KCNQ2

The M channel is a slowly activating and deactivating potassium channel that plays a critical role in the regulation of neuronal excitability. The M channel is formed by the association of the protein encoded by this gene and a related protein encoded by the KCNQ3 gene, both integral membrane proteins. M channel currents are inhibited by M1 muscarinic acetylcholine receptors and activated by retigabine, a novel anti-convulsant drug. Defects in this gene are a cause of benign familial neonatal convulsions type 1 (BFNC), also known as epilepsy, benign neonatal type 1 (EBN1). At least five transcript variants encoding five different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

Full Name

Potassium Voltage-Gated Channel Subfamily Q Member 2

Function

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).

Biological Process

Chemical synaptic transmissionManual Assertion Based On ExperimentTAS:ProtInc
Nervous system developmentManual Assertion Based On ExperimentTAS:ProtInc
Potassium ion transmembrane transportManual Assertion Based On ExperimentIDA:UniProtKB
Regulation of ion transmembrane transportIEA:UniProtKB-KW

Cellular Location

Cell membrane

Involvement in disease

Seizures, benign familial neonatal 1 (BFNS1):
A disorder characterized by clusters of seizures occurring in the first days of life. Most patients have spontaneous remission by 12 months of age and show normal psychomotor development. Some rare cases manifest an atypical severe phenotype associated with epileptic encephalopathy and psychomotor retardation. The disorder is distinguished from benign familial infantile seizures by an earlier age at onset. In some patients, neonatal convulsions are followed later in life by myokymia, a benign condition characterized by spontaneous involuntary contractions of skeletal muscles fiber groups that can be observed as vermiform movement of the overlying skin. Electromyography typically shows continuous motor unit activity with spontaneous oligo- and multiplet-discharges of high intraburst frequency (myokymic discharges). Some patients may have isolated myokymia.
Developmental and epileptic encephalopathy 7 (DEE7):
An autosomal dominant seizure disorder characterized by infantile onset of refractory seizures with resultant delayed neurologic development and persistent neurologic abnormalities.

Topology

Cytoplasmic: 1-91
Helical: 92-112
Extracellular: 113-122
Helical: 123-143
Cytoplasmic: 144-166
Helical: 167-187
Extracellular: 188-195
Helical: 196-218
Cytoplasmic: 219-231
Helical: 232-252
Extracellular: 253-264
Pore-forming: 265-285
Extracellular: 286-291
Helical: 292-312
Cytoplasmic: 313-872

PTM

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).