Photomodulation of Kv Channel Activity

Voltage-gated potassium (Kv) channels, essential for shaping action potentials, are influenced not only by voltage but also by mechanical stimuli. Membrane tension has been shown to stabilize the open state of the pore, suggesting that pore dilation occurs in a thinner membrane. However, structural studies using cryo-electron microscopy indicate that membrane thinning is associated with pore closure. To clarify the role of local hydrophobic membrane thickness in channel gating, we reconstituted Kv channels from Aeropyrum pernix (KvAP) into planar bilayers containing photoswitchable lipids. Blue light exposure increased membrane thickness and increased the KvAP activity at both single channel and ensemble levels, whereas UV light reversed these effects by decreasing thickness and reducing activity. These results support a model in which the positioning of lipid phosphates in a thicker membrane drives the upward movement of interacting arginine residues in the KvAP voltage sensor and primes the channel for opening. This light-driven regulation of Kv channel activity offers new possibilities for controlling neuronal excitability.