Inducible nuclear translocation of a STAT protein in Dictyostelium prespore cells: implications for morphogenesis and cell-type regulation

Development ◽  
2001 ◽  
Vol 128 (7) ◽  
pp. 1081-1088
Author(s):  
D. Dormann ◽  
T. Abe ◽  
C.J. Weijer ◽  
J. Williams
Keyword(s):  
Nuclear Translocation ◽  
Mechanical Damage ◽  
Specific Inhibitor ◽  
Nuclear Accumulation ◽  
Small Subset ◽  
Cell Type ◽  
Form Part ◽  
Tip Injection ◽  
Camp Receptor ◽  
Mechanical Disturbances

Dd-STATa, the Dictyostelium STAT (signal transducer and activator of transcription) protein, is selectively localised in the nuclei of a small subset of prestalk cells located in the slug tip. Injection of cAMP into the extracellular spaces in the rear of the slug induces rapid nuclear translocation of a Dd-GFP:STATa fusion protein in prespore cells surrounding the site of injection. This suggests that cAMP signals that emanate from the tip direct the localised nuclear accumulation of Dd-STATa. It also shows that prespore cells are competent to respond to cAMP, by Dd-STATa activation, and it implies that cAMP signalling is in some way limiting in the rear of the slug. Co-injection of a specific inhibitor of the cAR1 serpentine cAMP receptor almost completely prevents the cAMP-induced nuclear translocation, showing that most or all of the cAMP signal is transduced by cAR1. Dd-GFP:STATa also rapidly translocates into the nuclei of cells adjoining the front and back cut edges when a slug is bisected. Less severe mechanical disturbances, such as pricking the rear of a slug with an unfilled micropipette, also cause a more limited nuclear translocation of Dd-GFP:STATa. We propose that these signalling events form part of a repair mechanism that is activated when the migrating slug suffers mechanical damage.

scholarly journals DNase II mediates a parthanatos-like developmental cell death pathway in Drosophila primordial germ cells

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lama Tarayrah-Ibraheim ◽  
Elital Chass Maurice ◽  
Guy Hadary ◽  
Sharon Ben-Hur ◽  
Alina Kolpakova ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Germ Cells ◽  
Nuclear Translocation ◽  
Primordial Germ Cells ◽  
Nuclear Accumulation ◽  
Dependent Manner ◽  
Dnase Ii ◽  
Cell Death Pathway ◽  
Parp 1

AbstractDuring Drosophila embryonic development, cell death eliminates 30% of the primordial germ cells (PGCs). Inhibiting apoptosis does not prevent PGC death, suggesting a divergence from the conventional apoptotic program. Here, we demonstrate that PGCs normally activate an intrinsic alternative cell death (ACD) pathway mediated by DNase II release from lysosomes, leading to nuclear translocation and subsequent DNA double-strand breaks (DSBs). DSBs activate the DNA damage-sensing enzyme, Poly(ADP-ribose) (PAR) polymerase-1 (PARP-1) and the ATR/Chk1 branch of the DNA damage response. PARP-1 and DNase II engage in a positive feedback amplification loop mediated by the release of PAR polymers from the nucleus and the nuclear accumulation of DNase II in an AIF- and CypA-dependent manner, ultimately resulting in PGC death. Given the anatomical and molecular similarities with an ACD pathway called parthanatos, these findings reveal a parthanatos-like cell death pathway active during Drosophila development.

scholarly journals A Yes-Associated Protein (YAP) and Insulin-Like Growth Factor 1 Receptor (IGF-1R) Signaling Loop Is Involved in Sorafenib Resistance in Hepatocellular Carcinoma

Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3812
Author(s):  
Mai-Huong T. Ngo ◽  
Sue-Wei Peng ◽  
Yung-Che Kuo ◽  
Chun-Yen Lin ◽  
Ming-Heng Wu ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Combination Index ◽  
Specific Inhibitor ◽  
In Vivo Model ◽  
Mrna Levels ◽  
Margin Distribution ◽  
Related Proteins ◽  
Emt Markers

