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. KCNQ2/KCNQ3 current is blocked by linopirdine and XE991, and activated by the anticonvulsant retigabine (PubMed:9836639, PubMed:11572947, PubMed:14534157, PubMed:12742592, PubMed:17872363). As the native M-channel, the potassium channel composed of KCNQ2 and KCNQ3 is also suppressed by activation of the muscarinic acetylcholine receptor CHRM1 (PubMed:10684873). Heterotetramer with KCNQ3; form the heterotetrameric M potassium channel (PubMed:9836639, PubMed:27564677). Interacts with calmodulin; the interaction is calcium-independent, constitutive and participates in the proper assembly of a functional heterotetrameric M channel (PubMed:27564677). May associate with KCNE2 (PubMed:11034315). Interacts with IQCJ-SCHIP1 (By similarity). Additional isoforms seem to exist. In adult and fetal brain. Highly expressed in areas containing neuronal cell bodies, low in spinal cord and corpus callosum. Isoform 2 is preferentially expressed in differentiated neurons. Isoform 6 is prominent in fetal brain, undifferentiated neuroblastoma cells and brain tumors. 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 (Probable). Degradation induced by NEDD4L is inhibited by USP36 (PubMed:27445338). The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. Inclusion of isoform 6 in heteromultimers results in attenuation of potassium current. Prominent expression of isoform 6 in the developing brain may alter firing repertoires of immature neurons excitability to provide cues for proliferation rather than differentiation. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. Belongs to the potassium channel family. KQT (TC 1.A.1.15) subfamily. Kv7.2/KCNQ2 sub-subfamily.