| Protein Name |
P-glycoprotein (ABCB1) |
| Gene |
ABCB1 |
| UniProt ID |
P08183 |
| Molecular Weight |
170 kDa |
| Subcellular Localization |
Plasma membrane of brain endothelial cells |
| Protein Family |
ABC transporter family (ABCB/MDR/TAP subfamily) |
P Glycoprotein (Abcb1) is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
P-glycoprotein (ABCB1) is an ATP-dependent efflux transporter that pumps drugs and toxins out of cells. At the blood-brain barrier, it prevents many therapeutic drugs from entering the brain, limiting treatment options for neurological diseases [1].
ABCB1 is a 1280 amino acid protein with:
- Two transmembrane domains: Each with 6 transmembrane helices
- Two nucleotide-binding domains (NBDs): Bind and hydrolyze ATP
- Substrate-binding pocket: Recognizes diverse compounds
¶ Domain Architecture
TM1-6----NBD1----TM7-12----NBD2
Each TMD: 6 transmembrane helices
Each NBD: Walker A/B motifs for ATP binding
ABCB1 uses the energy from ATP hydrolysis to transport substrates:
- Substrate Binding: Drug binds to transmembrane domains
- ATP Binding: Two ATP molecules bind to NBDs
- Conformational Change: Substrate is released on the opposite side
- ATP Hydrolysis: Resets the transporter
ABCB1 is the main efflux transporter at the BBB:
- Efflux Pump: Actively pumps drugs out of the brain
- Protection: Prevents toxins from entering the CNS
- Homeostasis: Maintains brain microenvironment
- Highest expression at the blood-brain barrier
- Also expressed in liver, kidney, intestine
- Protects sanctuary sites from toxins
- ABCB1 function declines with age
- May contribute to amyloid-beta clearance
- Affects drug delivery for AD treatment [2]
- Altered expression in PD brains
- May affect levodopa pharmacokinetics
- Contributes to treatment resistance
- Overexpression causes drug-resistant epilepsy
- Major mechanism of antiepileptic drug resistance
- Target for epilepsy treatment strategies
- Contributes to chemotherapeutic drug resistance
- Major obstacle to effective brain tumor treatment
- ABCB1 inhibitors: Can enhance drug delivery but have toxicity
- Nanoparticle delivery: Bypasses ABCB1-mediated efflux
- Pro-drug strategies: Modified drugs that avoid efflux
- ABCB1 substrate prediction is critical
- Lead optimization to avoid efflux
- Focused ultrasound temporarily inhibits ABCB1
- ABCB1 polymorphisms affect drug response
- Genotyping guides treatment
- Functional assays measure activity
¶ Substrates and Inhibitors
- Chemotherapeutic agents (doxorubicin, paclitaxel)
- Antiepileptic drugs (phenytoin, carbamazepine)
- Antidepressants (fluoxetine, amitriptyline)
- Opioids (morphine, methadone)
- Verapamil (first-generation)
- Cyclosporine A (second-generation)
- Tariquidar, elacridar (third-generation)
-
Löscher & Potschka, Blood-brain barrier ABC transporters (2005). Trends in Pharmacological Sciences.
-
Schinkel, P-glycoprotein (1999). Nature Medicine.
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Pardridge, Blood-brain barrier drug delivery (2019). Nature Reviews Neurology.
The study of P Glycoprotein (Abcb1) 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.