title: A Role of myosin Vb and Rab11-FIP2 in the aquaporin-2 shuttle.
abstract: Arginine-vasopressin (AVP) regulates water reabsorption in renal collecting duct principal cells. Its binding to Gs-coupled vasopressin V2 receptors increases cyclic AMP (cAMP) and subsequently elicits the redistribution of the water channel aquaporin-2 (AQP2) from intracellular vesicles into the plasma membrane (AQP2 shuttle), thereby facilitating water reabsorption from primary urine. The AQP2 shuttle is a paradigm for cAMP-dependent exocytic processes. Using sections of rat kidney, the AQP2-expressing cell line CD8, and primary principal cells, we studied the role of the motor protein myosin Vb, its vesicular receptor Rab11, and the myosin Vb- and Rab11-binding protein Rab11-FIP2 in the AQP2 shuttle. Myosin Vb colocalized with AQP2 intracellularly in resting and at the plasma membrane in AVP-treated cells. Rab11 was found on AQP2-bearing vesicles. A dominant-negative myosin Vb tail construct and Rab11-FIP2 lacking the C2 domain (Rab11-FIP2-DeltaC2), which disrupt recycling, caused condensation of AQP2 in a Rab11-positive compartment and abolished the AQP2 shuttle. This effect was dependent on binding of myosin Vb tail and Rab11-FIP2-DeltaC2 to Rab11. In summary, we identified myosin Vb as a motor protein involved in AQP2 recycling and show that myosin Vb- and Rab11-FIP2-dependent recycling of AQP2 is an integral part of the AQP2 shuttle.
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, 13125 Berlin, Germany.
authors.forename: Pavel I
authors.initials: PI
authors.lastname: Nedvetsky
authors.forename: Eduard
authors.initials: E
authors.lastname: Stefan
authors.forename: Sebastian
authors.initials: S
authors.lastname: Frische
authors.forename: Katja
authors.initials: K
authors.lastname: Santamaria
authors.forename: Burkhard
authors.initials: B
authors.lastname: Wiesner
authors.forename: Giovanna
authors.initials: G
authors.lastname: Valenti
authors.forename: John A
authors.initials: JA
authors.lastname: Hammer
authors.forename: Søren
authors.initials: S
authors.lastname: Nielsen
authors.forename: James R
authors.initials: JR
authors.lastname: Goldenring
authors.forename: Walter
authors.initials: W
authors.lastname: Rosenthal
authors.forename: Enno
authors.initials: E
authors.lastname: Klussmann
mesh_terms: D000818:Animals; D051399:Aquaporin 2 / Q000096:biosynthesis / Q000378:metabolism*; D002352:Carrier Proteins / Q000096:biosynthesis / Q000502:physiology*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D007668:Kidney / Q000166:cytology / Q000378:metabolism*; D008565:Membrane Proteins / Q000096:biosynthesis / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000096:biosynthesis / Q000502:physiology*; D024701:Myosin Type V / Q000096:biosynthesis / Q000502:physiology*; D009218:Myosins / Q000096:biosynthesis / Q000502:physiology*; D011485:Protein Binding; D021381:Protein Transport; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection; D020691:rab GTP-Binding Proteins
chemical_list: C496023:AQP2 protein, human; C496025:Aqp2 protein, rat; D051399:Aquaporin 2; D002352:Carrier Proteins; C505832:MYO5B protein, human; D008565:Membrane Proteins; C101826:Myo5b protein, rat; D011993:Recombinant Fusion Proteins; D024701:Myosin Type V; D018995:Myosin Heavy Chains; D009218:Myosins; C463963:RAB11FIP2 protein, human; D020691:rab GTP-Binding Proteins