Equilibrative nucleoside transporter 1 (ENT1) is a protein that in humans is encoded by the SLC29A1gene.[5][6] Multiple alternatively spliced variants, encoding the same protein, have been found for this gene.[7] Expressed on red blood cell surfaces, these variants make up the Augustine blood group system.[8]
This gene is a member of the equilibrative nucleoside transporter family. The gene encodes a transmembrane glycoprotein that localizes to the plasma and mitochondrial membranes and mediates the cellular uptake of nucleosides from the surrounding medium. The protein is categorized as an equilibrative (as opposed to concentrative) transporter that is sensitive to inhibition by nitrobenzylmercaptopurine ribonucleoside (NBMPR). Nucleoside transporters are required for nucleotide synthesis in cells that lack de novo nucleoside synthesis pathways, and are also necessary for the uptake of cytotoxic nucleosides used for cancer and viral chemotherapies.[7]
The gene encoding this protein is located on the short arm of chromosome 6 at 6p21.2-p21.1 on the Watson (plus) strand. It is 14,647 bases in length. The encoded protein has 456 amino acid residues with 11 predicted transmembrane domains. The predicted molecular weight is 50.219 kilodaltons. The protein is post translationally glycosylated and expressed in all tissue with the apparent exception of skeletal muscle. The highest levels are found in the liver, heart, testis, spleen, lung, kidney and brain.
^"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.
^Griffiths M, Beaumont N, Yao SY, Sundaram M, Boumah CE, Davies A, et al. (January 1997). "Cloning of a human nucleoside transporter implicated in the cellular uptake of adenosine and chemotherapeutic drugs". Nature Medicine. 3 (1): 89–93. doi:10.1038/nm0197-89. PMID8986748. S2CID10182379.
^Coe IR, Griffiths M, Young JD, Baldwin SA, Cass CE (October 1997). "Assignment of the human equilibrative nucleoside transporter (hENT1) to 6p21.1-p21.2". Genomics. 45 (2): 459–60. doi:10.1006/geno.1997.4928. PMID9344680.
SenGupta DJ, Lum PY, Lai Y, Shubochkina E, Bakken AH, Schneider G, Unadkat JD (February 2002). "A single glycine mutation in the equilibrative nucleoside transporter gene, hENT1, alters nucleoside transport activity and sensitivity to nitrobenzylthioinosine". Biochemistry. 41 (5): 1512–9. doi:10.1021/bi015833w. PMID11814344.
Galmarini CM, Thomas X, Calvo F, Rousselot P, El Jafaari A, Cros E, Dumontet C (July 2002). "Potential mechanisms of resistance to cytarabine in AML patients". Leukemia Research. 26 (7): 621–9. doi:10.1016/S0145-2126(01)00184-9. PMID12008078.
Reiman T, Clarke ML, Dabbagh L, Vsianska M, Coupland RW, Belch AR, et al. (July 2002). "Differential expression of human equilibrative nucleoside transporter 1 (hENT1) protein in the Reed-Sternberg cells of Hodgkin's disease". Leukemia & Lymphoma. 43 (7): 1435–40. doi:10.1080/1042819022386725. PMID12389626. S2CID24497772.
Mangravite LM, Xiao G, Giacomini KM (May 2003). "Localization of human equilibrative nucleoside transporters, hENT1 and hENT2, in renal epithelial cells". American Journal of Physiology. Renal Physiology. 284 (5): F902-10. doi:10.1152/ajprenal.00215.2002. PMID12527552.
Szkotak AJ, Ng AM, Man SF, Baldwin SA, Cass CE, Young JD, Duszyk M (April 2003). "Coupling of CFTR-mediated anion secretion to nucleoside transporters and adenosine homeostasis in Calu-3 cells". The Journal of Membrane Biology. 192 (3): 169–79. doi:10.1007/s00232-002-1073-x. PMID12820662. S2CID23060872.
Lehner B, Semple JI, Brown SE, Counsell D, Campbell RD, Sanderson CM (January 2004). "Analysis of a high-throughput yeast two-hybrid system and its use to predict the function of intracellular proteins encoded within the human MHC class III region". Genomics. 83 (1): 153–67. doi:10.1016/S0888-7543(03)00235-0. PMID14667819.
