title: Stabilization of the angiotensin-(1-7) receptor Mas through interaction with PSD95.
abstract: The functions and signalling mechanisms of the Ang-(1-7) [angiotensin-(1-7)] receptor Mas have been studied extensively. However, less attention has been paid to the intracellular regulation of Mas protein. In the present study, PSD95 (postsynaptic density 95), a novel binding protein of Mas receptor, was identified, and their association was characterized further. Mas specifically interacts with PDZ1-2, but not the PDZ3, domain of PSD95 via Mas-CT (Mas C-terminus), and the last four amino acids [ETVV (Glu-Thr-Val-Val)] of Mas-CT were determined to be essential for this interaction, as shown by GST pull-down, co-immunoprecipitation and confocal co-localization experiments. Gain-of-function and loss-of-function studies indicated that PSD95 enhanced Mas protein expression by increasing the stabilization of the receptor. Mas degradation was robustly inhibited by the proteasome inhibitor MG132 in time- and dose-dependent manners, and the expression of PSD95 impaired Mas ubiquitination, indicating that the PSD95-Mas association inhibits Mas receptor degradation via the ubiquitin-proteasome proteolytic pathway. These findings reveal a novel mechanism of Mas receptor regulation by which its expression is modulated at the post-translational level by ubiquitination, and clarify the role of PSD95, which binds directly to Mas, blocking the ubiquitination and subsequent degradation of the receptor via the ubiquitin-proteasome proteolytic pathway.
authors.affiliation: Department of Biochemistry and Molecular Biology, Capital Medical University, Beijing 100069, China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Bian
authors.forename: Licui
authors.initials: L
authors.lastname: Sun
authors.forename: Longyan
authors.initials: L
authors.lastname: Yang
authors.forename: Ji-Feng
authors.initials: JF
authors.lastname: Li
authors.forename: Jia
authors.initials: J
authors.lastname: Hu
authors.forename: Shuai
authors.initials: S
authors.lastname: Zheng
authors.forename: Ruihan
authors.initials: R
authors.lastname: Guo
authors.forename: Duiping
authors.initials: D
authors.lastname: Feng
authors.forename: Qian
authors.initials: Q
authors.lastname: Ma
authors.forename: Xiaocui
authors.initials: X
authors.lastname: Shi
authors.forename: Ying
authors.initials: Y
authors.lastname: Xiong
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Yang
authors.forename: Ran
authors.initials: R
authors.lastname: Song
authors.forename: Jianguo
authors.initials: J
authors.lastname: Xu
authors.forename: Songlin
authors.initials: S
authors.lastname: Wang
authors.forename: Junqi
authors.initials: J
authors.lastname: He
mesh_terms: D000803:Angiotensin I / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D019556:COS Cells; D002460:Cell Line; D045744:Cell Line, Tumor; D006224:Cricetinae; D000076122:Disks Large Homolog 4 Protein; D006801:Humans; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D011817:Rabbits; D060888:Real-Time Polymerase Chain Reaction; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: C501444:DLG4 protein, human; D000076122:Disks Large Homolog 4 Protein; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D010446:Peptide Fragments; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D043562:Receptors, G-Protein-Coupled; D000803:Angiotensin I; C118790:angiotensin I (1-7)