The encoded protein is a high-affinity transporter specific to the intake of thiamine.[7][8] Thiamine transport is not inhibited by other organic cations nor affected by sodium ion concentration; it is stimulated by a proton gradient directed outward, with an optimal pH between 8.0 and 8.5.[9] TC1 is transported to the cell membrane by intracellular vesicles via microtubules.[10][11]
Clinical significance
Mutations in the SLC19A2 gene can cause thiamine-responsive megaloblastic anemia syndrome (TRMA), which is an autosomal recessive disease characterized by megaloblastic anemia, diabetes mellitus, and sensorineural deafness. Onset is typically between infancy and adolescence, but all of the cardinal findings are often not present initially. The anemia, and sometimes the diabetes, improves with high doses of thiamine. Other more variable features include optic atrophy, congenital heart defects, short stature, and stroke.[7][8]
↑Bay A, Keskin M, Hizli S, Uygun H, Dai A, Gumruk F (October 2010). "Thiamine-responsive megaloblastic anemia syndrome". International Journal of Hematology. 92 (3): 524–6. doi:10.1007/s12185-010-0681-y. PMID20835854.
↑ 9.09.1Dutta B, Huang W, Molero M, Kekuda R, Leibach FH, Devoe LD, Ganapathy V, Prasad PD (November 1999). "Cloning of the human thiamine transporter, a member of the folate transporter family". The Journal of Biological Chemistry. 274 (45): 31925–9. PMID10542220.
↑ 10.010.1Subramanian VS, Marchant JS, Parker I, Said HM (February 2003). "Cell biology of the human thiamine transporter-1 (hTHTR1). Intracellular trafficking and membrane targeting mechanisms". The Journal of Biological Chemistry. 278 (6): 3976–84. doi:10.1074/jbc.M210717200. PMID12454006.
↑ 11.011.1Online Mendelian Inheritance in Man, OMIM®. Johns Hopkins University, Baltimore, MD. MIM Number: {603941}: {11/22/2017}: . World Wide Web URL: https://omim.org/
↑Hoek KS, Schlegel NC, Eichhoff OM, Widmer DS, Praetorius C, Einarsson SO, Valgeirsdottir S, Bergsteinsdottir K, Schepsky A, Dummer R, Steingrimsson E (December 2008). "Novel MITF targets identified using a two-step DNA microarray strategy". Pigment Cell & Melanoma Research. 21 (6): 665–76. doi:10.1111/j.1755-148X.2008.00505.x. PMID19067971.
Scharfe C, Hauschild M, Klopstock T, Janssen AJ, Heidemann PH, Meitinger T, Jaksch M (September 2000). "A novel mutation in the thiamine responsive megaloblastic anaemia gene SLC19A2 in a patient with deficiency of respiratory chain complex I". Journal of Medical Genetics. 37 (9): 669–73. PMID10978358.
Guerrini I, Thomson AD, Cook CC, McQuillin A, Sharma V, Kopelman M, Reynolds G, Jauhar P, Harper C, Gurling HM (August 2005). "Direct genomic PCR sequencing of the high affinity thiamine transporter (SLC19A2) gene identifies three genetic variants in Wernicke Korsakoff syndrome (WKS)". American Journal of Medical Genetics. Part B, Neuropsychiatric Genetics. 137B (1): 17–9. doi:10.1002/ajmg.b.30194. PMID16015585.
Ashokkumar B, Vaziri ND, Said HM (October 2006). "Thiamin uptake by the human-derived renal epithelial (HEK-293) cells: cellular and molecular mechanisms". American Journal of Physiology. Renal Physiology. 291 (4): F796–805. doi:10.1152/ajprenal.00078.2006. PMID16705148.
Nabokina SM, Reidling JC, Said HM (September 2005). "Differentiation-dependent up-regulation of intestinal thiamin uptake: cellular and molecular mechanisms". The Journal of Biological Chemistry. 280 (38): 32676–82. doi:10.1074/jbc.M505243200. PMID16055442.
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Olsen BS, Hahnemann JM, Schwartz M, Østergaard E (August 2007). "Thiamine-responsive megaloblastic anaemia: a cause of syndromic diabetes in childhood". Pediatric Diabetes. 8 (4): 239–41. doi:10.1111/j.1399-5448.2007.00251.x. PMID17659067.
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