InterPro : IPR002652

Name  Importin-alpha, importin-beta-binding domain Short Name  Importin-a_IBB
Type  Domain Description  The exchange ofmacromolecules between the nucleus and cytoplasm takes place through nuclear pore complexes within the nuclear membrane. Active transport of large molecules through these pore complexes require carrier proteins, called karyopherins (importins and exportins), which shuttle between the two compartments.Members of the importin-alpha (karyopherin-alpha) family can form heterodimers with importin-beta. As part of a heterodimer, importin-beta mediates interactions with the pore complex, while importin-alpha acts as an adaptor protein to bind the nuclear localisation signal (NLS) on the cargo through the classical NLS import of proteins. Proteins can contain one (monopartite) or two (bipartite) NLS motifs. Importin-alpha contains several armadillo (ARM) repeats, which produce a curving structure with two NLS-binding sites, a major one close to the N terminus and a minor one close to the C terminus.Ran GTPase helps to control the unidirectional transfer of cargo. The cytoplasm contains primarily RanGDP and the nucleus RanGTP through the actions of RanGAP and RanGEF, respectively. In the nucleus, RanGTP binds to importin-beta within the importin/cargo complex, causing a conformational change in importin-beta that releases it from importin-alpha-bound cargo. The N-terminal importin-beta-binding (IBB) domain of importin-alpha contains an auto-regulatory region that mimics the NLS motif []. The release of importin-beta frees the auto-regulatory region on importin-alpha to loop back and bind to the major NLS-binding site, causing the cargo to be released [].This entry represents the N-terminal IBB domain of importin-alpha that contains the auto-regulatory region.

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



0 Child Features

0 Contains

1 Found In

Id Name Short Name Type
IPR017336 Snurportin-1 Snurportin-1 Family

0 Parent Features

2 Publications

First Author Title Year Journal Volume Pages
Lange A Classical nuclear localization signals: definition, function, and interaction with importin alpha. 2007 J Biol Chem 282 5101-5
Moroianu J The binding site of karyopherin alpha for karyopherin beta overlaps with a nuclear localization sequence. 1996 Proc Natl Acad Sci U S A 93 6572-6

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)