Structural Basis for Receptor Activity-Modifying Protein-Dependent Selective Peptide Recognition by a G Protein-Coupled Receptor

• Published in: Molecular cell Vol. 58; no. 6; pp. 1040 - 1052
• Main Authors: Booe, Jason M., Walker, Christopher S., Barwell, James, Kuteyi, Gabriel, Simms, John, Jamaluddin, Muhammad A., Warner, Margaret L., Bill, Roslyn M., Harris, Paul W., Brimble, Margaret A., Poyner, David R., Hay, Debbie L., Pioszak, Augen A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 18.06.2015; Elsevier; Cell Press
• Subjects: Adrenomedullin - chemistry; Adrenomedullin - genetics; Adrenomedullin - metabolism; Amino Acid Sequence; Animals; BASIC BIOLOGICAL SCIENCES; Binding Sites - genetics; Calcitonin Gene-Related Peptide - chemistry; Calcitonin Gene-Related Peptide - genetics; Calcitonin Gene-Related Peptide - metabolism; Calcitonin Receptor-Like Protein - chemistry; Calcitonin Receptor-Like Protein - genetics; Calcitonin Receptor-Like Protein - metabolism; Chlorocebus aethiops; COS Cells; Crystallography, X-Ray; Humans; Models, Molecular; Molecular Sequence Data; Mutation; Peptides - chemistry; Peptides - genetics; Peptides - metabolism; Protein Binding; Protein Multimerization; Protein Structure, Secondary; Protein Structure, Tertiary; Receptor Activity-Modifying Protein 1 - chemistry; Receptor Activity-Modifying Protein 1 - genetics; Receptor Activity-Modifying Protein 1 - metabolism; Receptor Activity-Modifying Protein 2 - chemistry; Receptor Activity-Modifying Protein 2 - genetics; Receptor Activity-Modifying Protein 2 - metabolism; Sequence Homology, Amino Acid
• DOI: 10.1016/j.molcel.2015.04.018
• ISSN: 1097-2765

Association of receptor activity-modifying proteins (RAMP1-3) with the G protein-coupled receptor (GPCR) calcitonin receptor-like receptor (CLR) enables selective recognition of the peptides calcitonin gene-related peptide (CGRP) and adrenomedullin (AM) that have diverse functions in the cardiovascular and lymphatic systems. How peptides selectively bind GPCR:RAMP complexes is unknown. We report crystal structures of CGRP analog-bound CLR:RAMP1 and AM-bound CLR:RAMP2 extracellular domain heterodimers at 2.5 and 1.8 Å resolutions, respectively. The peptides similarly occupy a shared binding site on CLR with conformations characterized by a β-turn structure near their C termini rather than the α-helical structure common to peptides that bind related GPCRs. The RAMPs augment the binding site with distinct contacts to the variable C-terminal peptide residues and elicit subtly different CLR conformations. The structures and accompanying pharmacology data reveal how a class of accessory membrane proteins modulate ligand binding of a GPCR and may inform drug development targeting CLR:RAMP complexes. [Display omitted] •Crystal structures reveal how CGRP and AM peptides bind their heterodimeric receptors•CGRP and AM occupy a shared binding site on CLR with minimal contact to the RAMPs•Peptide binding modes were confirmed for intact receptors in cells by mutagenesis•Peptide selectivity arises from RAMP-specific contacts and subtle alteration of CLR Booe et al. report two crystal structures that reveal how selectivity of the GPCR CLR for CGRP and AM peptides is modulated by RAMP proteins. The peptides similarly occupy a shared binding site on CLR. RAMPs augment the binding site with distinct contacts to the peptides and subtly alter CLR.