Ligand selectivity of gonadotropin receptors. Role of the beta-strands of extracellular leucine-rich repeats 3 and 6 of the human luteinizing hormone receptor.
J Biol Chem
; 278(18): 15505-13, 2003 May 02.
Article
en En
| MEDLINE
| ID: mdl-12598521
ABSTRACT
The difference in hormone selectivity between the human follicle-stimulating hormone receptor (hFSH-R) and human luteinizing hormone/chorionic gonadotropin receptor (hLH-R) is determined by their approximately 350 amino acid-long N-terminal receptor exodomains that allow the mutually exclusive binding of human follicle-stimulating hormone (hFSH) and human luteinizing hormone (hLH) when these hormones are present in physiological concentrations. The exodomains of each of these receptors consist of a nine-leucine-rich repeat-containing subdomain (LRR subdomain) flanked by N- and C-terminal cysteine-rich subdomains. Chimeric receptors, in which the structural subdomains of the hFSH-R exodomain were substituted with those of the hLH-R, showed a similar high responsiveness to human chorionic gonadotropin (hCG) and hLH as long as they harbored the LRR subdomain of the hLH-R. In addition, these chimeric receptors showed no responsiveness to hFSH. The LRR subdomains of the gonadotropin receptor exodomains are predicted to adopt a horseshoe-like conformation, of which the hormone-binding concave surface is composed of nine parallel beta-strands. Receptors in which individual beta-strands of the hFSH-R were replaced with the corresponding hLH-R sequences revealed that hCG and hLH selectivity is predominantly determined by hLH-R beta-strands 3 and 6. A mutant receptor in which the hFSH-R beta-strands 3 and 6 were substituted simultaneously with their hLH-R counterparts displayed a responsiveness to hCG and hLH similar to that of the wild type hLH-R. Responsiveness to hFSH was not affected by most beta-strand substitutions, suggesting the involvement of multiple low-impact determinants for this hormone.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Receptores de HL
/
Estructura Secundaria de Proteína
/
Secuencias Repetitivas de Aminoácido
Límite:
Humans
Idioma:
En
Revista:
J Biol Chem
Año:
2003
Tipo del documento:
Article
País de afiliación:
Países Bajos