InterPro domain: IPR027140

Importin or karyopherin subunit beta-1 forms a complex with an importin alpha subunit. The importin complex is required for nuclear protein import. Importins bind to NLSs in their protein cargos to transport them through the nuclear pore into the nucleus [ 1 ]. In Arabidopsis, the homologue of importin beta 1 is required for the abscisic acid (ABA) response and drought tolerance, both complicated biological processes that require the nuclear import of hundreds of proteins to initiate the necessary changes in gene expression [ 2 ].

1. Nuclear localization signals for four distinct karyopherin-β nuclear import systems. Biochem. J. 468, 353-62
2. An Arabidopsis homolog of importin β1 is required for ABA response and drought tolerance. Plant J. 75, 377-89