PT  - JOURNAL ARTICLE
AU  - Ken-ichiro Nakajima
AU  - Jürgen Wess
TI  - Design and Functional Characterization of a Novel, Arrestin-Biased Designer G Protein-Coupled Receptor
AID  - 10.1124/mol.112.080358
DP  - 2012 Oct 01
TA  - Molecular Pharmacology
PG  - 575--582
VI  - 82
IP  - 4
4099  - http://molpharm.aspetjournals.org/content/82/4/575.short
4100  - http://molpharm.aspetjournals.org/content/82/4/575.full
SO  - Mol Pharmacol2012 Oct 01; 82
AB  - Mutational modification of distinct muscarinic receptor subtypes has yielded novel designer G protein-coupled receptors (GPCRs) that are unable to bind acetylcholine (ACh), the endogenous muscarinic receptor ligand, but can be efficiently activated by clozapine-N-oxide (CNO), an otherwise pharmacologically inert compound. These CNO-sensitive designer GPCRs [alternative name: designer receptors exclusively activated by designer drug (DREADDs)] have emerged as powerful new tools to dissect the in vivo roles of distinct G protein signaling pathways in specific cell types or tissues. As is the case with other GPCRs, CNO-activated DREADDs not only couple to heterotrimeric G proteins but can also recruit proteins of the arrestin family (arrestin-2 and -3). Accumulating evidence suggests that arrestins can act as scaffolding proteins to promote signaling through G protein-independent signaling pathways. To explore the physiological relevance of these arrestin-dependent signaling pathways, the availability of an arrestin-biased DREADD would be highly desirable. In this study, we describe the development of an M3 muscarinic receptor-based DREADD [Rq(R165L)] that is no longer able to couple to G proteins but can recruit arrestins and promote extracellular signal-regulated kinase-1/2 phosphorylation in an arrestin- and CNO-dependent fashion. Moreover, CNO treatment of mouse insulinoma (MIN6) cells expressing the Rq(R165L) construct resulted in a robust, arrestin-dependent stimulation of insulin release, directly implicating arrestin signaling in the regulation of insulin secretion. This newly developed arrestin-biased DREADD represents an excellent novel tool to explore the physiological relevance of arrestin signaling pathways in distinct tissues and cell types.