Kv4

Kv4 refers to a subfamily of voltage-gated potassium channels. These channels are crucial for regulating neuronal excitability and play a significant role in the electrical activity of the heart. Kv4 channels are characterized by their fast inactivation kinetics, meaning they open and close very rapidly in response to changes in membrane potential. This rapid inactivation is a key feature contributing to their function in shaping action potentials. The Kv4 subfamily consists of three main genes: KCNS1, KCNS2, and KCNS3, which encode the alpha subunits of the channel. These alpha subunits assemble to form functional tetrameric channels. Accessory subunits, such as KChIPs and DPPX, can also co-assemble with Kv4 alpha subunits, modulating their expression, trafficking, and biophysical properties. Kv4 channels are widely expressed in the brain, particularly in dendrites of neurons, where they contribute to dendritic excitability and synaptic plasticity. In the heart, Kv4 channels are the primary components of the transient outward potassium current (Ito), which is essential for the repolarization phase of the cardiac action potential. Dysfunction of Kv4 channels has been implicated in various neurological disorders and cardiac arrhythmias. Research into Kv4 channels continues to uncover their diverse roles in cellular physiology and disease.