Regulation of the high-affinity H+/peptide cotransporter in renal LLC-PK1 cells

J Cell Physiol. 1999 Mar;178(3):341-8. doi: 10.1002/(SICI)1097-4652(199903)178:3<341::AID-JCP8>3.0.CO;2-H.


Di- and tripeptides and peptide mimetics such as beta-lactam antibiotics are efficiently reabsorbed from the tubular lumen by a high-affinity peptide transporter. We have recently identified and characterized this H+-coupled high-affinity peptide transport system in the porcine proximal tubular cell line LLC-PK1. Here we describe for the first time the regulation of the renal high-affinity peptide cotransporter at the cellular level. Uptake of 5 microM 3H-D-Phe-L-Ala into LLC-PK1 cells was significantly increased by lowering [Ca2+]in and decreased by increasing [Ca2+] in. Moreover, it was shown that the [Ca2+]in effects on peptide transport activity were dependent on Ca2+ entry from the extracellular site (e.g., via a store-regulated capacitative Ca2+ influx). Protein kinase C (PKC) was found to transmit the effects of [Ca2+]in on peptide transport. Although we demonstrate by pHin measurements that the PKC inhibitor staurosporine did decrease the transmembrane H+ gradient and consequently should have reduced the driving force for peptide uptake, the only effect on transport kinetics of 3H-D-Phe-L-Ala observed was a significant decrease in Km from 22.7+/-2.5 microM to 10.2+/-1.9 microM with no change in maximal velocity.

MeSH terms

  • Animals
  • Biological Transport
  • Calcium / metabolism*
  • Carrier Proteins / metabolism*
  • Cell Survival
  • Dipeptides / metabolism*
  • Enzyme Inhibitors / pharmacology
  • Hydrogen-Ion Concentration
  • Imidazoles / pharmacology
  • Kidney Tubules, Proximal / metabolism*
  • Kinetics
  • LLC-PK1 Cells
  • Protein Kinase C / metabolism
  • Signal Transduction / drug effects
  • Signal Transduction / physiology
  • Staurosporine / pharmacology
  • Stereoisomerism
  • Sulfonamides / pharmacology
  • Swine
  • Symporters*
  • Tetradecanoylphorbol Acetate / pharmacology
  • Trifluoperazine / pharmacology


  • Carrier Proteins
  • Dipeptides
  • Enzyme Inhibitors
  • Imidazoles
  • Sulfonamides
  • Symporters
  • hydrogen-coupled oligopeptide transporter PepT2
  • Trifluoperazine
  • phenylalanylalanine
  • calmidazolium
  • W 7
  • Protein Kinase C
  • Staurosporine
  • Tetradecanoylphorbol Acetate
  • Calcium