CNT1 - Concentrative Nucleoside Transporter 1 - SLC28A1
Concentrative Nucleoside Transporter (CNT) family
Subgroups and Members:
The 7 known human nucleosides transporters (hNTs) exhibit varying permeant selectivities and are found into 2 protein families: the solute carrier (SLC) 29 (SLC29A1, SLC29A2, SLC29A3, SLC29A4) and SLC28 (SLC28A1, SLC28A2, SLC28A3) proteins, otherwise known, respectively, as the human equilibrative NTs (hENTs, hENT1, hENT2, hENT3, hENT4) and human concentrative NTs (hCNTs, hCNT1, hCNT2, hCNT3).
Sequenced members of the CNT family are derived from Gram-negative and Gram-positive bacteria as well as yeast and animals. They are of about 400 residues (bacterial) or about 600-700 residues (eukaryotes) with 10-14 transmembrane α-helical spanners.
Nucleoside transporters are a group of membrane transport proteins which transport nucleoside substrates like adenosine across the membranes of cells and/or vesicles
CNT1 Background Information
CNT1, also called Sodium/nucleoside cotransporter 1 or concentrative Nucleoside Transporter 1, is a sodium-dependent and pyrimidine-preferring transporter which transports as well adenosine. It is localized primarily in epithelia and plays a major role in the uptake of pyrimidines, including uridine and cytidine from the extracellular milieu into the cytoplasm in nucleoside salvage pathways which is the first step of nucleoside biosynthesis.
Kidney, intestine, liver, localized in epithelial cells
Transport of nucleosides and free purine and pyrimidine bases across the plasma membrane
Uridine-cytidineuria (URCTU) is caused by a mutation of the CNT1 gene. An autosomal recessive inborn error of metabolism characterized by increased urinary uridine and cytidine excretion. It is a likely benign metabolic trait without clinical manifestations. CNT1 may be involved in the intestinal absorption and renal handling of pyrimidine nucleoside analogs used to treat acquired immunodeficiency syndrome (AIDS)
& SSM-based Electropyhsiology (SURFE²R instrument family)
- Attachement of CNT1-containing membrane fragments to the sensor
- Perfusion with a buffer containing NaCl and uridine
- Flushing of the sensor with KCl buffer before and after activation of CNT1
- Application of modulators
Reviews and Links
- Gray et al., (2004) The Concentrative Nucleoside Transporter Family, SLC28. Pflugers Arch 447(5):728-34. doi: 10.1007/s00424-003-1107-y.