13 February 2009 Angiotensin II-induced angiotensin II type I receptor lysosomal degradation studied by fluorescence lifetime imaging microscopy
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Abstract
Upon activation, the angiotensin (Ang) II type 1 receptor (AT1Rs) rapidly undergoes endocytosis. After a series of intracellular processes, the internalized AT1Rs recycle back to the plasma membrane or are trafficked to proteasomes or lysosomes for degradation. We recently reported that AT1Rs degrades in proteasomes upon stimulation of the D5 dopamine receptor (D5R) in human renal proximal tubule and HEK-293 cells. This is in contrast to the degradation of AT1R in lysosomes upon binding Ang II. However, the dynamic regulation of the AT1Rs in lysosomes is not well understood. Here we investigated the AT1Rs lysosomal degradation using FRET-FLIM in HEK 293 cells heterologously expressing the human AT1R tagged with EGFP as the donor fluorophore. Compared to its basal state, the lifetime of AT1Rs decreased after a 5-minute treatment with Ang II treatment and colocalized with Rab5 but not Rab7 and LAMP1. With longer Ang II treatment (30 min), the AT1Rs lifetime decreased and co-localized with Rab5, as well as Rab7 and LAMP1. The FLIM data are corroborated with morphological and biochemical co-immunoprecipitation studies. These data demonstrate that Ang II induces the internalization of AT1Rs into early sorting endosomes prior to trafficking to late endosomes and subsequent degradation in lysosomes.
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Hewang Li, Hewang Li, Peiying Yu, Peiying Yu, Robin A. Felder, Robin A. Felder, Ammasi Periasamy, Ammasi Periasamy, Pedro A. Jose, Pedro A. Jose, } "Angiotensin II-induced angiotensin II type I receptor lysosomal degradation studied by fluorescence lifetime imaging microscopy", Proc. SPIE 7183, Multiphoton Microscopy in the Biomedical Sciences IX, 71832G (13 February 2009); doi: 10.1117/12.811032; https://doi.org/10.1117/12.811032
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