The carboxy-terminal tail of human cytomegalovirus (HCMV) US28 regulates both chemokine-independent and chemokine-dependent signaling in HCMV-infected cells.
The carboxy-terminal tail of human cytomegalovirus (HCMV) US28 regulates both chemokine-independent and chemokine-dependent signaling in HCMV-infected cells.
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人巨细胞病毒 (HCMV) US28 的羧基末端尾部可调节 HCMV 感染细胞中的趋化因子依赖性和趋化因子依赖性信号传导。
DOI：
10.1128/jvi.00354-09
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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：
Stropes,MelissaP;Schneider,OliviaD;Zagorski,WilliamA;Miller,JeanetteLC;Miller,WilliamE
人巨细胞病毒 (HCMV) 编码的 G 蛋白偶联受体 (GPCR) US28 是 HCMV 感染细胞中许多信号通路的有效激活剂。 US28 的胞内羧基末端结构域含有对异源表达系统中 US28 信号传导调节至关重要的残基；然而，该结构域在 HCMV 感染过程中发挥的作用仍不清楚。在本研究中，我们构建了编码 US28 羧基末端结构域截短突变体 FLAG-US28/1-314 的 HCMV 重组病毒，以研究该结构域在 US28 信号传导中的作用。我们证明 US28/1-314 比野生型 US28 表现出更有效的磷脂酶 C-β (PLC-β) 信号，表明羧基末端结构域在调节受感染细胞中的激动剂非依赖性信号传导中发挥着重要作用。此外，表达 US28/1-314 突变体的 HMCV 感染细胞表现出响应 CCL5 的延长的钙信号，表明 US28 羧基末端结构域也调节激动剂依赖性信号传导。最后，虽然趋化因子CX3CL1充当PLC-β的组成型US28信号传导的反向激动剂或抑制剂，但我们证明CX3CL1在US28刺激的钙释放方面充当激动剂。这项研究首次证明 US28 的羧基末端在 HCMV 感染的情况下控制 US28 信号传导，并表明 CX3CL1 等趋化因子可以减少组成型 US28 信号，但同时促进非组成型 US28 信号。
The human cytomegalovirus (HCMV)-encoded G-protein-coupled receptor (GPCR) US28 is a potent activator of a number of signaling pathways in HCMV-infected cells. The intracellular carboxy-terminal domain of US28 contains residues critical for the regulation of US28 signaling in heterologous expression systems; however, the role that this domain plays during HCMV infection remains unknown. For this study, we constructed an HCMV recombinant virus encoding a carboxy-terminal domain truncation mutant of US28, FLAG-US28/1-314, to investigate the role that this domain plays in US28 signaling. We demonstrate that US28/1-314 exhibits a more potent phospholipase C-β (PLC-β) signal than does wild-type US28, indicating that the carboxy-terminal domain plays an important role in regulating agonist-independent signaling in infected cells. Moreover, HMCV-infected cells expressing the US28/1-314 mutant exhibit a prolonged calcium signal in response to CCL5, indicating that the US28 carboxy-terminal domain also regulates agonist-dependent signaling. Finally, while the chemokine CX3CL1 behaves as an inverse agonist or inhibitor of constitutive US28 signaling to PLC-β, we demonstrate that CX3CL1 functions as an agonist with regard to US28-stimulated calcium release. This study is the first to demonstrate that the carboxy terminus of US28 controls US28 signaling in the context of HCMV infection and indicates that chemokines such as CX3CL1 can decrease constitutive US28 signals and yet simultaneously promote nonconstitutive US28 signals.