P2X7 Receptor Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
The P2X7 receptor is an ATP-gated ion channel that plays a critical role in immune signaling and neuroinflammation. It is unique among P2X receptors for its ability to form large pores that allow passage of molecules up to 900 Da when repeatedly activated. This makes it a key player in the innate immune response and a therapeutic target for neurodegenerative diseases.
P2X7 is a purinergic receptor that responds to extracellular ATP and mediates fast calcium influx and inflammatory signaling. P2X7 activation triggers NLRP3 inflammasome assembly, cytokine release, and cell death. It is expressed in microglia and immune cells and is a therapeutic target for neuroinflammatory diseases.
This protein is involved in:
- ATP signaling: Responds to extracellular ATP
- Inflammasome activation: Triggers NLRP3 and IL-1β release
- Cell death: Mediates apoptosis and necroptosis
- Disease associations: Alzheimer's disease, Parkinson's disease, depression, chronic pain
| Attribute |
Value |
| Protein Name |
P2X7 Receptor |
| Gene |
P2RX7 |
| UniProt ID |
Q99572 |
| PDB Structures |
5U1L, 6U9V, 7KB5 |
| Molecular Weight |
66 kDa (monomer) |
| Subcellular Localization |
Plasma membrane, lipid rafts |
| Protein Family |
P2X purinergic receptor family |
The P2X7 receptor is a trimeric ATP-gated ion channel with the following structural features:
- Two Transmembrane Domains: TM1 and TM2 helices that form the ion pore
- Extracellular Loop: Contains the ATP-binding site and is heavily glycosylated
- Intracellular N- and C-termini: The C-terminus is notably long (~200 aa) and contains interaction domains
- C-terminal Protein-Protein Interaction Domain: Mediates formation of the large pore complex
The receptor exists as a homotrimer, and upon ATP binding, the channel opens to allow Na+ and Ca2+ influx. Repeated or prolonged stimulation leads to formation of the larger pore state.
P2X7 receptors mediate rapid ATP signaling in immune cells:
- ATP Sensing: Detects extracellular ATP released during tissue injury or stress
- Ion Channel Function: Permits Na+, K+, and Ca2+ flux during acute activation
- Large Pore Formation: Extended activation creates a membrane pore for dye uptake
- Inflammasome Activation: Triggers NLRP3 inflammasome assembly and IL-1β release
- Cell Death: Can induce apoptosis or necrosis in certain cell types under extreme conditions
In the central nervous system, P2X7 is expressed on microglia, astrocytes, neurons, and oligodendrocyte progenitor cells.
P2X7 contributes to AD pathogenesis through:
- Microglial Activation: Chronic ATP release from amyloid plaques activates P2X7 on microglia
- NLRP3 Inflammasome: P2X7-mediated inflammasome activation increases IL-1β and IL-18
- Amyloid Processing: Influences APP processing and Aβ clearance
- Synaptic Dysfunction: Affects synaptic plasticity and neuronal survival
In PD, P2X7:
- Mediates neuroinflammation in the substantia nigra
- Contributes to dopaminergic neuron death
- May interact with α-synuclein aggregation pathways
- Influences microglial phagocytosis of debris
P2X7 in ALS:
- Upregulated in microglia and astrocytes in SOD1 and C9orf72 models
- Contributes to neuroinflammation and motor neuron vulnerability
- P2X7 antagonists show protective effects in preclinical models
P2X7 signaling:
- Promotes demyelination through oligodendrocyte death
- Modulates T-cell responses
- Being targeted by BTK inhibitors in clinical trials
P2X7 activates multiple downstream pathways:
- NLRP3 Inflammasome: Pannexin-1 pore → K+ efflux → ASC speck formation → caspase-1 activation
- MAPK Pathways: ERK1/2, JNK, and p38 activation in immune cells
- NF-κB Pathway: Pro-inflammatory gene transcription
- PI3K/Akt Pathway: Cell survival signaling
- Calcium Signaling: Ca2+-dependent protease and phosphatase activation
Key interacting proteins include:
- Pannexin-1 (large pore formation)
- NLRP3 and ASC (inflammasome)
- Src family kinases (phosphorylation)
- β-catenin (transcription regulation)
P2X7 is a major drug target for neuroinflammation:
| Drug/Approach |
Mechanism |
Status |
Clinical Trials |
| Brilacidin |
P2X7 antagonist |
Phase 2 |
MS, inflammatory diseases |
| AZD9056 |
P2X7 antagonist |
Phase 2 |
Rheumatoid arthritis |
| CE-224535 |
P2X7 antagonist |
Phase 2 |
Rheumatoid arthritis |
| JNJ-47965567 |
P2X7 antagonist |
Phase 1 |
Healthy volunteers |
| Brilliant Blue G |
P2X7 antagonist |
Preclinical |
Neuroprotection |
| A-438079 |
P2X7 antagonist |
Preclinical |
Anti-inflammatory |
BTK inhibitors (tolebrutinib, fenestrinib) indirectly modulate P2X7 signaling.
Current areas of investigation:
- Blood-Brain Barrier Penetration: Developing brain-penetrant P2X7 antagonists
- Cell-Type Specific Effects: Understanding differential effects on microglia vs. neurons
- Biomarkers: P2X7 polymorphisms as disease risk modifiers
- Combination Therapies: P2X7 targeting with disease-modifying agents
- Communi D, et al. P2X7: An ATP-gated ion channel in the immune system. Cytokine Growth Factor Rev. 2003;14(1):1-25.
- Sperlágh B, et al. P2X7 receptors in CNS neurons: Key players in health and disease. Neural Plast. 2017;2017:8548690.
- Miras-Portugal MT, et al. P2X7 receptors in neurodegeneration. Curr Neuropharmacol. 2021;19(11):1934-1954.
- Liu HD, et al. P2X7 receptor: A potential therapeutic target in CNS disorders. Eur J Pharmacol. 2020;884:173372.
- Burnstock G. Purinergic signaling in neurodegenerative diseases. Aging Dis. 2014;5(6):423-437.
- Andrejew R, et al. The P2X7 receptor as a therapeutic target in Parkinson's disease. J Neurochem. 2020;153(4):468-479.
- Bartlett R, et al. P2X7 receptors in neurological disease. Cell Tissue Res. 2017;369(1):1-11.
The study of P2X7 Receptor Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
- Communi D, et al. P2X7: An ATP-gated ion channel in the immune system. Cytokine Growth Factor Rev. 2003;14(1):1-25.
- Sperlágh B, et al. P2X7 receptors in CNS neurons: Key players in health and disease. Neural Plast. 2017;2017:8548690.
- Miras-Portugal MT, et al. P2X7 receptors in neurodegeneration. Curr Neuropharmacol. 2021;19(11):1934-1954.
- Liu HD, et al. P2X7 receptor: A potential therapeutic target in CNS disorders. Eur J Pharmacol. 2020;884:173372.
- Burnstock G. Purinergic signaling in neurodegenerative diseases. Aging Dis. 2014;5(6):423-437.
- Andrejew R, et al. The P2X7 receptor as a therapeutic target in Parkinson's disease. J Neurochem. 2020;153(4):468-479.
- Bartlett R, et al. P2X7 receptors in neurological disease. Cell Tissue Res. 2017;369(1):1-11.