scholarly journals Hemps, a novel EGF-like protein, plays a central role in ascidian metamorphosis

Development ◽  
1999 ◽  
Vol 126 (24) ◽  
pp. 5809-5818 ◽  
Author(s):  
R. Eri ◽  
J.M. Arnold ◽  
V.F. Hinman ◽  
K.M. Green ◽  
M.K. Jones ◽  
...  
Keyword(s):  
Marine Invertebrates ◽  
Signal Sequence ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Secretion Signal ◽  
Terrestrial Arthropods ◽  
Aquatic Vertebrates ◽  
Epidermal Growth ◽  
Characteristic Features ◽  
Herdmania Curvata

All chordates share several characteristic features including a dorsal hollow neural tube, a notochord, a pharynx and an endostyle. Unlike other chordate taxa, ascidians have a biphasic life-history with two distinct body plans. During metamorphosis, the larval nerve cord and notochord degenerate and the pharyngeal gill slits and endostyle form. While ascidians, like other marine invertebrates, metamorphose in response to specific environmental cues, it remains unclear how these cues trigger metamorphosis. We have identified a novel gene (Hemps) which encodes a protein with a putative secretion signal sequence and four epidermal growth factor (EGF)-like repeats which is a key regulator of metamorphosis in the ascidian Herdmania curvata. Expression of Hemps increases markedly when the swimming tadpole larva becomes competent to undergo metamorphosis and then during the first 24 hours of metamorphosis. The Hemps protein is localised to the larval papillae and anterior epidermis of the larva in the region known to be required for metamorphosis. When the larva contacts an inductive cue the protein is released, spreading posteriorly and into the tunic as metamorphosis progresses. Metamorphosis is blocked by incubating larvae in anti-Hemps antibodies prior to the addition of the cue. Addition of recombinant Hemps protein to competent larvae induces metamorphosis in a concentration-dependent manner. A subgroup of genes are specifically induced during this process. These results demonstrate that the Hemps protein is a key regulator of ascidian metamorphosis and is distinct from previously described inducers of this process in terrestrial arthropods and aquatic vertebrates.

scholarly journals Boehmenan, a Lignan From the Chinese Medicinal Plant Clematis armandii, Inhibits A431 Cell Growth via Blocking p70S6/S6 Kinase Pathway

2016 ◽  
Vol 16 (3) ◽  
pp. 351-359 ◽  
Author(s):  
Li-Long Pan ◽  
Xi-Ling Wang ◽  
Xiao-Ling Luo ◽  
Si-Yu Liu ◽  
Peng Xu ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen Species Production ◽  
Intracellular Reactive Oxygen Species ◽  
Dependent Manner ◽  
Oxygen Species ◽  
A431 Cells ◽  
Concentration Dependent Manner ◽  
S6 Kinase ◽  
Epidermal Growth ◽  
Species Production

Previously, we have shown that boehmenan, a natural product isolated from the dried stem of Caulis clematidis armandii, exhibits various biological activities. The current study investigated the effects of boehmenan on the growth of human epidermoid carcinoma A431 cells. Cell viability and 50% inhibiting concentration (IC50) were assessed by CellTiter-Glo luminescent cell viability assay. Cell cycle arrest was measured by flow cytometry. Intracellular reactive oxygen species production and mitochondrial membrane potential (ΔΨm) collapse were analyzed by a fluorescence spectrophotometer. The activation of epidermal growth factor receptor signaling pathway was evaluated by Western blot. The results showed that boehmenan significantly inhibited the growth of A431 cells (IC50 = 1.6 µM) in a concentration- and time-dependent manner. This compound also blocked cell cycle progression at G2/M phase and modulated mitochondrial apoptosis-related proteins, as evidenced by upregulating p21, cleaved caspase-3, and cleaved poly (ADP-ribose) polymerase protein levels and by downregulating Bcl-2, pro-caspase-9 levels. In addition, boehmenan also markedly induced intracellular reactive oxygen species production and ΔΨm depolarization in a concentration-dependent manner. Furthermore, boehmenan-attenuated epidermal growth factor mediated the phosphorylation of signal transducer and activator of transcription 3 (STAT3), p70 ribosomal protein S6 kinase (p70S6)/S6 in a concentration-dependent manner. Taken together, our results suggest that boehmenan-mediated antiproliferative property in A431 cells was mediated partially by modulation of mitochondrial function and inhibition of STAT3 and p70S6 signal pathways.

