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Towards understanding the glycoprotein hormone receptors
R Salesse1, J J Remy, J M Levin
1Unité d'Ingénierie des Protéines, INRA-Biotechnologies, Jouy-en-Josas, France.
Biochimie
|January 1, 1991
Summary
Glycoprotein hormone receptors for lutropin (LH), follitropin (FSH), and thyrotropin (TSH) share conserved transmembrane regions but have variable extracellular domains. Sequence analysis reveals potential hormone binding sites within the extracellular loops.
Area of Science:
- Molecular Endocrinology
- G-Protein Coupled Receptors
- Structural Biology
Background:
- The glycoprotein hormone family includes lutropin (LH), follitropin (FSH), thyrotropin (TSH), and choriogonadotropin (CG).
- These hormones signal through specific G-protein coupled membrane receptors.
- Recent cloning of these three receptors allows for detailed molecular analysis.
Purpose of the Study:
- To analyze the amino acid sequences of glycoprotein hormone receptors.
- To identify conserved regions and predict structural features related to hormone binding.
- To explore future research directions enabled by receptor cloning.
Main Methods:
- Amino acid sequence analysis of glycoprotein hormone receptors.
- Comparison of homology across the three receptor types.
- Secondary structure prediction to identify ordered regions and loops.
Main Results:
- Extracellular domains show less than 45% homology, while transmembrane domains exhibit ~70% residue conservation.
- Limited sequence homology (~20%) exists with other G-protein coupled receptors.
- Secondary structure predictions indicate repeating ordered segments in the extracellular head, with intervening loops as potential hormone binding sites.
Conclusions:
- Glycoprotein hormone receptors possess distinct extracellular and conserved transmembrane regions.
- Intervening loops in the extracellular domain are proposed as key sites for hormone interaction.
- Receptor cloning facilitates further functional studies, including protein production and dimerization analysis.