Insights into the binding and activation sites of the receptors for cholecystokinin and gastrin.
CCK receptors represent potential targets in a number of diseases. Knowledge of CCK receptor binding sites is a prerequisite for the understanding of the molecular basis for their ligand recognition, partial agonism, ligand-induced trafficking of signalling. In the current paper, we report studies from our laboratory and others which have provided new data on the molecular basis of the pharmacology and functioning of CCK1 and CCK2 receptors. It has been shown that: 1) homologous regions of the two receptors are involved in the binding site of CCK, however, positioning of CCK slightly differs in agreement with distinct pharmacophores of CCK toward the two receptors and receptor sequence variations; 2) Binding sites of most of non-peptide agonists/ antagonist are buried in the pocket formed by transmembrane helices and overlap that of CCK; Aromatic amino acids within and near the binding site, especially in helix VI, are involved in receptor activation; 4) Like for other members of family A of G-protein coupled receptors, residues of the binding sites as well as of conserved motifs such as E/DRY, NPXXY are crucial for receptor activation.
Foucaud
Magali
M
INSERM, Institut National de la Santé et de la Recherche Médicale, Unit 531, Institut Fédératif de recherche, Toulouse, France.
Archer-Lahlou
Elodie
E
Marco
Esther
E
Tikhonova
Irina G
IG
Maigret
Bernard
B
Escrieut
Chantal
C
Langer
Ingrid
I
Fourmy
Daniel
D
D000818:Animals; D001665:Binding Sites; D002766:Cholecystokinin / Q000378:metabolism*; D005755:Gastrins / Q000378:metabolism*; D006801:Humans; D043887:Receptor, Cholecystokinin B / Q000737:chemistry / Q000378:metabolism*; D011949:Receptors, Cholecystokinin / Q000737:chemistry / Q000378:metabolism*
D005755:Gastrins; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin; D002766:Cholecystokinin