Substrate specificity of MATE1 and MATE2-K, human multidrug and toxin extrusions/H(+)-organic cation antiporters

Biochem Pharmacol. 2007 Jul 15;74(2):359-71. doi: 10.1016/j.bcp.2007.04.010. Epub 2007 Apr 13.


The substrate specificities of human (h) multidrug and toxin extrusion (MATE) 1 and hMATE2-K were examined to find functional differences between these two transporters by the transfection of the cDNA of hMATE1 and hMATE2-K into HEK293 cells. Western blotting revealed specific signals for hMATE1 and hMATE2-K consistent with a size of 50 and 40kDa, respectively, in the transfectants as well as human renal brush-border membranes under reducing conditions. In the presence of oppositely directed H(+)-gradient, the transport activities of various compounds such as tetraethylammonium, 1-methyl-4-phenylpyridinium, cimetidine, metformin, creatinine, guanidine, procainamide, and topotecan were stimulated in hMATE1- and hMATE2-K-expressing cells. In addition to cationic compounds, anionic estrone sulfate, acyclovir, and ganciclovir were also recognized as substrates of these transporters. Kinetic analyses demonstrated the Michaelis-Menten constants for the hMATE1-mediated transport of tetraethylammonium, 1-methyl-4-phenylpyridinium, cimetidine, metformin, guanidine, procainamide, topotecan, estrone sulfate, acycrovir, and ganciclovir to be (in mM) 0.38, 0.10, 0.17, 0.78, 2.10, 1.23, 0.07, 0.47, 2.64, and 5.12, respectively. Those for hMATE2-K were 0.76, 0.11, 0.12, 1.98, 4.20, 1.58, 0.06, 0.85, 4.32, and 4.28, respectively. Although their affinity for hMATE1 and hMATE2-K was similar, the zwitterionic cephalexin and cephradine were revealed to be specific substrates of hMATE1, but not of hMATE2-K. Levofloxacin and ciprofloxacin were not transported, but were demonstrated to be potent inhibitors of these transporters. These results suggest that hMATE1 and hMATE2-K function together as a detoxication system, by mediating the tubular secretion of intracellular ionic compounds across the brush-border membranes of the kidney.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cells, Cultured
  • Cephalexin / metabolism
  • Humans
  • Kidney / metabolism*
  • Organic Cation Transport Proteins / physiology*
  • Protons
  • Substrate Specificity
  • Tetraethylammonium Compounds / metabolism
  • Toxins, Biological / metabolism*


  • Organic Cation Transport Proteins
  • Protons
  • SLC47A1 protein, human
  • SLC47A2 protein, human
  • Tetraethylammonium Compounds
  • Toxins, Biological
  • Cephalexin