FBXO43
F-box protein 43, a key regulator of meiotic cell cycle progression and anaphase-promoting complex/cyclosome (APC/C) inhibition
Gene Information Card
| Symbol | FBXO43 |
|---|---|
| Full Name | F-box protein 43 |
| Gene Type | Protein coding |
| Chromosomal Location | 8q22.3 |
| NCBI Gene ID | 286151 ncbi.nlm.nih.gov/gene/286151 |
| Ensembl ID | ENSG00000147419 |
| UniProt ID | Q5H8A4 |
| OMIM ID | 609111 |
| HGNC ID | 28973 |
| Aliases | EMI2, FBX43, FLJ32421 |
Description
FBXO43 (F-box protein 43), also known as EMI2 (early mitotic inhibitor 2), encodes a protein that functions as an inhibitor of the anaphase-promoting complex/cyclosome (APC/C). It is essential for maintaining meiotic arrest in oocytes by preventing premature degradation of cyclin B and securing the metaphase II arrest until fertilization. The protein contains an F-box domain and a zinc-binding domain, and its expression is tightly regulated during the cell cycle.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Oocyte maturation defect | Loss of FBXO43 function leads to premature APC/C activation and failure of meiotic arrest | OMIM #609111; PMID: 16916642 |
| Infertility (female) | Disruption of EMI2-mediated APC/C inhibition causes parthenogenetic activation and infertility | PMID: 16916642 |
| Cancer (potential) | Dysregulation of APC/C inhibitors may contribute to aneuploidy and tumorigenesis | COSMIC; PMID: 23582326 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 0.3 | Low |
| Ovary | 0.2 | Low |
| Brain | 0.1 | Low |
| Spleen | 0.0 | Not detected |
| Liver | 0.0 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 0.0 | Not detected |
| K562 | 0.0 | Not detected |
| HEK293 | 0.0 | Not detected |
| Oocytes (human) | High (qualitative) | Detected by RT-PCR; PMID: 16916642 |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | Rare | Likely loss of start codon; predicted loss of function |
| c.100C>T (p.Arg34*) | Nonsense | Rare | Premature stop; loss of function |
| c.200_201del (p.Glu67fs) | Frameshift | Rare | Frameshift; loss of function |
Mutation functional classification
Loss of Function (LOF)
Nonsense and frameshift mutations in FBXO43 are predicted to cause loss of EMI2 function, leading to premature APC/C activation and meiotic failure.
Gain of Function (GOF)
No gain-of-function mutations have been reported for FBXO43.
Dominant Negative (DN)
No dominant-negative mutations have been described for FBXO43.
View complete mutation data：
Gene Ontology (GO)
| • protein binding (GO:0005515) | • ubiquitin-dependent protein catabolic process (GO:0006511) |
| • cell cycle (GO:0007049) | • protein ubiquitination (GO:0016567) |
| • cell division (GO:0051301) | • negative regulation of ubiquitin-protein ligase activity involved in mitotic cell cycle (GO:0051436) |
Pathways
• Cell cycle (KEGG: hsa04110)
• Oocyte meiosis (KEGG: hsa04114)
• APC/C-mediated degradation of cyclin B (Reactome: R-HSA-174048)
Protein Summary
FBXO43 encodes EMI2, a 651-amino acid protein that contains an N-terminal F-box domain and a C-terminal zinc-binding domain. EMI2 binds to SKP1 and inhibits the APC/C complex by competing with CDC20 and CDH1. It is highly expressed in oocytes and is critical for maintaining metaphase II arrest. Upon fertilization, EMI2 is degraded via the calcium/calmodulin-dependent kinase II pathway, allowing APC/C activation and completion of meiosis.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| FBXO43 Knockout HEK293 Cell Line | EDJ-KQ2696 | Human | 286151 | Details Get a Quote |
| FBXO43 Knockout A-549 Cell Line | EDJ-KQ23526 | Human | 286151 | Details Get a Quote |
| FBXO43 Knockout HeLa Cell Line | EDJ-KQ23527 | Human | 286151 | Details Get a Quote |
| FBXO43 Knockout HCT 116 Cell Line | EDJ-KQ76391 | Human | 286151 | Details Get a Quote |
