Localized cytosolic alkalization and its functional impact in ciliary cells

Liubov Lemberskiy-Kuzin, Michal Fainshtein, Polina Fridman, Elena Passwell, Alex Braiman, Zvi Priel

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Using confocal microscopy we demonstrate that ciliary cells from airway epithelium maintain two qualitatively distinct cytosolic regions in terms of pH regulation. While the bulk of the cytosol is stringently buffered and is virtually insensitive to changes in extracellular pH (pHo), the values of cytosolic pH in the vicinity of the ciliary membrane is largely determined by pHo. Variation of pHo from 6.2 up to 8.5 failed to affect ciliary beat frequency (CBF). Application of NH4Cl induced profound localized alkalization near cilia, which did not depress ciliary activity, but resulted in strong and prolonged enhancement of CBF. Calmodulin and protein kinase A (PKA) functionality was essential for the alkalization-induced CBF enhancement. We suggest that the ability of airway epithelium to sustain unusually strong but localized cytosolic alkalization near cilia facilitates CBF enhancement through altering the binding constants of Ca2+ to calmodulin and promotion of Ca2+-calmodulin complex formation. The NH4Cl-induced elevations in cytosolic pH and Ca2+ concentration act synergistically to activate calmodulin-dependent processes, cAMP pathway, and, thereby, stimulate CBF.

Original languageEnglish
Pages (from-to)1102-1110
Number of pages9
JournalBiochimica et Biophysica Acta - Molecular Cell Research
Volume1783
Issue number6
DOIs
StatePublished - 1 Jun 2008

Keywords

  • Acid-base balance
  • Airway epithelium
  • Ammonia
  • Ciliary beating
  • Cytosolic gradient
  • Mucociliary

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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