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

Mol Cell. 2015 Jun 18;58(6):1040-52. doi: 10.1016/j.molcel.2015.04.018. Epub 2015 May 14.

Abstract

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adrenomedullin / chemistry
  • Adrenomedullin / genetics
  • Adrenomedullin / metabolism
  • Amino Acid Sequence
  • Animals
  • Binding Sites / genetics
  • COS Cells
  • 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
  • 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

Substances

  • Calcitonin Receptor-Like Protein
  • Peptides
  • RAMP1 protein, human
  • RAMP2 protein, human
  • Receptor Activity-Modifying Protein 1
  • Receptor Activity-Modifying Protein 2
  • Adrenomedullin
  • Calcitonin Gene-Related Peptide

Associated data

  • PDB/4RWF
  • PDB/4RWG