Plasma Membrane Calcium ATPase 1 (PMCA1)
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ATP2B1 Protein is a protein encoded by the ATP2B1 gene. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.
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| Protein Name | Plasma Membrane Calcium ATPase 1 |
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| Gene | [ATP2B1](/genes/atp2b1) |
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| UniProt ID | [P20020](https://www.uniprot.org/uniprot/P20020) |
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| PDB Structures | [5W5T](https://www.rcsb.org/structure/5W5T), [6A2O](https://www.rcsb.org/structure/6A2O) |
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| Molecular Weight | ~127 kDa |
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| Subcellular Localization | Plasma membrane |
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| Protein Family | P-type ATPase (ER/SPCA family) |
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The plasma membrane calcium ATPase (PMCA) is a P-type ATPase with distinct structural features:
- 10 transmembrane helices forming the calcium channel
- Actuator domain (A-domain): Involved in conformational changes during transport
- Phosphorylation domain (P-domain): Contains the essential aspartate residue for ATP phosphorylation
- Nucleotide-binding domain (N-domain): Binds ATP for phosphorylation
- C-terminal regulatory domain: Contains calmodulin-binding site for activation
PMCA1 is one of four isoforms (PMCA1-4) encoded by separate genes with alternative splicing creating multiple variants.
PMCA1 is the ubiquitous isoform essential for cellular calcium homeostasis:
- Calcium extrusion: Pumps Ca2+ out of neurons against a 10,000-fold gradient
- Resting calcium levels: Maintains basal cytosolic Ca2+ (~100 nM)
- Signal termination: Clears calcium after synaptic signaling
- Synaptic plasticity: Regulates Ca2+ dynamics crucial for LTP and LTD
- Neuronal survival: Prevents calcium overload and excitotoxicity
- Gene regulation: Links calcium signaling to transcription factors
PMCA1 and PMCA4 are the major neuronal isoforms, with PMCA1 being essential for early development.
- Calcium dysregulation: PMCA dysfunction contributes to disrupted calcium homeostasis
- Amyloid-beta toxicity: Aβ oligomers impair PMCA function in neurons [1]
- Excitotoxicity: Reduced calcium extrusion increases vulnerability to glutamate toxicity
- Synaptic failure: Impaired calcium clearance affects synaptic plasticity and memory
- Therapeutic target: Enhancing PMCA activity is a potential therapeutic strategy [2]
- Dopaminergic neuron vulnerability: PMCA dysfunction compounds calcium dysregulation in SNc neurons
- Alpha-synuclein toxicity: PD-linked proteins may affect PMCA function
- Mitochondrial interactions: Calcium overload triggers mitochondrial apoptosis
¶ Stroke and Ischemia
- Ischemic injury: PMCA failure is an early event in excitotoxic cell death
- Reperfusion damage: Calcium overload during reperfusion overwhelms PMCA
- Therapeutic potential: PMCA modulators being investigated for neuroprotection
- Motor neuron vulnerability: High metabolic demands make motor neurons susceptible
- Excitotoxicity: Impaired calcium clearance contributes to excitotoxic cell death
- Calcium signaling disruption: Altered PMCA expression in HD models
- Transcriptional dysregulation: Calcium-dependent transcription affected
- Calmodulin mimetics: Enhancing PMCA activation through calmodulin-binding domain
- Direct activators: Small molecules increasing PMCA activity
- Gene therapy: AAV-based PMCA1 delivery for neuroprotection
- Biomarkers: PMCA autoantibodies in certain neurological conditions
- Model systems: PMCA1 knockout studies in neurodegeneration
| Interactor |
Function |
Reference |
| Calmodulin |
Calcium-dependent activation |
3 |
| PSD-95 |
Synaptic targeting |
4 |
| ANK2/Ankyrin-B |
Membrane domain organization |
5 |
| Na+/K+ ATPase |
Functional cooperation in calcium handling |
6 |
| CaMKII |
Calcium-dependent kinase regulation |
7 |