The human I-mfa domain containing protein, HIC, interacts with HIV-1 Tat and Rev and sequesters them in the cytoplasm

Tat and Rev are equally critical for HIV-1 replication and work in a sequential manner: first, transactivation of the HIV-1 LTR by Tat, followed by nuclear export of partially spliced and unspliced viral transcripts by Rev. Both functions require Tat and Rev to be imported to the nucleus, a process mediated by molecular recognition of their homologous arginine-rich NLS domains by importin-β.