KCNMA1
Potassium Calcium-Activated Channel Subfamily M Alpha 1
Gene Information Card
| Symbol | KCNMA1 |
|---|---|
| Full Name | Potassium Calcium-Activated Channel Subfamily M Alpha 1 |
| Gene Type | protein-coding |
| Chromosomal Location | 10q22.3 |
| NCBI Gene ID | 3778 ncbi.nlm.nih.gov/gene/3778 |
| Ensembl ID | ENSG00000156113 |
| UniProt ID | Q12791 |
| OMIM ID | 600150 |
| HGNC ID | 6284 |
| Aliases | BK, BKCA, SLO, SLO1, KCNMA, K(VCA)ALPHA, mSLO1 |
Description
KCNMA1 encodes the alpha subunit of the large-conductance calcium-activated potassium (BK) channel. This channel is activated by both membrane depolarization and intracellular calcium, playing critical roles in neuronal excitability, smooth muscle contraction, and neurotransmitter release. Mutations in KCNMA1 are associated with neurological disorders including epilepsy and paroxysmal dyskinesia.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Epilepsy, generalized, with paroxysmal dyskinesia (GEPD) | Loss-of-function mutations reduce BK channel activity, leading to neuronal hyperexcitability | ClinVar, OMIM |
| Paroxysmal nonkinesigenic dyskinesia (PNKD) | Gain-of-function mutations increase channel activity, altering basal ganglia output | ClinVar, OMIM |
| Hereditary spastic paraplegia (rare) | Missense variants impair channel trafficking or gating | NCBI Gene, ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 24.5 | High |
| Skeletal muscle | 18.2 | High |
| Heart | 12.1 | Medium |
| Smooth muscle | 15.3 | High |
| Liver | 2.4 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| SH-SY5Y (neuroblastoma) | 22.1 | High expression |
| HEK293 (embryonic kidney) | 8.5 | Moderate expression |
| A549 (lung carcinoma) | 3.2 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.4280G>A (p.Arg1427Gln) | Missense | <0.01% | Gain-of-function; associated with PNKD |
| c.3439C>T (p.Arg1147Trp) | Missense | <0.01% | Loss-of-function; associated with GEPD |
| c.2260_2261del (p.Glu754fs) | Frameshift | Rare | Loss-of-function; epilepsy |
Mutation functional classification
Loss of Function (LOF)
Reduced BK channel current; leads to neuronal hyperexcitability and epilepsy
Gain of Function (GOF)
Increased BK channel activity; alters neuronal firing patterns and causes dyskinesia
Dominant Negative (DN)
Not well documented for KCNMA1; most mutations act via haploinsufficiency or altered gating
View complete mutation data：
Gene Ontology (GO)
| • calcium-activated potassium channel activity | • voltage-gated potassium channel activity |
| • plasma membrane | • regulation of membrane potential |
| • neuronal action potential |
Pathways
• Potassium channels
• Transmembrane transport of small molecules
• Neuronal system
Protein Summary
The BK channel alpha subunit (KCNMA1) is a 1200+ amino acid protein with seven transmembrane domains and a large C-terminal tail containing calcium-binding domains. It forms a tetrameric channel that conducts potassium ions with high conductance. The channel is regulated by voltage, calcium, and auxiliary beta subunits. Mutations alter channel gating and are linked to neurological channelopathies.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| KCNMA1 Knockout HEK293 Cell Line | EDJ-KQ265 | Human | 3778 | Details Get a Quote |
| KCNMA1 Knockout HeLa Cell Line | EDJ-KQ18204 | Human | 3778 | Details Get a Quote |
| KCNMA1 Knockout A-549 Cell Line | EDJ-KQ21700 | Human | 3778 | Details Get a Quote |
| KCNMA1 Knockout HCT 116 Cell Line | EDJ-KQ70686 | Human | 3778 | Details Get a Quote |
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