Evidence for a direct and functional interaction between the regulators of G protein signaling-2 and phosphorylated C terminus of cholecystokinin-2 receptor.
Signaling of G protein-coupled receptors (GPCRs) is regulated by different mechanisms. One of these involves regulators of G protein signaling (RGS), which are diverse and multifunctional proteins that bind to active Galpha subunits of G proteins and act as GTPase-activating proteins. Little is known about the molecular mechanisms that govern the selective use of RGS proteins in living cells. We first demonstrated that CCK2R-mediated inositol phosphate production, known to be G(q)-dependent, is more sensitive to RGS2 than to RGS4 and is insensitive to RGS8. Both basal and agonist-stimulated activities of the CCK2R are regulated by RGS2. By combining biochemical, functional, and in silico structural approaches, we demonstrate that a direct and functional interaction occurs between RGS2 and agonist-stimulated cholecystokinin receptor-2 (CCK2R) and identified the precise residues involved: phosphorylated Ser434 and Thr439 located in the C-terminal tail of CCK2R and Lys62, Lys63, and Gln67, located in the N-terminal domain of RGS2. These findings confirm previous reports that RGS proteins can interact with GPCRs to modulate their signaling and provide a molecular basis for RGS2 recognition by the CCK2R.
Langer
Ingrid
I
Department of Biological Chemistry and Nutrition, Faculty of Medicine, UniversitéLibre de Bruxelles, Brussels, Belgium.
Tikhonova
Irina G
IG
Boulègue
Cyril
C
Estève
Jean-Pierre
JP
Vatinel
Sébastien
S
Ferrand
Audrey
A
Moroder
Luis
L
Robberecht
Patrick
P
Fourmy
Daniel
D
D020816:Amino Acid Motifs / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation / Q000502:physiology; D011485:Protein Binding / Q000502:physiology; D020710:RGS Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D043887:Receptor, Cholecystokinin B / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*
D010446:Peptide Fragments; D020710:RGS Proteins; C087182:RGS2 protein, human; D043887:Receptor, Cholecystokinin B