HIV-1 Vpu interacts with RBM10 to promote HIV-1 infection.

Viral protein U (Vpu), an accessory protein of HIV-1, functions by antagonizing or hijacking various host factors to allow the virus to evade host immune surveillance and facilitate viral release. Nevertheless, there is limited understanding regarding the impact of Vpu on the biogenesis of HIV-1 RNAs. In this study, we utilized ascorbate peroxidase 2 (APEX2)-based proximity labeling techniques in combination with mass spectrometry and immunoprecipitation-mass spectrometry (IP-MS) to characterize interactions between HIV-1 Vpu and host proteins. We identified nine cellular targets of Vpu. Among these targets, our research demonstrated the interaction between Vpu and RNA-binding motif protein 10 (RBM10), which results in the degradation of RBM10 through the ubiquitin-proteasome pathway. The expression of RBM10 exerted an inhibitory effect on virus replication by binding to viral RNA and reducing the levels of incompletely spliced HIV-1 transcripts. Additionally, it promoted the transcription of various antiviral genes. The findings elucidate the role of HIV-1 Vpu in RNA replication and identify RBM10 as a novel regulator of HIV-1 transcription.IMPORTANCEA comprehensive analysis utilizing APEX2-MS and IP-MS techniques identified a total of 24 cellular targets of Vpu, three of which have been documented as restriction factors. Vpu-interacting proteins were found to be significantly enriched in pathways related to cell adhesion, RNA transport, and the spliceosome. The identification of RBM10 as a novel regulator of HIV-1 replication and infectivity, and RBM10 regulated transcription of both viral and host RNA transcripts. Vpu interacted with RBM10 and promoted its degradation through the ubiquitin-proteasome pathway.