title: Rab4 and Rab11 coordinately regulate the recycling of angiotensin II type I receptor as demonstrated by fluorescence resonance energy transfer microscopy.
abstract: The recycling of G-protein-coupled receptors (GPCR) to the cell surface after internalization plays an important role in the regulation of overall GPCR activity. The angiotensin II type I receptor (AT1R) belongs to class B GPCRs that recycle slowly back to the cell surface. Previous studies have proposed that Rab11 controls the recycling of AT1R; however, recent reports show that Rab4, a rapid recycling regulator, co-localizes also with internalized AT1R. Different from the subcellular co-localization provided by fluorescence microscopy, fluorescence resonance energy transfer (FRET) microscopy provided the spatial relationship of AT1R with Rab4 and Rab11 in the nanometer-range proximity during the entire course of AT1R recycling. During the early recycling stage, internalized AT1Rs were mainly associated with Rab4 in the cytoplasm. During the mid-recycling stage, AT1Rs were associated with both Rab4 and Rab11 in the perinuclear compartments. However, during the late-recycling stage, AT1Rs were mainly associated with Rab11, both in the perinuclear compartments and the plasma membrane. Co-immunoprecipitation data confirmed these dynamic associations, which were disrupted by silencing of either the Rab4 or Rab11 gene. Based on these observations, we propose a Rab4 and Rab11 coordinated model for AT1R recycling.
authors.affiliation: Georgetown University Medical Center, Department of Pediatrics, Washington, DC 20057, USA.
authors.forename: Hewang
authors.initials: H
authors.lastname: Li
authors.forename: Hui-Fang
authors.initials: HF
authors.lastname: Li
authors.forename: Robin A
authors.initials: RA
authors.lastname: Felder
authors.forename: Ammasi
authors.initials: A
authors.lastname: Periasamy
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Jose
mesh_terms: D002460:Cell Line; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D008856:Microscopy, Fluorescence / Q000379:methods*; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism*; D020695:rab4 GTP-Binding Proteins / Q000378:metabolism*
chemical_list: D044140:Receptor, Angiotensin, Type 1; C492252:Wdr44 protein, rat; D019204:GTP-Binding Proteins; D020695:rab4 GTP-Binding Proteins