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Differential β‐arrestin2 requirements of constitutive and agonist‐induced internalization of the CB1 cannabinoid receptor
Author(s) -
Gyombolai Pál,
Boros Eszter,
Hunyady László,
Turu Gábor
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1172.9
Subject(s) - internalization , cannabinoid receptor , agonist , microbiology and biotechnology , receptor , cannabinoid , biology , chemistry , biophysics , biochemistry
Internalization of G protein‐coupled receptors is an important process in the regulation of receptor signaling. CB1 cannabinoid receptor (CB1R) internalizes both constitutively and upon stimulation by receptor agonists, however, the mechanisms underlying these processes and the roles of β‐arrestins in the regulation of CB1R function are not completely understood. In this study, we followed CB1R internalization in confocal microscope and by bioluminescence resonance energy transfer measurements. We found that upon activation CB1R binds β‐arrestin2 (β‐arr2), but not β‐arrestin1. Furthermore, both the expression of dominant‐negative β‐arr2 (β‐arr2‐V54D) and siRNA‐mediated knock‐down of β‐arr2 impaired the agonist‐induced internalization of CB1R. In contrast, neither β‐arr2‐V54D nor β‐arr2‐specific siRNA had a significant effect on the constitutive internalization of CB1R. We conclude that upon activation, CB1R binds to β‐arr2, and this binding is required for its agonist‐induced internalization. In contrast, constitutive CB1R internalization is β‐arr2‐independent, showing that the molecular mechanisms underlying these two processes are different.