scholarly journals δ-Catenin/NPRAP (neural plakophilin-related armadillo repeat protein) interacts with and activates sphingosine kinase 1

2004 ◽  
Vol 382 (2) ◽  
pp. 717-723 ◽  
Author(s):  
Toshitada FUJITA ◽  
Taro OKADA ◽  
Shun HAYASHI ◽  
Saleem JAHANGEER ◽  
Noriko MIWA ◽  
...  
Keyword(s):  
Cell Motility ◽  
Hippocampal Neurons ◽  
Mdck Cells ◽  
Specific Inhibitor ◽  
Sphingosine Kinase ◽  
Dependent Manner ◽  
Repeat Protein ◽  
Sphingosine 1 Phosphate ◽  
Key Enzyme ◽  
Armadillo Repeat

Sphingosine kinase (SPHK) is a key enzyme catalysing the formation of sphingosine 1-phosphate (SPP), a lipid messenger that is implicated in the regulation of a wide variety of important cellular events acting through intracellular, as well as extracellular, mechanisms. However, the molecular mechanism of intracellular actions of SPP remains unclear. Here, we have identified δ-catenin/NPRAP (neural plakophilin-related armadillo repeat protein) as a potential binding partner for SPHK1 by yeast two-hybrid screening. From co-immunoprecipitation analyses, the C-terminal portion of δ-catenin/NPRAP containing the seventh to tenth armadillo repeats was found to be required for interaction with SPHK1. Endogenous δ-catenin/NPRAP was co-localized with endogenous SPHK1 and transfected δ-catenin/NPRAP was co-localized with transfected SPHK1 in dissociated rat hippocampal neurons. MDCK (Madin–Darby canine kidney) cells stably expressing δ-catenin/NPRAP contained elevated levels of intracellular SPP. In a purified system δ-catenin/NPRAP stimulated SPHK1 in a dose-dependent manner. Furthermore, δ-catenin/NPRAP-induced increased cell motility in MDCK cells was completely inhibited by dimethylsphingosine, a specific inhibitor of SPHK1. These results strongly suggest that at least some of δ-catenin/NPRAP functions, including increased cell motility, are mediated by an SPHK–SPP signalling pathway.

scholarly journals Sphingosine Kinase as a Regulator of Calcium Entry through Autocrine Sphingosine 1-Phosphate Signaling in Thyroid FRTL-5 Cells

Endocrinology ◽  
2009 ◽  
Vol 150 (11) ◽  
pp. 5125-5134 ◽  
Author(s):  
Dan Gratschev ◽  
Christoffer Löf ◽  
Jari Heikkilä ◽  
Anders Björkbom ◽  
Pramod Sukumaran ◽  
...  
Keyword(s):  
Intracellular Signaling ◽  
Sphingosine Kinase ◽  
Calcium Entry ◽  
Dominant Negative ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Entry Pathway ◽  
Sphingosine 1 Phosphate ◽  
S1p Receptor ◽  
In Cells

Calcium entry is one of the main regulators of intracellular signaling. Here, we have described the importance of sphingosine, sphingosine kinase 1 (SK1), and sphingosine 1-phosphate (S1P) in regulating calcium entry in thyroid FRTL-5 cells. In cells incubated with the phosphatase inhibitor calyculin A, which evokes calcium entry without mobilizing sequestered intracellular calcium, sphingosine inhibited calcium entry in a concentration-dependent manner. Furthermore, inhibiting SK1 or the ATP-binding cassette ABCC1 multidrug transporter attenuated calcium entry. The addition of exogenous S1P restored calcium entry. Neither sphingosine nor inhibition of SK1 attenuated thapsigargin-evoked calcium entry. Blocking S1P receptor 2 or phospholipase C attenuated calcium entry, whereas blocking S1P receptor 3 did not. Overexpression of wild-type SK1, but not SK2, enhanced calyculin-evoked calcium entry compared with mock-transfected cells, whereas calcium entry was decreased in cells transfected with the dominant-negative G82D SK1 mutant. Exogenous S1P restored calcium entry in G82D cells. Our results suggest that the calcium entry pathway is blocked by sphingosine and that activation of SK1 and the production of S1P, through an autocrine mechanism, facilitate calcium entry through activation of S1P receptor 2. This is a novel mechanism by which the sphingosine-S1P rheostat regulates cellular calcium homeostasis.

