scholarly journals Sphingosine-1-phosphate receptor subtype-specific positive and negative regulation of Rac and haematogenous metastasis of melanoma cells

2003 ◽  
Vol 374 (3) ◽  
pp. 715-722 ◽  
Author(s):  
Hironori YAMAGUCHI ◽  
Joji KITAYAMA ◽  
Noriko TAKUWA ◽  
Kayo ARIKAWA ◽  
Isao INOKI ◽  
...  

We have recently reported that S1P (sphingosine-1-phosphate) differentially regulates cellular Rac activity and cell migration in either a positive or a negative direction via distinct G-protein-coupled receptor subtypes, i.e. S1P1/Edg1 (endothelial differentiation gene) and S1P2/Edg5 respectively, when each of the S1P receptor subtypes is expressed in CHO (Chinese-hamster ovary) cells. In B16F10 mouse melanoma cells, in which S1P2, but not the other S1P receptor subtypes, is endogenously expressed, S1P inhibited cell migration with concomitant inhibition of Rac and stimulation of RhoA in dose-dependent manners. Overexpression of S1P2 in the melanoma cells resulted in potentiation of S1P inhibition of both Rac and cell migration. In contrast, overexpression of S1P1 led to stimulation of cell migration, particularly at the lower S1P concentrations. Treatment of B16F10 cells with S1P inhibited lung metastasis 3 weeks after injection into mouse tail veins. Intriguingly, overexpression of S1P2 greatly potentiated the inhibition of metastasis by S1P, whereas that of S1P1 resulted in aggravation of metastasis. Suppression of cellular Rac activity by adenovirus-transduced expression of N17Rac, but not N19RhoA, strongly inhibited cell migration in vitro and lung metastasis in vivo. These results provide the first evidence that G-protein-coupled receptors could participate in the regulation of metastasis, in which ligand-dependent, subtype-specific regulation of the cellular Rac activity is probably critically involved as a mechanism.

Pharmacology ◽  
2017 ◽  
Vol 101 (1-2) ◽  
pp. 72-75 ◽  
Author(s):  
Amin Polzin ◽  
Betül Knoop ◽  
Andreas Böhm ◽  
Lisa Dannenberg ◽  
Mark Zurek ◽  
...  

Background: Aspirin plays a crucial role in the prevention of cardiovascular diseases. We previously described that aspirin has effects beyond inhibition of platelet aggregation, as it inhibited thrombin-mediated release of sphingosine-1-phosphate (S1P) from human platelets. S1P is a bioactive lipid with important functions on inflammation and apoptosis. In endothelial cells (EC), S1P is a key regulator of cell migration. In this study, we aimed to analyze the effects of aspirin on platelet-induced EC migration. Methods: Human umbilical EC migration was measured by Boyden chamber assay. EC migration was induced by platelet supernatants of thrombin receptor-activating peptide-1 (AP1) stimulated platelets. To investigate the S1P receptor subtype that promotes EC migration, specific inhibitors of S1P receptor subtypes were applied. Results: S1P induced EC migration in a concentration-dependent manner. EC migration induced by AP1-stimulated platelet supernatants was reduced by aspirin. S1P1 receptor inhibition almost completely abolished EC migration induced by activated platelets. The inhibition of S1P2 or S1P3 receptor had no effect. Conclusion: Aspirin inhibits EC migration induced by activated platelets that is in part due to S1P and mediated by the endothelial S1P1 receptor. The clinical significance of this novel mechanism of aspirin action has to be investigated in future studies.


2003 ◽  
Vol 23 (5) ◽  
pp. 1534-1545 ◽  
Author(s):  
Naotoshi Sugimoto ◽  
Noriko Takuwa ◽  
Hiroyuki Okamoto ◽  
Sotaro Sakurada ◽  
Yoh Takuwa

