Semaphorin3A signaling controls Fas (CD95)-mediated apoptosis by promoting Fas translocation into lipid rafts

Blood ◽  
2008 ◽  
Vol 111 (4) ◽  
pp. 2290-2299 ◽  
Author(s):  
Simona Moretti ◽  
Antonio Procopio ◽  
Raffaella Lazzarini ◽  
Maria Rita Rippo ◽  
Roberto Testa ◽  
...  
Keyword(s):  
Lipid Rafts ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Signaling Mechanism ◽  
Agonistic Antibody ◽  
Neuropilin 1 ◽  
Lipid Raft Microdomains ◽  
Biologic Function ◽  
Necrosis Factor

Semaphorins and their receptors (plexins) have pleiotropic biologic functions, including regulation of immune responses. However, the role of these molecules inside the immune system and the signal transduction mechanism(s) they use are largely unknown. Here, we show that Semaphorin3A (Sema3A) triggers a proapoptotic program that sensitizes leukemic T cells to Fas (CD95)-mediated apoptosis. We found that Sema3A stimulation provoked Fas translocation into lipid raft microdomains before binding with agonistic antibody or FasL (CD95L). Disruption of lipid rafts reduced sensitivity to Fas-mediated apoptosis in the presence of Sema3A. Furthermore, we show that plexin-A1, together with Sema3A-binding neuropilin-1, was rapidly incorporated into membrane rafts after ligand stimulation, resulting in the transport of actin-linking proteins into Fas-enriched rafts. Cells expressing a dominant-negative mutant of plexin-A1 did not show Fas clustering and apoptosis on Sema3A/Fas costimulation. This work identifies a novel biologic function of semaphorins and presents an unexpected signaling mechanism linking semaphorin to the tumor necrosis factor family receptors.

scholarly journals Different modes of internalization of apoptotic alkyl-lysophospholipid and cell-rescuing lysophosphatidylcholine

2003 ◽  
Vol 374 (3) ◽  
pp. 747-753 ◽  
Author(s):  
Arnold H. van der LUIT ◽  
Marianne BUDDE ◽  
Marcel VERHEIJ ◽  
Wim J. van BLITTERSWIJK
Keyword(s):  
Lipid Rafts ◽  
De Novo ◽  
Structural Similarity ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Chemotherapeutic Drugs ◽  
Alternative Substrate ◽  
High Structural Similarity ◽  
Additional Cell ◽  
Cell Membrane Level

The synthetic alkyl-lysophospholipid (ALP), Et-18-OCH3 (1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine), can induce apoptosis in tumour cells. Unlike conventional chemotherapeutic drugs, ALP acts at the cell-membrane level. We have reported previously that ALP is internalized, and interferes with phosphatidylcholine (PC) biosynthesis de novo, which appeared to be essential for survival in lymphoma cells [Van der Luit, Budde, Ruurs, Verheij and Van Blitterswijk (2002) J. Biol. Chem. 277, 39541–39547]. Here, we report that, in HeLa cells, ALP accumulates in lipid rafts, and that internalization is inhibited by low temperature, monensin, disruption of lipid rafts and expression of a dominant-negative mutant of dynamin bearing a replacement of Lys44 with alanine (K44A). Thus ALP is internalized via raft- and dynamin-mediated endocytosis. Dynamin-K44A alleviated the ALP-induced inhibition of PC synthesis and rescued the cells from apoptosis induction. Additional cell rescue was attained by exogenous lysoPC, which after internalization serves as an alternative substrate for PC synthesis (through acylation). Unlike ALP, and despite the high structural similarity to ALP, lysoPC uptake did not occur via lipid rafts and did not depend on functional dynamin, indicating no involvement of endocytosis. Albumin back-extraction experiments suggested that (radiolabelled) lysoPC undergoes transbilayer movement (flipping). We conclude that ALP is internalized by endocytosis via lipid rafts to cause apoptosis, while exogenous cell-rescuing lysoPC traverses the plasma membrane outside rafts by flipping. Additionally, our data imply the importance of ether bonds in lyso-phospholipids, such as in ALP, for partitioning in lipid rafts.

