title: Regulation of aquaporin-2 trafficking and its binding protein complex.
abstract: Trafficking of water channel aquaporin-2 (AQP2) to the apical membrane is critical to water reabsorption in renal collecting ducts and its regulation maintains body water homeostasis. However, exact molecular mechanisms which recruit AQP2 are unknown. Recent studies highlighted a key role for spatial and temporal regulation of actin dynamics in AQP2 trafficking. We have recently identified AQP2-binding proteins which directly regulate this trafficking: SPA-1, a GTPase-activating protein (GAP) for Rap1, and cytoskeletal protein actin. In addition, a multiprotein "force generator" complex which directly binds to AQP2 has been discovered. This review summarizes recent advances related to the mechanism for AQP2 trafficking.
authors.affiliation: Department of Nephrology, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Tokyo 113-8519, Japan. ynodmed2@tmd.ac.jp
authors.forename: Yumi
authors.initials: Y
authors.lastname: Noda
authors.forename: Sei
authors.initials: S
authors.lastname: Sasaki
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D051399:Aquaporin 2 / Q000235:genetics / Q000378:metabolism*; D001127:Arginine Vasopressin / Q000502:physiology; D002118:Calcium / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity / Q000502:physiology; D000242:Cyclic AMP / Q000502:physiology; D003599:Cytoskeleton / Q000502:physiology; D018500:Diabetes Insipidus, Nephrogenic / Q000235:genetics / Q000378:metabolism; D004705:Endocytosis; D020690:GTPase-Activating Proteins / Q000378:metabolism*; D006801:Humans; D007685:Kidney Tubules, Collecting / Q000378:metabolism; D009154:Mutation; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport
chemical_list: D000199:Actins; D051399:Aquaporin 2; D020690:GTPase-Activating Proteins; D001127:Arginine Vasopressin; D000242:Cyclic AMP; D002118:Calcium