N-linked glycosylation facilitates processing and cell surface expression of rat luteinizing hormone receptor

2005 ◽  
Vol 235 (1-2) ◽  
pp. 11-19 ◽  
Author(s):  
Christine L. Clouser ◽  
K.M.J. Menon
Keyword(s):  
Luteinizing Hormone ◽  
Cell Surface ◽  
Hormone Receptor ◽  
Surface Expression ◽  
Luteinizing Hormone Receptor ◽  
Cell Surface Expression

scholarly journals Differential Expression and Functional Characterization of Luteinizing Hormone Receptor Splice Variants in Human Luteal Cells: Implications for Luteolysis

Endocrinology ◽  
2009 ◽  
Vol 150 (6) ◽  
pp. 2873-2881 ◽  
Author(s):  
Rachel E. Dickinson ◽  
Alan J. Stewart ◽  
Michelle Myers ◽  
Robert P. Millar ◽  
W. Colin Duncan
Keyword(s):  
Cell Surface ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Splice Variants ◽  
Primary Cultures ◽  
Surface Expression ◽  
Full Length ◽  
Luteinizing Hormone Receptor ◽  
Cell Surface Expression ◽  
Truncated Form

The human LH receptor (LHR) plays a key role in luteal function and the establishment of pregnancy through its interaction with the gonadotropins LH and human chorionic gonadotropin. We previously identified four splice variants of the LHR in human luteinized granulosa cells (LGCs) and corpora lutea (CL). Real-time quantitative PCR revealed that expression of the full-length LHR (LHRa) and the most truncated form (LHRd) changed significantly in CL harvested at different stages of the ovarian cycle (P < 0.01, ANOVA). LHRa expression was reduced in the late luteal CL (P < 0.05). Conversely, an increase in LHRd expression was observed in the late luteal CL (P < 0.01). Chronic manipulation of human chorionic gonadotropin in LGC primary cultures supported the in vivo findings. LHRd encodes a protein lacking the transmembrane and carboxyl terminal domains. COS-7 cells expressing LHRd were unable to produce cAMP in response to LH stimulation. COS-7 cells coexpressing LHRd and LHRa also failed to generate cAMP in response to LH, suggesting that this truncated form has a negative effect on the signaling of LHRa. Immunofluorescence staining of LGC and COS-7 cells implied that there is a reduction in cell surface expression of LHRa when LHRd is present. Overall, these results imply expression of LHR splice variants is regulated in the human CL. Furthermore, during functional luteolysis a truncated variant could modulate the cell surface expression and activity of full-length LHR.

scholarly journals Loss-of-Function Mutations in the Human Luteinizing Hormone Receptor Predominantly Cause Intracellular Retention

Endocrinology ◽  
2016 ◽  
Vol 157 (11) ◽  
pp. 4364-4377 ◽  
Author(s):  
Claire Louise Newton ◽  
Ross Calley Anderson ◽  
Arieh Anthony Katz ◽  
Robert Peter Millar
Keyword(s):  
Luteinizing Hormone ◽  
Cell Surface ◽  
Ligand Binding ◽  
Hormone Receptors ◽  
Receptor Activation ◽  
Luteinizing Hormone Receptor ◽  
Cell Surface Expression ◽  
Receptor Function ◽  
Loss Of Function ◽  
Pharmacological Chaperone

Mutations in G protein–coupled receptors (GPCRs) have been identified for many endocrine hormone signaling deficiencies. Inactivating mutations can impair ligand binding, receptor activation/coupling to signaling pathways, or can cause receptor misfolding and consequent impaired expression at the cell membrane. Here we examine the cell surface expression, ligand binding, and signaling of a range of mutant human luteinizing hormone receptors (LHRs) identified as causing reproductive dysfunction in human patients. The data obtained reveal how mutations in GPCRs can have diverse and severely deleterious effects on receptor function. Furthermore, it was found that impaired functionality of the majority of the mutant LHRs was due to reduced expression at the cell surface (14/20) while only two mutations caused impaired binding affinity and two impaired in signaling. An additional two mutations were found to cause no impairment of receptor function. These data demonstrate that the majority of LHR mutations lead to intracellular retention and highlight the potential for novel pharmacological chaperone therapeutics that can “rescue” expression/function of retained mutant GPCRs.

