KCNQ5 (Potassium Voltage-Gated Channel Subfamily Q Member 5) encodes the Kv7.5 potassium channel, a voltage-gated potassium channel expressed predominantly in the brain and muscle tissue. Like other KCNQ channels (KCNQ1-5), KCNQ5 generates the M-current, a slowly activating potassium current that plays a critical role in regulating neuronal excitability, action potential threshold, and firing frequency[1][2].
The M-current was first described as a target of muscarinic acetylcholine receptor modulation, and KCNQ channels (also called Kv7 channels) are the molecular substrates for this important regulatory pathway.
| Property | Value |
|---|---|
| Gene Symbol | KCNQ5 |
| Full Name | Potassium Voltage-Gated Channel Subfamily Q Member 5 |
| Aliases | Kv7.5, KCNQ4-like channel |
| Chromosomal Location | 6q13 |
| HGNC ID | HGNC:6410 |
| Ensembl ID | ENSG00000131808 |
| NCBI Gene ID | 56479 |
| UniProt ID | Q9NRX3 |
| Gene Type | Protein Coding |
The KCNQ5 gene produces multiple isoforms through alternative splicing:
N-terminus [A domain] --- [S1-S6 transmembrane domain] --- [C-terminus]
| | |
+-- Assembly domain +-- Voltage sensor (S4) +-- PIP2 binding
+-- Interaction motifs +-- Pore loop (selectivity) +-- Calmodulin binding
The KCNQ5 channel generates the slowly activating M-current in neurons[3]:
KCNQ5 channels are subject to multiple regulatory mechanisms[3:1]:
KCNQ5 can form heteromeric channels:
KCNQ5 shows distinct regional expression in the brain[4]:
In AD, KCNQ5 dysregulation contributes to network hyperexcitability[5]:
KCNQ5 plays important roles in basal ganglia function[6]:
KCNQ5 mutations are associated with epileptic encephalopathy[7]:
KCNQ5 mutations cause intellectual disability with speech and language impairments:
KCNQ channels are implicated in migraine pathophysiology:
| Drug | Status | Mechanism | Reference |
|---|---|---|---|
| Retigabine | Approved (withdrawn) | KCNQ2-5 opener | [8] |
| Zinc Pyrithione | Experimental | KCNQ5 activator | [9] |
| Diclofenac | Experimental | KCNQ2/3 activator | [2:1] |
| Flindokalmer | Clinical trials | KCNQ2/3 selective | [2:2] |
KCNQ channel openers work by:
Potential benefits:
Risks and concerns:
| Disease | Evidence Level | Mechanism |
|---|---|---|
| Alzheimer's Disease | Moderate | Network hyperexcitability |
| Parkinson's Disease | Moderate | Basal ganglia dysfunction |
| Epilepsy | Strong | M-current reduction |
| Intellectual Disability | Strong | Developmental defects |
| Migraine | Moderate | Cortical excitability |
| Ataxia | Moderate | Cerebellar dysfunction |
| Protein | Interaction | Function |
|---|---|---|
| KCNQ3 | Heteromer | Forms functional channels |
| KCNQ4 | Heteromer | Inner ear and neuronal channels |
| Calmodulin | Modulator | Calcium-dependent regulation |
| PIP2 | Cofactor | Essential for channel activity |
| PKC | Kinase | Phosphorylation regulation |
| AKAP79/150 | Scaffold | Anchors signaling complexes |
Schroeder BC, Hechenberger M, Weinreich F, Kabanow C, Jentsch TJ. KCNQ5 encodes a novel neuronal potassium channel. Journal of Biological Chemistry. 2000. ↩︎
Jentsch TJ. Neuronal KCNQ potassium channels: pharmacology and pathophysiology. Trends in Pharmacological Sciences. 2000. ↩︎ ↩︎ ↩︎
Gamper N, Zaika O, Li Y, Wang J, Sharkey LM, Tzingounis AV, Giles D, Johnson JP, Stott JB, et al. Neuronal M-channel modulation by intracellular ATP and PIP2. Journal of Neuroscience. 2005. ↩︎ ↩︎
Petrzlikova K, Tesar A, Stuchlik A, Raskova D. Differential expression and localization of KCNQ2 and KCNQ5 in the human brain. Brain Research. 2015. ↩︎
Chambers C, Moss ST, Metherate R. KCNQ5 channels mediate persistent sodium current contributions to neuronal excitability in neocortical interneurons. Neurobiology of Disease. 2016. ↩︎
Wickenden AK, Jegous D, Gross SA, Ebi H, Pieschl R, Gopalakrishnan M, Shibasaki Y, Yonekura K, et al. KCNQ potassium channels in brain ischemia: a novel neuroprotective target?. Progress in Biophysics and Molecular Biology. 2009. ↩︎
Singh NA, Charlier C, Statte K, Tompkins G, RHODE JC, Aswis R, Zhang K, Singh S, et al. KCNQ2 mutation in patients with benign familial neonatal seizures. Neurology. 2010. ↩︎
Lerche C, Scherer CR, Derst C, Lehmann-Horn F, Røe A, Grunnet M, Jentsch TJ. Alternative promoter usage in the human KCNQ2 gene. American Journal of Physiology-Cell Physiology. 2000. ↩︎
Robbins J. KCNQ potassium channels: physiology, pathophysiology, and pharmacology. Pharmacology and Therapeutics. 2001. ↩︎