Importin-5 (IPO5)
The protein contains 1097 amino acids for an estimated molecular weight of 123630 Da.
Functions in nuclear protein import as nuclear transport receptor. Serves as receptor for nuclear localization signals (NLS) in cargo substrates. Is thought to mediate docking of the importin/substrate complex to the nuclear pore complex (NPC) through binding to nucleoporin and the complex is subsequently translocated through the pore by an energy requiring, Ran-dependent mechanism. At the nucleoplasmic side of the NPC, Ran binds to the importin, the importin/substrate complex dissociates and importin is re-exported from the nucleus to the cytoplasm where GTP hydrolysis releases Ran. 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 similarity). Mediates the nuclear import of ribosomal proteins RPL23A, RPS7 and RPL5. Binds to a beta-like import receptor binding (BIB) domain of RPL23A. In vitro, mediates nuclear import of H2A, H2B, H3 and H4 histones. Binds to CPEB3 and mediates its nuclear import following neuronal stimulation (By similarity). In case of HIV-1 infection, binds and mediates the nuclear import of HIV-1 Rev. (updated: Jan. 31, 2018)
Protein identification was indicated in the following studies:
- Goodman and co-workers. (2013) The proteomics and interactomics of human erythrocytes. Exp Biol Med (Maywood) 238(5), 509-518.
- Hegedűs and co-workers. (2015) Inconsistencies in the red blood cell membrane proteome analysis: generation of a database for research and diagnostic applications. Database (Oxford) 1-8.
- Wilson and co-workers. (2016) Comparison of the Proteome of Adult and Cord Erythroid Cells, and Changes in the Proteome Following Reticulocyte Maturation. Mol Cell Proteomics. 15(6), 1938-1946.
- Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
- D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
- Chu and co-workers. (2018) Quantitative mass spectrometry of human reticulocytes reveal proteome-wide modifications during maturation. Br J Haematol. 180(1), 118-133.
Methods
The following articles were analysed to gather the proteome content of erythrocytes.
The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.
| Publication | Identification 1 | Uniprot mapping 2 | Not mapped / Obsolete | TrEMBL | Swiss-Prot |
|---|---|---|---|---|---|
| Goodman (2013) | 2289 (gene list) | 2278 | 53 | 20599 | 2269 |
| Lange (2014) | 1234 | 1234 | 7 | 28 | 1224 |
| Hegedus (2015) | 2638 | 2622 | 0 | 235 | 2387 |
| Wilson (2016) | 1658 | 1528 | 170 | 291 | 1068 |
| d'Alessandro (2017) | 1826 | 1817 | 2 | 0 | 1815 |
| Bryk (2017) | 2090 | 2060 | 10 | 108 | 1942 |
| Chu (2018) | 1853 | 1804 | 55 | 362 | 1387 |
1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry
The compilation of older studies can be retrieved from the Red Blood Cell Collection database.
The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.
(right-click above to access to more options from the contextual menu)
| Variant | Description |
|---|---|
| dbSNP:rs1053814 | |
| dbSNP:rs632729 | |
| dbSNP:rs484770 | |
| dbSNP:rs1804740 | |
| dbSNP:rs1804741 |
Biological Process
Cellular response to amino acid stimulus
Negative regulation of catalytic activity
Negative regulation of cyclin-dependent protein serine/threonine kinase activity
NLS-bearing protein import into nucleus
Obsolete protein import into nucleus, translocation
Positive regulation of protein import into nucleus
Protein import into nucleus
Ribosomal protein import into nucleus
Viral process
The reference OMIM entry for this protein is 602008
Importin 5; ipo5
Ran-binding protein 5; ranbp5
Karyopherin beta-3; kpnb3
Importin beta-3
DESCRIPTION
Nuclear import of proteins is mediated by the karyopherins (see 600685) and other proteins. Karyopherin beta-3 is believed to be a nuclear transport factor involved in the import of ribosomal proteins (Yaseen and Blobel, 1997).CLONING
Yaseen and Blobel (1997) found a sequence in the EST database with significant homology to yeast Kap121p/Pse1p, which is involved in protein secretion and the nuclear import of ribosomal and other proteins. They cloned the human homolog from a bone marrow cDNA library. The human gene encodes a 1,097-amino acid polypeptide with a predicted mass of 123 kD, in agreement with the observed size of native karyopherin beta-3. The protein sequence shows 28% identity to yeast Kap121p/Pse1p and 17% identity to human karyopherin beta-1. Yaseen and Blobel (1997) reported that the sequence contains 2 putative binding sites for Ras-related nuclear protein (601179). Using immunofluorescence, Yaseen and Blobel (1997) demonstrated that karyopherin beta-3 is localized mainly to the cytosol and the nucleus, particularly the nuclear rim, in HeLa cells. They showed that karyopherin beta-3 binds to repeat-containing nucleoporins, Ran-GDP, Ran-GTP, and 2 ribosomal proteins. ... More on the omim web site
Feb. 10, 2018: Protein entry updated
Automatic update: Entry updated from uniprot information.
Feb. 2, 2018: Protein entry updated
Automatic update: Uniprot description updated
Dec. 19, 2017: Protein entry updated
Automatic update: Uniprot description updated
Nov. 23, 2017: Protein entry updated
Automatic update: Uniprot description updated
March 16, 2016: Protein entry updated
Automatic update: OMIM entry 602008 was added.