Antibodies to Purified Luteinizing Hormone Receptor Localize the Receptor at the Luteal Cell Surface*

Endocrinology ◽  
1981 ◽  
Vol 109 (5) ◽  
pp. 1399-1403 ◽  
Author(s):  
KALERVÖ METSIKKO ◽  
HANNU RAJANIEMI
Keyword(s):  
Luteinizing Hormone ◽  
Cell Surface ◽  
Hormone Receptor ◽  
Luteinizing Hormone Receptor ◽  
Luteal Cell

scholarly journals A Point Mutation in the Human Melanin Concentrating Hormone Receptor 1 Reveals an Important Domain for Cellular Trafficking

2005 ◽  
Vol 19 (10) ◽  
pp. 2579-2590 ◽  
Author(s):  
Jun Fan ◽  
Stephen J. Perry ◽  
Yinghong Gao ◽  
David A. Schwarz ◽  
Richard A. Maki
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Surface ◽  
Point Mutation ◽  
Hormone Receptor ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Single Mutation ◽  
Wild Type ◽  
Melanin Concentrating Hormone ◽  
Type Receptor

Abstract G protein-coupled receptors (GPCRs) are heptahelical integral membrane proteins that require cell surface expression to elicit their effects. The lack of appropriate expression of GPCRs may be the underlying cause of a number of inherited disorders. There is evidence that newly synthesized GPCRs must attain a specific conformation for their correct trafficking to the cell surface. In this study, we show that a single point mutation in human melanin-concentrating hormone receptor (hMCHR1) at position 255 (T255A), which is located at the junction of intracellular loop 3 and transmembrane domain 6, reduces the hMCHR1 cell surface expression level to 20% of that observed for the wild-type receptor. Most of these mutant receptors are located intracellularly, as opposed to the wild-type receptor, which is located primarily on the cell surface. Immunoprecipitation experiments show that hMCHR1-T255A has reduced glycosylation compared with the wild-type receptor and is associated with the chaperone protein, calnexin, and it colocalizes in the endoplasmic reticulum with KDEL-containing proteins. We also demonstrate that a cell-permeable small molecule antagonist of hMCHR1 can function as a pharmacological chaperone to restore cell surface expression of this and other MCHR1 mutants to wild-type levels. Once rescued, the T255A mutant couples to Gq proteins as efficiently as the wild-type receptor. These data suggest that this single mutation produces an hMCHR1 that folds incorrectly, resulting in its retention in the endoplasmic reticulum, but once rescued to the cell surface can still function normally.

scholarly journals A Homozygous Microdeletion in Helix 7 of the Luteinizing Hormone Receptor Associated with Familial Testicular and Ovarian Resistance Is Due to Both Decreased Cell Surface Expression and Impaired Effector Activation by the Cell Surface Receptor

1998 ◽  
Vol 12 (3) ◽  
pp. 442-450 ◽  
Author(s):  
Ana C. Latronico ◽  
Yaohui Chai ◽  
Ivo J.P. Arnhold ◽  
Xuebo Liu ◽  
Berenice B. Mendonca ◽  
...  
Keyword(s):  
Cell Surface ◽  
Transmembrane Helix ◽  
External Genitalia ◽  
Surface Expression ◽  
Luteinizing Hormone Receptor ◽  
Cell Surface Receptor ◽  
Cell Surface Expression ◽  
Binding Assays ◽  
Mutant Receptor ◽  
Surface Receptor

