Bioinformatics and type II G-protein-coupled receptors

2002 ◽  
Vol 30 (4) ◽  
pp. 473-479 ◽  
Author(s):  
S. M. Foord ◽  
S. Jupe ◽  
J. Holbrook
Keyword(s):  
Parathyroid Hormone ◽  
G Protein ◽  
Sequence Homology ◽  
G Protein Coupled Receptors ◽  
Type Ii ◽  
Corticotrophin Releasing Factor ◽  
Large N ◽  
G Protein Coupled ◽  
7Tm Receptors

The best known family B, or Type II, G-protein-coupled receptors (GPCRs) recognize peptides as ligands. The receptors for corticotrophin-releasing factor, parathyroid hormone and secretin typify this group. However, there are only 15 such GPCRs. Many other receptors share sequence homology and have been assigned to this family. The ten ‘Frizzled’ and one ‘Smoothened’ receptors show the lowest sequence homology and are not necessarily G-protein coupled. Drosophila genetics have enabled our understanding of their biology. In contrast, relatively little is known about the largest group with family B, the 33 ‘large amino termini’ or large N-terminal family B seven-transmembrane (LNB 7TM) receptors. This review highlights the similarities found between family B receptors and provides a classification of LNB 7TM receptors.

A cloning strategy for G-protein-coupled hormone receptors: the ovine beta 1-adrenergic receptor

1995 ◽  
Vol 7 (3) ◽  
pp. 521 ◽  
Author(s):  
JF Padbury ◽  
YT Tseng ◽  
JA Waschek
Keyword(s):  
G Protein ◽  
Sequence Homology ◽  
Hormone Receptors ◽  
Genomic Library ◽  
Receptor Gene ◽  
G Protein Coupled Receptors ◽  
Transcriptional Level ◽  
Fetal Life ◽  
Single Clone ◽  
G Protein Coupled

Regulation of beta 1-adrenergic receptors is unusual in developing animals. For example, glucocorticoid-and thyroid hormone-responsiveness for several genes is seen in animals treated during fetal life but beta 1-responsiveness is not seen until after birth. In order to investigate this at the transcriptional level, the ovine beta 1 receptor gene was cloned from a sheep genomic library. An approach using high-stringency screening with cDNA probes and oligonucleotides from regions of human and rat genes conserved but unique to the beta 1 receptor but not to other seven transmembrane, G-protein-coupled receptors. Over 800,000 clones were screened from which 40-50 positive clones were identified by each of the probes. There was, however, only a single clone which was recognized by each of the probes. A 5-kb insert was subcloned and shown to contain sequences which hybridized to each of the probes. Using the restriction map of the rat beta 1 receptor, a 1.0-kb Pst1 internal fragment was further subcloned for sequence identification. Confirmation of this fragment as the ovine beta 1 receptor was based on homology of the beta 1 receptor from other species and tissue distribution of mRNA. Nucleotide sequence homology was 93% with the human beta 1 receptor and 84% with rat. Amino acid sequence homology was > 75% and approached 100% in the transmembrane regions. The approach described represents a practical approach to cloning and identification of hormone receptors from the highly homologous members of the seven-transmembrane, G-protein-coupled receptors.

Adrenomedullin: receptor and signal transduction

2002 ◽  
Vol 30 (4) ◽  
pp. 432-437 ◽  
Author(s):  
D. M. Smith ◽  
H. A. Coppock ◽  
D. J. Withers ◽  
A. A. Owji ◽  
D. L. Hay ◽  
...  
Keyword(s):  
G Protein ◽  
Vascular Tissue ◽  
G Protein Coupled Receptors ◽  
Type Ii ◽  
Calcitonin Gene ◽  
Adrenomedullin Receptor ◽  
Receptor Activity Modifying Proteins ◽  
G Protein Coupled ◽  
Chemical Cross Linking

Adrenomedullin is a vascular tissue peptide and a member of the calcitonin family of peptides, which includes calcitonin, calcitonin-gene-related peptide (CGRP) and amylin. Its many biological actions are mediated via CGRP type 1 (CGRP1) receptors and by specific adrenomedullin receptors. Although the pharmacology of these receptors is distinct, they are both represented in molecular terms by the type II family G-protein-coupled receptor, calcitonin-receptor-like receptor (CRLR). The specificity here is defined by co-expression of receptor-activity-modifying proteins (RAMPs). CGRP1 receptors are represented by CRLR and RAMP1, and specific adrenomedullin receptors by CRLR and RAMP2 or 3. Here we discuss how CRLR/RAMP2 relates to adrenomedullin binding, pharmacology and pathophysiology, and how chemical cross-linking of receptor-ligand complexes in tissue relates to that in CRLR/RAMP2-expressing cells. CRLR, like other type II family G-protein-coupled receptors, signals via Gs and adenylate cyclase activation. We demonstrated that adrenomedullin signalling in cell lines expressing specific adrenomedullin receptors followed this expected pattern.

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