SLC44A4
Function
Choline transporter that plays a role in the choline-acetylcholine system and is required to the efferent innervation of hair cells in the olivocochlear bundle for the maintenance of physiological function of outer hair cells and the protection of hair cells from acoustic injury (By similarity) (PubMed:23651124, PubMed:28013291). Also described as a thiamine pyrophosphate transporter in colon, may mediate the absorption of microbiota-generated thiamine pyrophosphate and contribute to host thiamine (vitamin B1) homeostasis (PubMed:24379411, PubMed:26741288).
Isoform 3
Has also thiamine pyrophosphate transporter activity.
Involvement in disease
An interstitial deletion causing the fusion of exon 10 of CTL4 with the 3'-UTR of NEU has been detected in two patients affected by sialidosis.
Deafness, autosomal dominant, 72
DFNA72
A form of non-syndromic sensorineural hearing loss. Sensorineural deafness results from damage to the neural receptors of the inner ear, the nerve pathways to the brain, or the area of the brain that receives sound information. DFNA72 primarily affects the middle frequencies. It gradually progresses to whole-frequency hearing loss.
None
The disease is caused by variants affecting the gene represented in this entry.
Post-translational modifications
N-glycosylated; N-glycosylation of Asn-69, Asn-155 and Asn-393 is required for a proper thiamine pyrophosphate uptake.
Sequence Similarities
Belongs to the CTL (choline transporter-like) family.
Tissue Specificity
Highly expressed in colon, also detected in prostate, trachea and lung (PubMed:24379411). Isoform 3 is also expressed in colon but a lower levels (PubMed:24379411).
Isoform 3
Expressed in colon at low levels.
Cellular localization
- Membrane
- Multi-pass membrane protein
- Apical cell membrane
Alternative names
C6orf29, CTL4, NG22, TPPT1, UNQ441/PRO874, SLC44A4, Choline transporter-like protein 4, Solute carrier family 44 member 4, Thiamine pyrophosphate transporter 1, hTPPT1