SLC44A2: Solute Carrier Family 44 Member 2
A choline transporter involved in platelet antigenicity and hearing loss
Gene Information Card
| Symbol | SLC44A2 |
|---|---|
| Full Name | Solute Carrier Family 44 Member 2 |
| Gene Type | Protein coding |
| Chromosomal Location | 19p13.2 |
| NCBI Gene ID | 57153 ncbi.nlm.nih.gov/gene/57153 |
| Ensembl ID | ENSG00000105374 |
| UniProt ID | Q8IWA5 |
| OMIM ID | 606105 |
| HGNC ID | 10971 |
| Aliases | CTL2, HNA-3, PP1044, DKFZp686H17246 |
Description
SLC44A2 (solute carrier family 44 member 2) encodes a choline transporter protein (CTL2) that mediates high-affinity choline uptake in various tissues, including the inner ear and platelets. The gene is best known for harboring the HNA-3 (human neutrophil antigen-3) system, which is implicated in transfusion-related acute lung injury (TRALI). Mutations in SLC44A2 cause autosomal dominant nonsyndromic hearing loss (DFNA65).
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Deafness, autosomal dominant 65 (DFNA65) | Missense mutations (e.g., p.Gly117Arg) disrupt choline transport in cochlear hair cells, leading to progressive sensorineural hearing loss. | OMIM #616211; ClinVar |
| Transfusion-related acute lung injury (TRALI) | Anti-HNA-3a antibodies (directed against the SLC44A2-encoded antigen) activate neutrophils and pulmonary endothelium, causing capillary leak. | NCBI Gene; PubMed PMID: 20032506 |
| Platelet antigen HNA-3 incompatibility | Polymorphism rs2288904 (p.Arg154Gln) defines the HNA-3a/3b system; alloimmunization can cause neonatal alloimmune thrombocytopenia. | OMIM #606105; HGNC |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Lung | 15.2 | Medium |
| Inner ear (cochlea) | 12.8 | Medium |
| Spleen | 10.5 | Medium |
| Whole blood | 8.3 | Low |
| Brain (cerebellum) | 6.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 18.4 | High expression |
| K562 (leukemia) | 12.1 | Medium expression |
| HepG2 (liver) | 9.7 | Medium expression |
| SH-SY5Y (neuroblastoma) | 7.3 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.349G>A (p.Gly117Arg) | Missense | Rare | Dominant; causes DFNA65 hearing loss |
| c.461G>A (p.Arg154Gln) | Missense | Common (MAF ~0.05) | Defines HNA-3a/3b; risk factor for TRALI |
| c.1285C>T (p.Arg429*) | Nonsense | Very rare | Loss of function; associated with hearing loss |
Mutation functional classification
Loss of Function (LOF)
Nonsense mutations (e.g., p.Arg429*) lead to truncated protein and reduced choline transport.
Gain of Function (GOF)
Not described for SLC44A2.
Dominant Negative (DN)
p.Gly117Arg is proposed to exert a dominant-negative effect on the multimeric transporter complex.
View complete mutation data：
Gene Ontology (GO)
| • choline transmembrane transporter activity (GO:0015220) | • choline transport (GO:0015871) |
| • integral component of membrane (GO:0016021) | • plasma membrane (GO:0005886) |
| • sensory perception of sound (GO:0007605) |
Pathways
• Choline transport (Reactome: R-HSA-429593)
• Phospholipid metabolism (KEGG: map00564)
Protein Summary
SLC44A2 encodes a 657-amino acid multi-pass transmembrane protein (CTL2) that functions as a high-affinity choline transporter. The protein is expressed on the plasma membrane of various cell types, including platelets, neutrophils, and cochlear hair cells. It contains 10 predicted transmembrane domains and a large extracellular loop that harbors the HNA-3 antigenic site. Choline transport by CTL2 is essential for phospholipid synthesis and membrane integrity in auditory cells.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SLC44A2 Knockout HEK293 Cell Line | EDJ-KQ2487 | Human | 57153 | Details Get a Quote |
| SLC44A2 Knockout A-549 Cell Line | EDJ-KQ23071 | Human | 57153 | Details Get a Quote |
| SLC44A2 Knockout HCT 116 Cell Line | EDJ-KQ23072 | Human | 57153 | Details Get a Quote |
| SLC44A2 Knockout HeLa Cell Line | EDJ-KQ23073 | Human | 57153 | Details Get a Quote |
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