Impaired Sphingosine-1-Phosphate Synthesis Induces Preeclampsia by Deactivating Trophoblastic YAP (Yes-Associated Protein) Through S1PR2 (Sphingosine-1-Phosphate Receptor-2)-Induced Actin Polymerizations

Hypertension ◽  
2021 ◽  
Author(s):  
Jiujiang Liao ◽  
Yangxi Zheng ◽  
Mingyu Hu ◽  
Ping Xu ◽  
Li Lin ◽  
...  
Keyword(s):  
Actin Polymerization ◽  
Sphingosine Kinase ◽  
Actin Dynamics ◽  
Extravillous Trophoblast ◽  
Trophoblast Invasion ◽  
Hippo Signaling ◽  
Dependent Manner ◽  
Sphingosine Kinase 1 ◽  
Sphingosine 1 Phosphate

Incomplete spiral artery remodeling, caused by impaired extravillous trophoblast invasion, is a fundamental pathogenic process associated with malplacentation and the development of preeclampsia. Nevertheless, the mechanisms controlling this regulation of trophoblast invasion are largely unknown. We report that sphingosine-1-phosphate synthesis and expression is abundant in healthy trophoblast, whereas in pregnancies complicated by preeclampsia the placentae are associated with reduced sphingosine-1-phosphate and lower SPHK1 (sphingosine kinase 1) expression and activity. In vivo inhibition of sphingosine kinase 1 activity during placentation in pregnant mice led to decreased placental sphingosine-1-phosphate production and defective placentation, resulting in a preeclampsia phenotype. Moreover, sphingosine-1-phosphate increased HTR8/SVneo (immortalized trophoblast cells) cell invasion in a Hippo-signaling–dependent transcriptional coactivator YAP (Yes-associated protein) dependent manner, which is activated by S1PR2 (sphingosine-1-phosphate receptor-2) and downstream RhoA/ROCK induced actin polymerization. Mutation-based YAP-5SA demonstrated that sphingosine-1-phosphate activation of YAP could be either dependent or independent of Hippo signaling. Together, these findings suggest a novel pathogenic pathway of preeclampsia via disrupted sphingosine-1-phosphate metabolism and signaling-induced, interrupted actin dynamics and YAP deactivation; this may lead to potential novel intervention targets for the prevention and management of preeclampsia.

Modulation of cellular S1P levels with a novel, potent and specific inhibitor of sphingosine kinase-1

2012 ◽  
Vol 444 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Mark E. Schnute ◽  
Matthew D. McReynolds ◽  
Tom Kasten ◽  
Matthew Yates ◽  
Gina Jerome ◽  
...  
Keyword(s):  
Potent Inhibitor ◽  
Inflammatory Diseases ◽  
Specific Inhibitor ◽  
Sphingosine Kinase ◽  
Head And Neck Carcinoma ◽  
High Rate ◽  
Neck Carcinoma ◽  
Sphingosine 1 Phosphate ◽  
Proportional Increase ◽  
And Migration

SphK (sphingosine kinase) is the major source of the bioactive lipid and GPCR (G-protein-coupled receptor) agonist S1P (sphingosine 1-phosphate). S1P promotes cell growth, survival and migration, and is a key regulator of lymphocyte trafficking. Inhibition of S1P signalling has been proposed as a strategy for treatment of inflammatory diseases and cancer. In the present paper we describe the discovery and characterization of PF-543, a novel cell-permeant inhibitor of SphK1. PF-543 inhibits SphK1 with a Ki of 3.6 nM, is sphingosine-competitive and is more than 100-fold selective for SphK1 over the SphK2 isoform. In 1483 head and neck carcinoma cells, which are characterized by high levels of SphK1 expression and an unusually high rate of S1P production, PF-543 decreased the level of endogenous S1P 10-fold with a proportional increase in the level of sphingosine. In contrast with past reports that show that the growth of many cancer cell lines is SphK1-dependent, specific inhibition of SphK1 had no effect on the proliferation and survival of 1483 cells, despite a dramatic change in the cellular S1P/sphingosine ratio. PF-543 was effective as a potent inhibitor of S1P formation in whole blood, indicating that the SphK1 isoform of sphingosine kinase is the major source of S1P in human blood. PF-543 is the most potent inhibitor of SphK1 described to date and it will be useful for dissecting specific roles of SphK1-driven S1P signalling.

scholarly journals A mechanosensitive ion channel regulating cell volume

2010 ◽  
Vol 298 (6) ◽  
pp. C1424-C1430 ◽  
Author(s):  
Susan Z. Hua ◽  
Philip A. Gottlieb ◽  
Jinseok Heo ◽  
Frederick Sachs
Keyword(s):  
Cell Volume ◽  
Volume Regulation ◽  
Single Channel ◽  
Mdck Cells ◽  
Rat Kidney ◽  
Regulatory Volume Decrease ◽  
Specific Inhibitor ◽  
Cell Types ◽  
Dependent Manner ◽  
Mechanosensitive Channels

