CELL-INDUCED CONFORMATIONAL CHANGE IN POLIOVIRUS - EXTERNALIZATION OF THE AMINO TERMINUS OF VP1 IS RESPONSIBLE FOR LIPOSOME BINDING
CELL-INDUCED CONFORMATIONAL CHANGE IN POLIOVIRUS - EXTERNALIZATION OF THE AMINO TERMINUS OF VP1 IS RESPONSIBLE FOR LIPOSOME BINDING
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DOI：
10.1128/jvi.64.5.1934-1945.1990
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发表时间：
1990-05-01
影响因子：
5.4
通讯作者：
HOGLE, JM
中科院分区：
文献类型：
--
作者：
FRICKS, CE;HOGLE, JM
脊髓灰质炎病毒和许多其他小核糖核酸病毒在吸附到易感细胞后会发生构象转变，这导致抗原性改变、蛋白酶敏感性增加、内部衣壳蛋白VP4丢失以及吸附细胞能力丧失。利用多种序列特异性探针，包括两种蛋白酶、一组抗病毒单克隆抗体以及一组针对与衣壳蛋白VP1序列相对应的合成肽的抗血清，对这些构象改变的颗粒进行了表征。利用这些探针，细胞改变的病毒可与天然和热灭活的病毒粒子明显区分开来。这些探针还表明，细胞诱导的构象变化改变了病毒几个区域的可及性。特别是，在天然病毒粒子中完全位于内部的VP1的氨基末端变得外露。与天然和热灭活的病毒不同，细胞改变的病毒粒子能够吸附到脂质体上。已表明外露的VP1氨基末端是脂质体吸附的原因。我们提出，在感染过程中，VP1的氨基末端插入内体膜，从而在细胞进入机制中起作用。
Upon attachment to susceptible cells, poliovirus and a number of other picornaviruses undergo conformational transitions which result in changes in antigenicity, increased protease sensitivity, the loss of the internal capsid protein VP4, and a loss of the ability to attach to cells. These conformationally altered particles have been characterized by using a number of sequence-specific probes, including two proteases, a panel of antiviral monoclonal antibodies, and a panel of antisera against synthetic peptides which correspond to sequences from the capsid protein VP1. With these probes, cell-altered virus is clearly distinguishable from native and heat-inactivated virions. The probes also demonstrate that the cell-induced conformational change alters the accessibility of several regions of the virus. In particular, the amino terminus of VP1, which is entirely internal in the native virion, become externalized. Unlike native and heat-inactivated virus, cell-altered virions are able to attach to liposomes. The exposed amino terminus of VP1 is shown to be responsible for liposome attachment. We propose that during infection the amino terminus of VP1 inserts into endosomal membranes and thus plays a role in the mechanism of cell entry.