Appraising the apoptotic mimicry model and the role of phospholipids for poxvirus entry
Appraising the apoptotic mimicry model and the role of phospholipids for poxvirus entry
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DOI：
10.1073/pnas.0909376106
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发表时间：
2009-10-13
影响因子：
11.1
通讯作者：
Moss, Bernard
中科院分区：
文献类型：
--
作者：
Laliberte, Jason P.;Moss, Bernard
牛痘病毒（VACV）通过与质膜融合并通过低ph依赖性内体途径进入细胞，可能涉及未识别的细胞受体。除了大约25种病毒蛋白外，疫苗病毒成熟病毒粒子的膜还含有几种磷脂，包括磷脂酰丝氨酸（PS）。最近的一个模型假设，PS将病毒粒子标记为凋亡碎片，激活一个共同的细胞摄取途径，以获得细胞进入，可能是通过与PS特异性细胞表面受体的相互作用。为了评估细胞凋亡模拟模型，我们用几种不同的磷脂重组了洗洁精提取的病毒粒子膜。虽然证实了PS的l -立体异构体重建感染性的能力，但通常不存在于病毒粒子膜上的PS的非生物学相关的d -立体异构体和磷脂酰甘油也发挥了作用。无论哪一种磷脂重建了感染性，病毒的进入都被病毒粒子表面蛋白的中和单克隆抗体和药物blebbistatin和bafilomycin A1所抑制，这表明在每种情况下病毒的摄取都是特异性的，并且通过类似的机制发生，包括巨噬细胞作用和低ph的内吞途径。脂质重组和非重组、膜提取的病毒粒子同样能够与细胞结合。然而，在膜重构过程中磷脂与病毒颗粒的物理关联与颗粒感染性和细胞进入能力的恢复直接相关。我们的研究结果支持了PS在痘病毒入侵中的作用，但也证明了其他磷脂，不知道对凋亡碎片的摄取信号，也有类似的功能。
Entry of vaccinia virus (VACV) into cells occurs by fusion with the plasma membrane and via a low pH-dependent endosomal pathway, presumably involving unidentified cellular receptors. In addition to approximate to 25 viral proteins, the membrane of VACV mature virions contains several phospholipids including phosphatidylserine (PS). A recent model posits that PS flags virions as apoptotic debris to activate a common cellular uptake pathway to gain cell entry, perhaps through an interaction with a PS-specific cell surface receptor. To evaluate the apoptotic mimicry model, we reconstituted the membrane of detergent-extracted virions with several different phospholipids. Although the ability of the L-stereoisomer of PS to reconstitute infectivity was confirmed, the nonbiologically relevant D-stereoisomer of PS, and phosphatidylglycerol, which are not normally present in the virion membrane, functioned as well. Regardless of which phospholipid reconstituted infectivity, virus entry was inhibited by a neutralizing monoclonal antibody to a virion surface protein and by the drugs blebbistatin and bafilomycin A1, suggesting that in each case virus uptake was specific and occurred by a similar mechanism involving macropinocytosis and a low-pH endocytic pathway. Lipid-reconstituted and nonreconstituted, membrane-extracted virions were equally capable of binding to cells. However, the physical association of phospholipids with virus particles during membrane reconstitution correlated directly with rescue of particle infectivity and cell entry capability. Our results support a role for PS in poxvirus entry, but demonstrate that other phospholipids, not known to signal uptake of apoptotic debris, can function similarly.