scholarly journals Teratogenic and developmental toxic effects of etridiazole on zebrafish (Danio rerio) embryos

2020 ◽  
Vol 63 (1) ◽  
Author(s):  
Bala Murali Krishna Vasamsetti ◽  
Nam-Seok Kim ◽  
Kyongmi Chon ◽  
Hong-Hyun Park
Keyword(s):  
Danio Rerio ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Skeletal Malformations ◽  
Somite Formation ◽  
Aquatic Vertebrates ◽  
Pericardial Edema ◽  
Eye Pigmentation ◽  
Median Effective Concentration ◽  
Morphological Deformities

AbstractEtridiazole (EDZ), a thiadiazole-containing toxic chemical, is widely used as a fungicide. Regular usage of EDZ may reach and contaminate water bodies, but its adverse effects on aquatic vertebrates have not been well studied. Therefore, the present study aimed to evaluate the harmful effects of EDZ using zebrafish (ZF) (Danio rerio) embryos. ZF embryos were treated with 3.75, 7.5, 15, 30, and 60 mg/L of EDZ. Subsequently, mortality and developmental toxicities were quantified at 24, 48, 72, and 96 h post fertilization (hpf). The results showed that embryo mortality was concentration- and time-dependent. The median lethal concentration (LC50) of EDZ at 96-h was 25.58 ± 1.49 mg/L. Besides, EDZ induced a series of morphological deformities, including abnormal somite formation, abnormal eye pigmentation, abnormal tail morphology, tail kinks, skeletal malformations (lordosis, kyphosis, and scoliosis), and yolk sac edema in a concentration-dependent manner. Among the deformities, the most significant were reduced heartbeat and increased incidence of pericardial edema. The median effective concentration (EC50) of EDZ at 96-h was 17.93 ± 2.22 mg/L and the 96-h teratogenic index (TI) value was 1.52. Taken together, these results indicate that EDZ is a teratogen, and primarily affects the cardiovascular system of ZF.

scholarly journals An N-ethylmaleimide-sensitive cytosolic factor necessary for nuclear protein import: requirement in signal-mediated binding to the nuclear pore.

1990 ◽  
Vol 110 (3) ◽  
pp. 547-557 ◽  
Author(s):  
D D Newmeyer ◽  
D J Forbes
Keyword(s):  
Nuclear Import ◽  
Protein Import ◽  
Nuclear Protein ◽  
Signal Sequence ◽  
Nuclear Pore ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Sensitive Factor ◽  
Nuclear Protein Import ◽  
Cytosolic Factor

We described previously an assay for authentic nuclear protein import in vitro. In this assay, exogenous nuclei are placed in an extract of Xenopus eggs; a rhodamine-labeled protein possessing a nuclear localization signal is added, and fluorescence microscopy is used to measure nuclear uptake. The requirement in this system for a cytosolic extract suggests that nuclear import is dependent on at least one cytosolic factor. We now confirm this hypothesis. Treatment of the cytosol with N-ethylmaleimide (NEM) abolishes nuclear protein import; readdition of a cytosolic fraction to the NEM-inactivated extract rescues transport. Thus, at least one NEM-sensitive factor required for transport is supplied by the cytosol. This activity, called nuclear import factor-1, or NIF-1, is ammonium-sulfate-precipitable, protease-sensitive, and heat-labile; it is therefore at least partly proteinaceous. NIF-1 stimulates, in a concentration-dependent manner, the rate at which individual nuclei accumulate protein. The effect of NIF-1 is enhanced by a second cytosolic NEM-sensitive factor, NIF-2. Earlier we identified two steps in the nuclear import reaction: (a) ATP-independent binding of a signal-sequence-bearing protein to the nuclear pore; and (b) ATP-dependent translocation of that protein through the pore. We now show that NEM inhibits signal-mediated binding, and that readdition of NIF-1 restores binding. Thus, NIF-1 is required for at least the binding step and does not require ATP for its activity. NIF-1 may act as a cytoplasmic signal receptor that escorts signal-bearing proteins to the pore, or may instead promote signal-mediated binding to the pore in another manner, as discussed.

scholarly journals Tri-iodothyronine induces proliferation in cultured bovine thyroid cells: evidence for the involvement of epidermal growth factor-associated tyrosine kinase activity

