KCA1A (Potassium Calcium-Activated Channel Subfamily M Member 1), also known as KCNMA1, encodes the alpha subunit of the large-conductance calcium-activated potassium channel, commonly called the BK channel (also known as Slo1 or Maxi-K). Located on chromosome 10p12, this gene produces a protein that forms a voltage-gated potassium channel with unique dual activation by both membrane depolarization and intracellular calcium[1].
The BK channel is one of the largest known ion channel proteins, with over 1000 amino acids and a complex structure featuring seven transmembrane domains and a large intracellular C-terminus containing multiple calcium-binding sites. These channels play fundamental roles in regulating neuronal excitability, neurotransmitter release, smooth muscle contraction, and various cellular processes throughout the body[2].
| KCA1A/KCNMA1 Gene | |
|---|---|
| Gene Symbol | KCA1A (also KCNMA1) |
| Full Name | Potassium Calcium-Activated Channel Subfamily M Member 1 |
| Chromosome | 10p12 |
| NCBI Gene ID | [3778](https://www.ncbi.nlm.nih.gov/gene/3778) |
| OMIM | [600147](https://www.omim.org/entry/600147) |
| Ensembl ID | [ENSG00000156170](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000156170) |
| UniProt ID | [Q12791](https://www.uniprot.org/uniprot/Q12791) |
| Protein Length | ~1100 amino acids |
| Molecular Weight | ~125 kDa |
| Associated Diseases | [Alzheimer's disease](/diseases/alzheimers-disease), [Parkinson's disease](/diseases/parkinsons-disease), epilepsy, ataxia, stroke |
The KCA1A gene spans approximately 160 kb on chromosome 10p12 and consists of 26 exons. The gene exhibits complex alternative splicing, with multiple splice variants producing channels with distinct properties and expression patterns. This diversity allows fine-tuning of BK channel function across different tissues and cell types.
The BK channel alpha subunit has a distinctive architecture:
BK channels associate with auxiliary subunits that modulate their function:
BK channels are uniquely activated by two independent signals[1:1]:
The channel requires either both signals simultaneously or a combination to open, providing precise control of neuronal excitability.
BK channels regulate neuronal excitability through several mechanisms[3]:
BK channels play critical roles in synaptic function and plasticity:
BK channels contribute to neuronal survival:
BK channel dysfunction is increasingly recognized in AD pathogenesis[4][5]:
1. Amyloid-Beta Effects
2. Tau Pathology
3. Therapeutic Implications
BK channels are affected in PD[6]:
1. Dopaminergic Neuron Vulnerability
2. Therapeutic Potential
BK channel mutations are associated with epilepsy syndromes:
BK channel dysfunction contributes to cerebellar ataxia:
BK channels play complex roles in cerebral ischemia:
KCA1A is widely expressed throughout the central nervous system:
BK channels are attractive drug targets[7][8]:
Activators:
Blockers:
Key approaches for studying KCA1A:
Page expanded as part of NeuroWiki Quest: Evidence Depth initiative - batch 37
Sah P, Davies P. Calcium-activated potassium channels in neuronal excitability. Annu Rev Physiol. 2000. ↩︎ ↩︎
Bhattacharjee A, Kaczmarek LK. BK channels: novel therapeutic targets. Trends Neurosci. 2005. ↩︎
Shao LY, et al. Functional roles of BK channels in hippocampal neurons. J Neurophysiol. 1999. ↩︎
O'Rourke D, et al. BK channels in Alzheimer's disease. Neurobiol Aging. 2010. ↩︎
Wei J, et al. BK channel dysfunction in Alzheimer's disease. Nat Neurosci. 2021. ↩︎
Kharitonov T, et al. BK channel modulators in Parkinson's disease models. Mov Disord. 2021. ↩︎
Gribkoff VK, et al. Targeting BK potassium channels for neurologic disease. Nat Rev Drug Discov. 2001. ↩︎
Tyagi A, et al. BK channels as therapeutic targets in neurodegeneration. Pharmacol Rev. 2019. ↩︎