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Updated: Jul 12, 2025

Recombinant α- β- and γ-Synucleins Stimulate Protein Phosphatase 2A Catalytic Subunit Activity in Cell Free Assays
Published on: August 13, 2017
Monomeric α-synuclein activates the plasma membrane calcium pump
Antoni Kowalski1,2,3,4, Cristine Betzer2,5, Sigrid Thirup Larsen1,2
1Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
Monomeric alpha-synuclein (aSN) activates plasma membrane calcium ATPase (PMCA) to clear calcium in neurons. This finding reveals a new physiological role for aSN in neuronal calcium homeostasis.
Area of Science:
- Neuroscience
- Biochemistry
- Cell Biology
Background:
- Alpha-synuclein (aSN) is intrinsically disordered and linked to neurodegeneration.
- The physiological role of aSN remains unclear, though it's implicated in protein aggregation.
- Previous studies suggest aSN interacts with plasma membrane Ca2+-ATPase (PMCA).
Purpose of the Study:
- To investigate the physiological function of alpha-synuclein (aSN).
- To determine the interaction between aSN and plasma membrane Ca2+-ATPase (PMCA).
- To elucidate the role of aSN in neuronal calcium regulation.
Main Methods:
- Proximity ligation assays to assess aSN and PMCA colocalization.
- Biochemical assays to measure calcium expulsion activity.
- Site-mapping on PMCA to identify interaction domains.
Main Results:
- aSN and PMCA colocalize at neuronal synapses.
- aSN activates PMCA-mediated calcium expulsion.
- Monomeric aSN activates PMCA independently of its autoinhibitory domain, dependent on acidic phospholipids and membrane anchoring.
- The activation site on PMCA is mapped to the acidic lipid-binding site within a disordered loop.
Conclusions:
- Monomeric aSN acts as a novel stimulator of neuronal calcium clearance.
- aSN activates PMCA, highlighting a new physiological function in calcium homeostasis.
- This discovery offers insights into neurodegenerative disease mechanisms potentially linked to calcium dysregulation.
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