Cells respond to a hyposmotic challenge by swelling and then returning toward the resting volume, a process known as the regulatory volume decrease or RVD. The sensors for this process have been proposed to include cationic mechanosensitive ion channels that are opened by membrane tension. We tested this hypothesis using a microfluidic device to measure cell volume and the peptide GsMTx4, a specific inhibitor of cationic mechanosensitive channels. GsMTx4 had no effect on RVD in primary rat astrocytes or Madin-Darby canine kidney (MDCK) cells but was able to completely inhibit RVD and the associated Ca2+ uptake in normal rat kidney (NRK-49F) cells in a dose-dependent manner. Gadolinium (Gd3+), a nonspecific blocker of many mechanosensitive channels, inhibited RVD and Ca2+ uptake in all three cell types, demonstrating the existence of at least two types of volume sensors. Single-channel stretch-activated currents are present in outside-out patches from NRK-49F, MDCK, and astrocytes, and they are reversibly inhibited by GsMTx4. While mechanosensitive channels are involved in volume regulation, their role for volume sensing is specialized. The NRK cells form a stable platform from which to screen drugs that affect volume regulation via mechanosensory channels and as a sensitive system to clone the channel.

scholarly journals Involvement of Sphingosine-1-Phosphate in Glutamate Secretion in Hippocampal Neurons

2007 ◽  
Vol 27 (9) ◽  
pp. 3429-3440 ◽  
Author(s):  
Taketoshi Kajimoto ◽  
Taro Okada ◽  
Huan Yu ◽  
Sravan K. Goparaju ◽  
Saleem Jahangeer ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Receptor Activation ◽  
Lipid Mediator ◽  
Cellular Processes ◽  
Sphingosine 1 Phosphate ◽  
Key Enzyme ◽  
The Central Nervous System ◽  
Interfering Rna

ABSTRACT Neuronal activity greatly influences the formation and stabilization of synapses. Although receptors for sphingosine-1-phosphate (S1P), a lipid mediator regulating diverse cellular processes, are abundant in the central nervous system, neuron-specific functions of S1P remain largely undefined. Here, we report two novel actions of S1P using primary hippocampal neurons as a model system: (i) as a secretagogue where S1P triggers glutamate secretion and (ii) as an enhancer where S1P potentiates depolarization-evoked glutamate secretion. Sphingosine kinase 1 (SK1), a key enzyme for S1P production, was enriched in functional puncta of hippocampal neurons. Silencing SK1 expression by small interfering RNA as well as SK1 inhibition by dimethylsphingosine resulted in a strong inhibition of depolarization-evoked glutamate secretion. Fluorescence recovery after photobleaching analysis showed translocation of SK1 from cytosol to membranes at the puncta during depolarization, which resulted in subsequent accumulation of S1P within cells. Fluorescent resonance energy transfer analysis demonstrated that the S1P1 receptor at the puncta was activated during depolarization and that depolarization-induced S1P1 receptor activation was inhibited in SK1-knock-down cells. Importantly, exogenously added S1P at a nanomolar concentration by itself elicited glutamate secretion from hippocampal cells even when the Na+-channel was blocked by tetrodotoxin, suggesting that S1P acts on presynaptic membranes. Furthermore, exogenous S1P at a picomolar level potentiated depolarization-evoked secretion in the neurons. These findings indicate that S1P, through its autocrine action, facilitates glutamate secretion in hippocampal neurons both by secretagogue and enhancer actions and may be involved in mechanisms underlying regulation of synaptic transmission.

scholarly journals Transforming Growth Factor-β1 Induces Transdifferentiation of Myoblasts into Myofibroblasts via Up-Regulation of Sphingosine Kinase-1/S1P3 Axis

2010 ◽  
Vol 21 (6) ◽  
pp. 1111-1124 ◽  
Author(s):  
Francesca Cencetti ◽  
Caterina Bernacchioni ◽  
Paola Nincheri ◽  
Chiara Donati ◽  
Paola Bruni
Keyword(s):  
Skeletal Muscle ◽  
Growth Factor ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Rho Kinase ◽  
Sphingosine Kinase ◽  
Transforming Growth Factor Β1 ◽  
Dependent Manner ◽  
Muscle Fibrosis ◽  
Sphingosine 1 Phosphate

