scholarly journals Sphingosylphosphorylcholine as a novel calmodulin inhibitor

2008 ◽  
Vol 410 (2) ◽  
pp. 427-437 ◽  
Author(s):  
Erika Kovacs ◽  
Karoly Liliom
Keyword(s):  
Second Messengers ◽  
Cell Signalling ◽  
G Protein Coupled Receptors ◽  
Binding Assays ◽  
Cellular Processes ◽  
Intracellular Receptor ◽  
Dependent Activity ◽  
Intracellular Mechanism ◽  
Sphingosine 1 Phosphate ◽  
G Protein Coupled

S1P (sphingosine 1-phosphate) and SPC (sphingosylphosphorylcholine) have been recently recognized as important mediators of cell signalling, regulating basic cellular processes such as growth, differentiation, apoptosis, motility and Ca2+ homoeostasis. Interestingly, they can also act as first and second messengers. Although their activation of cell-surface G-protein-coupled receptors has been studied extensively, not much is known about their intracellular mechanism of action, and their target proteins are yet to be identified. We hypothesized that these sphingolipids might bind to CaM (calmodulin), the ubiquitous intracellular Ca2+ sensor. Binding assays utilizing intrinsic tyrosine fluorescence of the protein, dansyl-labelled CaM and surface plasmon resonance revealed that SPC binds to both apo- and Ca2+-saturated CaM selectively, when compared with the related lysophospholipid mediators S1P, LPA (lysophosphatidic acid) and LPC (lysophosphatidylcholine). Experiments carried out with the model CaM-binding domain melittin showed that SPC dissociates the CaM–target peptide complex, suggesting an inhibitory role. The functional effect of the interaction was examined on two target enzymes, phosphodiesterase and calcineurin, and SPC inhibited the Ca2+/CaM-dependent activity of both. Thus we propose that CaM might be an intracellular receptor for SPC, and raise the possibility of a novel endogenous regulation of CaM.

Exogenous and intracellularly generated sphingosine 1-phosphate can regulate cellular processes by divergent pathways

2003 ◽  
Vol 31 (6) ◽  
pp. 1216-1219 ◽  
Author(s):  
S. Spiegel ◽  
S. Milstien
Keyword(s):  
Cell Growth ◽  
Cell Motility ◽  
G Protein Coupled Receptors ◽  
Biological Processes ◽  
Cellular Functions ◽  
Cellular Processes ◽  
Sphingosine 1 Phosphate ◽  
Cytoskeletal Rearrangements ◽  
G Protein Coupled ◽  
Vascular Maturation

S1P (sphingosine 1-phosphate) is the ligand for a family of specific G-protein-coupled receptors that regulate a wide variety of important cellular functions, including vascular maturation, angiogenesis, cell growth, survival, cytoskeletal rearrangements and cell motility. However, S1P also may have intracellular functions. In this review, we discuss two examples that clearly indicate that intracellularly generated and exogenous S1P can regulate biological processes by divergent pathways.

scholarly journals Comparative Analysis of Functional Assays for Characterization of Agonist Ligands at G Protein-Coupled Receptors

2003 ◽  
Vol 8 (5) ◽  
pp. 500-510 ◽  
Author(s):  
Anke Niedernberg ◽  
Sorin Tunaru ◽  
Andree Blaukat ◽  
Bruce Harris ◽  
Evi Kostenis
Keyword(s):  
G Protein ◽  
Partial Agonist ◽  
A Priori ◽  
G Protein Coupled Receptors ◽  
Binding Assays ◽  
Functional Assays ◽  
Gtpγs Binding ◽  
Sphingosine 1 Phosphate ◽  
Intracellular Ca ◽  
G Protein Coupled

A variety of functional assays are available for agonist or antagonist screening of G protein-coupled receptors (GPCRs), but it is a priori not predictable which assay is the most suitable to identify agonists or antagonists of GPCRs with therapeutic value in humans. More specifically, it is not known how a given set of GPCR agonists compares in different functional assays with respect to potency and efficacy and whether the level of the signaling cascade that is analyzed has any impact on the detection of agonistic responses. To address this question, the authors used the recently cloned human S1P5 receptor as a model and compared a set of 3 lipid ligands (sphingosine 1-phosphate [S1P], dihydro sphingosine 1-phosphate [dhS1P], and sphingosine) in 5 different functional assays: GTPγS binding, inhibition of adenylyl cyclase activity, mobilization of intracellular Ca2+ via the FLIPR and aequorin technology, and MAP kinase (ERK1/2) activation. S1P induced agonistic responses in all except the ERK1/2 assays with EC50 values varying by a factor of 10. Whereas dhS1P was identified as a partial agonist in the GTPγS assay, it behaved as a full agonist in all other settings. Sphingosine displayed partial agonistic activity exclusively in GTPγS binding assays. The findings suggest that assays in a given cellular background may vary significantly with respect to suitability for agonist finding and that ligands producing a response may not readily be detectable in all agonist assays. ( Journal of Biomolecular Screening 2003:500-510)

scholarly journals Interaction of microRNAs with sphingosine kinases, sphingosine-1 phosphate, and sphingosine-1 phosphate receptors in cancer

