title: Attenuation of ligand-induced activation of angiotensin II type 1 receptor signaling by the type 2 receptor via protein kinase C.
abstract: Angiotensin II (AII) type 2 receptor (AT2R) negatively regulates type 1 receptor (AT1R) signaling. However, the precise molecular mechanism of AT2R-mediated AT1R inhibition remains poorly understood. Here, we characterized the local and functional interaction of AT2R with AT1R. AT2R colocalized and formed a complex with AT1R at the plasma membrane, even in the absence of AII. Upon AII stimulation, the spatial arrangement of the complex was modulated, as confirmed by Förster resonance energy transfer (FRET) analysis, followed by AT2R internalization along with AT1R. AT2R internalization was specifically observed only in the presence of AT1R; AT2R alone could not be internalized. The AT1R-specific inhibitor losartan completely inhibited both the conformational change and the internalization of AT2R with AT1R, whereas the AT2R-specific inhibitor PD123319 partially hindered these phenomena, demonstrating that the activation of both receptors was indispensable for these effects. In addition, treatment with the protein kinase C (PKC) inhibitors inhibited the ligand-dependent accumulation of AT2R but not that of AT1R in the endosomes. A mutation in the putative phosphorylation sites of AT2R also abrogated the co-internalization of ATR2 with AT1R and the inhibitory effect of ATR2 on AT1R. These data suggest that AT2R inhibits ligand-induced AT1R signaling through the PKC-dependent pathway.
authors: Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
authors: Takayuki
authors: T
authors: Inuzuka
authors: Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
authors: Yoichiro
authors: Y
authors: Fujioka
authors: Department of Cancer Pathology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
authors: Masumi
authors: M
authors: Tsuda
authors: Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
authors: Mari
authors: M
authors: Fujioka
authors: Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
authors: Aya O
authors: AO
authors: Satoh
authors: Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
authors: Kosui
authors: K
authors: Horiuchi
authors: Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
authors: Shinya
authors: S
authors: Nishide
authors: Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
authors: Asuka
authors: A
authors: Nanbo
authors: Department of Cancer Pathology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
authors: Shinya
authors: S
authors: Tanaka
authors: Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
authors: Yusuke
authors: Y
authors: Ohba
mesh_terms: D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D011992:Endosomes / Q000235:genetics / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D006367:HeLa Cells; D006801:Humans; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism*; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics / Q000378:metabolism*; D044139:Receptor, Angiotensin, Type 2 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011493:Protein Kinase C