Functional involvement of Annexin-2 in cAMP induced AQP2 trafficking

Autor: Giovanna Valenti, Grazia Tamma, Giuseppe Procino, Maria Svelto, Maria Grazia Mola
Rok vydání: 2008
Předmět:
Zdroj: Pflügers Archiv : European Journal of Physiology, 456, 729-36
Pflügers Archiv : European Journal of Physiology, 456, 4, pp. 729-36
ISSN: 1432-2013
0031-6768
DOI: 10.1007/s00424-008-0453-1
Popis: Contains fulltext : 70255.pdf (Publisher’s version ) (Closed access) Annexin-2 is required for the apical transport in epithelial cells. In this study, we investigated the involvement of annexin-2 in cAMP-induced aquaporin-2 (AQP2) translocation to the apical membrane in renal cells. We found that the cAMP-elevating agent forskolin increased annexin-2 abundance in the plasma membrane enriched fraction with a parallel decrease in the soluble fraction. Interestingly, forskolin stimulation resulted in annexin-2 enrichment in lipid rafts, suggesting that hormonal stimulation might be responsible for a new configuration of membrane interacting proteins involved in the fusion of AQP2 vesicles to the apical plasma membrane. To investigate the functional involvement of annexin-2 in AQP2 exocytosis, the fusion process between purified AQP2 membrane vesicles and plasma membranes was reconstructed in vitro and monitored by a fluorescence assay. An N-terminal peptide that comprises 14 residues of annexin-2 and that includes the binding site for the calcium binding protein p11 strongly inhibited the fusion process. Preincubation of cells with this annexin-2 peptide also failed to increase the osmotic water permeability in the presence of forskolin in intact cells. Altogether, these data demonstrate that annexin-2 is required for cAMP-induced AQP2 exocytosis in renal cells.
Databáze: OpenAIRE
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