2000 ◽  
Vol 166 (1) ◽  
pp. 173-182 ◽  
Author(s):  
M Di Fulvio ◽  
AH Coleoni ◽  
CG Pellizas ◽  
AM Masini-Repiso
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Western Blot ◽  
Blot Analysis ◽  
Thymidine Incorporation ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Thyroid Cells ◽  
Epidermal Growth ◽  
Bovine Thyroid

The effects of the tri-iodothyronine (T(3)) secreted by thyroid cells on the growth of the thyrocyte are poorly known. In this study we analyzed the effects of T(3) on the proliferation of bovine thyroid follicles in primary culture previously depleted of endogenous T(3). Cellular deoxiribonucleic acid (DNA) synthesis, determined by [(3)H]thymidine incorporation, was stimulated by T(3) (0.1-5.0 nM) for 24 h in a concentration-dependent fashion with a maximal effect at 1.0 nM T(3) (P<0.01). This T(3) action was time-dependent when assayed from 12 to 72 h. The induction of mitogenic activity was corroborated by the increase in proliferating cell nuclear antigen (PCNA) measured by Western blot analysis. PCNA increased after treatment with T(3) (0.1-5.0 nM) in a concentration-dependent manner. Since T(3) modifies the activity of growth factors whose actions are mainly mediated by tyrosine kinase (TK) activation in diverse cellular types, we assayed the effects of genistein, a general TK inhibitor, and tyrphostin A25, a specific epidermal growth factor (EGF)-receptor (EGFR)-dependent TK activity inhibitor, on the proliferative effects of T(3). The T(3)-induced [(3)H]thymidine incorporation was inhibited by both agents in a concentration-dependent manner. A significant increase in the total TK activity measured in cellular protein extracts was induced by 0.5 and 1.0 nM T(3) (P<0.001). Tyrosine phosphorylation of the EGFR was also stimulated by T(3) (P<0.001) with no change in the EGFR expression as determined by Western blot analysis. Both, the T(3)-stimulated [(3)H]thymidine incorporation and the TK activity were inhibited by a anti-mouse EGF antibody. These results lead us to propose that T(3) could operate as a proliferative agent in bovine thyroid cells through a mechanism involving an autocrine/paracrine EGF/EGFR-dependent regulation.

scholarly journals Design and synthesis of a consensus signal sequence that inhibits protein translocation into rough microsomal vesicles

1984 ◽  
Vol 224 (1) ◽  
pp. 317-325 ◽  
Author(s):  
B M Austen ◽  
J Hermon-Taylor ◽  
M A Kaderbhai ◽  
D H Ridd
Keyword(s):  
Solid Phase ◽  
Signal Sequence ◽  
Protein Translation ◽  
Structural Features ◽  
Signal Peptidase ◽  
Placental Lactogen ◽  
Translation System ◽  
Dependent Manner ◽  
Signal Sequences ◽  
Concentration Dependent Manner

Most signal sequences are found to vary considerably in length and primary sequence, but possess some common structural features. Analysis of known signal sequences has led to the design of a 19-residue sequence that, although not a naturally occurring signal, possesses the structural features that commonly occur in pre-proteins. This peptide has been synthesized by solid-phase methods, and has been shown to inhibit, in a concentration-dependent manner, the processing in vitro of nascent pre-prolactin, pre-forms of pancreatic digestive enzymes, and pre-placental lactogen. The peptide acts at the cytoplasmic surface of microsomal vesicles added to the protein translation system, preventing translocation of the nascent chains to the lumenal space of vesicles where signal peptidase normally cleaves to remove the signal from nascent pre-proteins.

scholarly journals Characterization of Musclin as a New Target for Treatment of Hypertension

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Jia-Wei Lin ◽  
Cheng-Chia Tsai ◽  
Li-Jen Chen ◽  
Ho-Shan Niu ◽  
Chen Kuei Chang ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Direct Effect ◽  
Signal Sequence ◽  
Dependent Manner ◽  
Hypertensive Rats ◽  
Concentration Dependent Manner ◽  
Spontaneously Hypertensive ◽  
Treatment Of Hypertension ◽  
Novel Target

Musclin is a novel skeletal muscle-derived factor found in the signal sequence trap of mouse skeletal muscle cDNAs. Recently, it has been demonstrated that musclin is involved in the pathogenesis of spontaneously hypertensive rats (SHRs). However, it is known as a genetic hypertension model. In the present study, we aim to investigate the role of musclin in another animal model of hypertension and characterize the direct effect of musclin on vascular contraction. The results show that expression of musclin was increased in arterial tissues isolated from DOCA-salt induced hypertensive rats or the normal rats received repeated vasoconstriction with phenylephrine. Additionally, direct incubation with phenylephrine did not modify the expression of musclin in thein vitrostudies. Also, the direct effect of musclin on the increase of intracellular calcium was observed in a concentration-dependent manner. These results provide the evidence to support that musclin is involved in hypertension. Thus, musclin is suitable to be considered as a novel target for treatment of hypertension.

