Reptilian reovirus utilizes a small type III protein with an external myristylated amino terminus to mediate cell-cell fusion
Reptilian reovirus utilizes a small type III protein with an external myristylated amino terminus to mediate cell-cell fusion
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DOI：
10.1128/jvi.78.8.4342-4351.2004
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发表时间：
2004-04-01
影响因子：
5.4
通讯作者：
Duncan, R
中科院分区：
文献类型：
--
作者：
Corcoran, JA;Duncan, R
爬行动物呼肠孤病毒是能够诱导细胞-细胞融合的有限数量的无包膜病毒之一。由双顺反子病毒mRNA的第一个开放阅读框编码的小的、疏水的、碱性的、125个氨基酸的融合蛋白负责这种融合活性。与先前表征的呼肠孤病毒融合蛋白的序列比较表明，p14代表融合相关小跨膜（FAST）蛋白家族的新成员。拓扑分析表明，p14是一个代表性的一个小子集的完整的膜蛋白，III型蛋白N-外质/C-胞质（N-exo/C-cyt），缺乏一个可切割的信号序列，并使用内部反向信号锚定序列，以指导膜插入和蛋白质拓扑结构。这种拓扑结构导致p14的必需肉豆蔻基化N-末端结构域跨细胞膜的意外共翻译易位。这种新型呼肠孤病毒膜融合蛋白中存在的拓扑结构和结构基序进一步强调了FAST蛋白家族的多样性和不寻常的性质，并清楚地表明FAST蛋白代表了第三类不同的病毒膜融合蛋白。
Reptilian reovirus is one of a limited number of nonenveloped viruses that are capable of inducing cell-cell fusion. A small, hydrophobic, basic, 125-amino-acid fusion protein encoded by the first open reading frame of a bicistronic viral mRNA is responsible for this fusion activity. Sequence comparisons to previously characterized reovirus fusion proteins indicated that p14 represents a new member of the fusion-associated small transmembrane (FAST) protein family. Topological analysis revealed that p14 is a representative of a minor subset of integral membrane proteins, the type III proteins N-exoplasmic/C-cytoplasmic (N-exo/C-cyt), that lack a cleavable signal sequence and use an internal reverse signal-anchor sequence to direct membrane insertion and protein topology. This topology results in the unexpected, cotranslational translocation of the essential myristylated N-terminal domain of p14 across the cell membrane. The topology and structural motifs present in this novel reovirus membrane fusion protein further accentuate the diversity and unusual properties of the FAST protein family and clearly indicate that the FAST proteins represent a third distinct class of viral membrane fusion proteins.