The role of a YAP-IGF-1R signaling loop in HCC resistance to sorafenib remains unknown. Method: Sorafenib-resistant cells were generated by treating naïve cells (HepG2215 and Hep3B) with sorafenib. Different cancer cell lines from databases were analyzed through the ONCOMINE web server. BIOSTORM–LIHC patient tissues (46 nonresponders and 21 responders to sorafenib) were used to compare YAP mRNA levels. The HepG2215_R-derived xenograft in SCID mice was used as an in vivo model. HCC tissues from a patient with sorafenib failure were used to examine differences in YAP and IGF-R signaling. Results: Positive associations exist among the levels of YAP, IGF-1R, and EMT markers in HCC tissues and the levels of these proteins increased with sorafenib failure, with a trend of tumor-margin distribution in vivo. Blocking YAP downregulated IGF-1R signaling-related proteins, while IGF-1/2 treatment enhanced the nuclear translocation of YAP in HCC cells through PI3K-mTOR regulation. The combination of YAP-specific inhibitor verteporfin (VP) and sorafenib effectively decreased cell viability in a synergistic manner, evidenced by the combination index (CI). Conclusion: A YAP-IGF-1R signaling loop may play a role in HCC sorafenib resistance and could provide novel potential targets for combination therapy with sorafenib to overcome drug resistance in HCC.

scholarly journals Live-Cell Fluorescence Imaging Reveals the Dynamics of Protein Kinase CK2 Individual Subunits

2003 ◽  
Vol 23 (3) ◽  
pp. 975-987 ◽  
Author(s):  
Odile Filhol ◽  
Arsenio Nueda ◽  
Véronique Martel ◽  
Delphine Gerber-Scokaert ◽  
Maria José Benitez ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Nuclear Localization ◽  
Protein Kinase Ck2 ◽  
Fluorescent Protein ◽  
Nuclear Translocation ◽  
Nuclear Accumulation ◽  
Nucleocytoplasmic Trafficking ◽  
Green Fluorescent ◽  
Nucleocytoplasmic Distribution ◽  
Kinase Ck2

ABSTRACT Protein kinase CK2 is a multifunctional enzyme which has long been described as a stable heterotetrameric complex resulting from the association of two catalytic (α or α′) and two regulatory (β) subunits. To track the spatiotemporal dynamics of CK2 in living cells, we fused its catalytic α and regulatory β subunits with green fluorescent protein (GFP). Both CK2 subunits contain nuclear localization domains that target them independently to the nucleus. Imaging of stable cell lines expressing low levels of GFP-CK2α or GFP-CK2β revealed the existence of CK2 subunit subpopulations exhibiting differential dynamics. Once in the nucleus, they diffuse randomly at different rates. Unlike CK2β, CK2α can shuttle, showing the dynamic nature of the nucleocytoplasmic trafficking of the kinase. When microinjected in the cytoplasm, the isolated CK2 subunits are rapidly translocated into the nucleus, whereas the holoenzyme complex remains in this cell compartment, suggesting an intramolecular masking of the nuclear localization sequences that suppresses nuclear accumulation. However, binding of FGF-2 to the holoenzyme triggers its nuclear translocation. Since the substrate specificity of CK2α is dramatically changed by its association with CK2β, the control of the nucleocytoplasmic distribution of each subunit may represent a unique potential regulatory mechanism for CK2 activity.

scholarly journals Dietary pterostilbene supplementation attenuates intestinal damage and immunological stress of broiler chickens challenged with lipopolysaccharide

2019 ◽  
Vol 98 (1) ◽  
Author(s):  
Hao Zhang ◽  
Yanan Chen ◽  
Yueping Chen ◽  
Yue Li ◽  
Peilu Jia ◽  
...  
Keyword(s):  
Broiler Chickens ◽  
Nuclear Translocation ◽  
Receptor Protein ◽  
Nuclear Accumulation ◽  
Broiler Chicks ◽  
Intestinal Damage ◽  
Mrna Levels ◽  
Lps Challenge ◽  
Junction Protein ◽  
Immunological Stress

