Nuclear import of Rev involves the cellular proteins including importin-beta and B23 and is mediated by an arginine-rich nuclear localization signal (NLS) within the RNA binding domain of the Rev protein. The NLS of Rev associates with importin- beta as well as B23 which has been shown to function in the nuclear import of ribosomal proteins. The Rev-importin beta-B23 complex associates with the nuclear pore through interactions between importin beta and nucleoporin. Upon entry into the nucleus, Ran-GTP associates with importin beta resulting in in the disassembly of the importin beta-Rev-B23 complex and the release of Rev cargo.