Calcitonin, calcitonin gene-related peptide, adrenomedullin and amylin: homologous peptides, separate receptors and overlapping biological actions

1995 ◽  
Vol 133 (1) ◽  
pp. 17-20 ◽  
Author(s):  
Roman Muff ◽  
Walter Born ◽  
Jan A Fischer

Muff R, Born W, Fischer JA. Calcitonin, calcitonin gene-related peptide, adrenomedullin and amylin: homologous peptides, separate receptors and overlapping biological actions. Eur J Endocrinol 1995;133:17–20. ISSN 0804–4643 Calcitonin, calcitonin gene-related peptide, adrenomedullin and amylin are structurally related peptides with N-terminal 6–7 amino acid ring structures linked by a disulfide bridge and with amidated C-termini. Among the related bioactive peptides, the structures of the calcitonin receptor and subtypes thereof have been identified so far through molecular cloning. Cross-reaction between receptors of calcitonin, calcitonin gene-related peptide, adrenomedullin and amylin, as well as overlapping biological actions, anticipate that the respective receptors belong to a family of G-protein-coupled receptors that include those of parathyroid hormone, secretin and vasointestinal peptide. Jan A Fischer, Klinik Balgrist, Forchstrasse 340, CH-8008 Zurich, Switzerland

1995 ◽  
Vol 73 (7) ◽  
pp. 963-967 ◽  
Author(s):  
Roman Muff ◽  
Walter Born ◽  
Jan A. Fischer

Calcitonin, calcitonin gene related peptide, amylin, and adrenomedullin are structurally related polypeptides characterized by a six or seven amino acid ring structure linked by a disulfide bridge and an amidated C-terminus. They exhibit overlapping biological actions as a result of cross-reactivity between the different receptors. In this article, the respective receptors and G-protein-coupled postreceptor events are reviewed in relation to some of the biological actions of the peptides.Key words: adrenomedullin, amylin, calcitonin gene related peptide, cyclic AMP, receptors.


2013 ◽  
Vol 10 (79) ◽  
pp. 20120846 ◽  
Author(s):  
Shabana Vohra ◽  
Bruck Taddese ◽  
Alex C. Conner ◽  
David R. Poyner ◽  
Debbie L. Hay ◽  
...  

Modelling class B G-protein-coupled receptors (GPCRs) using class A GPCR structural templates is difficult due to lack of homology. The plant GPCR, GCR1, has homology to both class A and class B GPCRs. We have used this to generate a class A–class B alignment, and by incorporating maximum lagged correlation of entropy and hydrophobicity into a consensus score, we have been able to align receptor transmembrane regions. We have applied this analysis to generate active and inactive homology models of the class B calcitonin gene-related peptide (CGRP) receptor, and have supported it with site-directed mutagenesis data using 122 CGRP receptor residues and 144 published mutagenesis results on other class B GPCRs. The variation of sequence variability with structure, the analysis of polarity violations, the alignment of group-conserved residues and the mutagenesis results at 27 key positions were particularly informative in distinguishing between the proposed and plausible alternative alignments. Furthermore, we have been able to associate the key molecular features of the class B GPCR signalling machinery with their class A counterparts for the first time. These include the [K/R]KLH motif in intracellular loop 1, [I/L]xxxL and KxxK at the intracellular end of TM5 and TM6, the NPXXY/VAVLY motif on TM7 and small group-conserved residues in TM1, TM2, TM3 and TM7. The equivalent of the class A DRY motif is proposed to involve Arg 2.39 , His 2.43 and Glu 3.46 , which makes a polar lock with T 6.37 . These alignments and models provide useful tools for understanding class B GPCR function.


2016 ◽  
Vol 2 (1) ◽  
Author(s):  
Joseph J Gingell ◽  
John Simms ◽  
James Barwell ◽  
David R Poyner ◽  
Harriet A Watkins ◽  
...  

