Phosphorylation patterns on the c-terminal tail of the angiotensin II type 1 receptor encode differential signaling pathways

ABSTRACT: Structural studies have recently shown that mechanism of selective AT1R activation by different classes of ligands is initiated by the ability of ligands to stabilize unique active conformations of the receptor. Active conformations enhance transducer coupling leading to effector mediated signaling, that has been proposed to be linked to differential phosphorylation of the c-terminal tail of the receptor. To determine how different classes of AT1R ligands effect receptor phosphorylation and activation of downstream signaling we used TMT-MS to identify the amino acid residues of the AT1R phosphorylated following treatment with the full balanced agonist Angiotensin II and a β-arrestin biased ligand, TRV023. Here we show that Ang and TRV 023 induce two distinct patterns of phosphorylation clusters a.a. residues along the entire c-tail with AngII inducing a greater magnitude than the β-arrestin biased ligand TRV 023, particularly in the proximal part of the tail. Selective mutagenesis of Ser and Thr residues, we found that of the 12 Ser/Thr residues within the c-tail, only the 4 proximal and 4 middle residues are all required for full β -arrestin functionality in response to either a balanced or β-arrestin-based ligand. Surprisingly, phosphorylation of 4 residues in the proximal c-tail is necessary for maximal G-protein activation to a full agonist. Taken together our data demonstrate that a AT1R ligands that stabilize different active confirmations of the receptor (full agonist vs. β-arrestin biased) induce distinct phosphorylation patterns on the c-tail of the receptor to evoke distinct receptor-transducer engagement and downstream receptor trafficking and signaling.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Homo Sapiens (human)

SUBMITTER: Joao Paulo  

LAB HEAD: Howard A. Rockman, M.D.

PROVIDER: PXD032672 | Pride | 2024-07-15

REPOSITORIES: Pride