Evolved regulation of gonadotropin-releasing hormone receptor cell surface expression

Author： Janovick Jo Ulloa-Aguirre Alfredo Conn P.

ISSN： 0969-711X

Source： Endocrine Journal, Vol.22, Iss.3, 2003-12, pp. : 317-327

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

Dominant negative effects of mutant gonadotropin-releasing hormone (GnRH) receptors (GnRHR; isolated from patients with idiopathic hypogonadotropic hypogonadism) on plasma membrane expression (PME) and function of the wt GnRHR were examined. In addition, we assessed the effect of mutants on wt GnRHR with receptor modifications that, by themselves, diminished PME. Among such mechanisms that restrict PME of GnRHR in primates are: (a) addition of the primate-specific K¹⁹¹ and (b) deletion of the carboxyl tail (“C-tail”) found in pre-mammalian species (fish, birds) of GnRHR. We prepared rat (r) and human (h) GnRHR plasmids (88% homologous), each with or without the K¹⁹¹; chimeras were then made with C-tail or each of four truncated fragments (selected to isolate consensus sites for palmitoylation or phosphorylation) of the 51-amino-acid Ser-rich piscine GnRHR C-tail and then expressed in COS-7 cells. The data suggest that the dominant negative effect of the mutants on the hGnRHR requires intrinsic low PME that co-evolved with the dominant-negative effect. The data further reveal that additional modifications must have occurred in primates that are important for both the diminution of the PME and the development of the dominant negative effect of the mutants.