Equilibrative nucleoside transporter 1

Function

Uniporter involved in the facilitative transport of nucleosides and nucleobases, and contributes to maintaining their cellular homeostasis. Functions as a Na(+)-independent transporter. Involved in the transport of nucleosides such as adenosine, guanosine, inosine, uridine, thymidine and cytidine. Also transports purine nucleobases (hypoxanthine, adenine, guanine) and pyrimidine nucleobases (thymine, uracil). Also mediates the uptake of nicotinamide; contributes to maintaining nicotinamide homeostasis but also regulated nicotinamide biological roles. Mediates basolateral nucleoside uptake into Sertoli cells, thereby regulating the transport of nucleosides in testis across the blood-testis barrier (By similarity). Regulates inosine levels in brown adipocytes tissues (BAT) and extracellular inosine levels, which controls BAT-dependent energy expenditure.

Classification

Family (Pfam)

PF01733 Nucleoside_tran

InterPro

ENT1/ENT2, Eqnu_transpt, MFS_trans_sf

Functional cluster

Membrane Transporters & GPCRs

Experimental structures · PDB · 3

• 6OB6 X-ray 2.90A
• 6OB7 X-ray 2.30A
• 8TZI X-ray 2.70A

A predicted model is available from AlphaFold.

Gene Ontology · 42

• GO:0016324 apical plasma membrane
• GO:0016323 basolateral plasma membrane
• GO:0016020 membrane
• GO:0005886 plasma membrane
• GO:0098794 postsynapse
• GO:0098793 presynapse
• GO:0015207 adenine transmembrane transporter activity
• GO:0015212 cytidine transmembrane transporter activity
• GO:0015208 guanine transmembrane transporter activity
• GO:0005326 neurotransmitter transmembrane transporter activity
• GO:0005337 nucleoside transmembrane transporter activity
• GO:0015211 purine nucleoside transmembrane transporter activity
• GO:0015389 pyrimidine- and adenosine-specific:sodium symporter activity
• GO:0015210 uracil transmembrane transporter activity
• GO:0015213 uridine transmembrane transporter activity
• GO:0015853 adenine transport
• GO:0032238 adenosine transport
• GO:0071333 cellular response to glucose stimulus
• GO:0071456 cellular response to hypoxia
• GO:0015861 cytidine transport
• GO:0060079 excitatory postsynaptic potential
• GO:1903716 guanine transmembrane transport
• GO:0035344 hypoxanthine transport
• GO:0035340 inosine transport
• GO:0007595 lactation
• GO:0006836 neurotransmitter transport
• GO:0001504 neurotransmitter uptake
• GO:0015851 nucleobase transport
• GO:0006139 nucleobase-containing compound metabolic process
• GO:1901642 nucleoside transmembrane transport
• GO:0015858 nucleoside transport
• GO:1904823 purine nucleobase transmembrane transport
• GO:0015860 purine nucleoside transmembrane transport
• GO:1904082 pyrimidine nucleobase transmembrane transport
• GO:0072531 pyrimidine-containing compound transmembrane transport
• GO:0046677 response to antibiotic
• GO:0035364 thymine transport
• GO:0150104 transport across blood-brain barrier
• GO:1903791 uracil transmembrane transport
• GO:0015862 uridine transmembrane transport
• GO:0006805 xenobiotic metabolic process
• GO:0006855 xenobiotic transmembrane transport

Drugs targeting this protein · 1

• DIPYRIDAMOLE inhibitor

Related proteins · sequence + function similarity

• Equilibrative nucleoside transporter 1 0.96
• Equilibrative nucleoside transporter 1 0.92
• Equilibrative nucleoside transporter 3 0.86
• Equilibrative nucleoside transporter 3 0.85
• Equilibrative nucleoside transporter 3 0.83
• Equilibrative nucleoside transporter 3 0.83
• Equilibrative nucleoside transporter 2 0.79
• Equilibrative nucleoside transporter 2 0.79
• Equilibrative nucleotide transporter 1 0.78
• Equilibrative nucleoside transporter 2 0.76
• Solute carrier family 52, riboflavin transporter, member 3-B 0.76
• Solute carrier family 52, riboflavin transporter, member 3-A 0.76

Co-cited proteins · studied together in the literature

• Equilibrative nucleoside transporter 2 5 shared papers
• Equilibrative nucleoside transporter 1 3 shared papers
• Equilibrative nucleoside transporter 1 2 shared papers
• Equilibrative nucleoside transporter 3 1 shared papers
• Equilibrative nucleoside transporter 2 1 shared papers
• Sodium/nucleoside cotransporter 1 1 shared papers
• Solute carrier family 28 member 3 1 shared papers
• Sodium/nucleoside cotransporter 2 1 shared papers
• Urea transporter 1 1 shared papers
• Aquaporin-1 1 shared papers
• Stomatin 1 shared papers
• Solute carrier family 2, facilitated glucose transporter member 1 1 shared papers

Literature · 28 cited papers

• SLC29A1 and SLC29A2 are human nicotinamide cell membrane transporters. Nat. Commun. · 2025
• Design of an equilibrative nucleoside transporter subtype 1 inhibitor for pain relief. Nat. Commun. · 2024
• Apoptotic brown adipocytes enhance energy expenditure via extracellular inosine. Nature · 2022
• Structures of human ENT1 in complex with adenosine reuptake inhibitors. Nat. Struct. Mol. Biol. · 2019
• Functional characterization of human equilibrative nucleoside transporter 1. Protein Cell · 2017
• The Role of Flexible Loops in Folding, Trafficking and Activity of Equilibrative Nucleoside Transporters. PLoS ONE · 2015
• N-terminome analysis of the human mitochondrial proteome. Proteomics · 2015
• Basolateral uptake of nucleosides by Sertoli cells is mediated primarily by equilibrative nucleoside transporter 1. J. Pharmacol. Exp. Ther. · 2013
• Stomatin interacts with GLUT1/SLC2A1, band 3/SLC4A1, and aquaporin-1 in human erythrocyte membrane domains. Biochim. Biophys. Acta · 2013
• Toward a comprehensive characterization of a human cancer cell phosphoproteome. J. Proteome Res. · 2013
• Nucleobase transport by human equilibrative nucleoside transporter 1 (hENT1). J. Biol. Chem. · 2011
• Mass-spectrometric identification and relative quantification of N-linked cell surface glycoproteins. Nat. Biotechnol. · 2009
• … and 16 more in the literature graph