Associates with KCNQ3 to form a potassium channel with essentially identical properties to the channel underlying the native M-current, a slowly activating and deactivating potassium conductance which plays a critical role in determining the subthreshold electrical excitability of neurons as well as the responsiveness to synaptic inputs. Therefore, it is important in the regulation of neuronal excitability. Heterotetramer with KCNQ3; form the heterotetrameric M potassium channel (By similarity). Interacts with calmodulin; the interaction is calcium-independent, constitutive and participates in the proper assembly of a functional heterotetrameric M channel (PubMed:12223552). May associate with KCNE2 (By similarity). Interacts with IQCJ-SCHIP1 (PubMed:27979964). Exclusively expressed in the brain. Expressed in every neuron-containing regions of the central nervous system examined, such as the cerebellum, cerebral cortex, occipital pole, substantia nigra, amygdala, caudate nucleus, hippocampus and thalamus. Also detected in the cochlea. Detected at day 11, 15 and 17 of the embryonic development. Expression increases by a factor of 2.5 at 1 week after birth. Then the expression level remains stable until the adult stage. The mRNAs for shorter forms (isoforms 9, 10 and 11) are specifically expressed in an embryo on the 11th day after gestation. The segment S4 is probably the voltage-sensor and is characterized by a series of positively charged amino acids at every third position. KCNQ2/KCNQ3 heteromeric current can be increased by intracellular cyclic AMP, an effect that depends on phosphorylation of Ser-52 in the N-terminal region. KCNQ2/KCNQ3 are ubiquitinated by NEDD4L. Ubiquitination leads to protein degradation. Degradation induced by NEDD4L is inhibited by USP36. Mice lacking Kcnq2 present no overt phenotype, but die a few hours after birth of pulmonary atelectasis which is not due to the status of epileptic seizures. May be due to an intron retention. May be due to an intron retention. May be due to an intron retention. May be due to an intron retention. May be due to an intron retention. May be due to an intron retention. Belongs to the potassium channel family. KQT (TC 1.A.1.15) subfamily. Kv7.2/KCNQ2 sub-subfamily.