NUCLEOSIDE TRANSPORTERS: CNTs AND ENTs - Drug Transporters: Molecular Characterization and Role in Drug Disposition - page 174

TABLE 8.1. Molecular and Functional Characteristics of Human Nucleoside Transporters
Molecular

Transporter Features Substrates Transport Mode Cellular Location Tissue Distribution

CNT family
hCNT1

Gene name:
SLC28A1
Gene locus:
15q25-26
Protein length:
649 a.a.
TMs predicted:
13 TMs

Nucleosides:
uridine, thymidine,
cytidine, adenosine
Nucleoside analogs:
gemcitabine, cytarabine,
5 -deoxy-5-fluorouridine,
2 -deoxycytidine, ddC,
3TC, AZT

Concentrative
Na + -nucleoside
cotransporter
1Na + : 1 nucleoside

Plasma membrane
Apical membrane

Liver, kidney,
intestine, brain

Concentrative
Na + -nucleoside
cotransporter
1Na + : 1 nucleoside

hCNT2
(hSPNT1)

Gene name:
SLC28A2
Gene locus:
15q15
Protein length:
658 a.a.
TMs predicted:
13 TMs

Nucleosides:
adenosine, guanosine,
inosine, uridine
Nucleoside analogs:
ribavirin
clofarabine
5-fluorouridine

Plasma membrane
Apical localization
in kidney and
intestine cells

Kidney, heart, liver,
skeletal muscle,
pancreas, placenta,
brain, cervix, prostate,
small intestine,
rectum, colon, lung

hCNT3 Gene name:

SLC28A3
Gene locus:
9q22.2
Protein length:
691 a.a.
TMs predicted:
13 TMs

Nucleosides:
adenosine, guanosine, inosine,
uridine, thymidine, cytidine
Nucleoside analogs:
5-fluorouridine,
5-fluoro-2 -deoxyuridine,
clofarabine, fludarabine,
zebularine, cladribine,

Concentrative
Na + -nucleoside
cotransporter
2Na + : 1 nucleoside

Plasma membrane Mammary gland,

pancreas, bone
marrow, trachea,
intestine, liver, lung,
placenta, prostate,
testis, brain, heart