Details

Autor(en) / Beteiligte

• Feighner, Scott D
• Howard, Andrew D
• Prendergast, Kristine
• Palyha, Oksana C
• Hreniuk, Donna L
• Nargund, Ravi
• Underwood, Dennis
• Tata, James R
• Dean, Dennis C
• Tan, Carina P
• McKee, Karen Kulju
• Woods, John W
• Patchett, Arthur A
• Smith, Roy G
• Van der Ploeg, Lex H. T

Titel

Structural Requirements for the Activation of the Human Growth Hormone Secretagogue Receptor by Peptide and Nonpeptide Secretagogues

Ist Teil von

• Molecular endocrinology (Baltimore, Md.), 1998-01, Vol.12 (1), p.137-145

Ort / Verlag

United States: Endocrine Society

Erscheinungsjahr

1998

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Antibodies raised against an intracellular and extracellular domain of the GH secretagogue receptor (GHS-R) confirmed that its topological orientation in the lipid bilayer is as predicted for G protein-coupled receptors with seven transmembrane domains. A strategy for mapping the agonist-binding site of the human GHS-R was conceived based on our understanding of ligand binding in biogenic amine and peptide hormone G protein-coupled receptors. Using site-directed mutagenesis and molecular modeling, we classified GHS peptide and nonpeptide agonist binding in the context of its receptor environment. All peptide and nonpeptide ligand classes shared a common binding domain in transmembrane (TM) region 3 of the GHS-R. This finding was based on TM-3 mutation E124Q, which eliminated the counter-ion to the shared basic N+ group of all GHSs and resulted in a nonfunctional receptor. Restoration of function for the E124Q mutant was achieved by a complementary change in the MK-0677 ligand through modification of its amine side-chain to the corresponding alcohol. Contacts in other TM domains [TM-2 (D99N), TM-5 (M213K, S117A), TM-6 (H280F), and extracellular loop 1 (C116A)] of the receptor revealed specificity for the different peptide, benzolactam, and spiroindolane GHSs. GHS-R agonism, therefore, does not require identical disposition of all agonist classes at the ligand-binding site. Our results support the hypothesis that the ligand-binding pocket in the GHS-R is spatially disposed similarly to the well characterized catechol-binding site in theβ 2-adrenergic receptor.