Long-term dynamics of multisite phosphorylation

Multisite phosphorylation cycles are ubiquitous in cell regulation systems and are studied at multiple levels of complexity, from molecules to organisms, with the ultimate goal of establishing predictive understanding of the effects of genetic and pharmacological perturbations of protein phosphorylation in vivo. Achieving this goal is essentially impossible without mathematical models, which provide a systematic framework for exploring dynamic interactions of multiple network components. Most of the models studied to date do not discriminate between the distinct partially phosphorylated forms and focus on two limiting reaction regimes, distributive and processive, which differ in the number of enzyme–substrate binding events needed for complete phosphorylation or dephosphorylation. Here we use a minimal model of extracellular signal-related kinase regulation to explore the dynamics of a reaction network that includes all essential phosphorylation forms and arbitrary levels of reaction processivity. In addition to bistability, which has been studied extensively in distributive mechanisms, this network can generate periodic oscillations. Both bistability and oscillations can be realized at high levels of reaction processivity. Our work provides a general framework for systematic analysis of dynamics in multisite phosphorylation systems.

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Solving the mechanisms responsible for organelle behavior in vivo by same-cell correlative light and electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100120473 ◽

1992 ◽

Vol 50 (1) ◽

pp. 14-15

Author(s):

Conly L. Rieder

Keyword(s):

Electron Microscopy ◽

Quantitative Analysis ◽

Light Microscopy ◽

Living Cell ◽

Light And Electron Microscopy ◽

Time Behavior ◽

Dynamic Interactions ◽

Positive Identification ◽

Cellular Components

The behavior of many cellular components, and their dynamic interactions, can be characterized in the living cell with considerable spatial and temporal resolution by video-enhanced light microscopy (video-LM). Indeed, under the appropriate conditions video-LM can be used to determine the real-time behavior of organelles ≤ 25-nm in diameter (e.g., individual microtubules—see). However, when pushed to its limit the structures and components observed within the cell by video-LM cannot be resolved nor necessarily even identified, only detected. Positive identification and a quantitative analysis often requires the corresponding electron microcopy (EM).

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L-Tetrahydropalmatine Inhibits the Progression of Glioblastoma Tumor by Suppressing the Extracellular-Signal-Regulated Kinase/Nuclear Factor-Kappa B Signaling Pathway

Current Topics in Nutraceutical Research ◽

10.37290/ctnr2641-452x.19:164-171 ◽

2020 ◽

Vol 19 (2) ◽

pp. 164-171

Author(s):

Feng Xue ◽

Tingting Chen

Keyword(s):

Glioblastoma Multiforme ◽

Nuclear Factor Kappa B ◽

Matrix Metalloproteinase 2 ◽

Nuclear Factor ◽

Nuclear Factor Kappa ◽

Extracellular Signal ◽

Apoptosis Protein ◽

Endothelial Growth Factor

Glioblastoma multiforme is the most common malignancy of central nervous system. Herein we have evaluated the effect of L-tetrahydropalmatine, an isoquinoline alkaloid, on the tumor growth both in vivo and in vitro using C6 glioblastoma multiforme cells and BALB/c mice injected subcutaneously with C6/luc2 cells. The results of these studies show that L-tetrahydropalmatine exhibited cytotoxic effect on C6 glioblastoma multiforme cells, suppressed nuclear factor-kappa B activity, suppressed the levels of tumor-linked proteins such as matrix metalloproteinase-2/9, Cyclin-D1, vascular endothelial growth factor, and X-linked inhibitor of apoptosis protein via ERK/nuclear factor-kappa B cascade. Further, L-tetrahydropalmatine inhibited the cell migration and invasion properties of C6 cells, and also suppressed the tumor weight and volume in mice. Immunohistochemical staining of tumor tissues suggested that L-tetrahydropalmatine inhibited the extracellular-signal-regulated kinase/nuclear factor-kappa B cascade and suppressed the levels of Cyclin-D1; matrix metalloproteinase-2/9; X-linked inhibitor of apoptosis protein; and vascular endothelial growth factor, and also the progression and growth of glioblastoma multiforme in mice. In summary, L-tetrahydropalmatine inhibits the ERK/nuclear factor-kappa B cascade, decreases the tumor volume, and inhibits the proteins responsible for tumor growth both in vivo and in vitro.

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Targeting Tau Hyperphosphorylation via Kinase Inhibition: Strategy to Address Alzheimer's Disease

Current Topics in Medicinal Chemistry ◽

10.2174/1568026620666200106125910 ◽

2020 ◽

Vol 20 (12) ◽

pp. 1059-1073 ◽

Cited By ~ 3

Author(s):

