14-3-3 Proteins regulate K_2P 5.1 surface expression on T lymphocytes

Area of Science:

• Immunology
• Molecular Biology
• Channel Physiology

Background:

• Potassium 2-pore domain (K2P) 5.1 channels (TASK-2) are implicated in autoimmune disease pathophysiology.
• These channels are upregulated on T lymphocytes in multiple sclerosis (MS) patients and enhance T-cell effector functions when overexpressed.

Purpose of the Study:

• To investigate the molecular mechanisms regulating intracellular K2P 5.1 channel trafficking in T lymphocytes.
• To identify proteins interacting with K2P 5.1 channels and their role in channel localization and function.

Main Methods:

• Mass spectrometry was used to identify binding partners of K2P 5.1 channels.
• Site-directed mutagenesis (K2P 5.1/S266A) was employed to disrupt the 14-3-3 binding motif.
• A 14-3-3 inhibitor (BV02) was used to assess the impact on channel trafficking and T-cell function.

Main Results:

• 14-3-3 proteins were identified as novel binding partners of K2P 5.1 channels via a non-classical C-terminal motif.
• Disruption of the 14-3-3 binding site (K2P 5.1/S266A) reduced protein interaction and membrane currents.
• Inhibition of 14-3-3 binding with BV02 decreased wild-type K2P 5.1 channel plasma membrane localization and T-cell effector functions, with no effect on the mutated channel.

Conclusions:

• 14-3-3 proteins interact with K2P 5.1 channels and are essential for their trafficking to the plasma membrane.
• This interaction regulates K2P 5.1 channel function and subsequent T-cell effector activities.
• Targeting the K2P 5.1-14-3-3 interaction may offer a therapeutic strategy for MS and other autoimmune diseases.