Abstract In this report, the genomic DNA was examined from two siblings with gonadal LH resistance. A 46,XY pseudohermaphrodite presented with female external genitalia and his 46,XX sister exhibited menstrual irregularities (oligoamenorrhea) and infertility. Exons 1–11 of the LH receptor (LHR) gene were amplified by the PCR using different sets of intronic primers and were directly sequenced. Sequencing revealed that both individuals carried a deletion of nucleotides 1822–1827, resulting in the deletion of Leu-608 and Val-609 within the seventh transmembrane helix. This mutation was introduced into a recombinant human (h) LHR cDNA. Transfections of 293 cells with hLHR(wt) vs. hLHR(ΔL608,V609) revealed that very little of the mutant receptor was expressed at the cell surface. This was due to both a decrease in the total amount of receptor expressed as well as to an increased intracellular retention of the mutant receptor. In spite of the decreased cell surface expression of the mutant, sufficient amounts were present to allow for assessment of its functions. Equilibrium binding assays showed that the cell surface hLHR(ΔL608,V609) binds hCG with an affinity comparable to that of the wild-type receptor. However, the cells expressing the hLHR(ΔL608,V609) exhibit only a 1.5- to 2.4-fold stimulation of cAMP production in response to hCG. In contrast, cells expressing comparably low levels of hLHR(wt) responded to hCG with 11- to 30-fold increases of cAMP levels. Therefore, the testicular and ovarian unresponsiveness to LH in these patients appears to be due to a mutation of the hLHR gene in which Leu-608 and Val-609 are deleted. As a consequence, the majority of the mutant receptor is retained intracellularly. The small percentage of mutant receptor that is expressed at the cell surface binds hormone normally but is unable to activate Gs.

scholarly journals Constitutive Activating and Inactivating Mutants of Eel Luteinizing Hormone Receptor

2020 ◽  
Author(s):  
Munkhzaya Byambaragchaa ◽  
Dong-An Kim ◽  
Dae-Jung Kim ◽  
Sun-Mee Hong ◽  
Myung-Hwa Kang ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Luteinizing Hormone ◽  
Cell Surface ◽  
Hormone Receptor ◽  
Luteinizing Hormone Receptor ◽  
Cell Surface Receptors ◽  
Wild Type ◽  
Surface Receptors ◽  
Agonist Stimulation ◽  
In Cells

We analyzed signal transduction of three constitutively activating mutants (M410T, L469R, and D590Y) and two inactivating mutants (D417N and Y558F) of the eel luteinizing hormone receptor (eel LHR), known to occur in human LHR. The objective of this study was to assess the functional effects of these mutations in signal transduction and cell surface loss of receptor. Mutant receptors were transiently expressed in Chinese hamster ovary (CHO-K1) cells. Eel LH-stimulated accumulation of cyclic adenosine monophosphate (cAMP) was measured by homogeneous time-resolved fluorescence (HTRF) assays. The loss of receptors from the cells surface was measured using an enzyme-linked immunosorbent assay (ELISA) in human embryonic kidney (HEK) 293 cells. The cAMP response in cells expressing the wild type eel LHR was increased in a dose-dependent manner using eel LH ligand stimulation. Compared with the wild type, cells expressing the activating mutants (M410T, L469R, and D590Y), exhibited a 4.0-, 19.1-, and 7.8-fold increase in basal cAMP response without agonist stimulation, respectively. Their maximal responses to agonist stimulation were approximately 65%, 52%, and 98%, respectively, of those of the wild type. The inactivating mutants (D417N and Y558F) did not completely impair signal transduction, and their maximal responses were only 33% and25 % of those of wild type. These data clearly showed that the eel LHR-L469R and D590Y, activating mutants enhanced the rate of the loss of cell surface receptors following treatment with eel LH. Thus, the loss of cell surface receptors in cells expressing mutant eel LHRs was consistent with the eel LH agonist-induced production of cAMP. Our results suggested that the activation of the eel LHR requires appropriate loss of LHR-ligand complexes from the cell surface.

Evolved Regulation of Gonadotropin-Releasing Hormone Receptor Cell Surface Expression

Endocrine ◽  
2003 ◽  
Vol 22 (3) ◽  
pp. 317-328 ◽  
Author(s):  
Jo Ann Janovick ◽  
Alfredo Ulloa-Aguirre ◽  
P. Michael Conn
Keyword(s):  
Cell Surface ◽  
Hormone Receptor ◽  
Receptor Cell ◽  
Surface Expression ◽  
Gonadotropin Releasing Hormone ◽  
Cell Surface Expression ◽  
Releasing Hormone ◽  
Gonadotropin Releasing Hormone Receptor
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