Regulation of aquaporin-2 trafficking by vasopressin in the renal collecting duct. Roles of ryanodine-sensitive Ca2+ stores and calmodulin.
J Biol Chem
; 275(47): 36839-46, 2000 Nov 24.
Article
em En
| MEDLINE
| ID: mdl-10973964
ABSTRACT
In the renal collecting duct, vasopressin increases osmotic water permeability (P(f)) by triggering trafficking of aquaporin-2 vesicles to the apical plasma membrane. We investigated the role of vasopressin-induced intracellular Ca(2+) mobilization in this process. In isolated inner medullary collecting ducts (IMCDs), vasopressin (0.1 nm) and 8-(4-chlorophenylthio)-cAMP (0.1 mm) elicited marked increases in [Ca(2+)](i) (fluo-4). Vasopressin-induced Ca(2+) mobilization was completely blocked by preloading with the Ca(2+) chelator BAPTA. In parallel experiments, BAPTA completely blocked the vasopressin-induced increase in P(f) without affecting adenosine 3',5'-cyclic monophosphate (cAMP) production. Previously, we demonstrated the lack of activation of the phosphoinositide-signaling pathway by vasopressin in IMCD, suggesting an inositol 1,4,5-trisphosphate-independent mechanism of Ca(2+) release. Evidence for expression of the type 1 ryanodine receptor (RyR1) in IMCD was obtained by immunofluorescence, immunoblotting, and reverse transcription-polymerase chain reaction. Ryanodine (100 microm), a ryanodine receptor antagonist, blocked the arginine vasopressin-mediated increase in P(f) and blocked vasopressin-stimulated redistribution of aquaporin-2 to the plasma membrane domain in primary cultures of IMCD cells, as assessed by immunofluorescence immunocytochemistry. Calmodulin inhibitors (W7 and trifluoperazine) blocked the P(f) response to vasopressin and the vasopressin-stimulated redistribution of aquaporin-2. The results suggest that Ca(2+) release from ryanodine-sensitive stores plays an essential role in vasopressin-mediated aquaporin-2 trafficking via a calmodulin-dependent mechanism.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Rianodina
/
Calmodulina
/
Vasopressinas
/
Cálcio
/
Canal de Liberação de Cálcio do Receptor de Rianodina
/
Aquaporinas
/
Túbulos Renais Coletores
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2000
Tipo de documento:
Article
País de afiliação:
Estados Unidos