Binding stoichiometry and structural model of the HIV-1 Rev/importin β complex

Life Sci Alliance. 2022 Aug 22;5(10):e202201431. doi: 10.26508/lsa.202201431. Print 2022 Oct.


HIV-1 Rev mediates the nuclear export of intron-containing viral RNA transcripts and is essential for viral replication. Rev is imported into the nucleus by the host protein importin β (Impβ), but how Rev associates with Impβ is poorly understood. Here, we report biochemical, mutational, and biophysical studies of the Impβ/Rev complex. We show that Impβ binds two Rev monomers through independent binding sites, in contrast to the 1:1 binding stoichiometry observed for most Impβ cargos. Peptide scanning data and charge-reversal mutations identify the N-terminal tip of Rev helix α2 within Rev's arginine-rich motif (ARM) as a primary Impβ-binding epitope. Cross-linking mass spectrometry and compensatory mutagenesis data combined with molecular docking simulations suggest a structural model in which one Rev monomer binds to the C-terminal half of Impβ with Rev helix α2 roughly parallel to the HEAT-repeat superhelical axis, whereas the other monomer binds to the N-terminal half. These findings shed light on the molecular basis of Rev recognition by Impβ and highlight an atypical binding behavior that distinguishes Rev from canonical cellular Impβ cargos.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • HIV-1* / metabolism
  • Models, Structural
  • Molecular Docking Simulation
  • RNA, Viral / metabolism
  • beta Karyopherins* / genetics
  • beta Karyopherins* / metabolism


  • RNA, Viral
  • beta Karyopherins

Associated data

  • PDB/1UKL
  • PDB/3W5K
  • PDB/1QGK
  • PDB/3LWW
  • PDB/2X7L
  • PDB/5DHV