scholarly journals A novel G protein-coupled receptor for starfish gonadotropic hormone, relaxin-like gonad-stimulating peptide

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242877
Author(s):  
Masatoshi Mita ◽  
Shin Matsubara ◽  
Tomohiro Osugi ◽  
Akira Shiraishi ◽  
Azumi Wada ◽  
...  
Keyword(s):  
G Protein ◽  
Ovarian Follicle ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Follicle Cells ◽  
G Protein Coupled Receptor ◽  
Asterias Amurensis ◽  
Relaxin Family ◽  
Species Specific ◽  
G Protein Coupled

Gonadotropic hormones play important regulatory roles in reproduction. Relaxin-like gonad-stimulating peptide (RGP) is a gonadotropin-like hormone in starfish. However, a receptor for RGP remains to be identified. Here, we describe the identification of an authentic receptor for RGP (RGPR) in the starfish, Patiria pectinifera. A binding assay using radioiodinated P. pectinifera RGP (PpeRGP) revealed that RGPR was expressed in ovarian follicle cells. A RGPR candidate was identified by homology-searching of transcriptome data of P. pectinifera follicle cells. Based on the contig sequences, a putative 947-amino acid PpeRGPR was cloned from follicle cells. Like the vertebrate relaxin family peptide receptors (RXFP 1 and 2), PpeRGPR was a G protein-coupled receptor that harbored a low-density lipoprotein-receptor class A motif and leucine-rich repeat sequences in the extracellular domain of the N-terminal region. Sf9 cells transfected with Gαq16-fused PpeRGPR activated calcium ion mobilization in response to PpeRGP, but not to RGP of another starfish Asterias amurensis, in a dose-dependent fashion. These results confirmed the species-specific reactivity of RGP and the cognate receptor. Thus, the present study provides evidence that PpeRGPR is a specific receptor for PpeRGP. To the best of our knowledge, this is the first report on the identification of a receptor for echinoderm RGP.

Low-density lipoprotein (LDL) binds to a G-protein coupled receptor in human platelets

2001 ◽  
Vol 155 (1) ◽  
pp. 99-112 ◽  
Author(s):  
Javier Pedreño ◽  
Eva Hurt-Camejo ◽  
Olov Wiklund ◽  
Lina Badimón ◽  
Lluis Masana
Keyword(s):  
G Protein ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Human Platelets ◽  
Low Density ◽  
G Protein Coupled Receptor ◽  
G Protein Coupled

scholarly journals The Low-Density Lipoprotein Class A Module of the Relaxin Receptor (Leucine-Rich Repeat Containing G-Protein Coupled Receptor 7): Its Role in Signaling and Trafficking to the Cell Membrane

Endocrinology ◽  
2007 ◽  
Vol 148 (3) ◽  
pp. 1181-1194 ◽  
Author(s):  
András Kern ◽  
Alexander I. Agoulnik ◽  
Gillian D. Bryant-Greenwood
Keyword(s):  
Cell Surface ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Lipoprotein Class ◽  
Class A ◽  
Relaxin Family ◽  
G Protein Coupled ◽  
Relaxin Receptor

The relaxin receptor (LGR7, relaxin family peptide receptor 1) is a member of the leucine-rich repeat containing G protein-coupled receptors subgroup C. This and the LGR8 (relaxin family peptide receptor 2) receptor are unique in having a low-density lipoprotein class A (LDL-A) module at their N termini. This study was designed to show the role of the LDL-A in LGR7 expression and function. Point mutants for the conserved cysteines (Cys47 and Cys53) and for calcium binding asparagine (Asp58), a mutant with deleted LDL-A domain and chimeric LGR7 receptor with LGR8 LDL-A all showed no cAMP response to human relaxins H1 or H2. We have shown that their cell surface delivery was uncompromised. The mutation of the putative N-linked glycosylation site (Asn36) decreased cAMP production and reduced cell surface expression to 37% of the wild-type LGR7. All point mutant, chimeric, and wild-type receptor proteins were expressed as the two forms. The immature or precursor form of the receptor was 80 kDa, whereas the mature receptor, delivered to the cell surface was 95 kDa. The glycosylation mutant was also expressed as two forms with appropriately smaller molecular masses. Deletion of the LDL-A module resulted in expression of the mature receptor only. These data suggest that the LDL-A module of LGR7 influences receptor maturation, cell surface expression, and relaxin-activated signal transduction.

