Ezrin, Radixin, and Moesin Phosphorylation in NIH3T3 Cells Revealed Angiotensin II Type 1 Receptor Cell-Type Dependent Biased Signaling

beta-Arrestin-biased agonists are a new class of drugs with promising therapeutic effects. The molecular mechanisms of beta-arrestin-biased agonists are still not completely identified. Here, we investigated the effect of angiotensin II (AngII) and {[}Sar1,Ile4,Ile8] AngII (SIT), a beta-arrestin-biased agonist, on ezrin radixin moesin (ERM) phosphorylation in NIH3T3 cells (a fibroblast cell line) stably expressing AngII type 1A receptor. ERM proteins are cross-linkers between the plasma membrane and the actin cytoskeleton and control a number of signaling pathways. We also investigated the role of G alpha q protein and beta-arrestins in mediating ERM phosphorylation. We found that AngII stimulates ERM phosphorylation by acting as a beta-arrestin-biased agonist and AngII-stimulated ERM phosphorylation is mediated by beta-arrestin2 not beta-arrestin1. We also found that SIT inhibits ERM phosphorylation by acting as a G alpha q protein biased agonist. We concluded that ERM phosphorylation is a unique beta-arrestin-biased agonism signal. Both AngII and SII can activate either G alpha q protein or beta-arrestin-mediated signaling as functional biased agonists according to the type of the cell on which they act.