Antimicrobial and immunostimulatory peptide, KLK, induces an increase in cytosolic Ca2+ concentration by mobilizing Ca2+ from intracellular stores

Julian Weghuber, Anna M. Lipp, Jacqueline Stadlbauer, Michael C. Aichinger, Verena Ruprecht, Alois Sonnleitner, Gerhard J. Schütz, Tamás Henics

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


The cationic antimicrobial immunomodulatory peptide, KLK (KLKL5KLK), exerts profound membrane interacting properties, impacting on ultrastructure and fluidity. KLK-membrane interactions that lead to these alterations require the ability of the peptide to move into an a-helical conformation. We show that KLK induces an increase of the intracellular Ca2+ concentration in human T24 cells. The effect of KLK is buffer-sensitive, as it is detected when HBSS buffer is used, but not with PBS. This, together with the lack of effect of the middle leucine-to-proline-substituted peptide derivative [KPK (KLKLLPLLKLK)], indicates that it is the conformational propensity rather than the net positive charge that contributes to the effect of KLK on intracellular Ca2+ level of T24 cells. We show that, although KLK slightly stimulates Ca2+ influx into the cell, the bulk increase of Ca2+ levels is due to KLK-induced depletion of intracellular Ca2+ stores. Finally, we demonstrate a KLK- induced switch of PS (phosphatidylserine) from the inner to the outer plasma membrane leaflet that contributes to the onset of early apoptotic changes in these cells.

Original languageEnglish
Pages (from-to)1109-1112
Number of pages4
JournalCell Biology International
Issue number11
Publication statusPublished - Nov 2010


  • Apoptosis
  • Ca
  • Influx
  • KLK
  • Store depletion
  • Humans
  • Cells, Cultured
  • Phosphatidylserines/metabolism
  • Calcium/metabolism
  • Microscopy, Confocal
  • Antimicrobial Cationic Peptides/pharmacology
  • Adjuvants, Immunologic/pharmacology
  • Cell Membrane/metabolism
  • Oligopeptides/pharmacology
  • Cytosol/metabolism

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