Prostaglandins induce proliferation of rat hepatocytes through a prostaglandin E2 receptor EP3 subtype

1997 ◽  
Vol 272 (3) ◽  
pp. G597-G604 ◽  
Author(s):  
N. Hashimoto ◽  
T. Watanabe ◽  
Y. Ikeda ◽  
H. Yamada ◽  
S. Taniguchi ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Rat Hepatocytes ◽  
Membrane Receptors ◽  
Dependent Manner ◽  
Camp Accumulation ◽  
Concentration Dependent Manner ◽  
Epidermal Growth ◽  
Cultured Rat Hepatocytes ◽  
Pge2 Receptor ◽  
Prostaglandin E2 Receptor

We characterized the proliferative action of prostaglandins (PGs) in relation to their membrane receptors on rat hepatocytes in primary culture. PGs in the order 16,16-dimethyl PGE2 > PGE2 > PGF2alpha >> PGD2 augmented epidermal growth factor (EGF)/insulin-induced DNA synthesis, assessed by [(3)H]thymidine incorporation, in a concentration-dependent manner, whereas PGs alone did not stimulate basal DNA synthesis without EGF and insulin. The cells exhibited [(3)H]PGE2 binding sites that were displaced by unlabeled PGs in the order PGE1 = PGE2 > PGF2alpha > PGD2. PGE2 inhibited glucagon-stimulated adenosine 3',5'-cyclic monophosphate (cAMP) accumulation concentration dependently. The mean effective concentration for DNA synthesis, median inhibitory concentration for cAMP accumulation, and dissociation constant for [(3)H]PGE2 binding at 25 degrees C were almost identical (approximately 70 nM). Treatment of the cells with pertussis toxin (100 ng/ml), which ADP-ribosylated most of the 41-kDa substrate, abolished the proliferative effects of PGs. We detected the expression of mRNA of the EP3 subtype PGE2 receptor using reverse transcription-polymerase chain reaction. Moreover, an EP3 agonist, enprostil, but not the EP1 agonist 17-phenyl-trinor-PGE2 or the EP2/EP4 agonist 11-deoxy-PGE1, stimulated EGF/insulin-induced DNA synthesis. These results indicate that PGs act as comitogenic growth factors through the EP3 subtype PGE2 receptor coupled with G(i) protein in cultured rat hepatocytes.

scholarly journals Two sites on P-selectin (the lectin and epidermal growth factor-like domains) are involved in the adhesion of monocytes to thrombin-activated endothelial cells

1994 ◽  
Vol 303 (2) ◽  
pp. 619-624 ◽  
Author(s):  
J F Murphy ◽  
J L McGregor
Keyword(s):  
Endothelial Cells ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Mononuclear Cells ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Activated Platelets ◽  
Epidermal Growth

P-selectin, also known as GMP-140, PADGEM or CD62, is expressed on the surface of thrombin-activated platelets and endothelial cells (EC). It is a member of the selectin family of adhesion molecules that regulate leucocyte interactions with the blood vessel wall. In this study we have found that peptides derived from both the lectin (residues 19-34 and 51-61) and epidermal growth factor (EGF)-like (residues 127-139) domains inhibit the adhesion of peripheral blood mononuclear cells (PBMC), elutriated monocytes and a monocytic cell line (U937) to thrombin-activated EC. This inhibition occurred in a concentration-dependent manner and the peptide most active at the lowest concentrations was the one derived from the EGF-like motif (127-139). The scrambled forms of these peptides, identical in amino acid composition to the authentic peptides but with altered sequences, were not inhibitory. Thrombin-activated platelets supported adhesion of U937 cells and this adhesion was dramatically inhibited by the two peptides derived from the lectin-like domain (residues 19-34 and 51-61). All three peptides, when conjugated to BSA and coated on plastic plates, mediated U937 cell adhesion. This study shows, for the first time, that two sites on P-selectin, the lectin and EGF-like domains, are involved in the adhesion of monocytes to thrombin-activated EC.

