Protein kinase C modulates synaptic vesicle acidification in a ribbon type nerve terminal in the retina

Bento J. Abreu, Maila Guimarães, Livia C. Uliana, Jozsef Vigh, Henrique Von Gersdorff, Marco A. Prado, Cristina Guatimosim

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

The driving force for neurotransmitter accumulation into synaptic vesicles is provided by the generation of a transmembrane electrochemical gradient (ΔμH+) that has two components: a chemical gradient (ΔpH, inside acidic) and an electrical potential across the vesicular membrane (ΔΨ, inside positive). This gradient is generated in situ by the electrogenic vacuolar H+-ATPase, which is responsible for the acidification and positive membrane potential of the vesicle lumen. Here, we investigate the modulation of vesicle acidification by using the acidic-organelle probe LysoTracker and the pH-sensitive probe LysoSensor at goldfish Mb-type bipolar cell terminals. Since phosphorylation can modulate secretory granule acidification in neuroendocrine cells, we investigated if drugs that affect protein kinases modulate LysoTracker staining of bipolar cell terminals. We find that protein kinase C (PKC) activation induces an increase in LysoTracker-fluorescence. By contrast, protein kinase A (PKA) or calcium/calmodulin kinase II (CaMKII) activation or inhibition did not change LysoTracker-fluorescence. Using a pH-dependent fluorescent dye (LysoSensor) we show that the PKC activation with PMA induces an increase in LysoSensor-fluorescence, whereas the inactive analog 4alpha-PMA was unable to cause the same effect. This increase induced by PMA was blocked by PKC inhibitors, calphostin C and staurosporine. These results suggest that phosphorylation by PKC may increase synaptic vesicle acidification in retinal bipolar cells and therefore has the potential to modulate glutamate concentrations inside synaptic vesicles.

Original languageEnglish (US)
Pages (from-to)155-164
Number of pages10
JournalNeurochemistry International
Volume53
Issue number5
DOIs
StatePublished - Nov 2008

Fingerprint

Synaptic Vesicles
Protein Kinase C
Retina
Fluorescence
Retinal Bipolar Cells
Phosphorylation
Vacuolar Proton-Translocating ATPases
Neuroendocrine Cells
Calcium-Calmodulin-Dependent Protein Kinases
Goldfish
Proton-Motive Force
Staurosporine
Protein C Inhibitor
Secretory Vesicles
Protein Kinase Inhibitors
Cyclic AMP-Dependent Protein Kinases
Fluorescent Dyes
Organelles
Membrane Potentials
Protein Kinases

Keywords

  • Acidification
  • Bipolar cell
  • Confocal microscopy
  • PKC
  • Retina
  • Synaptic vesicle

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology
  • Cellular and Molecular Neuroscience

Cite this

Protein kinase C modulates synaptic vesicle acidification in a ribbon type nerve terminal in the retina. / Abreu, Bento J.; Guimarães, Maila; Uliana, Livia C.; Vigh, Jozsef; Von Gersdorff, Henrique; Prado, Marco A.; Guatimosim, Cristina.

In: Neurochemistry International, Vol. 53, No. 5, 11.2008, p. 155-164.

Research output: Contribution to journalArticle

Abreu, Bento J. ; Guimarães, Maila ; Uliana, Livia C. ; Vigh, Jozsef ; Von Gersdorff, Henrique ; Prado, Marco A. ; Guatimosim, Cristina. / Protein kinase C modulates synaptic vesicle acidification in a ribbon type nerve terminal in the retina. In: Neurochemistry International. 2008 ; Vol. 53, No. 5. pp. 155-164.
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