Caspase-mediated cleavage of the feline calicivirus capsid protein
Caspase-mediated cleavage of the feline calicivirus capsid protein
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DOI：
10.1099/vir.0.18840-0
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发表时间：
2003-05-01
影响因子：
3.8
通讯作者：
Roberts, LO
中科院分区：
文献类型：
--
作者：
Al-Molawi, N;Beardmore, VA;Roberts, LO
猫杯状病毒(FCV)是猫的一种急性上呼吸道疾病。FCV衣壳蛋白是作为前体(76 KDa)合成的，翻译后通过去除N端124个氨基酸加工成成熟的62 kDa衣壳蛋白。我们之前的研究也检测到了一个40 kDa的分子。与FCV衣壳蛋白有关的蛋白质，在感染过程中产生。在这里，我们证明了在细胞感染培养过程中，半胱氨酸天冬氨酸氨基转移酶抑制剂可以阻止FCV衣壳蛋白的切割。此外，Caspase-2、-3和-7在FCV感染过程中被激活，如前形式加工、N-acetyl-Asp-Glu-Val-Asp-7-amido-4-trifluoromethylcoumarin裂解活性增加和原位多聚(腺苷二磷酸-核糖)聚合酶裂解。半胱氨酸天冬氨酸氨基转移酶的激活与诱导细胞凋亡和衣壳裂解40 kDa片段相一致。用重组人caspase和体外衍生的FCV衣壳蛋白进行体外切割试验表明，caspase-2和较小程度的caspase-6切割衣壳蛋白产生一个40 kDa的片段。综上所述，这些结果表明，FCV I在感染细胞内触发了细胞凋亡，caspase诱导的衣壳分裂伴随着细胞凋亡发生。对衣壳裂解在FCV感染发病机制中的可能作用进行了讨论。
Feline calicivirus (FCV) is responsible for an acute upper respiratory tract disease in cats. The FCV capsid protein is synthesized as a precursor (76 kDa) that is post-translationally processed into the mature 62 kDa capsid protein by removal of the N-terminal 124 amino acids. Our previous studies have also detected a 40 kDa. protein, related to the FCV capsid protein, produced during infection. Here we demonstrate that cleavage of the FCV capsid protein, during infection of cells in culture, was prevented by caspase inhibitors. In addition, caspase-2, -3 and -7 were activated during FCV infection, as shown by pro-form processing, an increase in N-acetyl-Asp-Glu-Val-Asp-7-amido-4-trifluoromethylcoumarin cleavage activity and in situ poly(ADP-ribose) polymerase cleavage. Caspase activation coincided with the induction of apoptosis and capsid cleavage to the 40 kDa fragment. An in vitro cleavage assay, using recombinant human caspases and in vitro-derived FCV capsid protein, revealed that caspase-2, and to a lesser extent caspase-6, cleaved the capsid protein to generate a 40 kDa fragment. Taken together, these results suggest that FCV I triggers apoptosis within infected cells and that caspase-induced capsid cleavage occurs concomitantly with apoptosis. The possible role of capsid cleavage in the pathogenesis of FCV infection is discussed.