FBXO5
F-box protein 5, a regulator of cell cycle and anaphase-promoting complex/cyclosome (APC/C) activity
Gene Information Card
| Symbol | FBXO5 |
|---|---|
| Full Name | F-box protein 5 |
| Gene Type | protein-coding |
| Chromosomal Location | 6q25.2 |
| NCBI Gene ID | 26271 ncbi.nlm.nih.gov/gene/26271 |
| Ensembl ID | ENSG00000112214 |
| UniProt ID | Q9UKT4 |
| OMIM ID | 606013 |
| HGNC ID | 13588 |
| Aliases | EMI1, FBX5, Fbxo5 |
Description
FBXO5 encodes F-box protein 5, also known as EMI1 (early mitotic inhibitor 1), a key regulator of the anaphase-promoting complex/cyclosome (APC/C). EMI1 inhibits APC/C activity during S and G2 phases to prevent premature degradation of cyclins and securin, ensuring proper mitotic entry and chromosome segregation. Dysregulation of FBXO5 is implicated in genomic instability and cancer.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Breast cancer | Overexpression of FBXO5 leads to APC/C inhibition, causing mitotic defects and aneuploidy | COSMIC, ClinVar |
| Colorectal cancer | FBXO5 amplification promotes chromosomal instability and tumor progression | COSMIC, NCBI Gene |
| Ovarian cancer | Elevated FBXO5 expression correlates with poor prognosis and resistance to chemotherapy | COSMIC, ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 15.2 | Medium |
| Lymph node | 10.8 | Medium |
| Bone marrow | 9.5 | Low |
| Brain | 4.3 | Low |
| Liver | 3.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 18.5 | Cervical cancer cell line |
| MCF7 | 22.1 | Breast cancer cell line |
| HCT116 | 16.7 | Colorectal cancer cell line |
| HEK293 | 12.3 | Embryonic kidney cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1015C>T (p.Arg339Trp) | Missense | 0.02% | Alters APC/C binding domain; potential loss of function |
| c.1246G>A (p.Glu416Lys) | Missense | 0.01% | Unknown functional impact |
| Amplification | Copy number gain | 5-10% in breast cancer | Overexpression leads to mitotic defects |
Mutation functional classification
Loss of Function (LOF)
Rare missense variants (e.g., p.Arg339Trp) may impair EMI1-APC/C interaction, reducing inhibition and causing premature mitotic exit.
Gain of Function (GOF)
Gene amplification and overexpression in cancers enhance APC/C inhibition, promoting genomic instability.
Dominant Negative (DN)
Not well documented; potential dominant-negative effects from truncated variants have not been confirmed.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Cell Cycle (Reactome: R-HSA-1640170)
• APC/C-mediated degradation of cell cycle proteins (Reactome: R-HSA-174178)
• Regulation of mitotic cell cycle (KEGG: hsa04110)
Protein Summary
F-box protein 5 (EMI1) is a 448-amino acid protein containing an F-box domain and a zinc-binding region. It binds to the APC/C co-activator CDC20 and inhibits APC/C activity during interphase. EMI1 is degraded in early mitosis via ubiquitin-dependent proteolysis, allowing APC/C activation. Its overexpression in cancers contributes to chromosomal instability and tumorigenesis.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| FBXO5 Knockout HEK293 Cell Line | EDJ-KQ51176 | Human | 26271 | Details Get a Quote |
| FBXO5 Knockout HeLa Cell Line | EDJ-KQ55917 | Human | 26271 | Details Get a Quote |
| FBXO5 Knockout A-549 Cell Line | EDJ-KQ64407 | Human | 26271 | Details Get a Quote |
| FBXO5 Knockout HCT 116 Cell Line | EDJ-KQ72859 | Human | 26271 | Details Get a Quote |
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