Virophagy, the selective autophagosomal engulfment and lysosomal degradation of viral components, is crucial for neuronal cell survival and antiviral immunity. However, the mechanisms leading to viral antigen recognition and capture by autophagic machinery remain poorly understood. Here, we identified cyclin-dependent kinase–like 5 (CDKL5), known to function in neurodevelopment, as an essential regulator of virophagy. Loss-of-function mutations in CDKL5 are associated with a severe neurodevelopmental encephalopathy. We found that deletion of CDKL5 or expression of a clinically relevant pathogenic mutant of CDKL5 reduced virophagy of Sindbis virus (SINV), a neurotropic RNA virus, and increased intracellular accumulation of SINV capsid protein aggregates and cellular cytotoxicity. Cdkl5-knockout mice displayed increased viral antigen accumulation and neuronal cell death after SINV infection and enhanced lethality after infection with several neurotropic viruses. Mechanistic studies demonstrated that CDKL5 directly binds the canonical selective autophagy receptor p62 and phosphorylates p62 at T269/S272 to promote its interaction with viral capsid aggregates. We found that CDKL5-mediated phosphorylation of p62 facilitated the formation of large p62 inclusion bodies that captured viral capsids to initiate capsid targeting to autophagic machinery. Overall, these findings identify a cell-autonomous innate immune mechanism for autophagy activation to clear intracellular toxic viral protein aggregates during infection.

中文翻译：

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CDKL5 调节 p62 介导的选择性自噬并提供针对嗜神经病毒的保护

病毒自噬，即病毒成分的选择性自噬体吞噬和溶酶体降解，对于神经元细胞的存活和抗病毒免疫至关重要。然而，自噬机制导致病毒抗原识别和捕获的机制仍然知之甚少。在这里，我们确定了细胞周期蛋白依赖性激酶样 5 (CDKL5)，已知其在神经发育中发挥作用，是病毒自噬的重要调节因子。CDKL5 的功能丧失突变与严重的神经发育性脑病有关。我们发现CDKL5的缺失或CDKL5的临床相关致病突变体的表达减少了辛德比斯病毒（SINV）（一种神经性RNA病毒）的病毒自噬，并增加了SINV衣壳蛋白聚集体的细胞内积累和细胞毒性。Cdk15敲除小鼠在SINV感染后表现出病毒抗原积累和神经元细胞死亡增加，并且在感染几种嗜神经病毒后致死率增强。机制研究表明，CDKL5 直接结合经典选择性自噬受体 p62，并在 T269/S272 位点磷酸化 p62，以促进其与病毒衣壳聚集体的相互作用。我们发现 CDKL5 介导的 p62 磷酸化促进了大型 p62 包涵体的形成，该包涵体捕获病毒衣壳以启动衣壳靶向自噬机制。总体而言，这些发现确定了细胞自主先天免疫机制，用于激活自噬，以清除感染期间细胞内的有毒病毒蛋白聚集体。