Ahmad Abu Turab Naqvi ◽

Gulam Mustafa Hasan ◽

Md. Imtaiyaz Hassan

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Tau Protein ◽

Glycogen Synthase ◽

Paired Helical Filaments ◽

Tau Hyperphosphorylation ◽

Microtubule Stabilization ◽

Extracellular Signal

Microtubule-associated protein tau is involved in the tubulin binding leading to microtubule stabilization in neuronal cells which is essential for stabilization of neuron cytoskeleton. The regulation of tau activity is accommodated by several kinases which phosphorylate tau protein on specific sites. In pathological conditions, abnormal activity of tau kinases such as glycogen synthase kinase-3 β (GSK3β), cyclin-dependent kinase 5 (CDK5), c-Jun N-terminal kinases (JNKs), extracellular signal-regulated kinase 1 and 2 (ERK1/2) and microtubule affinity regulating kinase (MARK) lead to tau hyperphosphorylation. Hyperphosphorylation of tau protein leads to aggregation of tau into paired helical filaments like structures which are major constituents of neurofibrillary tangles, a hallmark of Alzheimer’s disease. In this review, we discuss various tau protein kinases and their association with tau hyperphosphorylation. We also discuss various strategies and the advancements made in the area of Alzheimer's disease drug development by designing effective and specific inhibitors for such kinases using traditional in vitro/in vivo methods and state of the art in silico techniques.

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The Individual Effects of Cyclin-Dependent Kinase Inhibitors on Head and Neck Cancer Cells—A Systematic Analysis

Cancers ◽

10.3390/cancers13102396 ◽

2021 ◽

Vol 13 (10) ◽

pp. 2396

Author(s):

Nina Schoenwaelder ◽

Inken Salewski ◽

Nadja Engel ◽

Mareike Krause ◽

Björn Schneider ◽

...

Keyword(s):

Combination Therapy ◽

Head And Neck ◽

Kinase Inhibitors ◽

In Vivo Studies ◽

Specific Response ◽

Cyclin Dependent Kinase ◽

Systematic Analysis ◽

Mhc I ◽

Oncological Treatment

Cyclin-dependent kinase inhibitors (CDKi´s) display cytotoxic activity against different malignancies, including head and neck squamous cell carcinomas (HNSCC). By coordinating the DNA damage response, these substances may be combined with cytostatics to enhance cytotoxicity. Here, we investigated the influence of different CDKi´s (palbociclib, dinaciclib, THZ1) on two HNSCC cell lines in monotherapy and combination therapy with clinically-approved drugs (5-FU, Cisplatin, cetuximab). Apoptosis/necrosis, cell cycle, invasiveness, senescence, radiation-induced γ-H2AX DNA double-strand breaks, and effects on the actin filament were studied. Furthermore, the potential to increase tumor immunogenicity was assessed by analyzing Calreticulin translocation and immune relevant surface markers. Finally, an in vivo mouse model was used to analyze the effect of dinaciclib and Cisplatin combination therapy. Dinaciclib, palbociclib, and THZ1 displayed anti-neoplastic activity after low-dose treatment, while the two latter substances slightly enhanced radiosensitivity. Dinaciclib decelerated wound healing, decreased invasiveness, and induced MHC-I, accompanied by high amounts of surface-bound Calreticulin. Numbers of early and late apoptotic cells increased initially (24 h), while necrosis dominated afterward. Antitumoral effects of the selective CDKi palbociclib were weaker, but combinations with 5-FU potentiated effects of the monotherapy. Additionally, CDKi and CDKi/chemotherapy combinations induced MHC I, indicative of enhanced immunogenicity. The in vivo studies revealed a cell line-specific response with best tumor growth control in the combination approach. Global acting CDKi’s should be further investigated as targeting agents for HNSCC, either individually or in combination with selected drugs. The ability of dinaciclib to increase the immunogenicity of tumor cells renders this substance a particularly interesting candidate for immune-based oncological treatment regimens.

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Bromamine T (BAT) Exerts Stronger Anti-Cancer Properties than Taurine (Tau)

Cancers ◽

10.3390/cancers13020182 ◽

2021 ◽

Vol 13 (2) ◽

pp. 182

Author(s):

Stella Baliou ◽

Maria Goulielmaki ◽

Petros Ioannou ◽

Christina Cheimonidi ◽

Ioannis P. Trougakos ◽

...

Keyword(s):

Cytotoxic Effect ◽

Human Colon ◽

Mitogen Activated Protein Kinase ◽

Mitochondrial Apoptosis ◽

Therapeutic Modalities ◽

Cancer Pathogenesis ◽

Extracellular Signal ◽

Anti Cancer ◽

Mitogen Activated Protein

Background: Taurine (Tau) ameliorates cancer pathogenesis. Researchers have focused on the functional properties of bromamine T (BAT), a stable active bromine molecule. Both N-bromotaurine (TauNHBr) and BAT exert potent anti-inflammatory properties, but the landscape remains obscure concerning the anti-cancer effect of BAT. Methods: We used Crystal Violet, colony formation, flow cytometry and Western blot experiments to evaluate the effect of BAT and Tau on the apoptosis and autophagy of cancer cells. Xenograft experiments were used to determine the in vivo cytotoxicity of either agent. Results: We demonstrated that both BAT and Tau inhibited the growth of human colon, breast, cervical and skin cancer cell lines. Among them, BAT exerted the greatest cytotoxic effect on both RKO and MDA-MB-468 cells. In particular, BAT increased the phosphorylation of c-Jun N-terminal kinases (JNK½), p38 mitogen-activated protein kinase (MAPK), and extracellular-signal-regulated kinases (ERK½), thereby inducing mitochondrial apoptosis and autophagy in RKO cells. In contrast, Tau exerted its cytotoxic effect by upregulating JNK½ forms, thus triggering mitochondrial apoptosis in RKO cells. Accordingly, colon cancer growth was impaired in vivo. Conclusions: BAT and Tau exerted their anti-tumor properties through the induction of (i) mitochondrial apoptosis, (ii) the MAPK family, and iii) autophagy, providing novel anti-cancer therapeutic modalities.

