GPC receptors and not ligands decide the binding mode in neuropeptide Y multireceptor/multiligand system.
Many G protein-coupled receptors belong to families of different receptor subtypes, which are recognized by a variety of distinct ligands. To study such a multireceptor/multiligand system, we investigated the Y-receptor family. This family consists of four G protein-coupled Y receptors in humans (hY 1R, hY 2R, hY 4R, and hY 5R) and is activated by the so-called NPY hormone family, which itself consists of three native peptide ligands named neuropeptide Y (NPY), pancreatic polypeptide (PP), and peptide YY (PYY). The hY 5R shows high affinity for all ligands, although for PP binding, the affinity is slightly decreased. As a rational explanation, we suggest that Tyr (27) is lost as a contact point between PP and the hY 5R in contrast to NPY or PYY. Furthermore, several important residues for ligand binding were identified by the first extensive mutagenesis study of the hY 5R. Using a complementary mutagenesis approach, we were able to discover a novel interaction point between hY 5R and NPY. The interaction between NPY(Arg (25)) and hY 5R(Asp (2.68)) as well as between NPY(Arg (33)) and hY 5R(Asp (6.59)) is maintained in the binding of PYY and PP to hY 5R but different to the PP-hY 4R and NPY-hY 1R contact points. Therefore, we provide evidence that the receptor subtype and not the pre-orientated conformation of the ligand at the membrane decides the binding mode. Furthermore, the first hY 5R model was set up on the basis of the crystal structure of bovine rhodopsin. We can show that most of the residues identified to be critical for ligand binding are located within the now postulated binding pocket.
Lindner
Diana
D
Leipzig University, Institute of Biochemistry, Brüderstrasse 34, 04103 Leipzig, Germany.
van Dieck
Jan
J
Merten
Nicole
N
Mörl
Karin
K
Günther
Robert
R
Hofmann
Hans-Jörg
HJ
Beck-Sickinger
Annette G
AG
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001120:Arginine / Q000737:chemistry / Q000378:metabolism; D001224:Aspartic Acid / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D017124:Conserved Sequence; D006801:Humans; D008024:Ligands; D008954:Models, Biological; D008969:Molecular Sequence Data; D009478:Neuropeptide Y / Q000737:chemistry / Q000378:metabolism; D017476:Receptors, Neuropeptide Y / Q000737:chemistry* / Q000378:metabolism
D008024:Ligands; D009478:Neuropeptide Y; D017476:Receptors, Neuropeptide Y; D001224:Aspartic Acid; D001120:Arginine