Fiche publication
Date publication
décembre 2001
Journal
Proceedings of the National Academy of Sciences of the United States of America
Auteurs
Membres identifiés du Cancéropôle Est :
Dr BADER Marie-France
,
Dr CHASSEROT-GOLAZ Sylvette
,
Dr VITALE Nicolas
Tous les auteurs :
Humeau Y, Vitale N, Chasserot-Golaz S, Dupont JL, Du G, Frohman MA, Bader MF, Poulain B
Lien Pubmed
Résumé
Phosphatidic acid produced by phospholipase D (PLD) as a result of signaling activity is thought to play a role in membrane vesicle trafficking, either as an intracellular messenger or as a cone-shaped lipid that promotes membrane fusion. We recently described that, in neuroendocrine cells, plasma membrane-associated PLD1 operates at a stage of Ca(2+)-dependent exocytosis subsequent to cytoskeletal-mediated recruitment of secretory granules to exocytotic sites. We show here that PLD1 also plays a crucial role in neurotransmitter release. Using purified rat brain synaptosomes subjected to hypotonic lysis and centrifugation, we found that PLD1 is associated with the particulate fraction containing the plasma membrane. Immunostaining of rat cerebellar granule cells confirmed localization of PLD1 at the neuronal plasma membrane in zones specialized for neurotransmitter release (axonal neurites, varicosities, and growth cone-like structures). To determine the potential involvement of PLD1 in neurotransmitter release, we microinjected catalytically inactive PLD1(K898R) into Aplysia neurons and analyzed its effects on evoked acetylcholine (ACh) release. PLD1(K898R) produced a fast and potent dose-dependent inhibition of ACh release. By analyzing paired-pulse facilitation and postsynaptic responses evoked by high-frequency stimulations, we found that the exocytotic inhibition caused by PLD1(K898R) was not the result of an alteration in stimulus-secretion coupling or in vesicular trafficking. Analysis of the fluctuations in amplitude of the postsynaptic responses revealed that the PLD1(K898R) blocked ACh release by reducing the number of active presynaptic-releasing sites. Our results provide evidence that PLD1 plays a major role in neurotransmission, most likely by controlling the fusogenic status of presynaptic release sites.
Mots clés
Acetylcholine, metabolism, Animals, Aplysia, Catalysis, Cells, Cultured, Fluorescent Antibody Technique, Microscopy, Confocal, Neurons, enzymology, Neurotransmitter Agents, metabolism, Phospholipase D, metabolism, Rats, Rats, Wistar, Subcellular Fractions, enzymology, Synapses, metabolism
Référence
Proc. Natl. Acad. Sci. U.S.A.. 2001 Dec;98(26):15300-5
