β-arrestin1 phosphorylation by GRK5 regulates G protein-independent 5-HT 4 receptor signalling

Gaël Barthet (1) , Gaëlle Carrat (1) , Elisabeth Cassier (1) , Breann Barker (2) , Florence Gaven (1) , Marion Pillot (1) , Bérénice Framery (1) , Lucie P. Pellissier (1) , Julie Augier (1) , Dong Soo Kang (2) , Sylvie Claeysen (1) , Eric Reiter (3) , Jean-Louis Banères (1) , Jeffrey L Benovic (2) , Philippe Marin (1) , Joël Bockaert (1) , Aline Dumuis (1)

1 IGF - Institut de Génomique Fonctionnelle
2 Jefferson (Philadelphia University + Thomas Jefferson University)
3 PRC - Physiologie de la reproduction et des comportements [Nouzilly]

G protein‐coupled receptors (GPCRs) have been found to trigger G protein‐independent signalling. However, the regulation of G protein‐independent pathways, especially their desensitization, is poorly characterized. Here, we show that the G protein‐independent 5‐HT4 receptor (5‐HT4R)‐operated Src/ERK (extracellular signal‐regulated kinase) pathway, but not the Gs pathway, is inhibited by GPCR kinase 5 (GRK5), physically associated with the proximal region of receptor’ C‐terminus in both human embryonic kidney (HEK)‐293 cells and colliculi neurons. This inhibition required two sequences of events: the association of β–arrestin1 to a phosphorylated serine/threonine cluster located within the receptor C‐t domain and the phosphorylation, by GRK5, of β–arrestin1 (at Ser412) bound to the receptor. Phosphorylated β‐arrestin1 in turn prevented activation of Src constitutively bound to 5‐HT4Rs, a necessary step in receptor‐stimulated ERK signalling. This is the first demonstration that β‐arrestin1 phosphorylation by GRK5 regulates G protein‐independent signalling.

Mots clés: GRK5; GPCRs; ERK; BETA ARRESTINE 1; KINASE 5

Mots clés: BIOLOGIE MOLECULAIRE

Domaines: Biochimie, Biologie Moléculaire

Gaël Barthet, Gaëlle Carrat, Elisabeth Cassier, Breann Barker, Florence Gaven, et al.. β-arrestin1 phosphorylation by GRK5 regulates G protein-independent 5-HT 4 receptor signalling. EMBO Journal, 2009, 28 (18), pp.2706-2718. ⟨10.1038/emboj.2009.215⟩. ⟨hal-02483405⟩