In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 103, No. 10 ( 2006-03-07), p. 3926-3931
Abstract:
Reversible assembly of the V 0 V 1 holoenzyme from V 0 and V 1 subcomplexes is a widely used mechanism for regulation of vacuolar-type H + -ATPases (V-ATPases) in animal cells. In the blowfly ( Calliphora vicina ) salivary gland, V-ATPase is located in the apical membrane of the secretory cells and energizes the secretion of a KCl-rich saliva in response to the hormone serotonin. We have examined whether the cAMP pathway, known to be activated by serotonin, controls V-ATPase assembly and activity. Fluorescence measurements of pH changes at the luminal surface of isolated glands demonstrate that cAMP, Sp-adenosine-3′,5′-cyclic monophosphorothioate, or forskolin, similar to serotonin, cause V-ATPase-dependent luminal acidification. In addition, V-ATPase-dependent ATP hydrolysis increases upon treatment with these agents. Immunofluorescence microscopy and pelleting assays have demonstrated further that V 1 components become translocated from the cytoplasm to the apical membrane and V-ATPase holoenzymes are assembled at the apical membrane during conditions that increase intracellular cAMP. Because these actions occur without a change in cytosolic Ca 2+ , our findings suggest that the cAMP pathway mediates the reversible assembly and activation of V-ATPase molecules at the apical membrane upon hormonal stimulus.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.0600011103
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
2006
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
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