Send to

Choose Destination
See comment in PubMed Commons below
J Biol Chem. 2007 Dec 28;282(52):37730-7. Epub 2007 Oct 24.

Fertilization and nicotinic acid adenine dinucleotide phosphate induce pH changes in acidic Ca(2+) stores in sea urchin eggs.

Author information

  • 1Department of Pharmacology, University of Oxford, Oxford, UK.


The second messenger nicotinic acid adenine dinucleotide phosphate (NAADP) releases Ca(2+) from the acidic Ca(2+) stores of many organisms, including those of the sea urchin egg. We investigated whether the pH within the lumen of these acidic organelles changes in response to stimuli. Fertilization activates the egg by Ca(2+) release dependent upon NAADP, and accordingly, we report that fertilization also alters organellar pH in a spatio-temporally complex manner. Upon sperm fusion, vesicles deep in the egg center slowly acidify, whereas cortical vesicles undergo a rapid alkalinization. The cortical vesicle alkalinization is independent of exocytosis and cytosolic pH but coincides with the NAADP-dependent fertilization Ca(2+) wave. Microinjection of NAADP mimicked the fertilization cortical response, suggesting that it occurred within NAADP-sensitive acidic Ca(2+) stores. Our data show that NAADP and physiological stimuli alter the pH within intracellular organelles and suggest that NAADP signals through pH as well as Ca(2+).

[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Loading ...
    Support Center