| NPL4 (Nuclear Protein Localization 4) | |
|---|---|
| Gene | [NPLOC4](/genes/nploc4) |
| UniProt ID | [Q8TAT6](https://www.uniprot.org/uniprot/Q8TAT6) |
| PDB | 5C1V, 6TAN |
| Molecular Weight | 68.6 kDa |
| Localization | Nucleus, cytoplasm, ER membrane |
| Family | NPL4 family, VCP/p97 cofactor |
| Disease | ALS, FTD, Cancer |
NPL4 (nuclear protein localization 4 homolog) is a cofactor for VCP/p97 that forms a heterodimeric complex with UFD1. The UFD1-NPL4 complex recognizes ubiquitinated substrates and delivers them to VCP for ATP-dependent extraction. This complex is essential for ER-associated degradation (ERAD), chromatin remodeling, and mitophagy—processes disrupted in ALS and FTD.
NPL4 contains:
UFD1-NPL4 complex structure[1]:
NPL4 functions with VCP-UFD1:
Key pathways:
NPL4-UFD1-VCP complex dysfunction contributes to ALS/FTD[2]:
TDP-43 Pathology:
C9orf72 DPR Toxicity:
Mitophagy:
VCP mutations cause inclusion body myopathy with Paget's disease and FTD:
NPL4 dysfunction causes:
| Strategy | Mechanism | Status |
|---|---|---|
| VCP activators | Enhance complex function | Preclinical |
| Nrf2 activators | Boost proteostasis | Clinical |
| ER stress modulators | Reduce ERAD demand | Clinical trials |
| Proteasome enhancers | Support degradation | Research |
Isaacson et al. UFD1-NPL4 complex structure. Mol Cell. 2007. ↩︎
Ritson et al. NPL4-VCP in ALS. Hum Mol Genet. 2010. ↩︎