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guangmeng Xu ◽  
Zecheng Yang ◽  
Yamin Sun ◽  
Hongmei Dong ◽  
Jingru Ma
Keyword(s):  
Cell Proliferation ◽  
G Protein Coupled Receptors ◽  
Lipid Mediator ◽  
Cellular Processes ◽  
S1p Receptors ◽  
Carcinoma Prostate ◽  
Sphingosine 1 Phosphate ◽  
Sphingosine Kinases ◽  
Non Coding Rnas ◽  
G Protein Coupled

AbstractSphingosine-1-phosphate (S1P), a pleiotropic lipid mediator, participates in various cellular processes during tumorigenesis, including cell proliferation, survival, drug resistance, metastasis, and angiogenesis. S1P is formed by two sphingosine kinases (SphKs), SphK1 and SphK2. The intracellularly produced S1P is delivered to the extracellular space by ATP-binding cassette (ABC) transporters and spinster homolog 2 (SPNS2), where it binds to five transmembrane G protein-coupled receptors to mediate its oncogenic functions (S1PR1-S1PR5). MicroRNAs (miRNAs) are small non-coding RNAs, 21–25 nucleotides in length, that play numerous crucial roles in cancer, such as tumor initiation, progression, apoptosis, metastasis, and angiogenesis via binding to the 3′‐untranslated region (3′‐UTR) of the target mRNA. There is growing evidence that various miRNAs modulate tumorigenesis by regulating the expression of SphKs, and S1P receptors. We have reviewed various roles of miRNAs, SphKs, S1P, and S1P receptors (S1PRs) in malignancies and how notable miRNAs like miR-101, miR-125b, miR-128, and miR-506, miR-1246, miR-21, miR-126, miR499a, miR20a-5p, miR-140-5p, miR-224, miR-137, miR-183-5p, miR-194, miR181b, miR136, and miR-675-3p, modulate S1P signaling. These tumorigenesis modulating miRNAs are involved in different cancers including breast, gastric, hepatocellular carcinoma, prostate, colorectal, cervical, ovarian, and lung cancer via cell proliferation, invasion, angiogenesis, apoptosis, metastasis, immune evasion, chemoresistance, and chemosensitivity. Therefore, understanding the interaction of SphKs, S1P, and S1P receptors with miRNAs in human malignancies will lead to better insights for miRNA-based cancer therapy.

scholarly journals Integrating High-Content Analysis into a Multiplexed Screening Approach to Identify and Characterize GPCR Agonists

2014 ◽  
Vol 19 (7) ◽  
pp. 1079-1089 ◽  
Author(s):  
Yingjie Zhu ◽  
John Watson ◽  
Mengjie Chen ◽  
Ding Ren Shen ◽  
Melissa Yarde ◽  
...  
Keyword(s):  
Drug Discovery ◽  
G Protein Coupled Receptors ◽  
High Content Imaging ◽  
Biased Agonism ◽  
Receptor Oligomerization ◽  
Sphingosine 1 Phosphate ◽  
High Content Analysis ◽  
Screening Assays ◽  
Hit Identification ◽  
G Protein Coupled

G protein–coupled receptors (GPCRs) are one of the most popular and proven target classes for therapeutic intervention. The increased appreciation for allosteric modulation, receptor oligomerization, and biased agonism has led to the development of new assay platforms that seek to capitalize on these aspects of GPCR biology. High-content screening is particularly well suited for GPCR drug discovery given the ability to image and quantify changes in multiple cellular parameters, to resolve subcellular structures, and to monitor events within a physiologically relevant environment. Focusing on the sphingosine-1-phosphate (S1P1) receptor, we evaluated the utility of high-content approaches in hit identification efforts by developing and applying assays to monitor β-arrestin translocation, GPCR internalization, and GPCR recycling kinetics. Using these approaches in combination with more traditional GPCR screening assays, we identified compounds whose unique pharmacological profiles would have gone unnoticed if using a single platform. In addition, we identified a compound that induces an atypical pattern of β-arrestin translocation and GPCR recycling kinetics. Our results highlight the value of high-content imaging in GPCR drug discovery efforts and emphasize the value of a multiassay approach to study pharmacological properties of compounds of interest.

scholarly journals The Role of Prokineticin 2 in Oxidative Stress and in Neuropathological Processes

