This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hong, S. Articles by Ji, T. H. Search for Related Content PubMed PubMed Citation Articles by Hong, S. Articles by Ji, T. H.

The -Subunit of Human Choriogonadotropin Interacts with the Exodomain of the Luteinizing Hormone/Choriogonadotropin Receptor¹

Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071-3944

Address all correspondence and requests for reprints to: Dr. Tae H. Ji, Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071-3944. E-mail: ji{at}uwyo.edu

The LH/CG receptor, a G protein-coupled receptor, consists of two parts, the N-terminal extracellular segment (exodomain) and the membrane-associated C-terminal segment (endodomain). hCG initially binds the exodomain of the receptor and then, the hormone/exodomain complex is thought to make the secondary contact with the endodomain of the receptor and generate a hormone signal. However, little direct evidence is available about which hormone subunits ( or ß) interact with which domains of the receptor.

To determine whether the -subunit contacts the exodomain of its receptor, hCG containing [¹²⁵I] and truncated exodomain lacking the endodomain were prepared. They were chemically cross-linked, and the resulting cross-linked complexes were solubilized and electrophoresed. The results indicate that the -subunit of hCG was directly and specifically cross-linked to the exodomain. To verify the cross-linked exodomain by the independent method, the Flag epitope was inserted between the signal sequence and the mature exodomain. hCG containing [¹²⁵I] was cross-linked to the Flag exodomain, and the resulting cross-linked hCG/Flag exodomain complexes were immunoprecipitated with anti-Flag antibody. The results show that the material cross-linked to hCG containing [¹²⁵I] is indeed the exodomain. In conclusion, our results show the direct interaction of the -subunit with the exodomain and, therefore, its crucial role in the hormone-receptor interaction in addition to its involvement in signal generation.

This article has been cited by other articles:

				S. Roy, S. Setlur, R. A. Gadkari, H. N. Krishnamurthy, and R. R. Dighe Translational Fusion of Two {beta}-Subunits of Human Chorionic Gonadotropin Results in Production of a Novel Antagonist of the Hormone Endocrinology, August 1, 2007; 148(8): 3977 - 3986. [Abstract] [Full Text] [PDF]

				R. M. Thomas, C. A. Nechamen, J. E. Mazurkiewicz, M. Muda, S. Palmer, and J. A. Dias Follice-Stimulating Hormone Receptor Forms Oligomers and Shows Evidence of Carboxyl-Terminal Proteolytic Processing Endocrinology, May 1, 2007; 148(5): 1987 - 1995. [Abstract] [Full Text] [PDF]

				P. Nurwakagari, A. Breit, C. Hess, H. Salman-Livny, D. Ben-Menahem, and T. Gudermann A conformational contribution of the luteinizing hormone-receptor ectodomain to receptor activation J. Mol. Endocrinol., February 1, 2007; 38(2): 259 - 275. [Abstract] [Full Text] [PDF]

				I. Ji, C. Lee, Y. Song, P. M. Conn, and T. H. Ji Cis- and Trans-Activation of Hormone Receptors: the LH Receptor Mol. Endocrinol., June 1, 2002; 16(6): 1299 - 1308. [Abstract] [Full Text] [PDF]

				C. Lee, I. Ji, K. Ryu, Y. Song, P. M. Conn, and T. H. Ji Two Defective Heterozygous Luteinizing Hormone Receptors Can Rescue Hormone Action J. Biol. Chem., May 3, 2002; 277(18): 15795 - 15800. [Abstract] [Full Text] [PDF]