Centrosome cohesion is regulated by a balance of kinase and phosphatase activities

2001 ◽  
Vol 114 (20) ◽  
pp. 3749-3757 ◽  
Author(s):  
Patrick Meraldi ◽  
Erich A. Nigg
Keyword(s):  
Protein Phosphatase ◽  
Kinase Activity ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Microtubule Depolymerization ◽  
Drug Induced ◽  
Microtubule Network ◽  
Similar Phenotype ◽  
Underlying Mechanisms

Centrosome cohesion and separation are regulated throughout the cell cycle, but the underlying mechanisms are not well understood. Since overexpression of a protein kinase, Nek2, is able to trigger centrosome splitting (the separation of parental centrioles), we have surveyed a panel of centrosome-associated kinases for their ability to induce a similar phenotype. Cdk2, in association with either cyclin A or E, was as effective as Nek2, but several other kinases tested did not significantly interfere with centrosome cohesion. Centrosome splitting could also be triggered by inhibition of phosphatases, and protein phosphatase 1α (PP1α) was identified as a likely physiological antagonist of Nek2. Furthermore, we have revisited the role of the microtubule network in the control of centrosome cohesion. We could confirm that microtubule depolymerization by nocodazole causes centrosome splitting. Surprisingly, however, this drug-induced splitting also required kinase activity and could specifically be suppressed by a dominant-negative mutant of Nek2. These studies highlight the importance of protein phosphorylation in the control of centrosome cohesion, and they point to Nek2 and PP1α as critical regulators of centrosome structure.

scholarly journals MITOCHONDRIA AS REVERSIBLE REGULATORS OF AGING ASSOCIATED SKIN WRINKLES AND HAIR LOSS IN MICE

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S395-S395
Author(s):  
Keshav K Singh
Keyword(s):  
Mouse Model ◽  
Hair Loss ◽  
Transgene Expression ◽  
Skin Aging ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Dominant Negative Mutation ◽  
Polymerase Domain ◽  
Skin Wrinkles

Abstract To evaluate the consequences of the decline in mtDNA content associated with aging we have created an inducible mouse model expressing, in the polymerase domain of POLG1, a dominant-negative mutation that induces depletion of mtDNA. We utilized this inducible mouse model to modulate mitochondrial function by depleting and repleting the mtDNA content. We demonstrate that, in mice, ubiquitous expression of dominant-negative mutant POLG1 leads to 1) reduction of mtDNA content in skin, 2) skin wrinkles, and 3) hair loss. By turning off the mutant POLG1 transgene expression in the whole animal, the skin and hair phenotypes revert to normal after repletion of mtDNA. Thus, we have developed whole-animal mtDNA depleter-repleter mice. These mice present evidence that mtDNA homeostasis is involved in skin aging phenotype and loss of hair and provide an unprecedented opportunity to create tissue-specific mitochondrial modulation to determine the role of the mitochondria in a particular tissue.

scholarly journals Essential role of TNF receptor superfamily 25 (TNFRSF25) in the development of allergic lung inflammation

2008 ◽  
Vol 205 (5) ◽  
pp. 1037-1048 ◽  
Author(s):  
Lei Fang ◽  
Becky Adkins ◽  
Vadim Deyev ◽  
Eckhard R. Podack
Keyword(s):  
Lung Inflammation ◽  
Tumor Necrosis Factor Receptor ◽  
Nkt Cells ◽  
Dominant Negative ◽  
Th2 Cytokine ◽  
Early Signal ◽  
Allergic Lung Inflammation ◽  
Necrosis Factor

We identify the tumor necrosis factor receptor superfamily 25 (TNFRSF25)/TNFSF15 pair as critical trigger for allergic lung inflammation, which is a cardinal feature of asthma. TNFRSF25 (TNFR25) signals are required to exert T helper cell 2 (Th2) effector function in Th2-polarized CD4 cells and co-stimulate interleukin (IL)-13 production by glycosphingolipid-activated NKT cells. In vivo, antibody blockade of TNFSF15 (TL1A), which is the ligand for TNFR25, inhibits lung inflammation and production of Th2 cytokines such as IL-13, even when administered days after airway antigen exposure. Similarly, blockade of TNFR25 by a dominant-negative (DN) transgene, DN TNFR25, confers resistance to lung inflammation in mice. Allergic lung inflammation–resistant, NKT-deficient mice become susceptible upon adoptive transfer of wild-type NKT cells, but not after transfer of DN TNFR25 transgenic NKT cells. The TNFR25/TL1A pair appears to provide an early signal for Th2 cytokine production in the lung, and therefore may be a drug target in attempts to attenuate lung inflammation in asthmatics.

