的异源三聚体G蛋白。系统发育分析表明，硅藻GPCRs与C类GPCRs相似，但有很大的差异，其分支以GABAB受体亚家族为基础。这些推测的硅藻GPCR序列的胞外区和胞内区在序列长度上有很大的差异，其中7个序列包含C类GPCR激活所必需的配体结合域。转录数据表明，在不同的胁迫条件下，许多可能的GPCR序列在硅藻中表达，许多GPCR激活的信号蛋白，包括G蛋白，也得到了表达。所有四种硅藻中编码哺乳动物GPCR途径所需蛋白质的序列的存在突显了该途径的高度保守性，并暗示了这些单细胞生物体中与环境感知和反应有关的复杂信号机制。在一个或多个硅藻中缺乏一些gpr途径蛋白的证据，例如Gγ-亚单位，可能是由于四种硅藻的基因组完整性和基因组覆盖率的差异。推测的硅藻GPCRs序列与已知的C类GPCRs的高度差异表明，这些序列可能代表了C类GPCRs的另一个可能的祖先亚家族。
The G protein-coupled receptor (GPCR) signaling pathway plays an essential role in signal transmission and response to external stimuli in mammalian cells. Protein components of this pathway have been characterized in plants and simpler eukaryotes such as yeast, but their presence and role in unicellular photosynthetic eukaryotes have not been determined. We use a comparative genomics approach using whole genome sequences and gene expression libraries of four diatoms (Pseudo-nitzschia multiseries, Thalassiosira pseudonana, Phaeodactylum tricornutum and Fragilariopsis cylindrus) to search for evidence of GPCR signaling pathway proteins that share sequence conservation to known GPCR pathway proteins. The majority of the core components of GPCR signaling were well conserved in all four diatoms, with protein sequence similarity to GPCRs, human G protein α- and β-subunits and downstream effectors. There was evidence for the Gγ-subunit and thus a full heterotrimeric G protein only in T. pseudonana. Phylogenetic analysis of putative diatom GPCRs indicated similarity but deep divergence to the class C GPCRs, with branches basal to the GABAB receptor subfamily. The extracellular and intracellular regions of these putative diatom GPCR sequences exhibited large variation in sequence length, and seven of these sequences contained the necessary ligand binding domain for class C GPCR activation. Transcriptional data indicated that a number of the putative GPCR sequences are expressed in diatoms under various stress conditions in culture, and that many of the GPCR-activated signaling proteins, including the G protein, are also expressed. The presence of sequences in all four diatoms that code for the proteins required for a functional mammalian GPCR pathway highlights the highly conserved nature of this pathway and suggests a complex signaling machinery related to environmental perception and response in these unicellular organisms. The lack of evidence for some GPCR pathway proteins in one or more of the diatoms, such as the Gγ-subunit, may be due to differences in genome completeness and genome coverage for the four diatoms. The high divergence of putative diatom GPCR sequences to known class C GPCRs suggests these sequences may represent another, potentially ancestral, subfamily of class C GPCRs.
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影响因子：
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