ABSTRACT The G protein-coupled receptors S1P2/Edg5 and S1P3/Edg3 both mediate sphingosine-1-phosphate (S1P) stimulation of Rho, yet S1P2 but not S1P3 mediates downregulation of Rac activation, membrane ruffling, and cell migration in response to chemoattractants. Specific inhibition of endogenous Gα12 and Gα13, but not of Gαq, by expression of respective C-terminal peptides abolished S1P2-mediated inhibition of Rac, membrane ruffling, and migration, as well as stimulation of Rho and stress fiber formation. Fusion receptors comprising S1P2 and either Gα12 or Gα13, but not Gαq, mediated S1P stimulation of Rho and also inhibition of Rac and migration. Overexpression of Gαi, by contrast, specifically antagonized S1P2-mediated inhibition of Rac and migration. The S1P2 actions were mimicked by expression of V14Rho and were abolished by C3 toxin and N19Rho, but not Rho kinase inhibitors. In contrast to S1P2, S1P3 mediated S1P-directed, pertussis toxin-sensitive chemotaxis and Rac activation despite concurrent stimulation of Rho via G12/13. Upon inactivation of Gi by pertussis toxin, S1P3 mediated inhibition of Rac and migration just like S1P2. These results indicate that integration of counteracting signals from the Gi- and the G12/13-Rho pathways directs either positive or negative regulation of Rac, and thus cell migration, upon activation of a single S1P receptor isoform.


Cells ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 52
Author(s):  
Eugenia V. Gurevich ◽  
Vsevolod V. Gurevich

Many receptors for neurotransmitters, such as dopamine, norepinephrine, acetylcholine, and neuropeptides, belong to the superfamily of G protein-coupled receptors (GPCRs). A general model posits that GPCRs undergo two-step homologous desensitization: the active receptor is phosphorylated by kinases of the G protein-coupled receptor kinase (GRK) family, whereupon arrestin proteins specifically bind active phosphorylated receptors, shutting down G protein-mediated signaling, facilitating receptor internalization, and initiating distinct signaling pathways via arrestin-based scaffolding. Here, we review the mechanisms of GRK-dependent regulation of neurotransmitter receptors, focusing on the diverse modes of GRK-mediated phosphorylation of receptor subtypes. The immediate signaling consequences of GRK-mediated receptor phosphorylation, such as arrestin recruitment, desensitization, and internalization/resensitization, are equally diverse, depending not only on the receptor subtype but also on phosphorylation by GRKs of select receptor residues. We discuss the signaling outcome as well as the biological and behavioral consequences of the GRK-dependent phosphorylation of neurotransmitter receptors where known.


2006 ◽  
Vol 6 ◽  
pp. 946-966 ◽  
Author(s):  
Nicholas Young ◽  
James R. Van Brocklyn

Sphingosine-1-phosphate (S1P) is a bioactive lipid capable of eliciting dramatic effects in a variety of cell types. Signaling by this molecule is by a family of five G protein—coupled receptors named S1P1–5that signal through a variety of pathways to regulate cell proliferation, migration, cytoskeletal organization, and differentiation. These receptors are expressed in a wide variety of tissues and cell types, and their cellular effects contribute to important biological and pathological functions of S1P in many processes, including angiogenesis, vascular development, lymphocyte trafficking, and cancer. This review will focus on the current progress in the field of S1P receptor signaling and biology.


2000 ◽  
Vol 20 (24) ◽  
pp. 9247-9261 ◽  
Author(s):  
Hiroyuki Okamoto ◽  
Noriko Takuwa ◽  
Takehiko Yokomizo ◽  
Naotoshi Sugimoto ◽  
Soutaro Sakurada ◽  
...  