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Berberine Improves Benign Prostatic Hyperplasia via Suppression of 5 Alpha Reductase and Extracellular Signal-Regulated Kinase in Vivo and in Vitro

Frontiers in Pharmacology ◽

10.3389/fphar.2018.00773 ◽

2018 ◽

Vol 9 ◽

Cited By ~ 7

Author(s):

Dong-Hyun Youn ◽

Jinbong Park ◽

Hye-Lin Kim ◽

Yunu Jung ◽

JongWook Kang ◽

...

Keyword(s):

Benign Prostatic Hyperplasia ◽

Prostatic Hyperplasia ◽

Extracellular Signal Regulated Kinase ◽

Extracellular Signal

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Targeting of p38 Mitogen-Activated Protein Kinases to MEF2 Transcription Factors

Molecular and Cellular Biology ◽

10.1128/mcb.19.6.4028 ◽

1999 ◽

Vol 19 (6) ◽

pp. 4028-4038 ◽

Cited By ~ 172

Author(s):

Shen-Hsi Yang ◽

Alex Galanis ◽

Andrew D. Sharrocks

Keyword(s):

Transcription Factors ◽

Transcriptional Activation ◽

Cellular Response ◽

Map Kinases ◽

Biological Response ◽

Extracellular Signals ◽

Extracellular Signal ◽

Mitogen Activated Protein

ABSTRACT Mitogen-activated protein (MAP) kinase-mediated signalling to the nucleus is an important event in the conversion of extracellular signals into a cellular response. However, the existence of multiple MAP kinases which phosphorylate similar phosphoacceptor motifs poses a problem in maintaining substrate specificity and hence the correct biological response. Both the extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) subfamilies of MAP kinases use a second specificity determinant and require docking to their transcription factor substrates to achieve maximal substrate activation. In this study, we demonstrate that among the different MAP kinases, the MADS-box transcription factors MEF2A and MEF2C are preferentially phosphorylated and activated by the p38 subfamily members p38α and p38β2. The efficiency of phosphorylation in vitro and transcriptional activation in vivo of MEF2A and MEF2C by these p38 subtypes requires the presence of a kinase docking domain (D-domain). Furthermore, the D-domain from MEF2A is sufficient to confer p38 responsiveness on different transcription factors, and reciprocal effects are observed upon the introduction of alternative D-domains into MEF2A. These results therefore contribute to our understanding of signalling to MEF2 transcription factors and demonstrate that the requirement for substrate binding by MAP kinases is an important facet of three different subclasses of MAP kinases (ERK, JNK, and p38).

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Extracellular Signal-Regulated Kinase Binds to TFII-I and Regulates Its Activation of the c-fosPromoter

Molecular and Cellular Biology ◽

10.1128/mcb.20.4.1140-1148.2000 ◽

2000 ◽

Vol 20 (4) ◽

pp. 1140-1148 ◽

Cited By ~ 37

Author(s):

Dae-Won Kim ◽

Brent H. Cochran

Keyword(s):

Map Kinase ◽

Transcriptional Activation ◽

Dominant Negative ◽

Binding Motif ◽

Dependent Manner ◽

Consensus Map ◽

Interaction Domain ◽

Extracellular Signal

ABSTRACT We have previously shown that TFII-I enhances transcriptional activation of the c-fos promoter through interactions with upstream elements in a signal-dependent manner. Here we demonstrate that activated Ras and RhoA synergize with TFII-I for c-fospromoter activation, whereas dominant-negative Ras and RhoA inhibit these effects of TFII-I. The Mek1 inhibitor, PD98059 abrogates the enhancement of the c-fos promoter by TFII-I, indicating that TFII-I function is dependent on an active mitogen-activated protein (MAP) kinase pathway. Analysis of the TFII-I protein sequence revealed that TFII-I contains a consensus MAP kinase interaction domain (D box). Consistent with this, we have found that TFII-I forms an in vivo complex with extracellular signal-related kinase (ERK). Point mutations within the consensus MAP kinase binding motif of TFII-I inhibit its ability to bind ERK and its ability to enhance the c-fos promoter. Therefore, the D box of TFII-I is required for its activity on the c-fos promoter. Moreover, the interaction between TFII-I and ERK can be regulated. Serum stimulation enhances complex formation between TFII-I and ERK, and dominant-negative Ras abrogates this interaction. In addition, TFII-I can be phosphorylated in vitro by ERK and mutation of consensus MAP kinase substrate sites at serines 627 and 633 impairs the phosphorylation of TFII-I by ERK and its activity on the c-fos promoter. These results suggest that ERK regulates the activity of TFII-I by direct phosphorylation.

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