scholarly journals Multiple distinct pathways lead to hyperubiquitylated insoluble TDP-43 protein independent of its translocation into stress granules

2019 ◽  
Vol 295 (3) ◽  
pp. 673-689 ◽  
Author(s):  
Friederike Hans ◽  
Hanna Glasebach ◽  
Philipp J. Kahle
Keyword(s):  
Oxidative Stress ◽  
Protein Kinase ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Glycogen Synthase ◽  
Osmotic Shock ◽  
Protein Kinase R ◽  
Extracellular Signal ◽  
Rapid Dissolution ◽  
The Central Nervous System

Insoluble, hyperubiquitylated TAR DNA-binding protein of 43 kDa (TDP-43) in the central nervous system characterizes frontotemporal dementia and ALS in many individuals with these neurodegenerative diseases. The causes for neuropathological TDP-43 aggregation are unknown, but it has been suggested that stress granule (SG) formation is important in this process. Indeed, in human embryonic kidney HEK293E cells, various SG-forming conditions induced very strong TDP-43 ubiquitylation, insolubility, and reduced splicing activity. Osmotic stress–induced SG formation and TDP-43 ubiquitylation occurred rapidly and coincided with colocalization of TDP-43 and SG markers. Washout experiments confirmed the rapid dissolution of SGs, accompanied by normalization of TDP-43 ubiquitylation and solubility. Surprisingly, interference with the SG process using a protein kinase R–like endoplasmic reticulum kinase inhibitor (GSK2606414) or the translation blocker emetine did not prevent TDP-43 ubiquitylation and insolubility. Thus, parallel pathways may lead to pathological TDP-43 modifications independent of SG formation. Using a panel of kinase inhibitors targeting signaling pathways of the osmotic shock inducer sorbitol, we could largely rule out the stress-activated and extracellular signal–regulated protein kinase modules and glycogen synthase kinase 3β. For arsenite, but not for sorbitol, quenching oxidative stress with N-acetylcysteine did suppress both SG formation and TDP-43 ubiquitylation and insolubility. Thus, sodium arsenite appears to promote SG formation and TDP-43 modifications via oxidative stress, but sorbitol stimulates TDP-43 ubiquitylation and insolubility via a novel pathway(s) independent of SG formation. In conclusion, pathological TDP-43 modifications can be mediated via multiple distinct pathways for which SGs are not essential.

scholarly journals The activation of protein kinase B by H2O2 or heat shock is mediated by phosphoinositide 3-kinase and not by mitogen-activated protein kinase-activated protein kinase-2

1998 ◽  
Vol 336 (1) ◽  
pp. 241-246 ◽  
Author(s):  
Morag SHAW ◽  
Philip COHEN ◽  
Dario R. ALESSI
Keyword(s):  
Oxidative Stress ◽  
Heat Shock ◽  
Protein Kinase ◽  
Glycogen Synthase ◽  
Protein Kinase B ◽  
Osmotic Shock ◽  
Mitogen Activated Protein Kinase ◽  
Protein Synthesis Inhibitor ◽  
Mitogen Activated Protein ◽  
Sb 203580

Protein kinase B (PKB) isoforms became activated [and glycogen synthase kinase-3 (GSK3) became inhibited] when mouse Swiss 3T3 fibroblasts were exposed to oxidative stress (H2O2) or heat shock, but not when they were exposed to osmotic shock (0.5 M sorbitol or 0.7 M NaCl), chemical stress (sodium arsenite), the protein-synthesis inhibitor anisomycin, or UV radiation. In contrast, all seven stimuli activated mitogen-activated protein kinase-activated protein kinase-2 (MAPKAP-K2). The activation of MAPKAP-K2 was suppressed by the drug SB 203580, but not by inhibitors of phosphoinositide (phosphatidylinositide, PI) 3-kinase. In contrast, the activation of PKB isoforms and the inhibition of GSK3 by oxidative stress or heat shock were prevented by inhibitors of PI 3-kinase, but not by SB 203580. Thus the activation of PKB by oxidative stress or heat shock is mediated by PI 3-kinase and not by MAPKAP-K2. PKBα and PKBγ were also activated by heat shock and oxidative stress in human embryonic kidney 293 cells and PKBγ was activated by heat shock in NIH 3T3 cells; in each case activation was suppressed by inhibitors of PI 3-kinase. The activation of PKB isoforms by H2O2 may underlie some of the insulin-mimetic effects of this compound.

scholarly journals Betulin, a Newly Characterized Compound in Acacia auriculiformis Bark, Is a Multi-Target Protein Kinase Inhibitor

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4599
Author(s):  
Augustine Ahmadu ◽  
Claire Delehouzé ◽  
Anas Haruna ◽  
Lukman Mustapha ◽  
Bilqis Lawal ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Kinase Inhibitor ◽  
Glycogen Synthase ◽  
Growth Factor Receptor ◽  
Binding Pocket ◽  
Stem Bark ◽  
Janus Kinase ◽  
Myelogenous Leukemia ◽  
Acacia Auriculiformis

