Classical swine fever virus NS5A protein activates autophagy via the PP2A-DAPK3-Beclin 1 axis
Classical swine fever virus NS5A protein activates autophagy via the PP2A-DAPK3-Beclin 1 axis
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DOI：
10.1128/jvi.00988-23
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发表时间：
2023-12-01
影响因子：
5.4
通讯作者：
Tu，Changchun
中科院分区：
文献类型：
--
作者：
Sun，Jinfu;Yu，Haixiao;Tu，Changchun
猪瘟病毒非结构蛋白 NS5A 对于病毒基因组复制、蛋白质翻译、病毒组装和自噬至关重要。在本文中，细胞PPP2R1A、PP2Ac和DAPK3与NS5A的相互作用已被证实。这些相互作用介导 PP2A 从 Beclin 1 解离及其与 DAPK3 的关联。 DAPK3 或 PPP2R1A 的下调会抑制 CSFV 复制。 NS5A 诱导 Beclin 1 上 Ser88（PK-15 细胞）或 Ser90（HEK293T 细胞）的磷酸化。Beclin 1 的敲低抑制 NS5A 诱导的自噬，表明 NS5A 诱导 Beclin 1 依赖性自噬。 siRNA 下调 DAPK3、PPP2R1A 或 PP2Ac 可减少 NS5A 介导的 Beclin 1 磷酸化和自噬，表明 PP2A 和 DAPK3 在 NS5A 触发的 Beclin 1 磷酸化和自噬中发挥关键作用。 Beclin 1 磷酸化的体外分析表明 PP2A 对于 DAPK3 介导的 Beclin 1 磷酸化至关重要，表明PP2A可能使DAPK3去磷酸化，激活其蛋白激酶活性，激活的DAPK3磷酸化Beclin 1，进而引发自噬。这些数据首次表明DAPK3可以通过PP2A的去磷酸化来激活。这些发现揭示了一种新机制，即 CSFV NS5A 蛋白通过 PP2A-DAPK3-Beclin 1 轴激活自噬以促进病毒复制。重要性自噬是一种保守的降解过程，可维持细胞稳态并调节天然和适应性免疫。病毒已经进化出多种策略来抑制或激活自噬以使其受益。该论文揭示了CSFV NS5A通过与PPP2R1A和DAPK3相互作用介导PP2A与Beclin 1的解离以及PP2A与DAPK3的结合，PP2A使DAPK3去磷酸化以激活其蛋白激酶活性，并激活DAPK3使Beclin 1磷酸化以触发自噬，表明NS5A通过PP2A-DAPK3-Beclin 1 轴。这些数据强调了猪瘟病毒激活自噬以促进其复制的新机制，从而有助于抗病毒策略的发展。
Classical swine fever virus nonstructural protein NS5A is essential for viral genome replication, protein translation, virus assembly, and autophagy. In the present paper, the interaction of cellular PPP2R1A, PP2Ac, and DAPK3 with NS5A has been confirmed. These interactions mediate the dissociation of PP2A from Beclin 1 and its association with DAPK3. Downregulation of DAPK3 or PPP2R1A inhibits CSFV replication. NS5A induced phosphorylation of Ser88 (PK-15 cells) or Ser90 (HEK293T cells) on Beclin 1. Knockdown of Beclin 1 inhibited NS5A-induced autophagy, indicating that NS5A induces Beclin 1-dependent autophagy. Downregulation of DAPK3, PPP2R1A, or PP2Ac by siRNA reduced Beclin 1 phosphorylation and autophagy mediated by NS5A, showing a critical role of PP2A and DAPK3 in Beclin 1 phosphorylation and autophagy triggered by NS5A.In vitroanalysis of Beclin 1 phosphorylation revealed PP2A as being essential for DAPK3-mediated phosphorylation of Beclin 1, indicating that PP2A may dephosphorylate DAPK3 to activate its protein kinase activity, with activated DAPK3 phosphorylated Beclin 1, and then triggering autophagy. These data show for the first time that DAPK3 can be activated through dephosphorylation by PP2A. These findings reveal a novel mechanism whereby CSFV NS5A protein activates autophagy via PP2A-DAPK3-Beclin 1 axis to favor viral replication.IMPORTANCEAutophagy is a conserved degradation process that maintains cellular homeostasis and regulates native and adaptive immunity. Viruses have evolved diverse strategies to inhibit or activate autophagy for their benefit. The paper reveals that CSFV NS5A mediates the dissociation of PP2A from Beclin 1 and the association of PP2A with DAPK3 by interaction with PPP2R1A and DAPK3, PP2A dephosphorylates DAPK3 to activate its protein kinase activity, and activated DAPK3 phosphorylates Beclin 1 to trigger autophagy, indicating that NS5A activates autophagy via the PP2A-DAPK3-Beclin 1 axis. These data highlight a novel mechanism by which CSFV activates autophagy to favor its replication, thereby contributing to the development of antiviral strategies.