Associates with KCNQ3 to form a potassium channel which contributes to M-type current, a slowly activating and deactivating potassium conductance which plays a critical role in determining the subthreshold electrical excitability of neurons. Therefore, it is important in the regulation of neuronal excitability. May contribute, with other potassium channels, to the molecular diversity of a heterogeneous population of M-channels, varying in kinetic and pharmacological properties, which underlie this physiologically important current. Heteromultimer with KCNQ3. Heterotetramer with KCNQ1; has a voltage-gated potassium channel activity. The segment S4 is probably the voltage-sensor and is characterized by a series of positively charged amino acids at every third position. The activity of this channel is modulated by zinc, pH and volume changes. Belongs to the potassium channel family. KQT (TC 1.A.1.15) subfamily. Kv7.5/KCNQ5 sub-subfamily.