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Updated: May 28, 2025
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Isolation and Kv Channel Recordings in Murine Atrial and Ventricular Cardiomyocytes
Published on: March 12, 2013
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The Electrically Silent Kv5.1 Subunit Forms Heteromeric Kv2 Channels in Cortical Neurons and Confers Distinct
Michael Ferns1,2, Deborah van der List2, Nicholas C Vierra2
1Department of Anesthesiology and Pain Medicine, University of California Davis, Davis, California 95616 mjferns@ucdavis.edu.
Summary
KvS subunits, like Kv5.1, form novel Kv2 channel subtypes in the brain. These Kv2/Kv5.1 channels are found in cortical neurons and possess unique properties influencing neuronal function.
Area of Science:
- Neuroscience
- Molecular Biology
- Biophysics
Background:
- Voltage-gated potassium (K+) channels of the Kv2 family are crucial for neuronal excitability and endoplasmic reticulum-plasma membrane (ER-PM) junction organization.
- Previous studies in non-neuronal cells suggested Kv2 channels assemble with "electrically silent" KvS subunits, but their presence in native neurons remained unconfirmed.
Purpose of the Study:
- To investigate the prevalence and localization of KvS subunits in native Kv2 channels within the mouse brain.
- To characterize the biophysical properties and cellular distribution of Kv2/KvS channel complexes in neurons.
Main Methods:
- Mass spectrometry-based proteomics to identify KvS subunits associated with native Kv2.1 channels.
- Co-immunoprecipitation assays to confirm protein interactions between Kv2 and KvS subunits.
- RNAscope and immunolabeling techniques to determine the expression and subcellular localization of Kv5.1 in cortical neurons.
- Electrophysiological recordings and inhibitor sensitivity assays to assess channel properties.
Main Results:
- Five KvS subunits were identified as components of native Kv2.1 channels, with Kv5.1 being the most abundant.
- Kv5.1 protein levels were significantly reduced in Kv2.1 and Kv2.1/Kv2.2 knockout mice, confirming its dependence on Kv2 subunits.
- Kv5.1 was prominently expressed in neocortical neurons, co-localizing with Kv2.1 and Kv2.2 at ER-PM junctions.
- Kv2/Kv5.1 channels exhibited altered conductance, reduced phosphorylation, and insensitivity to a specific Kv2 channel inhibitor (RY785).
Conclusions:
- KvS subunits assemble with Kv2 channels in the brain, forming distinct functional subtypes.
- Kv2/Kv5.1 channels are significantly expressed in cortical neurons, suggesting a critical role in modulating neuronal excitability and ER-PM organization.
- These findings reveal novel Kv2 channel diversity in the brain with unique biophysical and regulatory properties.
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