Arrestin-mediated signaling at GPCRs

The arrestins are multifunctional adapter proteins that regulate G protein-coupled receptor (GPCR) signaling. There are four isoforms of arrestin: arrestins 1 and 4 are expressed exclusively in the visual system and are primarily associated with the visual receptors rhodopsin and cone opsins, whereas arrestin-2 and 3, better known as β-arrestin1 and 2, respectively, are expressed ubiquitously and bind to most GPCRs. The name “arrestin” was derived from its ability to inhibit rhodopsin signaling, but over the past decades, roles have been discovered for the arrestins in promoting signaling and regulating receptor trafficking through their action as scaffolding proteins. More recent studies have completely reversed the paradigm of arrestins as desensitizers of G protein signaling, showing that in certain situations they can actually promote G protein signaling. While there is still controversy as to the exact role that the arrestins play in signaling by GPCRs, novel paradigms for their activity continue to be discovered. Here we review the importance of these multifunctional adapters in promoting signaling by GPCRs.

Duke Scholars

Author Sudarshan Rajagopal Medicine, Cardiology