RT Journal Article
SR Electronic
T1 Mutation-Induced Functional Alterations of CCR6
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 106
OP 116
DO 10.1124/jpet.116.237669
VO 360
IS 1
A1 Julian, Bina
A1 Gao, Kevin
A1 Harwood, Benjamin N.
A1 Beinborn, Martin
A1 Kopin, Alan S.
YR 2017
UL http://jpet.aspetjournals.org/content/360/1/106.abstract
AB The Cys-Cys chemokine receptor 6 (CCR6) is a well-established modulator of inflammation. Although several genetic associations have been identified between CCR6 polymorphisms and immune system disorders (e.g., rheumatoid arthritis and Crohn’s disease), the pharmacological effects of naturally occurring missense mutations in this receptor have yet to be characterized. In this study, we initially assessed G protein–mediated signaling and observed that wild-type (WT) CCR6 exhibited ligand-independent activity. In addition, we found that the five most frequent CCR6 missense variants (A89T, A150V, R155W, G345S, and A369V) exhibited decreased basal and/or ligand induced Gαi protein signaling. To complement the study of these loss-of-function variants, we engineered a set of constitutively active CCR6 receptors. Selected mutations enhanced basal G protein–mediated signaling up to 3-fold relative to the WT value. Using a bioluminescence resonance energy transfer assay we investigated the ability of each naturally occurring and engineered CCR6 receptor mutant to recruit β-arrestin. In contrast to G protein–mediated signaling, β-arrestin mobilization was largely unperturbed by the naturally occurring loss-of-function CCR6 variants. Elevated recruitment of β-arrestin was observed in one of the engineered constitutively active mutants (T98P). Our results demonstrate that point mutations in CCR6 can result in either a gain or loss of receptor function. These observations underscore the need to explore how CCR6 natural variants may influence immune cell physiology and human disease.