scholarly journals Chemogenetic activation of astrocytes in the hippocampus and cortex changes the transcriptome of microglia and other cell types

2020 ◽  
Author(s):  
Stéphanie Philtjens ◽  
Marion T. Turnbull ◽  
Brian P. Thedy ◽  
Younghye Moon ◽  
Jungsu Kim
Keyword(s):  
Single Cell ◽  
G Protein ◽  
Low Density Lipoprotein ◽  
Ion Homeostasis ◽  
Density Lipoprotein ◽  
Cell Types ◽  
Designer Drugs ◽  
Specific Cell ◽  
G Protein Coupled

AbstractAstrocytes are the most common glial cell type in the brain, yet, it is still not clear how their activation affects the transcriptome of other brain cells such as microglia and neurons. Engineered G protein-coupled receptors called Designer Receptors Exclusively Activated by Designer Drugs (DREADDS) make it possible to selectively activate specific cell types, such as neurons and astrocytes. By combining the selective activation of astrocytes with single cell RNA sequencing, we were able to study transcriptional changes that occur in response to the activation of astrocytes at the single cell level. Interestingly, our data shows that long-term activation of astrocytes in healthy mice results in dramatic alteration in the transcriptome of astrocytes and microglia. Genes that were differentially expressed in these Gq-DREADD-activated astrocytes were involved in neurogenesis and low density lipoprotein particle biology, while those in the microglia were involved in the response to lipoproteins, and the migration and chemotaxis of immune cells. Furthermore, network analysis showed that Gq-DREADD-mediated activation in astrocytes resulted in an upregulation of genes involved in the G protein-coupled receptor signaling pathway and calcium ion homeostasis. This confirmed the activation of astrocytes through the expressed DREADDS. Our findings show the importance of considering the transcriptomic alteration in microglia and neurons after the activation of astrocytes in in vivo models. Therefore, our data will serve as a resource for the broader neuroscience community.

scholarly journals Evidence for Differential Regulation of GnRH Signaling via Heterodimerization among GnRH Receptor Paralogs in the Protochordate, Ciona intestinalis

Endocrinology ◽  
2012 ◽  
Vol 153 (4) ◽  
pp. 1841-1849 ◽  
Author(s):  
Tsubasa Sakai ◽  
Masato Aoyama ◽  
Tsuyoshi Kawada ◽  
Takehiro Kusakabe ◽  
Motoyuki Tsuda ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
G Protein ◽  
Ciona Intestinalis ◽  
Orphan Receptor ◽  
Receptor Subtype ◽  
Camp Production ◽  
G Protein Coupled Receptor ◽  
Gi Protein ◽  
Species Specific ◽  
G Protein Coupled

The endocrine and neuroendocrine systems for reproductive functions have diversified as a result of the generation of species-specific paralogs of peptide hormones and their receptors including GnRH and their receptors (GnRHR), which belong to the class A G protein-coupled receptor family. A protochordate, Ciona intestinalis, has been found to possess seven GnRH (tGnRH-3 to -8 and Ci-GnRH-X) and four GnRHR (Ci-GnRHR1 to -4). Moreover, Ci-GnRHR4 (R4) does not bind to any Ciona GnRH and activate any signaling pathways. Here we show novel functional diversification of GnRH signaling pathways via G protein-coupled receptor heterodimerization among Ciona GnRHR. R4 was shown to heterodimerize with R2 specifically in test cells of vitellogenic oocytes by coimmunoprecipitation. The R2-R4 heterodimerization in human embryonic kidney 293 cells cotransfected with R2 and R4 was also observed by coimmunoprecipitation and fluorescent energy transfer analyses. Of particular interest is that the R2-R4 heterodimer decreases the cAMP production in a nonligand-selective manner via shift of activation of Gs protein to Gi protein by R2, compared with R2 monomer/homodimer. Considering that the R1-R4 heterodimer elicits 10-fold more potent Ca2+ mobilization than R1 monomer/homodimer in a ligand-selective manner but does not affect cAMP production, these results indicate that R4 regulates differential GnRH signaling cascades via heterodimerization with R1 and R2 as an endogenous allosteric modulator. Collectively, the present study suggests that the heterodimerization among GnRHR paralogs, including the species-specific orphan receptor subtype, is involved in rigorous and diversified GnRHergic signaling of the protochordate, which lacks a hypothalamus-pituitary gonad axis.

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