Data_Sheet_1_Prolyl Isomerase Pin1 Regulates the Stability of Hepatitis B Virus Core Protein.PDF

The dynamic interplay between virus and host proteins is critical for establishing efficient viral replication and virus-induced pathogenesis. Phosphorylation-dependent prolyl isomerization by Pin1 provides a unique mechanism of molecular switching to control both protein function and stability. We demonstrate here that Pin1 binds and stabilizes hepatitis B virus core protein (HBc) in a phosphorylation-dependent manner, and promotes the efficient viral propagation. Phos-tag gel electrophoresis with various site-directed mutants of HBc revealed that Thr160 and Ser162 residues within the C terminal arginine-rich domain are phosphorylated concomitantly. GST pull-down assay and co-immunoprecipitation analysis demonstrated that Pin1 associated with phosphorylated HBc at the Thr160-Pro and Ser162-Pro motifs. Chemical or genetic inhibition of Pin1 significantly accelerated the rapid degradation of HBc via a lysosome-dependent pathway. Furthermore, we found that the pyruvate dehydrogenase phosphatase catalytic subunit 2 (PDP2) could dephosphorylate HBc at the Pin1-binding sites, thereby suppressing Pin1-mediated HBc stabilization. Our findings reveal an important regulatory mechanism of HBc stability catalyzed by Pin1 and may facilitate the development of new antiviral therapeutics targeting Pin1 function.

病毒与宿主蛋白之间的动态相互作用对于建立高效的病毒复制及病毒诱导的病理发生至关重要。Pin1依赖磷酸化的脯氨酸异构化作用提供了一种独特的分子转换机制，以调控蛋白的功能与稳定性。本研究证实，Pin1以磷酸化依赖的方式结合并稳定乙型肝炎病毒核心蛋白（HBc），并促进病毒的传播效率。通过对HBc的不同位点定向突变体进行磷酸化标记胶电泳，我们发现C端富含精氨酸的氨基酸残基中的Thr160和Ser162位点同时发生磷酸化。GST下拉实验和共免疫沉淀分析显示，Pin1与磷酸化的HBc在Thr160-Pro和Ser162-Pro基序处结合。化学或遗传学抑制Pin1显著加速了HBc通过溶酶体依赖途径的快速降解。此外，我们发现在Pin1结合位点，丙酮酸脱氢酶磷酸酶催化亚基2（PDP2）能够去磷酸化HBc，从而抑制Pin1介导的HBc稳定化。我们的研究揭示了由Pin1催化的HBc稳定性重要调控机制，可能有助于开发针对Pin1功能的新型抗病毒治疗药物。