title: TRPV5 is internalized via clathrin-dependent endocytosis to enter a Ca2+-controlled recycling pathway.
abstract: The epithelial Ca(2+) channel TRPV5 plays an essential role in transcellular Ca(2+) transport and is one of the most Ca(2+)-selective members of the transient receptor potential superfamily. Regulation of the abundance of TRPV5 at the cell surface is critical in body Ca(2+) homeostasis. However, little is known about the mechanisms underlying TRPV5 endo- and exocytosis. Here, we show that TRPV5 is constitutively internalized in a dynamin- and clathrin-dependent manner. Internalized TRPV5 first appears in small vesicular structures and then localizes to perinuclear structures positive for Rab11a. TRPV5 has a half-life of more than 8 h and is stable even after internalization from the cell surface for more than 3 h. Disruption of cell surface delivery of newly synthesized TRPV5 by brefeldin A does not reduce TRPV5-mediated Ca(2+) influx in cells, suggesting the presence of a stable intracellular pool of the channel capable of recycling back to the surface. Furthermore, the endocytic recycling kinetics is decreased upon treatment with Ca(2+) chelator BAPTA-AM, indicating that the channel's trafficking pathways are dynamically controlled by Ca(2+).
authors: Institute of Medical Biochemistry, Center for Molecular Biology of Inflammation, University of Münster, von-Esmarch-Strasse 56, Münster 48149, Germany. S.VandeGraaf-4@umcutrecht.nl
authors: Stan F J
authors: SF
authors: van de Graaf
authors: Ursula
authors: U
authors: Rescher
authors: Joost G J
authors: JG
authors: Hoenderop
authors: Sjoerd
authors: S
authors: Verkaart
authors: René J M
authors: RJ
authors: Bindels
authors: Volker
authors: V
authors: Gerke
mesh_terms: D001483:Base Sequence; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D002966:Clathrin / Q000378:metabolism*; D017931:DNA Primers; D004705:Endocytosis; D006801:Humans; D016297:Mutagenesis, Site-Directed; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: D002966:Clathrin; D017931:DNA Primers; D050916:TRPV Cation Channels; C492239:TRPV5 protein, human; D002118:Calcium