Granular pH

1. J Cell Biol. 2013 Oct 28;203(2):283-98. doi: 10.1083/jcb.201303104.

The V-ATPase membrane domain is a sensor of granular pH that controls the

exocytotic machinery.

Poëa-Guyon S(1), Ammar MR, Erard M, Amar M, Moreau AW, Fossier P, Gleize V,

Vitale N, Morel N.

Author information:

(1)Centre de Neurosciences Paris-Sud, Centre National de la Recherche

Scientifique Unité Mixte de Recherche 8195 and Université Paris-Sud, F-91405

Orsay, France.

Comment in

J Cell Biol. 2013 Oct 28;203(2):171-3.

Several studies have suggested that the V0 domain of the vacuolar-type

H(+)-adenosine triphosphatase (V-ATPase) is directly implicated in secretory

vesicle exocytosis through a role in membrane fusion. We report in this paper

that there was a rapid decrease in neurotransmitter release after acute

photoinactivation of the V0 a1-I subunit in neuronal pairs. Likewise,

inactivation of the V0 a1-I subunit in chromaffin cells resulted in a decreased

frequency and prolonged kinetics of amperometric spikes induced by

depolarization, with shortening of the fusion pore open time. Dissipation of the

granular pH gradient was associated with an inhibition of exocytosis and

correlated with the V1-V0 association status in secretory granules. We thus

conclude that V0 serves as a sensor of intragranular pH that controls exocytosis

and synaptic transmission via the reversible dissociation of V1 at acidic pH.

Hence, the V-ATPase membrane domain would allow the exocytotic machinery to

discriminate fully loaded and acidified vesicles from vesicles undergoing

neurotransmitter reloading.

PMCID: PMC3812966

PMID: 24165939  [PubMed - indexed for MEDLINE]