Engineered hyperphosphorylation of the ?2-adrenoceptor prolongs arrestin-3 binding and induces arrestin internalization.
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ABSTRACT: G protein-coupled receptor phosphorylation plays a major role in receptor desensitization and arrestin binding. It is, however, unclear how distinct receptor phosphorylation patterns may influence arrestin binding and subsequent trafficking. Here we engineer phosphorylation sites into the C-terminal tail of the ?2-adrenoceptor (?2AR) and demonstrate that this mutant, termed ?2AR(SSS), showed increased isoprenaline-stimulated phosphorylation and differences in arrestin-3 affinity and trafficking. By measuring arrestin-3 recruitment and the stability of arrestin-3 receptor complexes in real time using fluorescence resonance energy transfer and fluorescence recovery after photobleaching, we demonstrate that arrestin-3 dissociated quickly and almost completely from the ?2AR, whereas the interaction with ?2AR(SSS) was 2- to 4-fold prolonged. In contrast, arrestin-3 interaction with a ?2-adrenoceptor fused to the carboxyl-terminal tail of the vasopressin type 2 receptor was nearly irreversible. Further analysis of arrestin-3 localization revealed that by engineering phosphorylation sites into the ?2-adrenoceptor the receptor showed prolonged interaction with arrestin-3 and colocalization with arrestin in endosomes after internalization. This is in contrast to the wild-type receptor that interacts transiently with arrestin-3 at the plasma membrane. Furthermore, ?2AR(SSS) internalized more efficiently than the wild-type receptor, whereas recycling was very similar for both receptors. Thus, we show how the interaction between arrestins and receptors can be increased with minimal receptor modification and that relatively modest increases in receptor-arrestin affinity are sufficient to alter arrestin trafficking.
SUBMITTER: Zindel D
PROVIDER: S-EPMC4293452 | biostudies-literature | 2015 Feb
REPOSITORIES: biostudies-literature
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