Ingram Zachary, Kline Christopher, Hughson Alexandra K, Singh Parmit K, Fischer Hannah L, Sowd Gregory A, Watkins Simon C, Kane Melissa, Engelman Alan N, Ambrose Zandrea
Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA.
Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, PA.
bioRxiv. 2024 Apr 9:2024.04.08.588584. doi: 10.1101/2024.04.08.588584.
Human immunodeficiency virus type 1 (HIV-1) capsid, which is the target of the antiviral lenacapavir, protects the viral genome and binds multiple host proteins to influence intracellular trafficking, nuclear import, and integration. Previously, we showed that capsid binding to cleavage and polyadenylation specificity factor 6 (CPSF6) in the cytoplasm is competitively inhibited by cyclophilin A (CypA) binding and regulates capsid trafficking, nuclear import, and infection. Here we determined that a capsid mutant with increased CypA binding affinity had significantly reduced nuclear entry and mislocalized integration. However, disruption of CypA binding to the mutant capsid restored nuclear entry, integration, and infection in a CPSF6-dependent manner. Furthermore, relocalization of CypA expression from the cell cytoplasm to the nucleus failed to restore mutant HIV-1 infection. Our results clarify that sequential binding of CypA and CPSF6 to HIV-1 capsid is required for optimal nuclear entry and integration targeting, informing antiretroviral therapies that contain lenacapavir.
1型人类免疫缺陷病毒（HIV-1）衣壳是抗病毒药物来那卡帕韦的作用靶点，它保护病毒基因组并结合多种宿主蛋白以影响细胞内运输、核输入和整合。此前，我们发现衣壳在细胞质中与切割及聚腺苷酸化特异性因子6（CPSF6）的结合会受到亲环素A（CypA）结合的竞争性抑制，并且这种抑制作用会调节衣壳的运输、核输入和感染。在此，我们确定，具有增强的CypA结合亲和力的衣壳突变体的核进入显著减少且整合定位错误。然而，破坏CypA与突变体衣壳的结合以CPSF6依赖的方式恢复了核进入、整合和感染。此外，将CypA的表达从细胞质重新定位到细胞核未能恢复突变体HIV-1的感染。我们的结果表明，CypA和CPSF6依次与HIV-1衣壳结合是实现最佳核进入和整合靶向所必需的，这为包含来那卡帕韦的抗逆转录病毒疗法提供了依据。
