Solute transporter for tetraethylammonium (TEA), 1-methyl-4-phenylpyridinium (MPP), cimetidine, N-methylnicotinamide, metformin, creatinine, guanidine, procainamide, topotecan, estrone sulfate, acyclovir, and ganciclovir. Responsible for the secretion of cationic drugs across the brush border membranes. Optimum pH is 6.0. Predominantly found in the apical membrane of RPT cells. Expressed in renal cortical tissues. Belongs to the multi antimicrobial extrusion (MATE) (TC 2.A.66.1) family. It is uncertain whether Met-1 or Met-30 is the initiator.