NCOA4 is a selective cargo receptor for ferritinophagy, the autophagic degradation of ferritin. This protein plays a critical role in cellular iron homeostasis by mediating the release of iron from ferritin storage, and is essential for preventing iron accumulation in the brain that leads to neurodegenerative diseases.
NCOA4 (Nuclear Receptor Coactivator 4) was originally characterized as a transcriptional coactivator for nuclear receptors, but has gained prominence as the primary receptor mediating ferritinophagy. As a selective autophagy receptor, NCOA4 binds ferritin and delivers it to autophagosomes for lysosomal degradation, releasing stored iron for cellular use.
| Property |
Value |
| Protein Name |
NCOA4 (Nuclear Receptor Coactivator 4) |
| Gene |
NCOA4 |
| UniProt ID |
Q9UBR1 |
| PDB Structure |
6GJA (N-terminal domain) |
| Molecular Weight |
~70 kDa |
| Subcellular Localization |
Cytoplasmic, nuclear (shuttling) |
| Protein Family |
Nuclear receptor coactivator family |
NCOA4 has a multi-domain structure:
¶ N-Terminal Domain
- Contains the ferritin-binding site
- Essential for ferritinophagy function
- Mediates interaction with autophagic machinery
¶ C-Terminal Domain
- Transcriptional activation domain
- Nuclear receptor interaction motifs
- LXXLL motifs for coactivator function
- Coiled-coil domains for protein interactions
- LC3-interacting region (LIR) for autophagy
- Multiple post-translational modification sites
- Binds to ferritin (FTH1/FTL complex)
- Recruits the autophagic machinery via LC3 interaction
- Delivers ferritin to autophagosomes
- Releases iron from ferritin for cellular use
- Coactivator for nuclear receptors
- Binds thyroid hormone receptors, retinoic acid receptors
- Recruits CBP/p300 coactivators
- Regulates metabolism and development genes
- Ferritinophagy is impaired in AD brains
- Iron accumulates in neurons and amyloid plaques
- Dysregulated NCOA4 contributes to oxidative stress
- Therapeutic targeting is under investigation
- Iron accumulates in substantia nigra dopaminergic neurons
- NCOA4 deficiency leads to iron overload
- Implicated in PD pathogenesis
- Iron chelation may work partly through ferritinophagy
- NCOA4 variants cause certain NBIA subtypes
- Impaired ferritinophagy leads to iron accumulation
- Presents with movement disorders and dementia
- Compounds that enhance ferritinophagy
- Could reduce iron accumulation in neurodegeneration
- Currently in preclinical development
- Viral vector delivery of NCOA4
- Under investigation for NBIA treatment
- Mancias et al., Ferritinophagy via NCOA4 (2014)
- Dowdle et al., NCOA4 is a selective ferritin autophagy receptor (2014)