scholarly journals Mos induces the in vitro activation of mitogen-activated protein kinases in lysates of frog oocytes and mammalian somatic cells.

1993 ◽  
Vol 4 (8) ◽  
pp. 781-790 ◽  
Author(s):  
E K Shibuya ◽  
J V Ruderman
Keyword(s):  
Protein Kinases ◽  
Somatic Cells ◽  
Mapk Signaling ◽  
Mapk Activation ◽  
Free System ◽  
Mitogen Activated Protein Kinases ◽  
Activation Pathway ◽  
In Vitro Activation ◽  
Mitogen Activated Protein

Mitogen-activated protein kinases (MAPKs) are rapidly and transiently activated when both quiescent Go-arrested cells and G2-arrested oocytes are stimulated to reenter the cell cycle. We previously developed a cell-free system from lysates of quiescent Xenopus oocytes that responds to oncogenic H-ras protein by activating a MAPK, p42MAPK. Here, we show that the oncogenic protein kinase mos is also a potent activator of p42MAPK in these lysates. Mos also induces p42MAPK activation in lysates of activated eggs taken at a time when neither mos nor p42MAPK is normally active, showing that the mos-responsive MAPK activation pathway persists beyond the stage where mos normally functions. Similarly, lysates of somatic cells (rabbit reticulocytes) also retain a mos-inducible MAPK activation pathway. The mos-induced activation of MAPKs in all three lysates leads to phosphorylation of the pp90rsk proteins, downstream targets of the MAPK signaling pathway in vivo. The in vitro activation of MAPKs by mos in cell-free systems derived from oocytes and somatic cells suggests that mos contributes to oncogenic transformation by inappropriately inducing the activation of MAPKs.

scholarly journals Expanding the Toolkit of Fluorescent Biosensors for Studying Mitogen Activated Protein Kinases in Plants

2020 ◽  
Vol 21 (15) ◽  
pp. 5350
Author(s):  
Kati Seitz ◽  
Patrick J. Krysan
Keyword(s):  
Protein Kinases ◽  
Spatial Dynamics ◽  
Plant Signaling ◽  
Animal Cells ◽  
Mapk Activation ◽  
Vitro Assay ◽  
Mitogen Activated Protein Kinases ◽  
Fluorescent Biosensors ◽  
Mitogen Activated Protein

Mitogen-activated protein kinases (MAPKs) are key regulators of numerous biological processes in plants. To better understand the mechanisms by which these kinases function, high resolution measurement of MAPK activation kinetics in different biological contexts would be beneficial. One method to measure MAPK activation in plants is via fluorescence-based genetically-encoded biosensors, which can provide real-time readouts of the temporal and spatial dynamics of kinase activation in living tissue. Although fluorescent biosensors have been widely used to study MAPK dynamics in animal cells, there is currently only one MAPK biosensor that has been described for use in plants. To facilitate creation of additional plant-specific MAPK fluorescent biosensors, we report the development of two new tools: an in vitro assay for efficiently characterizing MAPK docking domains and a translocation-based kinase biosensor for use in plants. The implementation of these two methods has allowed us to expand the available pool of plant MAPK biosensors, while also providing a means to generate more specific and selective MAPK biosensors in the future. Biosensors developed using these methods have the potential to enhance our understanding of the roles MAPKs play in diverse plant signaling networks affecting growth, development, and stress response.

scholarly journals Two distinct roles of mitogen-activated protein kinases in platelets and a novel Rac1-MAPK–dependent integrin outside-in retractile signaling pathway

Blood ◽  
2009 ◽  
Vol 113 (4) ◽  
pp. 893-901 ◽  
Author(s):  
Panagiotis Flevaris ◽  
Zhenyu Li ◽  
Guoying Zhang ◽  
Yi Zheng ◽  
Junling Liu ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Signaling Pathway ◽  
Protein Kinases ◽  
Stimuli Responsive ◽  
Clot Retraction ◽  
Mapk Activation ◽  
Mitogen Activated Protein Kinases ◽  
Integrin Αiibβ3 ◽  
Mitogen Activated Protein ◽  
Mlc Phosphorylation

Abstract Mitogen-activated protein kinases (MAPK), p38, and extracellular stimuli-responsive kinase (ERK), are acutely but transiently activated in platelets by platelet agonists, and the agonist-induced platelet MAPK activation is inhibited by ligand binding to the integrin αIIbβ3. Here we show that, although the activation of MAPK, as indicated by MAPK phosphorylation, is initially inhibited after ligand binding to integrin αIIbβ3, integrin outside-insignaling results in a late but sustained activation of MAPKs in platelets. Furthermore, we show that the early agonist-induced MAPK activation and the late integrin-mediated MAPK activation play distinct roles in different stages of platelet activation. Agonist-induced MAPK activation primarily plays an important role in stimulating secretion of platelet granules, while integrin-mediated MAPK activation is important in facilitating clot retraction. The stimulatory role of MAPK in clot retraction is mediated by stimulating myosin light chain (MLC) phosphorylation. Importantly, integrin-dependent MAPK activation, MAPK-dependent MLC phosphorylation, and clot retraction are inhibited by a Rac1 inhibitor and in Rac1 knockout platelets, indicating that integrin-induced activation of MAPK and MLC and subsequent clot retraction is Rac1-dependent. Thus, our results reveal 2 different activation mechanisms of MAPKs that are involved in distinct aspects of platelet function and a novel Rac1-MAPK–dependent cell retractile signaling pathway.

