National and Kapodistrian University of Athens
Department of Biology
Biophysics & Bioinformatics Laboratory
Protein Information |
|
|---|---|
| Protein Name | Importin subunit beta-1 |
| Accession Code | O13864 |
| Gene | kap95 |
| Organism | Schizosaccharomyces pombe 972h- (Taxonomy: 284812) |
| Part of Reference Proteome? | Yes |
| Sequence (Length: 863) |
Description |
Position in the Nuclear Envelope |
|
|---|---|---|
| Location | Location ID | Description |
| Nuclear Envelope | SL-0178 | The nuclear envelope is a membrane system which surrounds the nucleoplasm of eukaryotic cells. It is composed of the nuclear lamina, nuclear pore complexes and two nuclear membranes. The space between the two membranes is called the nuclear intermembrane space. |
| Nuclear Pore Complex | SL-0185 | The nuclear pore complex (NPC) constitutes the exclusive means of nucleocytoplasmic transport. NPCs allow the passive diffusion of ions and small molecules and the active bidirectional transport of macromolecules such as proteins, RNAs etc across the double-membrane nuclear envelope.The NPC is composed of at least 30 distinct subunits known as Nucleoporins (NUPs). | Membrane Topology |
| Topology | Source | Annotation Type |
| Unknown | UniProt | Sequence Analysis | Assigned Ontology terms |
Description |
|
|---|---|
| Importin beta subunit that functions in nuclear protein import through association with the importin alpha subunit, which binds to the clasical nuclear localization signal (cNLS) in cargo substrates. Docking of the importin/substrate complex to the nuclear pore complex (NPC) is mediated by importin beta through binding to nucleoporin FxFG repeats and the complex is subsequently translocated through the pore by an energy requiring, Ran-dependent mechanism. At the nucleoplasmic side of the NPC, GTP-Ran binds to importin beta and the three components separate, leading to release of the cargo. Importin alpha and beta are re-exported from the nucleus to the cytoplasm where GTP hydrolysis releases Ran from importin beta. The directionality of nuclear import is thought to be conferred by an asymmetric distribution of the GTP- and GDP-bound forms of Ran between the cytoplasm and nucleus. {By SimilarityUniProtKB:Q06142}. | Assigned Ontology terms |
National and Kapodistrian University of Athens
Department of Biology
Biophysics & Bioinformatics Laboratory