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β2-subunit alternative splicing stabilizes Cav2.3 Ca2+ channel activity during continuous midbrain dopamine
Anita Siller1, Nadja T Hofer1, Giulia Tomagra2
1Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria.
Elife
|July 6, 2022
Summary
Alternative splicing of Cav2.3 channel beta-subunits stabilizes gating in dopamine neurons. This finding may explain neuroprotection in Parkinson
Area of Science:
- Neuroscience
- Molecular Biology
- Ion Channel Physiology
Background:
- Dopaminergic (DA) neurons in the substantia nigra (SN) exhibit somatodendritic Ca2+ oscillations mediated by Cav2.3 R-type Ca2+ currents.
- Selective degeneration of SN DA neurons is a hallmark of Parkinson's disease (PD), and Cav2.3 knockout demonstrates neuroprotection in PD mouse models.
Purpose of the Study:
- To investigate the role of Cav2.3 channel beta-subunits in stabilizing gating properties and modulating Ca2+ currents in SN DA neurons.
- To explore the potential contribution of beta-subunit alternative splicing to the pathophysiology of PD.
Main Methods:
- Utilized tsA-201 cells to study the effects of beta2-splice variants (β2a and β2e) on Cav2.3 channel function.
- Confirmed expression of β2a and β2e transcripts in mouse SN and identified SN DA neurons.
- Performed patch-clamp recordings on cultured mouse DA midbrain neurons and SN DA neurons in brain slices.
Main Results:
- Membrane-anchored β2a and β2e splice variants stabilize Cav2.3 gating, enabling sustained availability during pacemaking and enhanced currents during bursts.
- SNX-482-sensitive R-type Ca2+ currents in mouse SN DA neurons exhibit voltage-dependent gating, suggesting modulation by β2a/β2e subunits.
- Expression of β2a and β2e transcripts was confirmed in mouse SN DA neurons.
Conclusions:
- Alternative splicing of Cav2.3 beta-subunits may prevent channel inactivation in continuously active SN DA neurons.
- This modulation of Cav2.3 channels by beta-subunits could influence Ca2+ signaling relevant to the (patho)physiology of Parkinson's disease.
- Understanding these mechanisms offers insights into neuroprotective strategies for PD.
Keywords:
calcium channel blockerscalcium channel modulationmousemouse brain slicesmouse midbrain dopamine neuronsneurosciencevoltage-gated calcium channelsMore Related Videos
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