<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">SLC24A2 — Solute Carrier Family 2 Member 4A2 (SLC24A2)</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td>SLC24A2</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Solute Carrier Family 24 Member 2 (Na+/Ca2+ Exchanger 2)</td>
</tr>
<tr>
<td class="label">Chromosome</td>
<td>9p21</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>[8994](https://www.ncbi.nlm.nih.gov/gene/8994)</td>
</tr>
<tr>
<td class="label">OMIM</td>
<td>[609521](https://www.omim.org/entry/609521)</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000159339</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>[O43295](https://www.uniprot.org/uniprot/O43295)</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td>Potential role in neuronal calcium dysregulation</td>
</tr>
</table>
{{.infobox .infobox-gene}}
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">SLC24A2 — Solute Carrier Family 2 Member 4A2 (SLC24A2)</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td>SLC24A2</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Solute Carrier Family 24 Member 2 (Na+/Ca2+ Exchanger 2)</td>
</tr>
<tr>
<td class="label">Chromosome</td>
<td>9p21</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>[8994](https://www.ncbi.nlm.nih.gov/gene/8994)</td>
</tr>
<tr>
<td class="label">OMIM</td>
<td>[609521](https://www.omim.org/entry/609521)</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000159339</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>[O43295](https://www.uniprot.org/uniprot/O43295)</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td>Potential role in neuronal calcium dysregulation</td>
</tr>
</table>
{{.infobox .infobox-gene}}
The SLC24A2 gene encodes the Na+/Ca2+/K+ exchanger 2 (NCKX2), a critical neuronal calcium extrusion protein that plays a vital role in maintaining calcium homeostasis in [neurons](/entities/neurons) [@nckx]. NCKX2 is one of several sodium-calcium exchangers in the brain, but unlike the more ubiquitous NCX1-3, NCKX2 shows neuron-specific expression with particularly high levels in the olfactory bulb, [hippocampus](/brain-regions/hippocampus), and cerebral [cortex](/brain-regions/cortex) [@nckxa].
Calcium homeostasis is essential for normal neuronal function, and dysregulation of calcium signaling is a hallmark of many neurodegenerative diseases. By efficiently removing calcium from neurons, NCKX2 helps prevent calcium overload and excitotoxicity [@calcium].
NCKX2 operates as a reverse-mode Na⁺/Ca²⁺/K⁺ exchanger, exporting one Ca²⁺ ion in exchange for four Na⁺ ions and one K⁺ ion. This electrogenic transport is driven by the transmembrane sodium gradient established by the Na⁺/K⁺ ATPase [@nckxb].
The stoichiometry (1 Ca²⁺: 4 Na⁺: 1 K⁺) makes NCKX2 particularly efficient at calcium extrusion under conditions of high intracellular calcium, as the driving force increases with elevated intracellular Na⁺ concentrations that typically accompany cellular depolarization [@sodiumcalcium].
NCKX2 is expressed almost exclusively in neurons, with particularly high expression in:
NCKX2 is strategically positioned at synapses, where it contributes to rapid calcium clearance following synaptic activation. During excitatory neurotransmission, [NMDA receptor](/entities/nmda-receptor) and voltage-gated calcium channel activation leads to rapid calcium influx. NCKX2, alongside other calcium extrusion systems (NCX1-3, plasma membrane Ca²⁺ ATPase), helps restore basal calcium levels [@synaptic].
Studies have shown that NCKX2 is involved in synaptic plasticity, including [long-term potentiation](/mechanisms/long-term-potentiation) (LTP), a cellular correlate of learning and memory. The efficient calcium clearance provided by NCKX2 helps shape the temporal dynamics of calcium signaling necessary for LTP induction [@nckxc].
NCKX2 is highly expressed in the olfactory bulb, where it plays a critical role in olfactory receptor neuron function. The exchanger helps maintain the low resting calcium levels necessary for proper olfactory signal transduction [@nckxd].
Excessive glutamate release can lead to calcium overload and excitotoxicity, a major contributor to neuronal death in stroke, traumatic brain injury, and neurodegenerative diseases. NCKX2's role in calcium extrusion makes it a potential modifier of excitotoxic damage [@excitotoxicity].
Calcium dysregulation is a well-established feature of Alzheimer's disease. [Amyloid-beta](/proteins/amyloid-beta) peptides disrupt calcium homeostasis, and reduced NCKX2 function could exacerbate this dysregulation. Studies have found altered expression of calcium handling proteins in Alzheimer's disease brains [@calciuma].
Calcium homeostasis is also disrupted in Parkinson's disease, particularly in dopaminergic neurons of the substantia nigra. While NCKX2 expression in these neurons is limited, the general importance of calcium handling in PD pathogenesis makes NCKX2 relevant to understanding disease mechanisms [@calciumb].
NCKX2 is expressed in retinal photoreceptors and bipolar cells, where calcium regulation is critical for phototransduction. Mutations in related NCKX proteins cause retinal degeneration, suggesting similar roles for NCKX2 [@nckxe].
NCKX2 represents a potential therapeutic target for conditions involving neuronal calcium dysregulation:
The following diagram shows the key molecular relationships involving SLC24A2 — Solute Carrier Family 2 Member 4A2 (SLC24A2) discovered through SciDEX knowledge graph analysis: