scholarly journals Elevating the level of Cdc34/Ubc3 ubiquitin-conjugating enzyme in mitosis inhibits association of CENP-E with kinetochores and blocks the metaphase alignment of chromosomes

2001 ◽  
Vol 154 (4) ◽  
pp. 707-718 ◽  
Author(s):  
Leana M. Topper ◽  
Holger Bastians ◽  
Joan V. Ruderman ◽  
Gary J. Gorbsky
Keyword(s):  
Mammalian Cells ◽  
Proteasome Inhibitors ◽  
Metaphase Plate ◽  
Cytoplasmic Dynein ◽  
Mitogen Activated Protein Kinase ◽  
Protein Levels ◽  
Mitogen Activated Protein ◽  
Associated Proteins ◽  
Ubiquitin Conjugating Enzyme ◽  
Conjugating Enzyme

Cdc34/Ubc3 is a ubiquitin-conjugating enzyme that functions in targeting proteins for proteasome-mediated degradation at the G1 to S cell cycle transition. Elevation of Cdc34 protein levels by microinjection of bacterially expressed Cdc34 into mammalian cells at prophase inhibited chromosome congression to the metaphase plate with many chromosomes remaining near the spindle poles. Chromosome condensation and nuclear envelope breakdown occurred normally, and chromosomes showed oscillatory movements along mitotic spindle microtubules. Most injected cells arrested in a prometaphase-like state. Kinetochores, even those of chromosomes that failed to congress, possessed the normal trilaminar plate ultrastructure. The elevation of Cdc34 protein levels in early mitosis selectively blocked centromere protein E (CENP-E), a mitotic kinesin, from associating with kinetochores. Other proteins, including two CENP-E–associated proteins, BubR1 and phospho-p42/p44 mitogen-activated protein kinase, and mitotic centromere-associated kinesin, cytoplasmic dynein, Cdc20, and Mad2, all exhibited normal localization to kinetochores. Proteasome inhibitors did not affect the prometaphase arrest induced by Cdc34 injection. These studies suggest that CENP-E targeting to kinetochores is regulated by ubiquitylation not involving proteasome-mediated degradation.

ERK5 and its role in tumour development

2012 ◽  
Vol 40 (1) ◽  
pp. 251-256 ◽  
Author(s):  
Pamela A. Lochhead ◽  
Rebecca Gilley ◽  
Simon J. Cook
Keyword(s):  
Mitogen Activated Protein Kinase ◽  
Invasion And Migration ◽  
Extracellular Signal Regulated Kinase ◽  
Protein Levels ◽  
Extracellular Signal ◽  
Mapk Signalling ◽  
Mitogen Activated Protein ◽  
Tumour Cell Invasion ◽  
And Migration

The MEK5 [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase 5]/ERK5 pathway is the least well studied MAPK signalling module. It has been proposed to play a role in the pathology of cancer. In the present paper, we review the role of the MEK5/ERK5 pathway using the ‘hallmarks of cancer’ as a framework and consider how this pathway is deregulated. As well as playing a key role in endothelial cell survival and tubular morphogenesis during tumour neovascularization, ERK5 is also emerging as a regulator of tumour cell invasion and migration. Several oncogenes can stimulate ERK5 activity, and protein levels are increased by a novel amplification at chromosome locus 17p11 and by down-regulation of the microRNAs miR-143 and miR-145. Together, these finding underscore the case for further investigation into understanding the role of ERK5 in cancer.

scholarly journals Coordinated Regulation of Insulin Signaling by the Protein Tyrosine Phosphatases PTP1B and TCPTP

2005 ◽  
Vol 25 (2) ◽  
pp. 819-829 ◽  
Author(s):  
Sandra Galic ◽  
Christine Hauser ◽  
Barbara B. Kahn ◽  
Fawaz G. Haj ◽  
Benjamin G. Neel ◽  
...  
Keyword(s):  
Insulin Signaling ◽  
Tyrosine Phosphatase ◽  
Protein Tyrosine Phosphatases ◽  
Negative Regulator ◽  
Mitogen Activated Protein Kinase ◽  
Protein Tyrosine ◽  
Akt Activation ◽  
Protein Levels ◽  
Mitogen Activated Protein

ABSTRACT The protein tyrosine phosphatase PTP1B is a negative regulator of insulin signaling and a therapeutic target for type 2 diabetes. Our previous studies have shown that the closely related tyrosine phosphatase TCPTP might also contribute to the regulation of insulin receptor (IR) signaling in vivo (S. Galic, M. Klingler-Hoffmann, M. T. Fodero-Tavoletti, M. A. Puryer, T. C. Meng, N. K. Tonks, and T. Tiganis, Mol. Cell. Biol. 23:2096-2108, 2003). Here we show that PTP1B and TCPTP function in a coordinated and temporally distinct manner to achieve an overall regulation of IR phosphorylation and signaling. Whereas insulin-induced phosphatidylinositol 3-kinase/Akt signaling was prolonged in both TCPTP−/− and PTP1B−/− immortalized mouse embryo fibroblasts (MEFs), mitogen-activated protein kinase ERK1/2 signaling was elevated only in PTP1B-null MEFs. By using phosphorylation-specific antibodies, we demonstrate that both IR β-subunit Y1162/Y1163 and Y972 phosphorylation are elevated in PTP1B−/− MEFs, whereas Y972 phosphorylation was elevated and Y1162/Y1163 phosphorylation was sustained in TCPTP−/− MEFs, indicating that PTP1B and TCPTP differentially contribute to the regulation of IR phosphorylation and signaling. Consistent with this, suppression of TCPTP protein levels by RNA interference in PTP1B−/− MEFs resulted in no change in ERK1/2 signaling but caused prolonged Akt activation and Y1162/Y1163 phosphorylation. These results demonstrate that PTP1B and TCPTP are not redundant in insulin signaling and that they act to control both common as well as distinct insulin signaling pathways in the same cell.

scholarly journals Nuclear Translocation of Soybean MPK6, GmMPK6, Is Mediated by Hydrogen Peroxide in Salt Stress

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2611
Author(s):  
Jong Hee Im ◽  
Seungmin Son ◽  
Jae-Heung Ko ◽  
Kyung-Hwan Kim ◽  
Chung Sun An ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Hydrogen Peroxide ◽  
Salt Stress ◽  
Mammalian Cells ◽  
Nuclear Translocation ◽  
Signaling Molecules ◽  
Mitogen Activated Protein Kinase ◽  
Signal Transduction System ◽  
Diphenylene Iodonium ◽  
Mitogen Activated Protein

The plant mitogen-activated protein kinase (MPK) cascade, a highly conserved signal transduction system in eukaryotes, plays a crucial role in the plant’s response to environmental stimuli and phytohormones. It is well-known that nuclear translocation of MPKs is necessary for their activities in mammalian cells. However, the mechanism underlying nuclear translocation of plant MPKs is not well elucidated. In the previous study, it has been shown that soybean MPK6 (GmMPK6) is activated by phosphatidic acid (PA) and hydrogen peroxide (H2O2), which are two signaling molecules generated during salt stress. Using the two signaling molecules, we investigated how salt stress triggers its translocation to the nucleus. Our results show that the translocation of GmMPK6 to the nucleus is mediated by H2O2, but not by PA. Furthermore, the translocation was interrupted by diphenylene iodonium (DPI) (an inhibitor of RBOH), confirming that H2O2 is the signaling molecule for the nuclear translocation of GmMPK6 during salt stress.

Mesodermal patterning defect in mice lacking the Ste20 NCK interacting kinase (NIK)

Development ◽  
2001 ◽  
Vol 128 (9) ◽  
pp. 1559-1572 ◽  
Author(s):  
Y. Xue ◽  
X. Wang ◽  
Z. Li ◽  
N. Gotoh ◽  
D. Chapman ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Mammalian Cells ◽  
Essential Gene ◽  
Primitive Streak ◽  
Mitogen Activated Protein Kinase ◽  
Drosophila Embryo ◽  
Mammalian Development ◽  
Mitogen Activated Protein ◽  
Patterning Defect ◽  
Correct Location

We have previously shown that the Drosophila Ste20 kinase encoded by misshapen (msn) is an essential gene in Drosophila development. msn function is required to activate the Drosophila c-Jun N-terminal kinase (JNK), basket (Bsk), to promote dorsal closure of the Drosophila embryo. Later in development, msn expression is required in photoreceptors in order for their axons to project normally. A mammalian homolog of msn, the NCK-interacting kinase (NIK) (recently renamed to mitogen-activated protein kinase kinase kinase kinase 4; Map4k4), has been shown to activate JNK and to bind the SH3 domains of the SH2/SH3 adapter NCK. To determine whether NIK also plays an essential role in mammalian development, we created mice deficient in NIK by homologous recombination at the Nik gene. Nik(−/−) mice die postgastrulation between embryonic day (E) 9.5 and E10.5. The most striking phenotype in Nik(−/−) embryos is the failure of mesodermal and endodermal cells that arise from the anterior end of the primitive streak (PS) to migrate to their correct location. As a result Nik(−/−)embryos fail to develop somites or a hindgut and are truncated posteriorly. Interestingly, chimeric analysis demonstrated that NIK has a cell nonautonomous function in stimulating migration of presomitic mesodermal cells away from the PS and a second cell autonomous function in stimulating the differentiation of presomitic mesoderm into dermomyotome. These findings indicate that despite the large number of Ste20 kinases in mammalian cells, members of this family play essential nonredundant function in regulating specific signaling pathways. In addition, these studies provide evidence that the signaling pathways regulated by these kinases are diverse and not limited to the activation of JNK because mesodermal and somite development are not perturbed in JNK1-, and JNK2-deficient mice.

scholarly journals Short-Term Microgravity Influences Cell Adhesion in Human Breast Cancer Cells

2019 ◽  
Vol 20 (22) ◽  
pp. 5730 ◽  
Author(s):  
Mohamed Zakaria Nassef ◽  
Sascha Kopp ◽  
Daniela Melnik ◽  
Thomas J. Corydon ◽  
Jayashree Sahana ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Adhesion ◽  
Parabolic Flight ◽  
Three Dimensional ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Protective Mechanisms ◽  
Protein Levels ◽  
Mitogen Activated Protein ◽  
Real Microgravity

With the commercialization of spaceflight and the exploration of space, it is important to understand the changes occurring in human cells exposed to real microgravity (r-µg) conditions. We examined the influence of r-µg, simulated microgravity (s-µg, incubator random positioning machine (iRPM)), hypergravity (hyper-g), and vibration (VIB) on triple-negative breast cancer (TNBC) cells (MDA-MB-231 cell line) with the aim to study early changes in the gene expression of factors associated with cell adhesion, apoptosis, nuclear factor “kappa-light-chain-enhancer” of activated B-cells (NF-κB) and mitogen-activated protein kinase (MAPK) signaling. We had the opportunity to attend a parabolic flight (PF) mission and to study changes in RNA transcription in the MDA-MB cells exposed to PF maneuvers (29th Deutsches Zentrum für Luft- und Raumfahrt (DLR) PF campaign). PF maneuvers induced an early up-regulation of ICAM1, CD44 and ERK1 mRNAs after the first parabola (P1) and a delayed upregulation of NFKB1, NFKBIA, NFKBIB, and FAK1 after the last parabola (P31). ICAM-1, VCAM-1 and CD44 protein levels were elevated, whereas the NF-κB subunit p-65 and annexin-A2 protein levels were reduced after the 31st parabola (P31). The PRKCA, RAF1, BAX mRNA were not changed and cleaved caspase-3 was not detectable in MDA-MB-231 cells exposed to PF maneuvers. Hyper-g-exposure of the cells elevated the expression of CD44 and NFKBIA mRNAs, iRPM-exposure downregulated ANXA2 and BAX, whereas VIB did not affect the TNBC cells. The early changes in ICAM-1 and VCAM-1 and the rapid decrease in the NF-κB subunit p-65 might be considered as fast-reacting, gravity-regulated and cell-protective mechanisms of TNBC cells exposed to altered gravity conditions. This data suggest a key role for the detected gravity-signaling elements in three-dimensional growth and metastasis.

Isoflurane Preconditions Hippocampal Neurons against Oxygen–Glucose Deprivation

2005 ◽  
Vol 103 (3) ◽  
pp. 532-539 ◽  
Author(s):  
Philip E. Bickler ◽  
Xinhua Zhan ◽  
Christian S. Fahlman
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Kinase ◽  
Hippocampal Slice ◽  
Binding Protein ◽  
Glucose Deprivation ◽  
Mitogen Activated Protein Kinase ◽  
Oxygen Glucose Deprivation ◽  
Hippocampal Slice Cultures ◽  
Mitogen Activated Protein ◽  
Associated Proteins

Background Isoflurane preconditions neurons to improve tolerance of subsequent ischemia in both intact animal models and in in vitro preparations. The mechanisms for this protection remain largely undefined. Because isoflurane increases intracellular Ca2+ concentrations and Ca2+ is involved in many processes related to preconditioning, the authors hypothesized that isoflurane preconditions neurons via Ca2+-dependent processes involving the Ca2+- binding protein calmodulin and the mitogen-activated protein kinase-ERK pathway. Methods The authors used a preconditioning model in which organotypic cultures of rat hippocampus were exposed to 0.5-1.5% isoflurane for a 2-h period 24 h before an ischemia-like injury of oxygen-glucose deprivation. Survival of CA1, CA3, and dentate neurons was assessed 48 later, along with interval measurements of intracellular Ca2+ concentration (fura-2 fluorescence microscopy in CA1 neurons), mitogen-activated protein kinase p42/44, and the survival associated proteins Akt and GSK-3beta (in situ immunostaining and Western blots). Results Preconditioning with 0.5-1.5% isoflurane decreased neuron death in CA1 and CA3 regions of hippocampal slice cultures after oxygen-glucose deprivation. The preconditioning period was associated with an increase in basal intracellular Ca2+ concentration of 7-15%, which involved Ca2+ release from inositol triphosphate-sensitive stores in the endoplasmic reticulum, and transient phosphorylation of mitogen-activated protein kinase p42/44 and the survival-associated proteins Akt and GSK-3beta. Preconditioning protection was eliminated by the mitogen-activated extracellular kinase inhibitor U0126, which prevented phosphorylation of p44 during preconditioning, and by calmidazolium, which antagonizes the effects of Ca2+-bound calmodulin. Conclusions Isoflurane, at clinical concentrations, preconditions neurons in hippocampal slice cultures by mechanisms that apparently involve release of Ca2+ from the endoplasmic reticulum, transient increases in intracellular Ca2+ concentration, the Ca2+ binding protein calmodulin, and phosphorylation of the mitogen-activated protein kinase p42/44.

scholarly journals Two human cDNAs, including a homolog of Arabidopsis FUS6 (COP11), suppress G-protein- and mitogen-activated protein kinase-mediated signal transduction in yeast and mammalian cells.

1996 ◽  
Vol 16 (12) ◽  
pp. 6698-6706 ◽  
Author(s):  
B H Spain ◽  
K S Bowdish ◽  
A R Pacal ◽  
S F Staub ◽  
D Koo ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Protein Kinase ◽  
G Protein ◽  
Mammalian Cells ◽  
Enhanced Recovery ◽  
Negative Regulator ◽  
Mitogen Activated Protein Kinase ◽  
Striking Similarity ◽  
Protein Subunit ◽  
Mitogen Activated Protein

We have isolated two novel human cDNAs, gps1-1 and gps2, that suppress lethal G-protein subunit-activating mutations in the pheromone response pathway of the yeast Saccharomyces cerevisiae. Suppression of other pathway-activating events was examined. In wild-type cells, expression of either gps1-1 or gps2 led to enhanced recovery from cell cycle arrest induced by pheromone. Sequence analysis indicated that gps1-1 contains only the carboxy-terminal half of the gps1 coding sequence. The predicted gene product of gps1 has striking similarity to the protein encoded by the Arabidopsis FUS6 (COP11) gene, a negative regulator of light-mediated signal transduction that is known to be essential for normal development. A chimeric construct containing gps1 and FUS6 sequences also suppressed the yeast pheromone pathway, indicating functional conservation between these human and plant genes. In addition, when overexpressed in mammalian cells, gps1 or gps2 potently suppressed a RAS- and mitogen-activated protein kinase-mediated signal and interfered with JNK activity, suggesting that signal repression is part of their normal function. For gps1, these results are consistent with the proposed function of FUS6 (COP11) as a signal transduction repressor in plants.

Identification of the autophosphorylation sites and characterization of their effects in the protein kinase DYRK1A

2001 ◽  
Vol 359 (3) ◽  
pp. 497-505 ◽  
Author(s):  
Sunke HIMPEL ◽  
Pascal PANZER ◽  
Klaus EIRMBTER ◽  
Hanna CZAJKOWSKA ◽  
Muhammed SAYED ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Mammalian Cells ◽  
Catalytic Domain ◽  
Molecular Model ◽  
Enzymic Activity ◽  
Mitogen Activated Protein Kinase ◽  
Kinase Family ◽  
Extracellular Signal ◽  
Mitogen Activated Protein

Protein kinases of the DYRK (‘dual-specificity tyrosine-regulated kinase’) family are characterized by a conserved Tyr-Xaa-Tyr motif (Tyr-319–Tyr-321) in a position exactly corresponding to the activation motif of the mitogen-activated protein kinase (MAP kinase) family (Thr-Xaa-Tyr). In a molecular model of the catalytic domain of DYRK1A, the orientation of phosphorylated Tyr-321 is strikingly similar to that of Tyr-185 in the known structure of the activated MAP kinase, extracellular-signal-regulated kinase 2. Consistent with our model, substitution of Tyr-321 but not of Tyr-319 by phenylalanine markedly reduced the enzymic activity of recombinant DYRK1A expressed in either Escherichia coli or mammalian cells. Direct identification of phosphorylated residues by tandem MS confirmed that Tyr-321, but not Tyr-319, was phosphorylated. When expressed in COS-7 cells, DYRK1A was found to be fully phosphorylated on Tyr-321. A catalytically inactive mutant of DYRK1A contained no detectable phosphotyrosine, indicating that Tyr-321 is autophosphorylated by DYRK1A. MS identified Tyr-111 and Ser-97 as additional autophosphorylation sites in the non-catalytic N-terminal domain of bacterially expressed DYRK1A. Enzymic activity was not affected in the DYRK1A-Y111F mutant. The present experimental data and the molecular model indicate that the activity of DYRK1A is dependent on the autophosphorylation of a conserved tyrosine residue in the activation loop.

scholarly journals Praeruptorin B Mitigates the Metastatic Ability of Human Renal Carcinoma Cells through Targeting CTSC and CTSV Expression

2020 ◽  
Vol 21 (8) ◽  
pp. 2919
Author(s):  
Chia-Liang Lin ◽  
Tung-Wei Hung ◽  
Tsung-Ho Ying ◽  
Chi-Jui Lin ◽  
Yi-Hsien Hsieh ◽  
...  
Keyword(s):  
Growth Factor Receptor ◽  
Cellular Migration ◽  
Mitogen Activated Protein Kinase ◽  
Migration And Invasion ◽  
Antitumor Effects ◽  
Protein Levels ◽  
Extracellular Signal ◽  
Adult Kidney ◽  
Mitogen Activated Protein ◽  
Underlying Mechanisms

Renal cell carcinoma (RCC) is the most common adult kidney cancer, and accounts for 85% of all cases of kidney cancers worldwide. Praeruptorin B (Pra-B) is a bioactive constituent of Peucedanum praeruptorum Dunn and exhibits several pharmacological activities, including potent antitumor effects. However, the anti-RCC effects of Pra-B and their underlying mechanisms are unclear; therefore, we explored the effects of Pra-B on RCC cells in this study. We found that Pra-B nonsignificantly influenced the cell viability of human RCC cell lines 786-O and ACHN at a dose of less than 30 μM for 24 h treatment. Further study revealed that Pra-B potently inhibited the migration and invasion of 786-O and ACHN cells, as well as downregulated the mRNA and protein expression of cathepsin C (CTSC) and cathepsin V (CTSV) of 786-O and ACHN cells. Mechanistically, Pra-B also reduced the protein levels of phospho (p)-epidermal growth factor receptor (EGFR), p-mitogen-activated protein kinase kinase (MEK), and p-extracellular signal-regulated kinases (ERK) in RCC cells. In addition, Pra-B treatment inhibited the effect of EGF on the upregulation of EGFR–MEK–ERK, CTSC and CTSV expression, cellular migration, and invasion of 786-O cells. Our findings are the first to demonstrate that Pra-B can reduce the migration and invasion ability of human RCC cells through suppressing the EGFR-MEK-ERK signaling pathway and subsequently downregulating CTSC and CTSV. This evidence suggests that Pra-B can be developed as an effective antimetastatic agent for the treatment of RCC.

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