The B vitamins folic acid and thiamine are transported across the cell membrane, particularly in the intestine, kidneys and placenta, using pH differences as driving forces. Topological modelling suggests the transporters have 12 TM domains.

Loss-of-function mutations in ThTr1 underlie thiamine-responsive megaloblastic anemia syndrome [2].

Ganapathy, V; Smith, SB; Prasad, PD. (2004) SLC19: the folate/thiamine transporter family. Pflugers Arch., 447 (5): 641-6. [PMID:14770311]

Yuasa, H; Inoue, K; Hayashi, Y. (2009) Molecular and functional characteristics of proton-coupled folate transporter. J Pharm Sci, 98 (5): 1608-16. [PMID:18823045]

1. Assaraf, YG; Babani, S; Goldman, ID. (1998) Increased activity of a novel low pH folate transporter associated with lipophilic antifolate resistance in chinese hamster ovary cells. J. Biol. Chem., 273 (14): 8106-11. [PMID:9525913]

2. Diaz, GA; Banikazemi, M; Oishi, K; Desnick, RJ; Gelb, BD. (1999) Mutations in a new gene encoding a thiamine transporter cause thiamine-responsive megaloblastic anaemia syndrome. Nat. Genet., 22 (3): 309-12. [PMID:10391223]

3. Dutta, B; Huang, W; Molero, M; Kekuda, R; Leibach, FH; Devoe, LD; Ganapathy, V; Prasad, PD. (1999) Cloning of the human thiamine transporter, a member of the folate transporter family. J. Biol. Chem., 274 (45): 31925-9. [PMID:10542220]

4. Prasad, PD; Ramamoorthy, S; Leibach, FH; Ganapathy, V. (1995) Molecular cloning of the human placental folate transporter. Biochem. Biophys. Res. Commun., 206 (2): 681-7. [PMID:7826387]

5. Rajgopal, A; Edmondnson, A; Goldman, ID; Zhao, R. (2001) SLC19A3 encodes a second thiamine transporter ThTr2. Biochim. Biophys. Acta, 1537 (3): 175-8. [PMID:11731220]

6. Zhao, R; Gao, F; Goldman, ID. (2002) Reduced folate carrier transports thiamine monophosphate: an alternative route for thiamine delivery into mammalian cells. Am. J. Physiol., Cell Physiol., 282 (6): C1512-7. [PMID:11997266]