Abstract G protein-coupled receptors are allosteric proteins that control transmission of external signals to regulate cellular response. Although agonist binding promotes canonical G protein signalling transmitted through conformational changes, G protein-coupled receptors also interact with other proteins. These include other G protein-coupled receptors, other receptors and channels, regulatory proteins and receptor-modifying proteins, notably receptor activity-modifying proteins (RAMPs). RAMPs have at least 11 G protein-coupled receptor partners, including many class B G protein-coupled receptors. Prototypic is the calcitonin receptor, with altered ligand specificity when co-expressed with RAMPs. To gain molecular insight into the consequences of this protein–protein interaction, we combined molecular modelling with mutagenesis of the calcitonin receptor extracellular domain, assessed in ligand binding and functional assays. Although some calcitonin receptor residues are universally important for peptide interactions (calcitonin, amylin and calcitonin gene-related peptide) in calcitonin receptor alone or with receptor activity-modifying protein, others have RAMP-dependent effects, whereby mutations decreased amylin/calcitonin gene-related peptide potency substantially only when RAMP was present. Remarkably, the key residues were completely conserved between calcitonin receptor and AMY receptors, and between subtypes of AMY receptor that have different ligand preferences. Mutations at the interface between calcitonin receptor and RAMP affected ligand pharmacology in a RAMP-dependent manner, suggesting that RAMP may allosterically influence the calcitonin receptor conformation. Supporting this, molecular dynamics simulations suggested that the calcitonin receptor extracellular N-terminal domain is more flexible in the presence of receptor activity-modifying protein 1. Thus, RAMPs may act in an allosteric manner to generate a spectrum of unique calcitonin receptor conformational states, explaining the pharmacological preferences of calcitonin receptor-RAMP complexes. This provides novel insight into our understanding of G protein-coupled receptor-protein interaction that is likely broadly applicable for this receptor class.


2002 ◽  
Vol 30 (4) ◽  
pp. 451-455 ◽  
Author(s):  
A. C. Conner ◽  
D. L. Hay ◽  
S. G. Howitt ◽  
K. Kilk ◽  
Ü. Langel ◽  
...  

The receptor for calcitonin-gene-related peptide (CGRP) is a heterodimer formed by calcitonin-receptor-like receptor (CRLR), a type II (family B) G-protein-coupled receptor, and receptor-activity-modifying protein 1 (RAMP1), a single-membrane-pass protein. It is likely that the first seven or so amino acids of CGRP (which form a disulphide-bonded loop) interact with the transmembrane domain of CRLR to cause receptor activation. The rest of the CGRP molecule falls into three domains. Residues 28–37 and 8–18 are normally required for high-affinity binding, while residues 19–27 form a hinge region. The 28–37 region is almost certainly in direct contact with the receptor; 8–18 may make additional receptor contacts or may stabilize an appropriate conformation of 28–37. It is likely that these regions of CGRP interact both with CRLR and with the extracellular domain of RAMP1.


1993 ◽  
Vol 85 (4) ◽  
pp. 385-388 ◽  
Author(s):  
F. Njuki ◽  
C. G. Nicholl ◽  
A. Howard ◽  
J. C. W. Mak ◽  
P. J. Barnes ◽  
...  

1. Two rat clones have been isolated which are similar to known calcitonin-receptor sequences. One of these does not have the distribution expected of a calcitonin receptor. It is widely distributed, with extremely high levels of expression in the lung, where it is associated with the blood vessels. 2. This rat sequence may represent the receptor for calcitonin-gene-related peptide or islet amyloid polypeptide. Both have binding activity in the lung and are potent vasodilators. The gene represented by this sequence may therefore play an important role in the maintenance of vascular tone.


2021 ◽  
Vol 8 ◽  
Author(s):  
Giuseppe Deganutti ◽  
Silvia Atanasio ◽  
Roxana-Maria Rujan ◽  
Patrick M. Sexton ◽  
Denise Wootten ◽  
...  

Class B1 G protein-coupled receptors (GPCRs) are important targets for many diseases, including cancer, diabetes, and heart disease. All the approved drugs for this receptor family are peptides that mimic the endogenous activating hormones. An understanding of how agonists bind and activate class B1 GPCRs is fundamental for the development of therapeutic small molecules. We combined supervised molecular dynamics (SuMD) and classic molecular dynamics (cMD) simulations to study the binding of the calcitonin gene-related peptide (CGRP) to the CGRP receptor (CGRPR). We also evaluated the association and dissociation of the antagonist telcagepant from the extracellular domain (ECD) of CGRPR and the water network perturbation upon binding. This study, which represents the first example of dynamic docking of a class B1 GPCR peptide, delivers insights on several aspects of ligand binding to CGRPR, expanding understanding of the role of the ECD and the receptor-activity modifying protein 1 (RAMP1) on agonist selectivity.


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