2021 ◽  
Vol 12 ◽  
Author(s):  
Roberta Lattanzi ◽  
Cinzia Severini ◽  
Daniela Maftei ◽  
Luciano Saso ◽  
Aldo Badiani
Keyword(s):  
Pain Perception ◽  
G Protein Coupled Receptors ◽  
Cellular Processes ◽  
Prokineticin 2 ◽  
Physiological Processes ◽  
Pathological Conditions ◽  
Double Function ◽  
The Central Nervous System ◽  
G Protein Coupled

The prokineticin (PK) family, prokineticin 1 and Bv8/prokineticin 2 (PROK2), initially discovered as regulators of gastrointestinal motility, interacts with two G protein-coupled receptors, PKR1 and PKR2, regulating important biological functions such as circadian rhythms, metabolism, angiogenesis, neurogenesis, muscle contractility, hematopoiesis, immune response, reproduction and pain perception. PROK2 and PK receptors, in particular PKR2, are widespread distributed in the central nervous system, in both neurons and glial cells. The PROK2 expression levels can be increased by a series of pathological insults, such as hypoxia, reactive oxygen species, beta amyloid and excitotoxic glutamate. This suggests that the PK system, participating in different cellular processes that cause neuronal death, can be a key mediator in neurological/neurodegenerative diseases. While many PROK2/PKRs effects in physiological processes have been documented, their role in neuropathological conditions is not fully clarified, since PROK2 can have a double function in the mechanisms underlying to neurodegeneration or neuroprotection. Here, we briefly outline the latest findings on the modulation of PROK2 and its cognate receptors following different pathological insults, providing information about their opposite neurotoxic and neuroprotective role in different pathological conditions.

scholarly journals Natural polyamines stimulate G-proteins

1992 ◽  
Vol 282 (2) ◽  
pp. 545-550 ◽  
Author(s):  
J L Bueb ◽  
A Da Silva ◽  
M Mousli ◽  
Y Landry
Keyword(s):  
Mast Cells ◽  
Pertussis Toxin ◽  
Inositol Phosphates ◽  
Second Messengers ◽  
G Protein Coupled Receptors ◽  
Extracellular Signals ◽  
Physiological Relevance ◽  
G Protein Coupled ◽  
Stimulation Of ◽  
Rat Mast Cells

The natural polyamines spermine and spermidine, the biosynthetic precursor putrescine and their analogues cadaverine and tyramine stimulate the GTPase activity of purified GTP-binding proteins (Go/Gi) from calf brain reconstituted into phospholipid vesicles. The order of potency was spermine greater than spermidine greater than putrescine = cadaverine greater than tyramine. The physiological relevance of this observation was assessed, showing the same order of potency of polyamines in the stimulation of peritoneal and tracheal rat mast cells. The activation of rat mast cells by polyamines was inhibited by benzalkonium chloride or by a 2 h pretreatment of the cells with pertussis toxin. The increase in inositol phosphates evoked by polyamines was also inhibited by pertussis toxin. Therefore we propose that intracellular polyamines might control the basal level of second messengers and modulate extracellular signals transduced through G-protein-coupled receptors.

scholarly journals Sphingosine 1-phosphate signalling through the G-protein-coupled receptor Edg-1

1998 ◽  
Vol 330 (2) ◽  
pp. 605-609 ◽  
Author(s):  
C. M. Gerben ZONDAG ◽  
R. Friso POSTMA ◽  
Ingrid VAN ETTEN ◽  
Ingrid VERLAAN ◽  
H. Wouter MOOLENAAR
Keyword(s):  
Adenylate Cyclase ◽  
Map Kinase ◽  
G Protein ◽  
G Protein Coupled Receptors ◽  
Lpa Receptor ◽  
Kinase Activation ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Sphingosine 1 Phosphate ◽  
G Protein Coupled

Sphingosine 1-phosphate (S1P) and lysophosphatidic acid (LPA) are structurally related lipid mediators that act on distinct G-protein-coupled receptors to evoke similar responses, including Ca2+ mobilization, adenylate cyclase inhibition, and mitogen-activated protein (MAP) kinase activation. However, little is still known about the respective receptors. A recently cloned putative LPA receptor (Vzg-1/Edg-2) is similar to an orphan Gi-coupled receptor termed Edg-1. Here we show that expression of Edg-1 in Sf9 and COS-7 cells results in inhibition of adenylate cyclase and activation of MAP kinase (Gi-mediated), but not Ca2+ mobilization, in response to S1P. These responses are specific in that (i) S1P action is not mimicked by LPA, and (ii) Vzg-1/Edg-2 cannot substitute for Edg-1. Thus the Edg-1 receptor is capable of mediating a subset of the cellular responses to S1P.

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