Based on cryo-microscopy experiments analyzing the complex of INI-IN-LEDGF/p75, Maillot and coworkers developed a model in which during assembly and nuclear translocation, INI interacts with the catalytic domain of IN preventing autocatalytic reactions. Consistently, the association of IN with INI-1 in the context of a functional SWI/SNF/BAF complex was found to be required for integration into chromatinized DNA templates and was able to restore the capacity of the virus to integrate into stable nucleosomes in vitro ( Lesbats et al., 2011). Mutations affecting the interaction between INI-1 and IN have been linked to multiple phenotypes including impaired viral reverse transcription and production of defective progeny ( Mathew et al., 2013). Consistent with a role in viral replication, using INI-1 transdominant mutants, the GAG-mediated incorporation of INI-1 into HIV-1 virions has also been demonstrated ( Yung et al., 2001 Cano and Kalpana, 2011). Structurally, INI-1 binds IN on the opposite side of LEDGF/p75 and is thought to contribute to the stabilization of the PIC ( Michel et al., 2009). Following infection, INI-1 undergoes nuclear export from the nucleus into the cytoplasm where it associates with the PIC as it is imported into the nucleus ( Turelli et al., 2001). INI-1/hSNF5, a core subunit of the SWI/SNF/BAF ATP-dependent chromatin-remodeling complex, was initially identified in a yeast 2 hybrid screen as a specific interactor of HIV-1 IN ( Kalpana et al., 1994), and has later been found to be involved in several steps of the HIV-1 viral cycle ( Turelli et al., 2001 Ariumi et al., 2006 Mahmoudi et al., 2006 Sorin et al., 2006 Boese et al., 2009 Cano and Kalpana, 2011 Lesbats et al., 2011 Rafati et al., 2011 Maillot et al., 2013 Mathew et al., 2013). Mahmoudi, in International Review of Cell and Molecular Biology, 2017 2.5.4 Integrase Interactor 1 (INI-1)
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