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This Article Full Text Full Text (PDF) Supplemental Figure All Versions of this Article: 293/3/C1129    most recent 00628.2006v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Vossenkämper, A. Articles by Klussmann, E. Search for Related Content PubMed PubMed Citation Articles by Vossenkämper, A. Articles by Klussmann, E.

PROTEIN AND VESICLE TRAFFICKING, CYTOSKELETON

Microtubules are needed for the perinuclear positioning of aquaporin-2 after its endocytic retrieval in renal principal cells

¹Leibniz-Institut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, Berlin, Germany; and ²Institut für Pharmakologie, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Freie Universität Berlin, Berlin, Germany

Submitted 21 December 2006 ; accepted in final form 6 July 2007

Water reabsorption in the renal collecting duct is regulated by arginine vasopressin (AVP). AVP induces the insertion of the water channel aquaporin-2 (AQP2) into the plasma membrane of principal cells, thereby increasing the osmotic water permeability. The redistribution of AQP2 to the plasma membrane is a cAMP-dependent process and thus a paradigm for cAMP-controlled exocytic processes. Using primary cultured rat inner medullary collecting duct cells, we show that the redistribution of AQP2 to the plasma membrane is accompanied by the reorganization of microtubules and the redistribution of the small GTPase Rab11. In resting cells, AQP2 is colocalized with Rab11 perinuclearly. AVP induced the redistribution of AQP2 to the plasma membrane and of Rab11 to the cell periphery. The redistribution of both proteins was increased when microtubules were depolymerized by nocodazole. In addition, the depolymerization of microtubules prevented the perinuclear positioning of AQP2 and Rab11 in resting cells, which was restored if nocodazole was washed out and microtubules repolymerized. After internalization of AQP2, induced by removal of AVP, forskolin triggered the AQP2 redistribution to the plasma membrane even if microtubules were depolymerized and without the previous positioning of AQP2 in the perinuclear recycling compartment. Collectively, the data indicate that microtubule-dependent transport of AQP2 is predominantly responsible for trafficking and localization of AQP2 inside the cell after its internalization but not for the exocytic transport of the water channel. We also demonstrate that cAMP-signaling regulates the localization of Rab11-positive recycling endosomes in renal principal cells.

dynein; Rab11

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