Abstract The present study explored the potential effect of pterostilbene as a prophylactic treatment on the lipopolysaccharide (LPS)-induced intestinal injury of broiler chickens by monitoring changes in mucosal injury indicators, redox status, and inflammatory responses. In total, 192 one-day-old male Ross 308 broiler chicks were randomly divided into four groups. This trial consisted of a 2 × 2 factorial design with a diet factor (supplemented with 0 or 400 mg/kg pterostilbene from 1 to 22 d of age) and a stress factor (intraperitoneally injected with saline or LPS at 5.0 mg/kg BW at 21 da of age). The results showed that LPS challenge induced a decrease in BW gain (P < 0.001) of broilers during a 24-h period postinjection; however, this decrease was prevented by pterostilbene supplementation (P = 0.031). Administration of LPS impaired the intestinal integrity of broilers, as indicated by increased plasma diamine oxidase (DAO) activity (P = 0.014) and d-lactate content (P < 0.001), reduced jejunal villus height (VH; P < 0.001) and the ratio of VH to crypt depth (VH:CD; P < 0.001), as well as a decreased mRNA level of jejunal tight junction protein 1 (ZO-1; P = 0.002). In contrast, pterostilbene treatment increased VH:CD (P = 0.018) and upregulated the mRNA levels of ZO-1 (P = 0.031) and occludin (P = 0.024) in the jejunum. Consistently, pterostilbene counteracted the LPS-induced increased DAO activity (P = 0.011) in the plasma. In addition, the LPS-challenged broilers exhibited increases in nuclear accumulation of nuclear factor kappa B (NF-κB) p65 (P < 0.001), the protein content of tumor necrosis factor α (P = 0.033), and the mRNA abundance of IL-1β (P = 0.042) and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3; P = 0.019). In contrast, pterostilbene inhibited the nuclear translocation of NF-κB p65 (P = 0.039) and suppressed the mRNA expression of IL-1β (P = 0.003) and NLRP3 (P = 0.049) in the jejunum. Moreover, pterostilbene administration induced a greater amount of reduced glutathione (P = 0.017) but a lower content of malondialdehyde (P = 0.023) in the jejunum of broilers compared with those received a basal diet. Overall, the current study indicates that dietary supplementation with pterostilbene may play a beneficial role in alleviating the intestinal damage of broiler chicks under the conditions of immunological stress.

scholarly journals Complex Formation with Monomeric α-Tubulin and Importin 13 Fosters c-Jun Protein Stability and Is Required for c-Jun’s Nuclear Translocation and Activity

Cancers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1806
Author(s):  
Melanie Kappelmann-Fenzl ◽  
Silke Kuphal ◽  
Rosemarie Krupar ◽  
Dirk Schadendorf ◽  
Viktor Umansky ◽  
...  
Keyword(s):  
Complex Formation ◽  
Protein Stability ◽  
Nuclear Translocation ◽  
Nuclear Accumulation ◽  
Nuclear Localization Sequence ◽  
Microtubule Network ◽  
Localization Sequence ◽  
Dynamic Structures ◽  
Main Regulator ◽  
Factor C

Microtubules are highly dynamic structures, which consist of α- and β-tubulin heterodimers. They are essential for a number of cellular processes, including intracellular trafficking and mitosis. Tubulin-binding chemotherapeutics are used to treat different types of tumors, including malignant melanoma. The transcription factor c-Jun is a central driver of melanoma development and progression. Here, we identify the microtubule network as a main regulator of c-Jun activity. Monomeric α-tubulin fosters c-Jun protein stability by protein–protein interaction. In addition, this complex formation is necessary for c-Jun’s nuclear localization sequence binding to importin 13, and consequent nuclear import and activity of c-Jun. A reduction in monomeric α-tubulin levels by treatment with the chemotherapeutic paclitaxel resulted in a decline in the nuclear accumulation of c-Jun in melanoma cells in an experimental murine model and in patients’ tissues. These findings add important knowledge to the mechanism of the action of microtubule-targeting drugs and indicate the newly discovered regulation of c-Jun by the microtubule cytoskeleton as a novel therapeutic target for melanoma and potentially also other types of cancer.

