Protein complex analysis of native brain potassium channels by proteomics

Area of Science:

• Neuroscience
• Molecular Biology
• Biochemistry

Background:

• TREK1 (TWIK-related potassium channel 1) is a two-pore domain potassium channel (K2P).
• TREK1 knockout mice exhibit altered responses to pain, anesthetics, and ischemia, highlighting its physiological importance.
• Understanding TREK1's native environment and interacting proteins is crucial for elucidating its function.

Purpose of the Study:

• To identify native protein partners of TREK1 channels in the mouse brain.
• To investigate the functional consequences of TREK1 interaction with identified partners.
• To compare proteomic approaches with classical methods for studying channel composition.

Main Methods:

• Proteomic analysis (mass spectrometry) of isolated native TREK1 channels from mouse brain.
• Electrophysiological recordings to assess TREK1 channel activity and regulation.
• Investigating the impact of G protein-coupled receptor signaling on TREK1/AKAP150 complexes.

Main Results:

• The A-Kinase Anchoring Protein 150 (AKAP150) was identified as a key binding partner of TREK1.
• AKAP150 acts as a molecular switch, converting low-activity TREK1 currents into robust leak conductances resistant to certain stimuli.
• TREK1/AKAP150 channel inhibition by Gs-coupled receptors is enhanced, while inhibition by Gq-coupled receptors is reduced.
• AKAP150 integrates TREK1 into postsynaptic scaffolds, facilitating co-localization with G protein-coupled receptors.

Conclusions:

• AKAP150 is a critical regulator of TREK1 channel function and localization.
• The TREK1/AKAP150 complex plays a significant role in modulating neuronal excitability and synaptic function.
• Proteomics offers advantages over traditional methods for characterizing native ion channel complexes.