Transport of folate compounds into mammalian cells can occur via receptor-mediated (see folate receptor 1) or carrier-mediated mechanisms. A functional coordination between these 2 mechanisms has been proposed to be the method of folate uptake in certain cell types. Methotrexate (MTX) is an antifolate chemotherapeutic agent that is actively transported by the carrier-mediated uptake system. RFC1 plays a role in maintaining intracellular concentrations of folate.[6] SLC19A1 has also been shown to transport the immune second messenger 2'3'-cGAMP.[7]
Individuals carrying a specific polymorphism of SLC19A1 (c.80GG) have lower levels of folate.[8] Other studies have also shown that individuals carrying the c.80AA polymorphism who are treated with methotrexate have higher levels of this anti-folate chemotherapeutic agent. Personalized dosing of the drug depending on the patient's genotype may therefore be required.
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Lapenta V, Sossi V, Gosset P, Vayssettes C, Vitali T, Rabatel N, Tassone F, Blouin JL, Scott HS, Antonarakis SE, Créau N, Brahe C (April 1998). "Construction of a 2.5-Mb integrated physical and gene map of distal 21q22.3". Genomics. 49 (1): 1–13. doi:10.1006/geno.1997.5185. PMID9570943.
Matherly LH, Hou Z, Deng Y (March 2007). "Human reduced folate carrier: translation of basic biology to cancer etiology and therapy". Cancer and Metastasis Reviews. 26 (1): 111–28. doi:10.1007/s10555-007-9046-2. PMID17334909. S2CID26489607.
Moscow JA, Gong M, He R, Sgagias MK, Dixon KH, Anzick SL, Meltzer PS, Cowan KH (September 1995). "Isolation of a gene encoding a human reduced folate carrier (RFC1) and analysis of its expression in transport-deficient, methotrexate-resistant human breast cancer cells". Cancer Research. 55 (17): 3790–4. PMID7641195.
Prasad PD, Ramamoorthy S, Leibach FH, Ganapathy V (January 1995). "Molecular cloning of the human placental folate transporter". Biochemical and Biophysical Research Communications. 206 (2): 681–7. doi:10.1006/bbrc.1995.1096. PMID7826387.
Nguyen TT, Dyer DL, Dunning DD, Rubin SA, Grant KE, Said HM (March 1997). "Human intestinal folate transport: cloning, expression, and distribution of complementary RNA". Gastroenterology. 112 (3): 783–91. doi:10.1053/gast.1997.v112.pm9041240. PMID9041240.
Lapenta V, Sossi V, Gosset P, Vayssettes C, Vitali T, Rabatel N, Tassone F, Blouin JL, Scott HS, Antonarakis SE, Créau N, Brahe C (April 1998). "Construction of a 2.5-Mb integrated physical and gene map of distal 21q22.3". Genomics. 49 (1): 1–13. doi:10.1006/geno.1997.5185. PMID9570943.
Zhang L, Wong SC, Matherly LH (November 1998). "Structure and organization of the human reduced folate carrier gene". Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression. 1442 (2–3): 389–93. doi:10.1016/s0167-4781(98)00168-7. PMID9804996.
Hattori M, Fujiyama A, Taylor TD, Watanabe H, Yada T, Park HS, Toyoda A, Ishii K, Totoki Y, Choi DK, Groner Y, Soeda E, Ohki M, Takagi T, Sakaki Y, Taudien S, Blechschmidt K, Polley A, Menzel U, Delabar J, Kumpf K, Lehmann R, Patterson D, Reichwald K, Rump A, Schillhabel M, Schudy A, Zimmermann W, Rosenthal A, Kudoh J, Schibuya K, Kawasaki K, Asakawa S, Shintani A, Sasaki T, Nagamine K, Mitsuyama S, Antonarakis SE, Minoshima S, Shimizu N, Nordsiek G, Hornischer K, Brant P, Scharfe M, Schon O, Desario A, Reichelt J, Kauer G, Blocker H, Ramser J, Beck A, Klages S, Hennig S, Riesselmann L, Dagand E, Haaf T, Wehrmeyer S, Borzym K, Gardiner K, Nizetic D, Francis F, Lehrach H, Reinhardt R, Yaspo ML (May 2000). "The DNA sequence of human chromosome 21". Nature. 405 (6784): 311–9. Bibcode:2000Natur.405..311H. doi:10.1038/35012518. PMID10830953.
Whetstine JR, Gifford AJ, Witt T, Liu XY, Flatley RM, Norris M, Haber M, Taub JW, Ravindranath Y, Matherly LH (November 2001). "Single nucleotide polymorphisms in the human reduced folate carrier: characterization of a high-frequency G/A variant at position 80 and transport properties of the His(27) and Arg(27) carriers". Clinical Cancer Research. 7 (11): 3416–22. PMID11705857.
Liu XY, Matherly LH (August 2002). "Analysis of membrane topology of the human reduced folate carrier protein by hemagglutinin epitope insertion and scanning glycosylation insertion mutagenesis". Biochimica et Biophysica Acta (BBA) - Biomembranes. 1564 (2): 333–42. doi:10.1016/S0005-2736(02)00467-4. PMID12175915.