Biochemical and Biophysical Research Communications, Vol.457, No.1, 50-57, 2015
Different conformational dynamics of beta-arrestin1 and beta-arrestin2 analyzed by hydrogen/deuterium exchange mass spectrometry
Arrestins have important roles in G protein-coupled receptor (GPCR) signaling including desensitization of GPCRs and G protein-independent signaling. There have been four arrestins identified: arrestin1, arrestin2 (e.g. beta-arrestin1), arrestin3 (e.g. beta-arrestin2), and arrestin4. beta-Arrestin1 and beta-arrestin2 are ubiquitously expressed and regulate a broad range of GPCRs, while arrestin1 and arrestin4 are expressed in the visual system. Although the functions of beta-arrestin1 and beta-arrestin2 widely overlap, beta-arrestin2 has broader receptor selectivity, and a few studies have suggested that beta-arrestin1 and beta-arrestin2 have distinct cellular functions. Here, we compared the conformational dynamics of beta-arrestin1 and beta-arrestin2 by hydrogen/deuterium exchange mass spectrometry (HDX-MS). We also used the R169E mutant as a pre-activation model system. HDX-MS data revealed that beta-strands II through IV were more dynamic in beta-arrestin2 in the basal state, while the middle loop was more dynamic in beta-arrestin1 With pre-activation, both beta-arrestin1 and beta-arrestin2 became more flexible, but broader regions of beta-arrestin1 became flexible compared to beta-arrestin2. The conformational differences between beta-arrestin1 and beta-arrestin2 in both the basal and pre-activated states might determine their different receptor selectivities and different cellular functions. (C) 2014 Elsevier Inc. All rights reserved.