scholarly journals Foxl2 Up-Regulates Aromatase Gene Transcription in a Female-Specific Manner by Binding to the Promoter as Well as Interacting with Ad4 Binding Protein/Steroidogenic Factor 1

2007 ◽  
Vol 21 (3) ◽  
pp. 712-725 ◽  
Author(s):  
De-Shou Wang ◽  
Tohru Kobayashi ◽  
Lin-Yan Zhou ◽  
Bindhu Paul-Prasanth ◽  
Shigeho Ijiri ◽  
...  
Keyword(s):  
Serum Levels ◽  
Sex Reversal ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Testicular Development ◽  
Aromatase Gene ◽  
Ovarian Differentiation ◽  
Forkhead Domain ◽  
17Β Estradiol

Abstract Increasing evidence suggests the crucial role of estrogen in ovarian differentiation of nonmammalian vertebrates including fish. The present study has investigated the plausible role of Foxl2 in ovarian differentiation through transcriptional regulation of aromatase gene, using monosex fry of tilapia. Foxl2 expression is sexually dimorphic, like Cyp19a1, colocalizing with Cyp19a1 and Ad4BP/SF-1 in the stromal cells and interstitial cells in gonads of normal XX and sex-reversed XY fish, before the occurrence of morphological sex differentiation. Under in vitro conditions, Foxl2 binds to the sequence ACAAATA in the promoter region of the Cyp19a1 gene directly through its forkhead domain and activates the transcription of Cyp19a1 with its C terminus. Foxl2 can also interact through the forkhead domain with the ligand-binding domain of Ad4BP/SF-1 to form a heterodimer and enhance the Ad4BP/SF-1 mediated Cyp19a1 transcription. Disruption of endogenous Foxl2 in XX tilapia by overexpression of its dominant negative mutant (M3) induces varying degrees of testicular development with occasional sex reversal from ovary to testis. Such fish display reduced expression of Cyp19a1 as well as a drop in the serum levels of 17β-estradiol and 11-ketotestosterone. Although the XY fish with wild-type tilapia Foxl2 (tFoxl2) overexpression never exhibited a complete sex reversal, there were significant structural changes, such as tissue degeneration, somatic cell proliferation, and induction of aromatase, with increased serum levels of 17β-estradiol and 11-ketotestosterone. Altogether, these results suggest that Foxl2 plays a decisive role in the ovarian differentiation of the Nile tilapia by regulating aromatase expression and possibly the entire steroidogenic pathway.

scholarly journals The Death Domain Kinase RIP Is Essential for TRAIL (Apo2L)-Induced Activation of IκB Kinase and c-Jun N-Terminal Kinase

2000 ◽  
Vol 20 (18) ◽  
pp. 6638-6645 ◽  
Author(s):  
Yong Lin ◽  
Anne Devin ◽  
Amy Cook ◽  
Maccon M. Keane ◽  
Michelle Kelliher ◽  
...  
Keyword(s):  
Ectopic Expression ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Death Domain ◽  
Iκb Kinase ◽  
Tnf Superfamily ◽  
Key Factor ◽  
Induced Apoptosis ◽  
Jnk Activation ◽  
Necrosis Factor

ABSTRACT Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) (Apo2 ligand [Apo2L]) is a member of the TNF superfamily and has been shown to have selective antitumor activity. Although it is known that TRAIL (Apo2L) induces apoptosis and activates NF-κB and Jun N-terminal kinase (JNK) through receptors such as TRAIL-R1 (DR4) and TRAIL-R2 (DR5), the components of its signaling cascade have not been well defined. In this report, we demonstrated that the death domain kinase RIP is essential for TRAIL-induced IκB kinase (IKK) and JNK activation. We found that ectopic expression of the dominant negative mutant RIP, RIP(559–671), blocks TRAIL-induced IKK and JNK activation. In the RIP null fibroblasts, TRAIL failed to activate IKK and only partially activated JNK. The endogenous RIP protein was detected by immunoprecipitation in the TRAIL-R1 complex after TRAIL treatment. More importantly, we found that RIP is not involved in TRAIL-induced apoptosis. In addition, we also demonstrated that the TNF receptor-associated factor 2 (TRAF2) plays little role in TRAIL-induced IKK activation although it is required for TRAIL-mediated JNK activation. These results indicated that the death domain kinase RIP, a key factor in TNF signaling, also plays a pivotal role in TRAIL-induced IKK and JNK activation.

