NGFR (nerve growth factor receptor), also known as p75NTR or CD271, is a member of the tumor necrosis factor receptor superfamily. It functions as a neurotrophin receptor capable of binding multiple neurotrophins (NGF, BDNF, NT-3, NT-4) and mediating diverse biological effects including neuronal survival, apoptosis, and synaptic plasticity.
- Gene: NGFR
- UniProt: P08138
- Molecular Weight: ~75 kDa
- Structure: Extracellular domain with 4 cysteine-rich repeats (CRDs), single transmembrane helix, intracellular death domain
- Isoforms: Multiple isoforms generated by alternative splicing
- Localization: Cell surface, lipid rafts, endosomes, nucleus
p75NTR is a unique neurotrophin receptor that can signal independently or cooperate with Trk receptors:
- Neuronal survival: Triggers survival pathways (NF-κB, PI3K/Akt) via neurotrophin binding
- Apoptosis: Death domain can activate caspase-dependent apoptosis in absence of Trk co-receptor
- Synaptic plasticity: Modulates NMDA receptor function and synaptic strength
- Axon guidance: Guides developing axons via chemorepulsion
- Myelination: Regulates Schwann cell function and myelination
The receptor's outcome depends on co-receptor usage (TrkA vs sortilin), ligand type, and cellular context.
- Increased p75NTR expression in AD brains, particularly in cholinergic neurons
- Mediates amyloid-beta-induced neuronal death
- Associates with neurofibrillary tangles
- Potential biomarker: soluble p75NTR (sP75NTR) in CSF
- Expressed on dopaminergic neurons
- Mediates BDNF-induced neuroprotection
- Involved in alpha-synuclein toxicity
- Gene therapy target for neuroprotection
- Upregulated in motor neurons of ALS patients
- Mediates excitotoxicity-induced cell death
- Contributes to non-cell autonomous degeneration
- Sortilin-p75NTR pathway implicated in ALS progression
- Mutations in NGFR cause CMT2D (autosomal dominant)
- Affects peripheral nerve function
- Leads to distal motor weakness
- Expressed on oligodendrocyte precursor cells
- Regulates myelination and remyelination
- May promote oligodendrocyte survival
- BDNF mimetics: Designed to engage p75NTR-TrkA heterodimers
- Small molecule agonists: Being developed for PD and AD
- Selective p75NTR antagonists: Block pro-apoptotic signaling
- Antisense oligonucleotides: Reduce p75NTR expression
- sP75NTR in CSF as biomarker for axonal injury
- Soluble receptor fragments as disease progression markers
| Partner | Interaction Type | Pathway |
|---------|-----------------|---------|
| NGF | Ligand | Survival/apoptosis |
| BDNF | Ligand | Neuroprotection |
| TrkA | Co-receptor | High-affinity NGF binding |
| TrkB | Co-receptor | BDNF signaling |
| Sortilin | Co-receptor | Pro-apoptotic signaling |
| RIP2 | Adaptor | NF-κB activation |