Sec24C is an HIV-1 host dependency factor crucial for virus replication

• DOI: 10.1038/s41564-021-00868-1
• Publication Date: 2021-03-01T17:03:41Z
• Authors: Stephanie V. Rebe...; Guochao Wei; Ross C. Larue; Jared Lindenberger; Ashwanth C. Francis; Arun S. Annamalai; James Morrison; Nikoloz Shkriabai; Szu-Wei Huang; Vineet KewalRamani; Eric M. Poeschla; Gregory B. Melikyan; Mamuka Kvaratskhelia
• Keywords: Cell Nucleus; 0301 basic medicine; Cytoplasm; Binding Sites; Virus Integration; Amino Acid Motifs; Active Transport, Cell Nucleus; Lentiviruses, Primate; Vesicular Transport Proteins; Reverse Transcription; Virus Replication; Article; 3. Good health; Structure-Activity Relationship; 03 medical and health sciences; Capsid; Host-Pathogen Interactions; HIV-1; Nuclear Pore; Humans; Protein Binding

Early events of the human immunodeficiency virus 1 (HIV-1) lifecycle, such as post-entry virus trafficking, uncoating and nuclear import, are poorly characterized because of limited understanding of virus-host interactions. Here, we used mass spectrometry-based proteomics to delineate cellular binding partners of curved HIV-1 capsid lattices and identified Sec24C as an HIV-1 host dependency factor. Gene deletion and complementation in Jurkat cells revealed that Sec24C facilitates infection and markedly enhances HIV-1 spreading infection. Downregulation of Sec24C in HeLa cells substantially reduced HIV-1 core stability and adversely affected reverse transcription, nuclear import and infectivity. Live-cell microscopy showed that Sec24C co-trafficked with HIV-1 cores in the cytoplasm during virus ingress. Biochemical assays demonstrated that Sec24C directly and specifically interacted with hexameric capsid lattices. A 2.3-Å resolution crystal structure of Sec24C228-242 in the complex with a capsid hexamer revealed that the Sec24C FG-motif bound to a pocket comprised of two adjoining capsid subunits. Combined with previous data1-4, our findings indicate that a capsid-binding FG-motif is conserved in unrelated proteins present in the cytoplasm (Sec24C), the nuclear pore (Nup153; refs. 3,4) and the nucleus (CPSF6; refs. 1,2). We propose that these virus-host interactions during HIV-1 trafficking across different cellular compartments are crucial for productive infection of target cells.