Kca3.1 Protein — Potassium Calcium Activated Channel Subfamily M Member 2 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Kca3.1 Protein — Potassium Calcium Activated Channel Subfamily M Member 2 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
<div class="infobox infobox-protein"> [@wulff2007]
<div class="infobox-header">KCa3.1 Protein — Potassium Calcium-Activated Channel Subfamily M Member 2</div> [@r2019]
<div class="infobox-row"> [@ma2022]
<div class="infobox-label">Protein Name</div>
<div class="infobox-value">KCa3.1 Protein</div>
</div>
<div class="infobox-row">
<div class="infobox-label">Gene</div>
<div class="infobox-value"><a href="/genes/kcnn2" target="_blank">KCNN2</a></div>
</div>
<div class="infobox-row">
<div class="infobox-label">UniProt ID</div>
<div class="infobox-value"><a href="https://www.uniprot.org/uniprot/Q9H6X5" target="_blank">Q9H6X5</a></div>
</div>
<div class="infobox-row">
<div class="infobox-label">PDB ID</div>
<div class="infobox-value"><a href="https://www.rcsb.org/structure/6CNN" target="_blank">6CNN</a></div>
</div>
<div class="infobox-row">
<div class="infobox-label">Molecular Weight</div>
<div class="infobox-value">65-75 kDa</div>
</div>
<div class="infobox-row">
<div class="infobox-label">Subcellular Localization</div>
<div class="infobox-value">Plasma Membrane (Neurons, Immune Cells)</div>
</div>
<div class="infobox-row">
<div class="infobox-label">Protein Family</div>
<div class="infobox-value">Small-Conductance KCa Channel Family</div>
</div>
</div>
KCa3.1 (also known as SK2 or KCNN2) is a small-conductance calcium-activated potassium channel. These channels are activated by intracellular calcium through binding to calmodulin, which is constitutively associated with the channel. KCa3.1 channels play important roles in regulating neuronal excitability, afterhyperpolarization, and synaptic integration. They are also expressed in [microglia](/cell-types/microglia-neuroinflammation) and other immune cells where they regulate migration and cytokine release.
KCa3.1 (KCNN2) is a ~65 kDa protein with six transmembrane domains (S1-S6), a pore loop between S5 and S6, and intracellular N- and C-termini. The channel forms tetramers in the plasma membrane. Calmodulin is constitutively bound to the C-terminus, providing calcium sensitivity. The channel lacks intrinsic voltage sensitivity but is regulated by phosphorylation, trafficking, and association with other proteins.
KCa3.1 channels provide the medium afterhyperpolarization (mAHP) in [neurons](/entities/neurons), limiting firing rates and promoting spike frequency adaptation. They regulate: (1) neuronal excitability and firing patterns; (2) synaptic integration and plasticity; (3) calcium signaling in dendrites; (4) neurotransmitter release. In microglia, KCa3.1 controls process motility, migration toward lesions, and cytokine production in response to brain injury.
KCa3.1 dysfunction is implicated in several neurological conditions. In Alzheimer's disease, KCa3.1 activity is reduced, contributing to neuronal hyperexcitability and network dysfunction. The channel is upregulated in reactive microglia in AD and other neurodegenerative conditions. KCa3.1 blockers have shown cognitive-enhancing effects in AD models. In epilepsy, altered KCa3.1 function contributes to seizure susceptibility.
KCa3.1 modulators are being developed for multiple indications. KCa3.1 blockers (e.g., TRAM-34) have shown: (1) cognitive enhancement in AD mouse models; (2) anti-epileptic effects; (3) reduction of neuropathic pain. KCa3.1 activators may have applications in enhancing neuronal repolarization after injury. Several clinical trials are evaluating KCa3.1 modulators for various conditions.
The study of Kca3.1 Protein — Potassium Calcium Activated Channel Subfamily M Member 2 has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.