Polarized efflux of iodide in porcine thyrocytes occurs via a cAMP-regulated iodide channel in the apical plasma membrane

1992 ◽  
Vol 126 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Mikael Nilsson ◽  
Ulla Björkman ◽  
Ragnar Ekholm ◽  
Lars E Ericson
Keyword(s):  
Plasma Membrane ◽  
Apical Plasma Membrane ◽  
Intracellular Camp ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Selective Stimulation ◽  
Kinase C ◽  
Apical Direction ◽  
Intracellular Regulation ◽  
Epidermal Growth

The intracellular regulation of thyrotropin-stimulated iodide efflux was studied in polarized porcine thyrocytes grown as a continuous, tight monolayer in bicameral culture chambers. From a previous study using this system we know that thyrotropin rapidly increases iodide efflux in the apical but not basal direction of the polarized epithelium. [125I]-iodide efflux in apical direction was stimulated by thyrotropin in a concentration-dependent manner (1–10 U/I), whereas efflux in basal direction was unchanged at any thyrotropin dose. Thyrotropin-induced elevation of intracellular cAMP showed a corresponding concentration dependence. The selective stimulation of apical efflux by thyrotropin was evident also when re-uptake of iodide released in basal direction was blocked by perchlorate. The effect of thyrotropin on apical efflux was mimicked by 8-bromo-cAMP and forskolin, whereas agents known to activate the Ca2+/phosphatidylinositol cascade (epidermal growth factor) and protein kinase C (phorbol ester) or increase cytosolic [Ca2+] (A23187) were inactive. We conclude that the selective stimulation by thyrotropin of apical iodide efflux, corresponding to efflux in luminal direction in intact follicles, occurs via cAMP-regulated iodide channels present in the apical domain of the plasma membrane.

Inhibition of geranylgeranyltransferase inhibits bronchial smooth muscle hyperresponsiveness in mice

2009 ◽  
Vol 297 (5) ◽  
pp. L984-L991 ◽  
Author(s):  
Yoshihiko Chiba ◽  
Shunsuke Sato ◽  
Motohiko Hanazaki ◽  
Hiroyasu Sakai ◽  
Miwa Misawa
Keyword(s):  
Smooth Muscle ◽  
Rho Kinase ◽  
Selective Inhibition ◽  
Dependent Manner ◽  
Bronchial Smooth Muscle ◽  
Concentration Dependent Manner ◽  
Characteristic Features ◽  
Novel Strategy

Recent studies revealed an involvement of RhoA/Rho-kinase in the contraction of bronchial smooth muscle (BSM), and this pathway has now been proposed as a new target for asthma therapy. A posttranslational geranylgeranylation of RhoA is required for its activation. Thus selective inhibition of geranylgeranyltransferase may be a novel strategy for treatment of the BSM hyperresponsiveness in asthmatics. To test this hypothesis, we investigated the effect of a geranylgeranyltransferase inhibitor, GGTI-2133, on antigen-induced BSM hyperresponsiveness by using mice with experimental asthma. Mice were sensitized and repeatedly challenged with ovalbumin antigen. Animals also were treated with GGTI-2133 (5 mg/kg ip) once a day before and during the antigen inhalation period. Repeated antigen inhalation caused a BSM hyperresponsiveness to acetylcholine with the increased expressions of RhoA and the anti-farnesyl-positive 21-kDa proteins, probably geranylgeranylated RhoA. The in vivo GGTI-2133 treatments significantly inhibited BSM hyperresponsiveness induced by antigen exposure. In another series of experiments, BSM tissues isolated from the repeatedly antigen-challenged mice were cultured for 48 h in the absence or presence of GGTI-2133. Under these conditions, the putative geranylgeranylated RhoA was decreased in a GGTI-2133 concentration-dependent manner. The in vitro incubation with GGTI-2133 also inhibited BSM hyperresponsiveness induced by antigen exposure. These findings suggest that GGTI-2133 inhibits antigen-induced BSM hyperresponsiveness, probably by reducing downstream signal transduction of RhoA. Selective geranylgeranyltransferase inhibitors may be beneficial for the treatment of airway hyperresponsiveness, one of the characteristic features of allergic bronchial asthma.

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