Activity-dependent isomerization of Kv4.2 by Pin1 regulates cognitive flexibility.

Area of Science:

• Neuroscience
• Molecular Biology
• Ion Channel Physiology

Background:

• Voltage-gated potassium (K+) channels, specifically A-type channels involving Kv4.2 subunits, are crucial for regulating neuronal excitability and cognitive functions.
• These channels assemble into macromolecular complexes with auxiliary subunits like dipeptidyl peptidase 6 (DPP6), influencing their activity and localization.
• Dysregulation of neuronal excitability and cognitive flexibility is implicated in various neuropsychiatric disorders.

Purpose of the Study:

• To elucidate a peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1)-dependent mechanism that governs the Kv4.2-DPP6 complex association.
• To investigate how this mechanism impacts neuronal excitability and cognitive flexibility.
• To explore the therapeutic potential of targeting this pathway for neuropsychiatric disorders.

Main Methods:

• Utilized a novel knock-in mouse model (Kv4.2TA) with a mutation abolishing dynamic Pin1 binding to Kv4.2.
• Electrophysiological recordings from hippocampal CA1 pyramidal neurons to assess A-type K+ currents and neuronal excitability.
• Behavioral testing using Morris water maze and lever press paradigms to evaluate learning and cognitive flexibility, particularly reversal learning.

Main Results:

• Activity-induced phosphorylation of Kv4.2 at pThr607 triggers Pin1 binding and isomerization, leading to Kv4.2-DPP6 complex dissociation.
• Kv4.2TA mice exhibited altered Kv4.2-DPP6 interaction, increased A-type K+ current, and reduced neuronal excitability in hippocampal neurons.
• Kv4.2TA mice showed normal initial learning but enhanced reversal learning, indicating improved cognitive flexibility.

Conclusions:

• A Pin1-mediated mechanism dynamically regulates Kv4.2-DPP6 complex formation, influencing neuronal excitability and cognitive flexibility.
• The Kv4.2TA mutation disrupts this mechanism, leading to altered neuronal function and improved reversal learning.
• This Pin1-dependent pathway represents a potential therapeutic target for neuropsychiatric conditions characterized by cognitive inflexibility.