scholarly journals The Ebola Virus VP35 Protein Inhibits Activation of Interferon Regulatory Factor 3

2003 ◽  
Vol 77 (14) ◽  
pp. 7945-7956 ◽  
Author(s):  
Christopher F. Basler ◽  
Andrea Mikulasova ◽  
Luis Martinez-Sobrido ◽  
Jason Paragas ◽  
Elke Mühlberger ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Transcriptional Activation ◽  
Ebola Virus ◽  
Nuclear Translocation ◽  
Sendai Virus ◽  
Vero Cells ◽  
Nuclear Accumulation ◽  
Regulatory Factor ◽  
Cellular Transcription Factor

ABSTRACT The Ebola virus VP35 protein was previously found to act as an interferon (IFN) antagonist which could complement growth of influenza delNS1 virus, a mutant influenza virus lacking the influenza virus IFN antagonist protein, NS1. The Ebola virus VP35 could also prevent the virus- or double-stranded RNA-mediated transcriptional activation of both the beta IFN (IFN-β) promoter and the IFN-stimulated ISG54 promoter (C. Basler et al., Proc. Natl. Acad. Sci. USA 97:12289-12294, 2000). We now show that VP35 inhibits virus infection-induced transcriptional activation of IFN regulatory factor 3 (IRF-3)-responsive mammalian promoters and that VP35 does not block signaling from the IFN-α/β receptor. The ability of VP35 to inhibit this virus-induced transcription correlates with its ability to block activation of IRF-3, a cellular transcription factor of central importance in initiating the host cell IFN response. We demonstrate that VP35 blocks the Sendai virus-induced activation of two promoters which can be directly activated by IRF-3, namely, the ISG54 promoter and the ISG56 promoter. Further, expression of VP35 prevents the IRF-3-dependent activation of the IFN-α4 promoter in response to viral infection. The inhibition of IRF-3 appears to occur through an inhibition of IRF-3 phosphorylation. VP35 blocks virus-induced IRF-3 phosphorylation and subsequent IRF-3 dimerization and nuclear translocation. Consistent with these observations, Ebola virus infection of Vero cells activated neither transcription from the ISG54 promoter nor nuclear accumulation of IRF-3. These data suggest that in Ebola virus-infected cells, VP35 inhibits the induction of antiviral genes, including the IFN-β gene, by blocking IRF-3 activation.

Levels of phospho-Smad2/3 are sensors of the interplay between effects of TGF-β and retinoic acid on monocytic and granulocytic differentiation of HL-60 cells

Blood ◽  
2003 ◽  
Vol 101 (2) ◽  
pp. 498-507 ◽  
Author(s):  
Zhouhong Cao ◽  
Kathleen C. Flanders ◽  
Daniel Bertolette ◽  
Lyudmila A. Lyakh ◽  
Jens U. Wurthner ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Transforming Growth Factor ◽  
Nuclear Translocation ◽  
Leukemia Cell ◽  
Leukemia Cell Line ◽  
Nuclear Accumulation ◽  
Monocytic Differentiation ◽  
Granulocytic Differentiation ◽  
End Points ◽  
Tgf Β1

