Analysis of the role of autophagy inhibition by two complementary human cytomegalovirus BECN1/Beclin 1-binding proteins
Analysis of the role of autophagy inhibition by two complementary human cytomegalovirus BECN1/Beclin 1-binding proteins
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DOI：
10.1080/15548627.2015.1125071
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发表时间：
2016-01-01
期刊：
影响因子：
13.3
通讯作者：
Esclatine, Audrey
中科院分区：
文献类型：
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作者：
Mouna, Lina;Hernandez, Eva;Esclatine, Audrey
自噬在人类巨细胞病毒(HCMV)感染后早期被激活，但后来，病毒阻止了自噬。在这里，我们鉴定了两种HCMV蛋白，TRS1和IRS1，它们在感染过程中抑制自噬。TRS1或IRS1的表达能够阻断不同细胞系的自噬，而不依赖于EIF2S1激酶、EIF2AK2/PKR。相反，TRS1和IRS1与自噬蛋白BECN1/Beclin 1相互作用。我们定位了IRS1和TRS1的BECN1结合域(BBD)，发现它对自噬抑制是必不可少的。只表达IRS1或TRS1的突变病毒部分控制了自噬，而两种蛋白都不表达的双突变病毒刺激了自噬。一种不表达IRS1的突变病毒表达截短形式的TRS1，其中BBD被删除，但未能控制自噬。然而，该突变病毒具有与野生型病毒相似的复制动力学，这表明自噬抑制对病毒复制不是关键。事实上，利用自噬的药物调节剂和通过shRNA敲除抑制自噬，我们发现刺激自噬增强了病毒的复制。相反，抑制自噬可以减少人巨细胞病毒感染。因此，我们的结果证明了自噬对DNA病毒的一种新的前驱作用。
Autophagy is activated early after human cytomegalovirus (HCMV) infection but, later on, the virus blocks autophagy. Here we characterized 2 HCMV proteins, TRS1 and IRS1, which inhibit autophagy during infection. Expression of either TRS1 or IRS1 was able to block autophagy in different cell lines, independently of the EIF2S1 kinase, EIF2AK2/PKR. Instead, TRS1 and IRS1 interacted with the autophagy protein BECN1/Beclin 1. We mapped the BECN1-binding domain (BBD) of IRS1 and TRS1 and found it to be essential for autophagy inhibition. Mutant viruses that express only IRS1 or TRS1 partially controlled autophagy, whereas a double mutant virus expressing neither protein stimulated autophagy. A mutant virus that did not express IRS1 and expressed a truncated form of TRS1 in which the BBD was deleted, failed to control autophagy. However, this mutant virus had similar replication kinetics as wild-type virus, suggesting that autophagy inhibition is not critical for viral replication. In fact, using pharmacological modulators of autophagy and inhibition of autophagy by shRNA knockdown, we discovered that stimulating autophagy enhanced viral replication. Conversely, inhibiting autophagy decreased HCMV infection. Thus, our results demonstrate a new proviral role of autophagy for a DNA virus.