Pharmacological characterization of soluble human FSH receptor extracellular domain: facilitated secretion by coexpression with FSH.
Follicle-stimulating hormone (FSH) is a member of the glycoprotein hormone family that regulates gametogenesis and steroidogenesis. Glycoprotein hormones signal through a unique class of G-protein-coupled receptors (GPCRs) that have a long extracellular domain (ECD), which is the primary site for hormone binding. The hFSHR-ECD was expressed in insect cells as a C-terminal, epitope-tagged protein resulting in production of soluble active receptor in the intracellular compartment and in the secreted culture medium. Coexpression of hFSHR-ECD with FSHbeta or FSHalpha/beta increased the secretion of the truncated receptor. Pharmacological studies to assess ligand-receptor interactions without the transmembrane domains showed higher affinity values (K(D)S) for [125I]hFSH using mammalian-expressed full-length receptor, secreted hFSHR-ECD, or secreted hFSHR-ECD coexpressed with FSHbeta, whereas the K(D) value for hFSHR-ECD coexpressed with FSHalpha/beta subunits showed lower affinity. Competition of other glycoprotein hormones for secreted hFSHR-ECD coexpressed with FSHbeta or mammalian full-length hFSHR resulted in similar binding profiles, indicating analogous pharmacology. Finally, we have demonstrated that a small molecule, suramin, which has been reported to interact with the mammalian full-length FSHR, competes for the binding of [125I]hFSH by interacting directly at the hFSHR-ECD.
Stevis
P E
PE
Molecular Biology Division, Women's Health Research Institute, Wyeth-Ayerst Research, Radnor, PA 19087, USA. StevisP@WAR.Wyeth.com
Deecher
D C
DC
Lopez
F J
FJ
Frail
D E
DE
D000818:Animals; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D005110:Extracellular Space / Q000737:chemistry; D005640:Follicle Stimulating Hormone / Q000096:biosynthesis*; D006801:Humans; D007700:Kinetics; D009036:Moths; D011485:Protein Binding; D011962:Receptors, FSH / Q000096:biosynthesis* / Q000737:chemistry; D011994:Recombinant Proteins / Q000096:biosynthesis; D012995:Solubility; D018411:Spodoptera; D013498:Suramin / Q000494:pharmacology
D011962:Receptors, FSH; D011994:Recombinant Proteins; D013498:Suramin; D005640:Follicle Stimulating Hormone