Monocarboxylate transporter MCT14 is a member of the solute carrier family Slc16. It was shown that MCT14 mRNA is mostly expressed in kidney but so far the localization, transport properties and regulation of MCT14 are poorly understood. The aim of this work was to characterize the localization of MCT14 in murine kidney. To this end an antibody was raised against a peptide located at the extracellular side of MCT14 and its specifity was confirmed by peptide protection.

Immunostaining of perfusion fixed mouse kidneys showed colocalization of MCT14 protein with uromodulin (Tamm-Horsefall protein) and the Na-K-Cl cotransporter (NKCC2), which are exclusively expressed in epithelial cells of the the thick ascending limb of loop of Henle (TAL). Moreover, in TAL cells, MCT14 was only detected at the luminal (apical) side.

Previous data suggested that MCT14 mRNA is modulated by dietary phosphate. Western blot analysis performed with total kidney homogenates revealed that the abundance of MCT14 protein is also influenced by diets containing different amounts of phosphate. Compared to low phosphate diet condition, the amount of MCT14 was slightly increased after high phosphate diet. No effect on the renal localization of MCT14 by dietary phosphate was observed.