| KCNMB1 | |
|---|---|
| Full Name | Potassium Calcium-Activated Channel Regulatory Subunit Beta 1 |
| Symbol | KCNMB1 |
| Chromosomal Location | 5q22.1 |
| NCBI Gene ID | [3776](https://www.ncbi.nlm.nih.gov/gene/3776) |
| OMIM | [603951](https://www.omim.org/entry/603951) |
| Ensembl ID | [ENSG00000112984](https://ensembl.org/Homo_species/Gene/Summary?g=ENSG00000112984) |
| UniProt ID | [Q9NZU5](https://www.uniprot.org/uniprot/Q9NZU5) |
| Associated Diseases | [Epilepsy](/diseases/epilepsy), [Intellectual Disability](/diseases/intellectual-disability), [Ataxia](/diseases/ataxia) |
KCNMB1 (Potassium Calcium-Activated Channel Regulatory Subunit Beta 1) encodes the beta-1 subunit of the large-conductance calcium-activated potassium (BK) channel, also known as MaxiK or Slo1. BK channels are widely expressed in neurons where they regulate neuronal excitability, action potential duration, and neurotransmitter release.
The KCNMB1 protein modulates BK channel function by:
KCNMB1 is expressed in various brain regions including:
KCNMB1 variants have been associated with epilepsy susceptibility. BK channel dysfunction can lead to neuronal hyperexcitability and seizure generation. Studies have identified rare missense variants in epilepsy patients affecting channel gating properties.
Loss-of-function variants in KCNMB1 have been linked to neurodevelopmental disorders including intellectual disability, possibly through impaired synaptic plasticity and neuronal connectivity.
KCNMB1 mutations may contribute to cerebellar ataxia through disrupted Purkinje cell function and impaired cerebellar circuit signaling.
KCNMB1 is overexpressed in several cancers and may promote tumor progression through effects on cell proliferation and migration.
| Brain Region | Expression Level |
|---|---|
| Hippocampus | High |
| Cerebral Cortex | Moderate-High |
| Cerebellum | High (Purkinje cells) |
| Brainstem | Moderate |
| Thalamus | Low-Moderate |
| Variant | Type | Function | Associated Phenotype |
|---|---|---|---|
| p.E23K | Missense | Reduced calcium sensitivity | Seizure risk |
| p.V171I | Missense | Neutral | Common polymorphism |
| p.R8W | Missense | Loss of function | Developmental delay |