Energetic cross-talk of filter gate and lower helices drives polymodal regulation and disease in TREK K2P channels

Abstract

The TREK subfamily of two-pore domain potassium (K2P) channels are essential regulators of membrane excitability, and their activity is modulated by a wide range of physiological stimuli, including phosphorylation and membrane stretch. Single-site mutations in this subfamily have been identified in patients with FHEIG symptom (facial dysmorphism, hypertrichosis, epilepsy, intellectual disability/developmental delay, and gingival overgrowth), where they cause pathological channel hyperactivation. Using OneOPES framework, which unifies multiple enhanced-sampling molecular dynamics strategies, we provide a detailed energetic characterization of the TREK-2 conformational landscape. Our simulations uncover a unifying mechanism in which coupling between the lower transmembrane helices, the proximal C-terminal domain, and selectivity filter stability governs channel gating under different physiological stimuli, as well as disease-mimicking conditions. The predicted conformational effects of an FHEIG syndrome-associated mutation were further validated by electrophysiological measurements using a conformation-sensitive TREK-2 inhibitor. Together, these results establish an energetic framework for TREK-2 regulation and dysfunction and provide a foundation for structure-based drug discovery targeting the K2P TREK channel family.