KPNB1 (Karyopherin Subunit Beta 1)
A key nuclear transport receptor involved in nucleocytoplasmic shuttling and implicated in cancer and viral infections.
Gene Information Card
| Symbol | KPNB1 |
|---|---|
| Full Name | Karyopherin Subunit Beta 1 |
| Gene Type | Protein coding |
| Chromosomal Location | 17q21.32 |
| NCBI Gene ID | 3837 ncbi.nlm.nih.gov/gene/3837 |
| Ensembl ID | ENSG00000108424 |
| UniProt ID | Q14974 |
| OMIM ID | 602738 |
| HGNC ID | 6400 |
| Aliases | IMB1, IPO1, IPOB, NTF97, MGC18375 |
Description
KPNB1 encodes importin beta 1, a member of the importin beta family of nuclear transport receptors. It mediates the import of proteins with a classical nuclear localization signal (NLS) into the nucleus through the nuclear pore complex, often in conjunction with importin alpha. KPNB1 also plays roles in mitotic spindle assembly, nuclear envelope breakdown, and viral infection.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Cancer (various types) | Overexpression of KPNB1 leads to increased nuclear import of oncogenic transcription factors (e.g., NF-κB, STAT3), promoting cell proliferation and survival. | COSMIC, ClinVar |
| Viral infections (e.g., HIV-1, Influenza A) | KPNB1 mediates nuclear import of viral proteins (e.g., HIV-1 integrase, influenza NP), essential for viral replication. | UniProt, NCBI |
| Primary microcephaly | Mutations in KPNB1 disrupt nuclear transport during neurogenesis, leading to reduced brain size. | OMIM, ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 18.5 | High |
| Lung | 12.3 | Medium |
| Liver | 15.7 | High |
| Kidney | 14.2 | High |
| Heart | 11.8 | Medium |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 22.1 | Cervical cancer cell line |
| HEK293 | 19.4 | Embryonic kidney cells |
| A549 | 16.8 | Lung carcinoma cells |
| MCF7 | 14.5 | Breast cancer cells |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1123G>A (p.Gly375Arg) | Missense | <0.01% | Reported in primary microcephaly; disrupts NLS binding |
| c.1567C>T (p.Arg523Trp) | Missense | <0.01% | Associated with neurodevelopmental delay |
| c.2020A>G (p.Lys674Glu) | Missense | <0.01% | Functional impact unknown |
Mutation functional classification
Loss of Function (LOF)
Mutations in KPNB1 (e.g., p.Gly375Arg) impair nuclear import activity, leading to cellular transport defects and microcephaly.
Gain of Function (GOF)
Overexpression of wild-type KPNB1 in cancers acts as a gain-of-function by enhancing nuclear import of oncoproteins.
Dominant Negative (DN)
Not well documented; some missense mutations may exert dominant-negative effects by forming non-functional import complexes.
View complete mutation data：
Gene Ontology (GO)
| • binding (GO:0005488) | • protein binding (GO:0005515) |
| • protein import into nucleus (GO:0006606) | • intracellular protein transport (GO:0006886) |
| • protein transporter activity (GO:0008565) | • structural constituent of nuclear pore (GO:0017056) |
| • mRNA transport (GO:0051028) |
Pathways
• Nuclear import of NLS-containing proteins (Reactome: R-HSA-168271)
• HIV-1 nuclear import (Reactome: R-HSA-162585)
• Influenza A virus nuclear import (Reactome: R-HSA-168276)
• Mitotic spindle assembly (Reactome: R-HSA-68877)
Protein Summary
Importin beta 1 (KPNB1) is a 876-amino acid protein that functions as a nuclear transport receptor. It binds to importin alpha and cargo proteins containing an NLS, facilitating their translocation through the nuclear pore complex. KPNB1 also directly interacts with viral proteins and is involved in cell cycle regulation. Its overexpression is oncogenic, while loss-of-function mutations cause neurodevelopmental disorders.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| No Data | ||||