ABSTRACT Sphingosine-1-phosphate (S1P) is a bioactive lysophospholipid that induces a variety of biological responses in diverse cell types. Many, if not all, of these responses are mediated by members of the EDG (endothelial differentiation gene) family G protein-coupled receptors EDG1, EDG3, and EDG5 (AGR16). Among prominent activities of S1P is the regulation of cell motility; S1P stimulates or inhibits cell motility depending on cell types. In the present study, we provide evidence for EDG subtype-specific, contrasting regulation of cell motility and cellular Rac activity. In CHO cells expressing EDG1 or EDG3 (EDG1 cells or EDG3 cells, respectively) S1P as well as insulin-like growth factor I (IGF I) induced chemotaxis and membrane ruffling in phosphoinositide (PI) 3-kinase- and Rac-dependent manners. Both S1P and IGF I induced a biphasic increase in the amount of the GTP-bound active form of Rac. In CHO cells expressing EDG5 (EDG5 cells), IGF I similarly stimulated cell migration; however, in contrast to what was found for EDG1 and EDG3 cells, S1P did not stimulate migration but totally abolished IGF I-directed chemotaxis and membrane ruffling, in a manner dependent on a concentration gradient of S1P. In EDG5 cells, S1P stimulated PI 3-kinase activity as it did in EDG1 cells but inhibited the basal Rac activity and totally abolished IGF I-induced Rac activation, which involved stimulation of Rac-GTPase-activating protein activity rather than inhibition of Rac-guanine nucleotide exchange activity. S1P induced comparable increases in the amounts of GTP-RhoA in EDG3 and EDG5 cells. Neither S1P nor IGF I increased the amount of GTP-bound Cdc42. However, expression of N17-Cdc42, but not N19-RhoA, suppressed S1P- and IGF I-directed chemotaxis, suggesting a requirement for basal Cdc42 activity for chemotaxis. Taken together, the present results demonstrate that EDG5 is the first example of a hitherto-unrecognized type of receptors that negatively regulate Rac activity, thereby inhibiting cell migration and membrane ruffling.


2001 ◽  
Vol 414 (2-3) ◽  
pp. 145-154 ◽  
Author(s):  
Dagmar Meyer zu Heringdorf ◽  
Holger Lass ◽  
Igor Kuchar ◽  
Mathias Lipinski ◽  
Regina Alemany ◽  
...  

2021 ◽  
pp. 247255522097979
Author(s):  
Kyung-Soon Lee ◽  
Edelmar Navaluna ◽  
Nicole M. Marsh ◽  
Eric M. Janezic ◽  
Chris Hague

We have developed a novel reporter assay that leverages SNAP-epitope tag/near-infrared (NIR) imaging technology to monitor G protein-coupled receptor (GPCR) degradation in human cell lines. N-terminal SNAP-tagged GPCRs were subcloned and expressed in human embryonic kidney (HEK) 293 cells and then subjected to 24 h of cycloheximide (CHX)-chase degradation assays to quantify receptor degradation half-lives ( t1/2) using LICOR NIR imaging–polyacrylamide gel electrophoresis (PAGE) analysis. Thus far, we have used this method to quantify t1/2 for all nine adrenergic (ADRA1A, ADRA1B, ADRA1D, ADRA2A, ADRA2B, ADRA2C, ADRB1, ADRB2, ADRB3), five somatostatin (SSTR1, SSTR2, SSTR3, SSTR4, SSTR5), four chemokine (CXCR1, CXCR2, CXCR3, CXCR5), and three 5-HT2 (5HT2A, 5HT2B, 5HT2C) receptor subtypes. SNAP-GPCR-CHX degradation t1/2 values ranged from 0.52 h (ADRA1D) to 5.5 h (SSTR3). On the contrary, both the SNAP-tag alone and SNAP-tagged and endogenous β-actin were resistant to degradation with CHX treatment. Treatment with the proteasome inhibitor bortezomib produced significant but variable increases in SNAP-GPCR protein expression levels, indicating that SNAP-GPCR degradation primarily occurs through the proteasome. Remarkably, endogenous β2-adrenergic receptor/ADRB2 dynamic mass redistribution functional responses to norepinephrine were significantly decreased following CHX treatment, with a time course equivalent to that observed with the SNAP-ADRB2 degradation assay. We subsequently adapted this assay into a 96-well glass-bottom plate format to facilitate high-throughput GPCR degradation screening. t1/2 values quantified for the α1-adrenergic receptor subtypes (ADRA1A, ADRA1B, ADR1D) using the 96-well-plate format correlated with t1/2 values quantified using NIR-PAGE imaging analysis. In summary, this novel assay permits precise quantitative analysis of GPCR degradation in human cells and can be readily adapted to quantify degradation for any membrane protein of interest.


2004 ◽  
Vol 279 (14) ◽  
pp. 13839-13848 ◽  
Author(s):  
M. Germana Sanna ◽  
Jiayu Liao ◽  
Euijung Jo ◽  
Christopher Alfonso ◽  
Min-Young Ahn ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document