The purpose of this work is to investigate the protein kinase inhibitory activity of constituents from Acacia auriculiformis stem bark. Column chromatography and NMR spectroscopy were used to purify and characterize betulin from an ethyl acetate soluble fraction of acacia bark. Betulin, a known inducer of apoptosis, was screened against a panel of 16 disease-related protein kinases. Betulin was shown to inhibit Abelson murine leukemia viral oncogene homolog 1 (ABL1) kinase, casein kinase 1ε (CK1ε), glycogen synthase kinase 3α/β (GSK-3 α/β), Janus kinase 3 (JAK3), NIMA Related Kinase 6 (NEK6), and vascular endothelial growth factor receptor 2 kinase (VEGFR2) with activities in the micromolar range for each. The effect of betulin on the cell viability of doxorubicin-resistant K562R chronic myelogenous leukemia cells was then verified to investigate its putative use as an anti-cancer compound. Betulin was shown to modulate the mitogen-activated protein (MAP) kinase pathway, with activity similar to that of imatinib mesylate, a known ABL1 kinase inhibitor. The interaction of betulin and ABL1 was studied by molecular docking, revealing an interaction of the inhibitor with the ABL1 ATP binding pocket. Together, these data demonstrate that betulin is a multi-target inhibitor of protein kinases, an activity that can contribute to the anticancer properties of the natural compound and to potential treatments for leukemia.

scholarly journals Effects of Sunitinib and Other Kinase Inhibitors on Cells Harboring a PDGFRB Mutation Associated with Infantile Myofibromatosis

2018 ◽  
Vol 19 (9) ◽  
pp. 2599 ◽  
Author(s):  
Martin Sramek ◽  
Jakub Neradil ◽  
Petra Macigova ◽  
Peter Mudry ◽  
Kristyna Polaskova ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cell Line ◽  
Tumor Cells ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Growth Factor Receptor ◽  
Tumor Cell Line ◽  
Protein Kinase Inhibitors ◽  
Infantile Myofibromatosis ◽  
Pdgfr Beta

Infantile myofibromatosis represents one of the most common proliferative fibrous tumors of infancy and childhood. More effective treatment is needed for drug-resistant patients, and targeted therapy using specific protein kinase inhibitors could be a promising strategy. To date, several studies have confirmed a connection between the p.R561C mutation in gene encoding platelet-derived growth factor receptor beta (PDGFR-beta) and the development of infantile myofibromatosis. This study aimed to analyze the phosphorylation of important kinases in the NSTS-47 cell line derived from a tumor of a boy with infantile myofibromatosis who harbored the p.R561C mutation in PDGFR-beta. The second aim of this study was to investigate the effects of selected protein kinase inhibitors on cell signaling and the proliferative activity of NSTS-47 cells. We confirmed that this tumor cell line showed very high phosphorylation levels of PDGFR-beta, extracellular signal-regulated kinases (ERK) 1/2 and several other protein kinases. We also observed that PDGFR-beta phosphorylation in tumor cells is reduced by the receptor tyrosine kinase inhibitor sunitinib. In contrast, MAPK/ERK kinases (MEK) 1/2 and ERK1/2 kinases remained constitutively phosphorylated after treatment with sunitinib and other relevant protein kinase inhibitors. Our study showed that sunitinib is a very promising agent that affects the proliferation of tumor cells with a p.R561C mutation in PDGFR-beta.

scholarly journals New tools for carbohydrate sulfation analysis: heparan sulfate 2-O-sulfotransferase (HS2ST) is a target for small-molecule protein kinase inhibitors

2018 ◽  
Vol 475 (15) ◽  
pp. 2417-2433 ◽  
Author(s):  
Dominic P. Byrne ◽  
Yong Li ◽  
Krithika Ramakrishnan ◽  
Igor L. Barsukov ◽  
Edwin A. Yates ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Heparan Sulfate ◽  
Small Molecule ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Protein Kinase Inhibitors ◽  
Fluorescent Substrate ◽  
Raf Kinase ◽  
Shift Analysis

