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Serine 269 phosphorylated aquaporin-2 is targeted to the apical membrane of collecting duct principal cells.

ABSTRACT: Trafficking of the water channel aquaporin-2 to the apical plasma membrane of the collecting duct is mediated by arginine vasopressin, rendering the cell permeable to water. We recently identified a novel form of aquaporin-2 that is phosphorylated at serine-269 (pS269-AQP2). Using antibodies specific for this form of the water channel, we detected rat and mouse pS269-AQP2 in the connecting tubule and throughout the collecting duct system. Using confocal immunofluorescence microscopy with organelle-specific markers and immunogold electron microscopy, we found that pS269-AQP2 was found only on the apical plasma membrane of principal cells. In vasopressin-deficient Brattleboro rats, pS269-AQP2 was undetectable but dramatically increased in abundance after these rats were treated with [deamino-Cys-1, d-Arg-8]vasopressin (dDAVP). This increase occurred only at the apical plasma membrane, even after long-term dDAVP treatment. Following dDAVP there was a time-dependent redistribution of total aquaporin-2 from predominantly intracellular vesicles to the apical plasma membrane, clathrin-coated vesicles, early endosomal compartments, and lysosomes. However, pS269-AQP2 was found only on the apical plasma membrane at any time. Our results show that S269 phosphorylated aquaporin-2 is exclusively associated with the apical plasma membrane, where it escapes endocytosis to remain at the cell surface.

SUBMITTER: Moeller HB

PROVIDER: S-EPMC3502047 | biostudies-literature | 2009 Feb

REPOSITORIES: biostudies-literature

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Serine 269 phosphorylated aquaporin-2 is targeted to the apical membrane of collecting duct principal cells.

Moeller Hanne B HB Knepper Mark A MA Fenton Robert A RA

Kidney international 20081008 3

Trafficking of the water channel aquaporin-2 to the apical plasma membrane of the collecting duct is mediated by arginine vasopressin, rendering the cell permeable to water. We recently identified a novel form of aquaporin-2 that is phosphorylated at serine-269 (pS269-AQP2). Using antibodies specific for this form of the water channel, we detected rat and mouse pS269-AQP2 in the connecting tubule and throughout the collecting duct system. Using confocal immunofluorescence microscopy with organel ...[more]

PMID: 18843259

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Serine 269 phosphorylated aquaporin-2 is targeted to the apical membrane of collecting duct principal cells.

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Serine 269 phosphorylated aquaporin-2 is targeted to the apical membrane of collecting duct principal cells.

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