Activation of intracellular signaling pathways by the murine cytomegalovirus G protein-coupled receptor M33 occurs via PLC-{beta}/PKC-dependent and -independent mechanisms.
Activation of intracellular signaling pathways by the murine cytomegalovirus G protein-coupled receptor M33 occurs via PLC-{beta}/PKC-dependent and -independent mechanisms.
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鼠巨细胞病毒 G 蛋白偶联受体 M33 对细胞内信号传导途径的激活通过 PLC-{β}/PKC 依赖性和非依赖性机制发生。
DOI：
10.1128/jvi.02116-08
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发表时间：
2009
影响因子：
5.4
通讯作者：
Miller,WilliamE
中科院分区：
文献类型：
--
作者：
Sherrill,JosephD;Stropes,MelissaP;Schneider,OliviaD;Koch,DianaE;Bittencourt,FabiolaM;Miller,JeanetteLC;Miller,WilliamE
疱疹病毒基因组内存在大量G蛋白偶联受体（GPCR）同源物，表明这些基因在感染宿主的病毒复制中起重要作用。对于鼠巨细胞病毒（MCMV）就是这种情况，其中M33 GPCR的缺失或用信号传导缺陷突变体替换M33已显示出严重减弱体内复制。在本研究中，我们利用M33的遗传改变版本（称为R131 A）与药理学抑制剂的组合，以进一步表征M33激活下游信号通路的机制。这种M33的R131 A突变体不能支持唾液腺在体内的复制，因此，是一种重要的工具，可用于检查M33的信号传导活性。我们发现M33通过异源三聚体Gq/11蛋白刺激转录因子CREB，而不是通过M33与Gspathway的混杂偶联。使用Gq/11下游信号分子的抑制剂，我们证明M33以磷脂酶C-β和蛋白激酶C（PKC）依赖的方式刺激CREB转录活性。最后，利用野生型和R131 A版本的M33，我们表明，M33介导的其他信号节点，包括促分裂原活化蛋白激酶家族成员p38α和转录因子NF-κB的激活，发生在Gq/11和PKC信号转导的情况下。本研究的结果表明，M33利用多种机制来调节细胞内信号级联，并表明通过PLC-β和PKC的信号转导在体内MCMV发病机制中起着核心作用。
The presence of numerous G protein-coupled receptor (GPCR) homologs within the herpesvirus genomes suggests an essential role for these genes in viral replication in the infected host. Such is the case for murine cytomegalovirus (MCMV), where deletion of the M33 GPCR or replacement of M33 with a signaling defective mutant has been shown to severely attenuate replication in vivo. In the present study we utilized a genetically altered version of M33 (termed R131A) in combination with pharmacological inhibitors to further characterize the mechanisms by which M33 activates downstream signaling pathways. This R131A mutant of M33 fails to support salivary gland replication in vivo and, as such, is an important tool that can be used to examine the signaling activities of M33. We show that M33 stimulates the transcription factor CREB via heterotrimeric Gq/11proteins and not through promiscuous coupling of M33 to the Gspathway. Using inhibitors of signaling molecules downstream of Gq/11, we demonstrate that M33 stimulates CREB transcriptional activity in a phospholipase C-β and protein kinase C (PKC)-dependent manner. Finally, utilizing wild-type and R131A versions of M33, we show that M33-mediated activation of other signaling nodes, including the mitogen-activated protein kinase family member p38α and transcription factor NF-κB, occurs in the absence of Gq/11and PKC signaling. The results from the present study indicate that M33 utilizes multiple mechanisms to modulate intracellular signaling cascades and suggest that signaling through PLC-β and PKC plays a central role in MCMV pathogenesis in vivo.