Activating and inactivating mutations of the human, rat, equine and eel luteinizing hormone/ chorionic gonadotropin receptors (LH/CGRs)

Abstract

Gonadotropin receptors, such as luteinizing hormone/ chorionic gonadotropin receptor (LH/CGR), belong to a large superfamily of G protein-coupled receptors (GPCRs) characterized functionally by their interaction with guanine nucleotide-binding proteins and structurally by their seven transmembrane spanning domains, extracellular amino-terminus, and intracellular carboxy-terminus (Min et al., 1998;Byambaragchaa et al., 2021a).GPCRs exert their effects through G proteins, found at the cytoplasmic face of a cell's plasma membrane. G proteins are composed of three subunits: alpha (α), beta (β), and gamma (γ). The Gα subunit contains a highly conserved GTPase domain. The G protein β-and γ-subunits form a functional unit that can only be dissociated under denaturing conditions. Different combinations of these three subunits are important in governing the diverse signaling pathways regulated by GPCRs

Signal Transduction of C-Terminal Phosphorylation Regions for Equine Luteinizing Hormone/Chorionic Gonadotropin Receptor (eLH/CGR)

“…GPCR internalization is a specific process triggered by agonist stimulation, following desensitization of the signaling function of receptors, and increases cAMP responsiveness ( Min et al, 1998 ; Kim et al, 2019 ; Byambaragchaa et al, 2020 ; Min et al, 2021 ). Protein phosphorylation sites in various signaling pathways are important in regulating cell proliferation ( Seong et al, 2020 ).…”

“…Therefore, the C-terminal region of eLH/CGR has 14 potential phosphorylation sites and a highly conserved leucine motif that is essential for trafficking ( Duvernay et al, 2004 ; Byambaragchaa et al, 2021a , b , e ). The eCG, secreted from the placenta during early pregnancy, is a unique molecule that displays both LH- and FSH-like activities in non-equid species ( Min et al., 2019 , 2020 , 2021 ; Lee et al, 2021 ) and exhibits only LH-like activity in equine species ( Lee et al, 2017 , 2021 ; Park et al, 2017 ; Min et al, 2019 , 2020 ; Byambaragchaa et al, 2021c , d ).…”