%0 Journal Article %A Chen, Nan-Yu %A Zhou, Lihong %A Gane, Paul J %A Opp, Silvana %A Ball, Neil J %A Nicastro, Giuseppe %A Zufferey, Madeleine %A Buffone, Cindy %A Luban, Jeremy %A Selwood, David %A Diaz-Griffero, Felipe %A Taylor, Ian %A Fassati, Ariberto %D 2020 %T HIV-1 capsid is involved in post-nuclear entry steps %U https://crick.figshare.com/articles/journal_contribution/HIV-1_capsid_is_involved_in_post-nuclear_entry_steps/12620651 %2 https://crick.figshare.com/ndownloader/files/23731889 %K Capsid %K Coumermycin-A1 %K HIV-1 %K Integration %K Nucleoporins %K Nucleus %K Nup153 %K Uncoating %K Aminocoumarins %K Antiviral Agents %K Cell Line %K HIV Core Protein p24 %K Humans %K Virus Internalization %K Taylor, I FC001178 %K NMR-ack %K Virology %K 1103 Clinical Sciences %X BACKGROUND: HIV-1 capsid influences viral uncoating and nuclear import. Some capsid is detected in the nucleus but it is unclear if it has any function. We reported that the antibiotic Coumermycin-A1 (C-A1) inhibits HIV-1 integration and that a capsid mutation confers resistance to C-A1, suggesting that capsid might affect post-nuclear entry steps. RESULTS: Here we report that C-A1 inhibits HIV-1 integration in a capsid-dependent way. Using molecular docking, we identify an extended binding pocket delimited by two adjacent capsid monomers where C-A1 is predicted to bind. Isothermal titration calorimetry confirmed that C-A1 binds to hexameric capsid. Cyclosporine washout assays in Jurkat CD4+ T cells expressing engineered human TRIMCyp showed that C-A1 causes faster and greater escape from TRIMCyp restriction. Sub-cellular fractionation showed that small amounts of capsid accumulated in the nuclei of infected cells and C-A1 reduced the nuclear capsid. A105S and N74D capsid mutant viruses did not accumulate capsid in the nucleus, irrespective of C-A1 treatment. Depletion of Nup153, a nucleoporin located at the nuclear side of the nuclear pore that binds to HIV-1 capsid, made the virus less susceptible to TRIMCyp restriction, suggesting that Nup153 may help maintain some integrity of the viral core in the nucleus. Furthermore C-A1 increased binding of CPSF6, a nuclear protein, to capsid. CONCLUSIONS: Our results indicate that capsid is involved in post-nuclear entry steps preceding integration. %I The Francis Crick Institute