The pleiotropic cytokine transforming growth factor (TGF)-β1 is a key player in the onset of skeletal muscle fibrosis, which hampers tissue repair. However, the molecular mechanisms implicated in TGFβ1-dependent transdifferentiation of myoblasts into myofibroblasts are presently unknown. Here, we show that TGFβ1 up-regulates sphingosine kinase (SK)-1 in C2C12 myoblasts in a Smad-dependent manner, and concomitantly modifies the expression of sphingosine 1-phosphate (S1P) receptors (S1PRs). Notably, pharmacological or short interfering RNA-mediated inhibition of SK1 prevented the induction of fibrotic markers by TGFβ1. Moreover, inhibition of S1P3, which became the highest expressed S1PR after TGFβ1 challenge, strongly attenuated the profibrotic response to TGFβ1. Furthermore, downstream of S1P3, Rho/Rho kinase signaling was found critically implicated in the profibrotic action of TGFβ1. Importantly, we demonstrate that SK/S1P axis, known to play a key role in myogenesis via S1P2, consequently to TGFβ1-dependent S1PR pattern remodeling, becomes responsible for transmitting a profibrotic, antidifferentiating action. This study provides new compelling information on the mechanism by which TGFβ1 gives rise to fibrosis in skeletal muscle, opening new perspectives for its pharmacological treatment. Moreover, it highlights the pleiotropic role of SK/S1P axis in skeletal myoblasts that, depending on the expressed S1PR pattern, seems capable of eliciting multiple, even contrasting biological responses.

scholarly journals Estrogen transactivates EGFR via the sphingosine 1-phosphate receptor Edg-3: the role of sphingosine kinase-1

2006 ◽  
Vol 173 (2) ◽  
pp. 301-310 ◽  
Author(s):  
Olga Sukocheva ◽  
Carol Wadham ◽  
Andrew Holmes ◽  
Nathaniel Albanese ◽  
Emily Verrier ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Growth Factor Receptor ◽  
Sphingosine Kinase ◽  
Dependent Manner ◽  
Sphingosine Kinase 1 ◽  
Egfr Transactivation ◽  
Signaling Mechanism ◽  
Lipid Kinase ◽  
Sphingosine 1 Phosphate ◽  
Membrane Spanning

The transactivation of enhanced growth factor receptor (EGFR) by G protein–coupled receptor (GPCR) ligands is recognized as an important signaling mechanism in the regulation of complex biological processes, such as cancer development. Estrogen (E2), which is a steroid hormone that is intimately implicated in breast cancer, has also been suggested to function via EGFR transactivation. In this study, we demonstrate that E2-induced EGFR transactivation in human breast cancer cells is driven via a novel signaling system controlled by the lipid kinase sphingosine kinase-1 (SphK1). We show that E2 stimulates SphK1 activation and the release of sphingosine 1-phosphate (S1P), by which E2 is capable of activating the S1P receptor Edg-3, resulting in the EGFR transactivation in a matrix metalloprotease–dependent manner. Thus, these findings reveal a key role for SphK1 in the coupling of the signals between three membrane-spanning events induced by E2, S1P, and EGF. They also suggest a new signal transduction model across three individual ligand-receptor systems, i.e., “criss-cross” transactivation.

scholarly journals Sphingosine 1-phosphate induces filopodia formation through S1PR2 activation of ERM proteins

2013 ◽  
Vol 449 (3) ◽  
pp. 661-672 ◽  
Author(s):  
K. Alexa Orr Gandy ◽  
Daniel Canals ◽  
Mohamad Adada ◽  
Masayuki Wada ◽  
Patrick Roddy ◽  
...  
Keyword(s):  
Small Interfering Rna ◽  
Sphingosine Kinase ◽  
Cytoskeletal Proteins ◽  
Dependent Manner ◽  
Erm Proteins ◽  
Cellular Architecture ◽  
Sphingosine 1 Phosphate ◽  
S1p Receptor ◽  
Interfering Rna ◽  
Receptor Agonists And Antagonists

Previously we demonstrated that the sphingolipids ceramide and S1P (sphingosine 1-phosphate) regulate phosphorylation of the ERM (ezrin/radixin/moesin) family of cytoskeletal proteins [Canals, Jenkins, Roddy, Hernande-Corbacho, Obeid and Hannun (2010) J. Biol. Chem. 285, 32476–3285]. In the present article, we show that exogenously applied or endogenously generated S1P (in a sphingosine kinase-dependent manner) results in significant increases in phosphorylation of ERM proteins as well as filopodia formation. Using phosphomimetic and non-phosphorylatable ezrin mutants, we show that the S1P-induced cytoskeletal protrusions are dependent on ERM phosphorylation. Employing various pharmacological S1PR (S1P receptor) agonists and antagonists, along with siRNA (small interfering RNA) techniques and genetic knockout approaches, we identify the S1PR2 as the specific and necessary receptor to induce phosphorylation of ERM proteins and subsequent filopodia formation. Taken together, the results demonstrate a novel mechanism by which S1P regulates cellular architecture that requires S1PR2 and subsequent phosphorylation of ERM proteins.

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