Sulfation of carbohydrate residues occurs on a variety of glycans destined for secretion, and this modification is essential for efficient matrix-based signal transduction. Heparan sulfate (HS) glycosaminoglycans control physiological functions ranging from blood coagulation to cell proliferation. HS biosynthesis involves membrane-bound Golgi sulfotransferases, including HS 2-O-sulfotransferase (HS2ST), which transfers sulfate from the cofactor PAPS (3′-phosphoadenosine 5′-phosphosulfate) to the 2-O position of α-l-iduronate in the maturing polysaccharide chain. The current lack of simple non-radioactive enzyme assays that can be used to quantify the levels of carbohydrate sulfation hampers kinetic analysis of this process and the discovery of HS2ST inhibitors. In the present paper, we describe a new procedure for thermal shift analysis of purified HS2ST. Using this approach, we quantify HS2ST-catalysed oligosaccharide sulfation using a novel synthetic fluorescent substrate and screen the Published Kinase Inhibitor Set, to evaluate compounds that inhibit catalysis. We report the susceptibility of HS2ST to a variety of cell-permeable compounds in vitro, including polyanionic polar molecules, the protein kinase inhibitor rottlerin and oxindole-based RAF kinase inhibitors. In a related study, published back-to-back with the present study, we demonstrated that tyrosyl protein sulfotranferases are also inhibited by a variety of protein kinase inhibitors. We propose that appropriately validated small-molecule compounds could become new tools for rapid inhibition of glycan (and protein) sulfation in cells, and that protein kinase inhibitors might be repurposed or redesigned for the specific inhibition of HS2ST.

scholarly journals Identification of Two Kinase Inhibitors with Synergistic Toxicity with Low-Dose Hydrogen Peroxide in Colorectal Cancer Cells In vitro

Cancers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 122 ◽  
Author(s):  
Eric Freund ◽  
Kim-Rouven Liedtke ◽  
Lea Miebach ◽  
Kristian Wende ◽  
Amanda Heidecke ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Colorectal Cancer ◽  
Hydrogen Peroxide ◽  
Protein Kinase ◽  
Tumor Cells ◽  
Low Dose ◽  
Kinase Inhibitors ◽  
Protein Kinase Inhibitors ◽  
Colorectal Cancer Cells

Colorectal carcinoma is among the most common types of cancers. With this disease, diffuse scattering in the abdominal area (peritoneal carcinosis) often occurs before diagnosis, making surgical removal of the entire malignant tissue impossible due to a large number of tumor nodules. Previous treatment options include radiation and its combination with intraperitoneal heat-induced chemotherapy (HIPEC). Both options have strong side effects and are often poor in therapeutic efficacy. Tumor cells often grow and proliferate dysregulated, with enzymes of the protein kinase family often playing a crucial role. The present study investigated whether a combination of protein kinase inhibitors and low-dose induction of oxidative stress (using hydrogen peroxide, H2O2) has an additive cytotoxic effect on murine, colorectal tumor cells (CT26). Protein kinase inhibitors from a library of 80 substances were used to investigate colorectal cancer cells for their activity, morphology, and immunogenicity (immunogenic cancer cell death, ICD) upon mono or combination. Toxic compounds identified in 2D cultures were confirmed in 3D cultures, and additive cytotoxicity was identified for the substances lavendustin A, GF109203X, and rapamycin. Toxicity was concomitant with cell cycle arrest, but except HMGB1, no increased expression of immunogenic markers was identified with the combination treatment. The results were validated for GF109203X and rapamycin but not lavendustin A in the 3D model of different colorectal (HT29, SW480) and pancreatic cancer cell lines (MiaPaca, Panc01). In conclusion, our in vitro data suggest that combining oxidative stress with chemotherapy would be conceivable to enhance antitumor efficacy in HIPEC.

Animal model for angiotensin II effects in the internal anal sphincter smooth muscle: mechanism of action

2002 ◽  
Vol 282 (3) ◽  
pp. G461-G469 ◽  
Author(s):  
Ya-Ping Fan ◽  
Rajinder N. Puri ◽  
Satish Rattan
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Rho Kinase ◽  
Ang Ii ◽  
Kinase C ◽  
Rho Kinase Inhibitor ◽  
Isolated Smooth Muscle Cells

Effect of ANG II was investigated in in vitro smooth muscle strips and in isolated smooth muscle cells (SMC). Among different species, rat internal and sphincter (IAS) smooth muscle showed significant and reproducible contraction that remained unmodified by different neurohumoral inhibitors. The AT1antagonist losartan but not AT2 antagonist PD-123319 antagonized ANG II-induced contraction of the IAS smooth muscle and SMC. ANG II-induced contraction of rat IAS smooth muscle and SMC was attenuated by tyrosine kinase inhibitors genistein and tyrphostin, protein kinase C (PKC) inhibitor H-7, Ca2+ channel blocker nicardipine, Rho kinase inhibitor Y-27632 or p44/42mitogen-activating protein kinase (MAPK44/42) inhibitor PD-98059. Combinations of nicardipine and H-7, Y-27632, and PD-98059 caused further attenuation of the ANG II effects. Western blot analyses revealed the presence of both AT1 and AT2receptors. We conclude that ANG II causes contraction of rat IAS smooth muscle by the activation of AT1 receptors at the SMC and involves multiple intracellular pathways, influx of Ca2+, and activation of PKC, Rho kinase, and MAPK44/42.

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