We have investigated the role of Smad family proteins, known to be important cytoplasmic mediators of signals from the transforming growth factor–β (TGF-β) receptor serine/threonine kinases, in TGF-β–dependent differentiation of hematopoietic cells, using as a model the human promyelocytic leukemia cell line, HL-60. TGF-β–dependent differentiation of these cells to monocytes, but not retinoic acid–dependent differentiation to granulocytes, was accompanied by rapid phosphorylation and nuclear translocation of Smad2 and Smad3. Vitamin D3 also induced phosphorylation of Smad2/3 and monocytic differentiation; however the effects were indirect, dependent on its ability to induce expression of TGF-β1. Simultaneous treatment of these cells with TGF-β1 and all-trans-retinoic acid (ATRA), which leads to almost equal numbers of granulocytes and monocytes, significantly reduced the level of phospho–Smad2/3 and its nuclear accumulation, compared with that in cells treated with TGF-β1 alone. TGF-β1 and ATRA activate P42/44 mitogen-activated protein (MAP) kinase with nearly identical kinetics, ruling out its involvement in these effects on Smad phosphorylation. Addition of the inhibitor-of-protein serine/threonine phosphatases, okadaic acid, blocks the ATRA-mediated reduction in TGF-β–induced phospho-Smad2 and shifts the differentiation toward monocytic end points. In HL-60R mutant cells, which harbor a defective retinoic acid receptor–α (RAR-α), ATRA is unable to reduce levels of TGF-β–induced phospho-Smad2/3, coincident with its inability to differentiate these cells along granulocytic pathways. Together, these data suggest a new level of cross-talk between ATRA and TGF-β, whereby a putative RAR-α–dependent phosphatase activity limits the levels of phospho-Smad2/3 induced by TGF-β, ultimately reducing the levels of nuclear Smad complexes mediating the TGF-β–dependent differentiation of the cells to monocytic end points.

scholarly journals Identification of the human c-myc protein nuclear translocation signal.

1988 ◽  
Vol 8 (10) ◽  
pp. 4048-4054 ◽  
Author(s):  
C V Dang ◽  
W M Lee
Keyword(s):  
Nuclear Localization ◽  
Nuclear Translocation ◽  
Vero Cells ◽  
Embryo Cell ◽  
Nuclear Accumulation ◽  
Nuclear Targeting ◽  
Mutant Proteins ◽  
Chicken Muscle ◽  
Localization Signal ◽  
Muscle Pyruvate Kinase

We identified and characterized two regions of the human c-myc protein that target proteins into the nucleus. Using mutant c-myc proteins and proteins that fuse portions of c-myc to chicken muscle pyruvate kinase, we found that residues 320 to 328 (PAAKRVKLD; peptide M1) induced complete nuclear localization, and their removal from c-myc resulted in mutant proteins that distributed in both the nucleus and cytoplasm but retained rat embryo cell cotransforming activity. Residues 364 to 374 (RQRRNELKRSP; peptide M2) induced only partial nuclear targeting, and their removal from c-myc resulted in mutant proteins that remained nuclear but were cotransformationally inactive. We conjugated synthetic peptides containing M1 or M2 to human serum albumin and microinjected the conjugate into the cytoplasm of Vero cells. The peptide containing M1 caused rapid and complete nuclear accumulation, whereas that containing M2 caused slower and only partial nuclear localization. Thus, M1 functions as the nuclear localization signal of c-myc, and M2 serves some other and essential function.

scholarly journals Monoclonal Antibodies to NTF2 Inhibit Nuclear Protein Import by Preventing Nuclear Translocation of the GTPase Ran

2000 ◽  
Vol 11 (2) ◽  
pp. 703-719 ◽  
Author(s):  
Susanne M. Steggerda ◽  
Ben E. Black ◽  
Bryce M. Paschal
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Import ◽  
Protein Import ◽  
Nuclear Translocation ◽  
Living Cells ◽  
Nuclear Accumulation ◽  
Nuclear Pore ◽  
Permeabilized Cells ◽  
Dependent Protein