scholarly journals Src Family Kinases Are Required for Prolactin Induction of Cell Proliferation

2001 ◽  
Vol 12 (7) ◽  
pp. 2171-2183 ◽  
Author(s):  
Juan Ángel Fresno Vara ◽  
Ma Aurora Domı́nguez Cáceres ◽  
Augusto Silva ◽  
Jorge Martı́n-Pérez
Keyword(s):  
Cell Proliferation ◽  
Tyrosine Kinases ◽  
Cellular Proliferation ◽  
Tyrosine Phosphatase ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Herbimycin A ◽  
Serine Kinases ◽  
Dependent Cell

Prolactin (PRL) is a pleiotropic cytokine promoting cellular proliferation and differentiation. Because PRL activates the Src family of tyrosine kinases (SFK), we have studied the role of these kinases in PRL cell proliferation signaling. PRL induced [3H]thymidine incorporation upon transient transfection of BaF-3 cells with the PRL receptor. This effect was inhibited by cotransfection with the dominant negative mutant of c-Src (K>A295/Y>F527, SrcDM). The role of SFK in PRL-induced proliferation was confirmed in the BaF-3 PRL receptor-stable transfectant, W53 cells, where PRL induced Fyn and Lyn activation. The SFK-selective inhibitors PP1/PP2 and herbimycin A blocked PRL-dependent cell proliferation by arresting the W53 cells in G1, with no evident apoptosis. In parallel, PP1/PP2 inhibited PRL induction of cell growth-related genes c-fos, c-jun, c-myc, andodc. These inhibitors have no effect on PRL-mediated activation of Ras/Mapk and Jak/Start pathways. In contrast, they inhibited the PRL-dependent stimulation of the SFKs substrate Sam68, the phosphorylation of the tyrosine phosphatase Shp2, and the PI3K-dependent Akt and p70S6k serine kinases. Consistently, transient expression of SrcDM in W53 cells also blocked PRL activation of Akt. These results demonstrate that activation of SFKs is required for cell proliferation induced by PRL.

Essential roles of IκB kinases α and β in serum- and IL-1-induced human VSMC proliferation

2000 ◽  
Vol 278 (6) ◽  
pp. H1823-H1831 ◽  
Author(s):  
Sebastian Sasu ◽  
Debbie Beasley
Keyword(s):  
Smooth Muscle ◽  
Fluorescent Protein ◽  
Interleukin 1 ◽  
Fold Increase ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Mutant Form ◽  
Mobility Shift ◽  
Vsmc Proliferation

Interleukin-1 (IL-1) is a potent vascular smooth muscle cell (VSMC) mitogen, which can stimulate cells via activation of nuclear factor-κB (NF-κB) following phosphorylation of its inhibitory subunit (IκB). Because the proliferative effect of IL-1 is additive with that of serum, the present studies assessed the role of IκB kinases (IKKs) and NF-κB in both IL-1- and serum-induced VSMC proliferation. IL-1β (1 ng/ml) induced marked and persistent NF-κB activation in VSMC that was maximal at 1 h and persisted for 3 days. There was a 3-fold increase in DNA synthesis after acute IL-1 exposure (24–96 h) and a 12-fold increase after chronic IL-1 exposure (>7 days). Electrophoretic mobility shift assay and supershift analysis indicated that IL-1-induced NF-κB complexes consisted of p65/p50 heterodimers and p50 homodimers. Human saphenous vein smooth muscle cells (HSVSMC) were transiently cotransfected with expression plasmids encoding a dominant negative mutant form of either IKKα or IKKβ, in which K44 was mutated to A (K44A), and a green fluorescent protein expression plasmid that allows identification of transfected cells. IL-1 induced nuclear localization of p65 in 95% of cells transfected with vector alone but in only 69% and 26% of cells expressing IKKα (K44A) or IKKβ (K44A), respectively. Likewise, proliferation increased 3.2-fold in IL-1-treated HSVSMC which had been transfected with vector alone, but only 2.2- and 1.5-fold proliferation in HSVSMC expressing IKKα (K44A) or IKKβ (K44A), respectively. Although serum activated NF-κB transiently, serum-induced proliferation was markedly attenuated in HSVSMC expressing IKKα (K44A) and IKKβ (K44A) compared with HSVSMC transfected with vector alone. The results support an essential role of IKKs in the proliferative response of HSVSMC to IL-1 and to serum.

