Choline transporter-like protein 2 (SLC44A2)
The protein contains 706 amino acids for an estimated molecular weight of 80124 Da.
Isoform 1, but not isoform 3, exhibits some choline transporter activity. (updated: Oct. 10, 2018)
Protein identification was indicated in the following studies:
- Hegedűs and co-workers. (2015) Inconsistencies in the red blood cell membrane proteome analysis: generation of a database for research and diagnostic applications. Database (Oxford) 1-8.
- Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
- D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
Methods
The following articles were analysed to gather the proteome content of erythrocytes.
The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.
| Publication | Identification 1 | Uniprot mapping 2 | Not mapped / Obsolete | TrEMBL | Swiss-Prot |
|---|---|---|---|---|---|
| Goodman (2013) | 2289 (gene list) | 2278 | 53 | 20599 | 2269 |
| Lange (2014) | 1234 | 1234 | 7 | 28 | 1224 |
| Hegedus (2015) | 2638 | 2622 | 0 | 235 | 2387 |
| Wilson (2016) | 1658 | 1528 | 170 | 291 | 1068 |
| d'Alessandro (2017) | 1826 | 1817 | 2 | 0 | 1815 |
| Bryk (2017) | 2090 | 2060 | 10 | 108 | 1942 |
| Chu (2018) | 1853 | 1804 | 55 | 362 | 1387 |
1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry
The compilation of older studies can be retrieved from the Red Blood Cell Collection database.
The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.
This protein is annotated as membranous in Gene Ontology, is predicted to be membranous by TOPCONS.
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| Variant | Description |
|---|---|
| dbSNP:rs2288904 |
No binding partner found
Biological Process
Choline transport
Neutrophil degranulation
Phosphatidylcholine biosynthetic process
Positive regulation of I-kappaB kinase/NF-kappaB signaling
Transmembrane transport
The reference OMIM entry for this protein is 606106
Solute carrier family 44, member 2; slc44a2
Choline transporter-like protein 2; ctl2
CLONING
Choline, a major constituent of cell membranes, participates in the synthesis of acetylcholine in cholinergic neurons. It is taken up with high affinity at cholinergic nerve terminals in a sodium-dependent manner. O'Regan et al. (2000) cloned CTL1, a suppressor for a yeast choline transport mutation, from a Torpedo electric lobe yeast expression library by functional complementation. By EST database searching and PCR on a sarcoma cell line, they obtained cDNAs encoding human CTL1 (606105), CTL2, and CTL4 (606107). The predicted 706-amino acid CTL2 protein is 43% and 67% homologous to human CTL1 and CTL4, respectively. The CTL proteins contain 10 transmembrane domains and 11 highly conserved cysteines, and they lack signal peptides.MAPPING
By STS analysis, O'Regan et al. (2000) mapped the CTL2 gene to chromosome 19p13.1.MOLECULAR GENETICS
Transfusion-related acute lung injury (TRALI) is a life-threatening complication of blood transfusion. Severe TRALI is often due to antibodies in blood components directed at human neutrophil alloantigen-3a (HNA3a). Using serologic, flow cytometric, and immunoprecipitation analyses of HNA3a-positive granulocytes together with plasma containing HNA3a-specific antibodies, Greinacher et al. (2010) identified an 80- to 100-kD protein that shifted to 64 kD after deglycosylation. Peptide analysis identified the protein as SLC44A2. Analysis of 54 individuals of known HNA3 phenotype revealed a 461A-G SNP (dbSNP rs2288904), resulting in either gln or arg at residue 154, that was fully concordant with HNA3 status. The 461G variant encodes arg154, or HNA3a phenotype, whereas the 461A variant encodes gln154, or HNA3b phenotype. The 461G variant was found in all 6 individuals who developed TRALI after transfusion of HNA3a-specific alloantibody-containing blood components. SNP array analysis suggested that approximately 95% of the European population is either homozygous or heterozygous for 461G and is therefore at risk for TRALI if transfused with anti-HNA3a-containing products. ... More on the omim web site
Feb. 23, 2019: Protein entry updated
Automatic update: model status changed
Oct. 19, 2018: Protein entry updated
Automatic update: OMIM entry 606106 was added.
Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).