Nuclear transport factor 2 (NTF2) is a soluble transport protein originally identified by its ability to stimulate nuclear localization signal (NLS)-dependent protein import in digitonin-permeabilized cells. NTF2 has been shown to bind nuclear pore complex proteins and the GDP form of Ran in vitro. Recently, it has been reported that NTF2 can stimulate the accumulation of Ran in digitonin-permeabilized cells. Evidence that NTF2 directly mediates Ran import or that NTF2 is required to maintain the nuclear concentration of Ran in living cells has not been obtained. Here we show that cytoplasmic injection of anti-NTF2 mAbs resulted in a dramatic relocalization of Ran to the cytoplasm. This provides the first evidence that NTF2 regulates the distribution of Ran in vivo. Moreover, anti-NTF2 mAbs inhibited nuclear import of both Ran and NLS-containing protein in vitro, suggesting that NTF2 stimulates NLS-dependent protein import by driving the nuclear accumulation of Ran. We also show that biotinylated NTF2-streptavidin microinjected into the cytoplasm accumulated at the nuclear envelope, indicating that NTF2 can target a binding partner to the nuclear pore complex. Taken together, our data show that NTF2 is an essential regulator of the Ran distribution in living cells and that NTF2-mediated Ran nuclear import is required for NLS-dependent protein import.

Reciprocal Regulation of DSCR1 (Down Syndrome Critical Region 1) Expression and NFAT (Nuclear Factor of Activated T Cells) Activation in Megakaryocytes.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2204-2204
Author(s):  
Satu Kyttaelae ◽  
Ivonne Habermann ◽  
Martin Bornhaeuser ◽  
Gerhard Ehninger ◽  
Alexander Kiani
Keyword(s):  
T Cells ◽  
Down Syndrome ◽  
Critical Region ◽  
Fas Ligand ◽  
Nuclear Translocation ◽  
Specific Inhibitor ◽  
Chromosome 21 ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Retroviral Transduction

Abstract NFAT (Nuclear Factor of Activated T cells) is a family of calcium-induced, calcineurin-dependent transcription factors, well characterized as central regulators of inducible gene expression in T lymphocytes but now known to function also in several other cell types in various adaptation and differentiation processes. Activation of NFAT by the phosphatase calcineurin is counteracted by several inhibitory kinases and can be completely blocked by the immunosuppressant Cyclosporin A. The Down syndrome critical region 1 (DSCR1; also termed CSP1, MCIP1 or RCAN1) gene belongs to the calcipressin family of endogenous calcineurin inhibitors and is expressed in several isoforms, one of which (isoform C, coded by exons 4–7) has been described to be a transcriptional target for NFAT in striated muscle, endothelial, and neural cells. The DSCR1 gene is located within the Down syndrome critical region of human chromosome 21 and is, together with 200–300 other genes, overexpressed about 1.5-fold in patients with Down syndrome (DS). Previously, dysregulation of NFAT signaling by overexpression of DSCR1 has been implicated in causing various of the pathophysiological features observed in DS patients. Children with DS also suffer from an about 500-fold increased incidence of acute megakaryocytic leukemia; the respective roles of NFAT or DSCR1 in megakaryocytes of either normal individuals or those with DS, however, has not yet been established. Here we show that DSCR1 is upregulated during megakaryocytic differentiation in a lineage-specific manner, and in mature megakaryocytes is further strongly induced by calcineurin stimulation. DSCR1 expression in megakaryocytes is regulated by NFAT, since overexpression of NFATc2 enhances, while overexpression of the specific inhibitor of NFAT activation, VIVIT, suppresses expression of the gene. We further demonstrate that DSCR1 does not only represent an NFAT target in megakaryocytes, but itself acts an inhibitor of NFAT signaling in these cells. Overexpression of DSCR1 in CMK cells as well as in primary megakaryocytes by retroviral transduction profoundly suppressed ionomycin-induced dephosphorylation and nuclear translocation of NFATc2, as well as transactivation of an NFAT-dependent promoter construct. Finally, overexpression of DSCR1 in megakaryocytes markedly downregulated both the constitutive and induced expression of Fas Ligand, a pro-apoptotic gene recently established as a NFAT target in megakaryocytes. Together, these results suggest that DSCR1 acts as an NFAT-induced NFAT inhibitor in megakaryocytes and, when overexpressed, interferes with the expression of NFAT-dependent megakaryocytic genes.

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