Activation of the Inositol (1,4,5)-Triphosphate Calcium Gate Receptor Is Required for HIV-1 Gag Release
Activation of the Inositol (1,4,5)-Triphosphate Calcium Gate Receptor Is Required for HIV-1 Gag Release
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DOI：
10.1128/jvi.01588-09
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发表时间：
2010-07-01
影响因子：
5.4
通讯作者：
Carter, Carol A.
中科院分区：
文献类型：
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作者：
Ehrlich, Lorna S.;Medina, Gisselle N.;Carter, Carol A.
包括人类免疫缺陷病毒1型(HIV-1)在内的所有逆转录病毒编码的结构前体多蛋白GAG是组装和释放形态上类似于未成熟病毒颗粒的颗粒所必需的，也是充分的。先前的研究表明，向表达GAG的细胞中添加钙离子可以增强病毒颗粒的产生。然而，没有特定的细胞因子被认为是钙供应的中介。肌醇(1，4，5)-三磷酸受体(IP3R)门控细胞内钙的储存。在被其配体IP3结合激活后，它从存储器中释放出钙离子。我们在这里证明了IP3R功能是有效释放HIV-1病毒颗粒所必需的。通过小干扰RNA耗尽IP3R，通过表达IP3R的突变片段以非常高的亲和力结合IP3R来封存其激活的配体，或者通过抑制磷脂酶C介导的前体磷脂酰肌醇-4，5-二磷酸的水解来阻断配体的形成，从而抑制GAG颗粒的释放。这些干扰，以及使用针对IP3R上配体结合位点的抗体对配体-受体相互作用的干扰，阻止了GAG的质膜积累。这些发现确认IP3R是HIV-1在Gag组装过程中运输的新决定因素，并引入IP3R调节的钙信号作为潜在的病毒颗粒释放的新辅助因子。
The structural precursor polyprotein, Gag, encoded by all retroviruses, including the human immunodeficiency virus type 1 (HIV-1), is necessary and sufficient for the assembly and release of particles that morphologically resemble immature virus particles. Previous studies have shown that the addition of Ca2+ to cells expressing Gag enhances virus particle production. However, no specific cellular factor has been implicated as mediator of Ca2+ provision. The inositol (1,4,5)-triphosphate receptor (IP3R) gates intracellular Ca2+ stores. Following activation by binding of its ligand, IP3, it releases Ca2+ from the stores. We demonstrate here that IP3R function is required for efficient release of HIV-1 virus particles. Depletion of IP3R by small interfering RNA, sequestration of its activating ligand by expression of a mutated fragment of IP3R that binds IP3 with very high affinity, or blocking formation of the ligand by inhibiting phospholipase C-mediated hydrolysis of the precursor, phosphatidylinositol-4,5-biphosphate, inhibited Gag particle release. These disruptions, as well as interference with ligand-receptor interaction using antibody targeted to the ligand-binding site on IP3R, blocked plasma membrane accumulation of Gag. These findings identify IP3R as a new determinant in HIV-1 trafficking during Gag assembly and introduce IP3R-regulated Ca2+ signaling as a potential novel cofactor in viral particle release.