scholarly journals An Essential Role of the Jak-2/STAT-3/Cytosolic Phospholipase A2Axis in Platelet-derived Growth Factor BB-induced Vascular Smooth Muscle Cell Motility

2004 ◽  
Vol 279 (44) ◽  
pp. 46122-46128 ◽  
Author(s):  
Indira Neeli ◽  
Zhimin Liu ◽  
Nagadhara Dronadula ◽  
Z. Alex Ma ◽  
Gadiparthi N. Rao
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Tyrosine Phosphorylation ◽  
Dominant Negative ◽  
Platelet Derived Growth Factor ◽  
Dominant Negative Mutant ◽  
Dependent Manner ◽  
Cytosolic Phospholipase ◽  
Negative Mutant

Platelet-derived growth factor-BB (PDGF-BB) is a potent motogen for vascular smooth muscle cells (VSMCs). To understand its motogenic signaling events, we have studied the role of the Janus-activated kinase/signal transducers and activators of transcription (Jak/STAT) pathway and cytosolic phospholipase A2(cPLA2). PDGF-BB stimulated tyrosine phosphorylation of Jak-2 and STAT-3 in a time-dependent manner in VSMCs. In addition, AG490 and Jak-2KEpRK5, a selective pharmacological inhibitor and a dominant negative mutant, respectively, of Jak-2, attenuated PDGF-BB-induced STAT-3 tyrosine phosphorylation and its DNA binding and reporter gene activities. PDGF-BB induced VSMC motility in a dose-dependent manner with a maximum effect at 10 ng/ml. Dominant negative mutant-dependent suppression of Jak-2 and STAT-3 blocked PDGF-BB-induced VSMC motility. PDGF-BB induced the expression of cPLA2in a Jak-2/STAT-3-dependent manner, and pharmacological inhibitors of cPLA2prevented PDGFBB-induced VSMC motility. Furthermore, either exogenous addition of arachidonic acid or forced expression of cPLA2rescued PDGF-BB-induced VSMC motility from inhibition by blockade of Jak-2 and STAT-3 activation. Together, these results for the first time show that PDGF-BB-induced VSMC motility requires activation of the Jak-2/STAT-3/cPLA2signaling axis.

scholarly journals Role of EGR-1 in thapsigargin-inducible apoptosis in the melanoma cell line A375-C6.

1995 ◽  
Vol 15 (11) ◽  
pp. 6262-6272 ◽  
Author(s):  
S Muthukkumar ◽  
P Nair ◽  
S F Sells ◽  
N G Maddiwar ◽  
R J Jacob ◽  
...  
Keyword(s):  
Actinomycin D ◽  
Interleukin 1 ◽  
Growth Control ◽  
Melanoma Cells ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Functional Relevance ◽  
Antisense Oligomer ◽  
Negative Mutant

Induction of apoptosis by diverse exogenous signals is dependent on elevation of intracellular Ca2+. This process of cell death can be blocked by actinomycin D, indicating that it requires gene transcription events. To identify genes that are required for apoptosis, we used thapsigargin (TG), which inhibits endoplasmic reticulum-dependent Ca(2+)-ATPase and thereby increases cytosolic Ca2+. Exposure to TG led to induction of the zinc finger transcription factor, EGR-1, and apoptosis in human melanoma cells, A375-C6. To determine the functional relevance of EGR-1 expression in TG-inducible apoptosis, we employed a dominant negative mutant which functionally competes with EGR-1 in these cells. Interestingly, the dominant negative mutant inhibited TG-inducible apoptosis. Consistent with this observation, an antisense oligomer directed against Egr-1 also led to a diminution of the number of cells that undergo TG-inducible apoptosis. These results suggest a novel regulatory role for EGR-1 in mediating apoptosis that is induced by intracellular Ca2+ elevation. We have previously shown that in these melanoma cells, EGR-1 acts to inhibit the growth arresting action of interleukin-1. Together, these results imply that EGR-1 plays inducer-specific roles in growth control.

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