The long-term objective of this project is to identify how the interaction between the gonadotropins and their receptors results in signal transduction. Particular emphasis will be placed on developing a model of receptor structure and identifying changes in receptor structure which occur after binding of hormone agonists and antagonists.
Specific aims are: 1) to identify the disulfide bonds of the luteinizing hormone receptor (LHR) and follicle stimulating hormone receptors (FSHR), 2) to characterize changes in the extracellular N-terminus and extracellular portions of the transmembrane domain which occur following binding of human chorionic gonadotropin (hCG) and hFSH, 3) to characterize changes in the intracellular portions of the receptors caused by hormone binding, and 4) to distinguish changes in the receptors which are essential for hormone activity from those which occur on binding of antagonists.
Specific aim #1 depends on the use of mutagenesis to introduce methionine residues into various portions of the LHR and FSHR. This will permit the receptors to be cleaved with CNBr into known fragments. The locations of the disulfide bonds will be determined from the molecular weights of the fragments as determined in Western blots.
Specific aim #2 depends on incorporation f radioiodine into specific tyrosine residues which are on the extracellular surface of the receptor. These will be identified by immunoprecipitation of the receptors, cleaving the receptors with CNBr, and monitoring radioactivity in specific peptide fragments. Studies are planned to determine if the presence of hormone alters the incorporation of radioiodine into these tyrosines. Procedures for specific aim #3 are similar to those of aim #2 except that the cytoplasmic surface of the receptor will be studied.
In specific aim #4 the influences of deglycosylated hormones and other antagonists on tyrosine radiolabeling will be compared with those of the native hormones. These studies should improve knowledge of the manner in which the glycoprotein hormones initiate their biological responses. Further, since the gonadotropin receptors are part of a larger class of similar proteins which participate in signal transduction, information learned should be widely applicable.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD014907-12
Application #
2197141
Study Section
Biochemical Endocrinology Study Section (BCE)
Project Start
1983-08-01
Project End
1996-03-31
Budget Start
1995-04-01
Budget End
1996-03-31
Support Year
12
Fiscal Year
1995
Total Cost
Indirect Cost
Name
University of Medicine & Dentistry of NJ
Department
Obstetrics & Gynecology
Type
Schools of Medicine
DUNS #
622146454
City
Piscataway
State
NJ
Country
United States
Zip Code
08854
Moyle, William R; Lin, Win; Myers, Rebecca V et al. (2005) Models of glycoprotein hormone receptor interaction. Endocrine 26:189-205
Bernard, Michael P; Lin, Win; Myers, Rebecca et al. (2005) Crosslinked bifunctional gonadotropin analogs with reduced efficacy. Mol Cell Endocrinol 233:25-31
Xing, Yongna; Myers, Rebecca V; Cao, Donghui et al. (2004) Glycoprotein hormone assembly in the endoplasmic reticulum: II. Multiple roles of a redox sensitive beta-subunit disulfide switch. J Biol Chem 279:35437-48
Bernard, Michael P; Cao, Donghui; Myers, Rebecca V et al. (2004) Tight attachment of chitin-binding-domain-tagged proteins to surfaces coated with acetylated chitosan. Anal Biochem 327:278-83
Moyle, William R; Xing, Yongna; Lin, Win et al. (2004) Model of glycoprotein hormone receptor ligand binding and signaling. J Biol Chem 279:44442-59
Bernard, Michael P; Lin, Win; Cao, Donghui et al. (2004) Only a portion of the small seatbelt loop in human choriogonadotropin appears capable of contacting the lutropin receptor. J Biol Chem 279:44438-41
Xing, Yongna; Myers, Rebecca V; Cao, Donghui et al. (2004) Glycoprotein hormone assembly in the endoplasmic reticulum: IV. Probable mechanism of subunit docking and completion of assembly. J Biol Chem 279:35458-68
Xing, Yongna; Myers, Rebecca V; Cao, Donghui et al. (2004) Glycoprotein hormone assembly in the endoplasmic reticulum: I. The glycosylated end of human alpha-subunit loop 2 is threaded through a beta-subunit hole. J Biol Chem 279:35426-36
Xing, Yongna; Myers, Rebecca V; Cao, Donghui et al. (2004) Glycoprotein hormone assembly in the endoplasmic reticulum: III. The seatbelt and its latch site determine the assembly pathway. J Biol Chem 279:35449-57
Xing, Yongna; Lin, Win; Jiang, Mei et al. (2004) Use of protein knobs to characterize the position of conserved alpha-subunit regions in lutropin receptor complexes. J Biol Chem 279:44427-37

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