Identification of paramyxovirus V protein residues essential for STAT protein degradation and promotion of virus replication
Identification of paramyxovirus V protein residues essential for STAT protein degradation and promotion of virus replication
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DOI：
10.1128/jvi.79.13.8591-8601.2005
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发表时间：
2005-07-01
影响因子：
5.4
通讯作者：
Ito, Y
中科院分区：
文献类型：
--
作者：
Nishio, M;Tsurudome, M;Ito, Y
一些副粘病毒V蛋白诱导STAT蛋白降解，并已研究了人副流感病毒2型（hPIV 2）V蛋白中此过程所必需的氨基酸。产生了组成型表达各种突变V蛋白的各种重组hPIV 2和细胞系。我们发现，与Cys簇的Cys残基的替换V蛋白仍然能够结合STAT，但不能诱导其降解。hPIV 2 V蛋白通过位于Cys簇上游的W-（X）（3）-W-（X）（9）-W Trp基序结合STAT。在该基序中替换两个或更多个Trp残基导致未能形成V/STAT 2复合物。我们还鉴定了hPIV 2 V蛋白的两个对于STAT降解至关重要的Phe残基，即位于Cys簇内的Phe 207和蛋白质P/V共同区中的Phe][43]。有趣的是，用hPIV 2感染BHK细胞导致STAT 1而不是STAT 2的特异性降解。提供了hPIV 2诱导STAT降解的细胞种属特异性的其他证据。最后，产生并部分表征了仅能从其P基因表达P蛋白的V-阴性hPIV 2。与其他副粘病毒属的V-病毒相反，这种V-风疹病毒是高度衰弱的，即使在Vero细胞中生长也非常有限。因此，正如预期的那样，结构性风疹病毒V蛋白在促进病毒生长方面显然是重要的，与其抗干扰素（IFN）活性无关。有趣的是，许多对于抗IFN活性至关重要的残基，例如，该簇的Cys和该簇内的Phe 207以及该基序的Trp对于促进病毒生长也是必需的。
Some paramyxovirus V proteins induce STAT protein degradation, and the amino acids essential for this process in the human parainfluenza virus type 2 (hPIV2) V protein have been studied. Various recombinant hPIV2s and cell lines constitutively expressing various mutant V proteins were generated. We found that V proteins with replacement of Cys residues of the Cys cluster were still able to bind STATs but were unable to induce their degradation. The hPIV2 V protein binds STATs via a W-(X)(3)-W-(X)(9)-W Trp motif located just upstream of the Cys cluster. Replacements of two or more Trp residues in this motif resulted in a failure to form a V/STAT2 complex. We have also identified two Phe residues of the hPIV2 V protein that are essential for STAT degradation, namely, Phe207, lying within the Cys cluster, and Phe][43, in the P/V common region of the protein. Interestingly, infection of BHK cells with hPIV2 led to the specific degradation of STAT1 and not STAT2. Other evidence for the cell species specificity of hPIV2-induced STAT degradation is presented. Finally, a V-minus hPIV2, which can express only the P protein from its P gene, was generated and partially characterized. In contrast to V-minus viruses of other paramyxovirus genera, this V-minus rubulavirus was highly debilitated, and its growth even in Vero cells was very limited. The structural rubulavirus V proteins, as expected, are thus clearly important in promoting virus growth, independent of their anti-interferon (IFN) activity. Interestingly, many of the residues that are essential for anti-IFN activity, e.g., the Cys of this cluster and Phe207 within this cluster, as well as the Trp of this motif, are also essential for promoting virus growth.