Characterizing features of Kv channel activation currents by a minimal-state kinetic model

Voltage-gated Potassium channels (Kv channels) comprise twelve subfamilies found in the human genome. They demonstrate diversified activation behaviors, represented by the varied shapes of activation currents, which are usually modeled by individual kinetic schemes of many parameters that make channel comparisons difficult. Here, we present a minimal-state kinetic model, aiming to compare different Kv channel activation currents by a unified model system. By omitting the short-lived transient states and neglecting the detailed transition pathways, this model employs only minimal significant states necessary to approximate the activation currents. Few model-parameters are used that capture the varied current-features, leading to a convenient comparison among Kv channels. In addition, this model incorporates a gating factor, which accurately represents the channel opening event upon applying a voltage pulse. A special feature of the model is its adaptability via simple modifications, that any channel-dependent kinetic scheme can be easily incorporated into this model framework, helping develop exact channel mechanisms.