Byambaragchaa M, Joo HE, Kim SG, Kim YJ, Park GE, Min KS. Signal Transduction of C-Terminal Phosphorylation Regions for Equine Luteinizing Hormone/Chorionic Gonadotropin Receptor (eLH/CGR).
Dev Reprod 2022;
26:1-12. [PMID:
35528321 PMCID:
PMC9042392 DOI:
10.12717/dr.2022.26.1.1]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/04/2022] [Accepted: 02/12/2022] [Indexed: 12/05/2022]
Abstract
This study aimed to investigate the signal transduction of phosphorylation sites
at the carboxyl (C)-terminal region of equine luteinizing hormone/chorionic
gonadotropin receptor (eLH/ CGR). The eLH/CGR has a large extracellular domain
of glycoprotein hormone receptors within the G protein-coupled receptors. We
constructed a mutant (eLH/CGR-t656) of eLH/ CGR, in which the C-terminal
cytoplasmic tail was truncated at the Phe656 residue, through polymerase chain
reaction. The eLH/CGR-t656 removed 14 potential phosphorylation sites in the
intracellular C-terminal region. The plasmids were transfected into Chinese
hamster ovary (CHO)-K1 and PathHunter Parental cells expressing
β-arrestin, and agonist-induced cAMP responsiveness was analyzed. In
CHO-K1 cells, those expressing eLH/CGR-t656 were lower than those expressing
eLH/CGR wild-type (eLH/CGR-wt). The EC50 of the eLH/ CGR-t656 mutant
was approximately 72.2% of the expression observed in eLH/CGR-wt. The maximal
response in eLH/CGR-t656 also decreased to approximately 43% of that observed in
eLH/CGR-wt. However, in PathHunter Parental cells, cAMP activity and maximal
response of the eLH/CGR-t656 mutant were approximately 173.5% and 100.8%,
respectively, of that of eLH/CGR-wt. These results provide evidence that the
signal transduction of C-terminal phosphorylation in eLH/CGR plays a pivotal
role in CHO-K1 cells. The cAMP level was recovered in PathHunter Parental cells
expressing β-arrestin. We suggest that the signal transduction of the
C-terminal region phosphorylation sites is remarkably different depending on the
cells expressing β-arrestin in CHO-K1 cells.
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