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11:33
Isolation and Kv Channel Recordings in Murine Atrial and Ventricular Cardiomyocytes
Published on: March 12, 2013
KCNE4 suppresses Kv1.3 currents by modulating trafficking, surface expression and channel gating
Laura Solé1, Meritxell Roura-Ferrer, Mireia Pérez-Verdaguer
1Departament de Bioquímica i Biologia Molecular, Molecular Physiology Laboratory, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 645, 08028 Barcelona, Spain.
Journal of Cell Science
|September 24, 2009
Summary
KCNE4 inhibits Kv1.3 channels in leukocytes, reducing cell surface expression and altering activity. This interaction impacts immune cell function and suggests KCNE4 as a target for immunomodulation.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- Voltage-dependent potassium channels (Kv) are critical for leukocyte activation and proliferation.
- Kv channel activity is regulated by their oligomeric composition and interactions with accessory subunits.
- Understanding these interactions is key to modulating immune responses.
Purpose of the Study:
- To investigate the role of KCNE4 as an accessory subunit for Kv1.3 channels in leukocytes.
- To determine how KCNE4 affects Kv1.3 channel trafficking, surface expression, and activity.
- To explore the differential regulation of Kv1.3 and KCNE4 during immune cell activation and suppression.
Main Methods:
- Co-immunoprecipitation to assess Kv1.3 and KCNE4 association.
- Electrophysiology to measure Kv1.3 channel function.
- Confocal microscopy and cell surface biotinylation to analyze channel localization and surface expression.
- Quantitative PCR to examine mRNA levels of Kv1.3 and KCNE4.
Main Results:
- KCNE4, but not KCNE2, directly interacts with Kv1.3 channels in leukocytes.
- KCNE4 significantly reduces Kv1.3 current density, slows activation, accelerates inactivation, and increases cumulative inactivation.
- KCNE4 retains Kv1.3 in the endoplasmic reticulum and impairs its targeting to lipid rafts, decreasing cell surface expression and excitability.
- Kv1.3 and KCNE4 mRNA levels are differentially regulated during macrophage activation (LPS) and immunosuppression (dexamethasone).
Conclusions:
- KCNE4 acts as an inhibitory partner for Kv1.3 channels in leukocytes, modulating their surface expression and activity.
- The interaction between KCNE4 and Kv1.3 influences leukocyte excitability and immunological responses.
- KCNE ancillary subunits represent potential novel targets for immunomodulatory therapies.
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