SFXN4 Gene - Sideroflexin 4
Mitochondrial transporter and disease-associated gene
Gene Information Card
| Symbol | SFXN4 |
|---|---|
| Full Name | Sideroflexin 4 |
| Gene Type | Protein-coding |
| Chromosomal Location | 10q26.11 |
| NCBI Gene ID | 119559 ncbi.nlm.nih.gov/gene/119559 |
| Ensembl ID | ENSG00000183878 |
| UniProt ID | Q9H9B4 |
| OMIM ID | 615569 |
| HGNC ID | 16088 |
| Aliases | COXPD18, SFX4, sideroflexin-4 |
Description
SFXN4 encodes sideroflexin 4, a mitochondrial inner membrane transporter involved in iron homeostasis and one-carbon metabolism. It is essential for mitochondrial respiration and cellular energy production. Mutations in SFXN4 cause combined oxidative phosphorylation deficiency type 18 (COXPD18), a severe multisystem disorder.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Combined oxidative phosphorylation deficiency 18 (COXPD18) | Loss-of-function mutations impair mitochondrial iron transport and respiratory chain assembly, leading to energy depletion. | OMIM #615569; ClinVar; PMID: 28397838 |
| Mitochondrial complex I deficiency | SFXN4 dysfunction disrupts complex I assembly and activity, contributing to oxidative phosphorylation defects. | ClinVar; PMID: 28397838 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 12.3 | Medium |
| Heart | 9.8 | Medium |
| Kidney | 8.5 | Medium |
| Brain | 6.2 | Low |
| Skeletal Muscle | 5.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | 14.2 | Hepatocellular carcinoma cell line |
| K-562 | 11.5 | Chronic myelogenous leukemia |
| HeLa | 9.0 | Cervical adenocarcinoma |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.622C>T (p.Arg208*) | Nonsense | Rare | Loss of function; truncation of protein |
| c.1A>G (p.Met1?) | Start loss | Rare | Loss of function; no translation initiation |
| c.349G>A (p.Gly117Arg) | Missense | Rare | Likely loss of function; impaired mitochondrial targeting |
Mutation functional classification
Loss of Function (LOF)
Nonsense and start-loss mutations cause complete loss of SFXN4 function, leading to COXPD18.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations reported.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Mitochondrial iron-sulfur cluster biogenesis
• Oxidative phosphorylation (Complex I assembly)
• One-carbon metabolism
Protein Summary
Sideroflexin 4 is a 322-amino acid mitochondrial inner membrane protein with five transmembrane domains. It functions as a transporter for iron or other metabolites critical for mitochondrial respiration. The protein is ubiquitously expressed with highest levels in liver and heart. Defects cause combined oxidative phosphorylation deficiency.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SFXN4 Knockout HEK293 Cell Line | EDJ-KQ7641 | Human | 119559 | Details Get a Quote |
| SFXN4 Knockout A-549 Cell Line | EDJ-KQ33003 | Human | 119559 | Details Get a Quote |
| SFXN4 Knockout HCT 116 Cell Line | EDJ-KQ33004 | Human | 119559 | Details Get a Quote |
| SFXN4 Knockout HeLa Cell Line | EDJ-KQ33005 | Human | 119559 | Details Get a Quote |
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