Campylobacter jejuni activates mitogen-activated protein kinases in Caco-2 cell monolayers and in vitro infected primary human colonic tissue

Microbiology ◽  
2005 ◽  
Vol 151 (8) ◽  
pp. 2765-2772 ◽  
Author(s):  
Amanda MacCallum ◽  
Graham Haddock ◽  
Paul H. Everest
Keyword(s):  
Protein Kinases ◽  
Campylobacter Jejuni ◽  
Inflammatory Responses ◽  
Host Responses ◽  
Epithelial Cell Line ◽  
Colonic Tissue ◽  
Mitogen Activated Protein Kinases ◽  
Cell Monolayers ◽  
Mitogen Activated Protein

The mitogen-activated protein kinases (MAPKs) play a central role in many host signalling pathways. These signalling proteins are known to be involved in host responses against invasive bacteria including generation of chemotactic and inflammatory cytokines. It was hypothesized that Campylobacter jejuni may activate MAPKs, as intestinal infection may induce a clinical and pathological picture of acute colonic inflammation. Infection of Caco-2 cell monolayers (human colonic epithelial cell line) and human colonic tissue with C. jejuni in vitro demonstrated increased MAPK activity for ERK 1/2 (p44/42 MAPK), JNK and p38 MAPKs. Kinase activity and phosphorylated forms were increased in infected Caco-2 cells and human colonic explants, suggesting that these pathways are important in inflammatory responses induced by C. jejuni in man.

scholarly journals Expression and activity of mitogen activated protein kinases in human colorectal carcinoma

Gut ◽  
1999 ◽  
Vol 44 (6) ◽  
pp. 834-838 ◽  
Author(s):  
S Eggstein ◽  
M Franke ◽  
I Kutschka ◽  
G Manthey ◽  
B U von Specht ◽  
...  
Keyword(s):  
Protein Kinases ◽  
Normal Mucosa ◽  
Mitogen Activated Protein Kinases ◽  
Colorectal Mucosa ◽  
Mapk Activity ◽  
Mitogen Activated Protein ◽  
Colonic Carcinogenesis ◽  
Cell Growth And Differentiation ◽  
Expression And Activity

BACKGROUNDMitogen activated protein kinases (MAPKs) play a central role in the regulation of both cell growth and differentiation. They are involved in signal transduction of oncogenes and growth factors. The role of MAPK in colonic carcinoma is unknown.AIMSTo establish whether the expression and activity of p42/44 MAPKs are altered in colorectal tumours as compared with normal mucosa.METHODSThe expression and activity of p42/p44 MAPK were investigated in 22 colorectal carcinomas, four adenomas, and the corresponding normal colorectal mucosa by the use of western blotting, immunoprecipitation, and in vitro kinase assays.RESULTSAfter immunoprecipitation with an antibody specific for p42 MAPK, we found significant inactivation of p42 MAPK in colonic carcinomas as well as in adenomas, whereas most sample pairs showed only minor differences in p42 MAPK expression. Investigation of MAPK with an antibody capable of detecting both p42 and p44 MAPK showed a slight but significant decrease in p44 MAPK content in malignant tissues. With this antibody, only minor alterations in MAPK activity and no correlation with p42 MAPK activity were found.CONCLUSIONSInactivation of p42 MAPK could be associated with colonic carcinogenesis.

scholarly journals Activation of mitogen-activated protein kinases by a splice variant of GHRH receptor

2009 ◽  
Vol 44 (2) ◽  
pp. 127-134 ◽  
Author(s):  
Nektarios Barabutis ◽  
Agnieszka Siejka ◽  
Andrew V Schally ◽  
Norman L Block ◽  
Renzhi Cai ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Protein Kinases ◽  
Mechanism Of Action ◽  
Intracellular Signaling ◽  
Splice Variants ◽  
Nuclear Antigen ◽  
Proliferative Cell Nuclear Antigen ◽  
Mitogen Activated Protein Kinases ◽  
Mitogen Activated Protein

Hypothalamic GHRH controls the release of GH from the pituitary gland and also acts as a growth factor in a variety of cancers. The mitogenetic activity of GHRH is exerted through the binding to the pituitary type receptor (pGHRH-R) and its splice variants, mainly SV1. The intracellular signaling pathways that are activated upon the binding of GHRH to the SV1 receptor have not been elucidated. HeLa cervical cancer cells do not express GHRH or GHRH receptors (GHRHRs) and thus do not respond to GHRH or GHRH antagonists. In order to elucidate the mechanism of action of SV1 receptor, we transfected HeLa cells with plasmids for pcDNA3-GHRHR or pcDNA3-SV1. The transfected cells responded to both GHRH (1–29)NH2 and GHRH antagonist MZ-5-156, as shown by an increase or decrease respectively in the proliferation rate in vitro and the expression of proliferative cell nuclear antigen. We also demonstrated that when the cells transfected with SV1 plasmid are stimulated with GHRH (1–29)NH2, SV1 receptor activates the mitogen-activated protein kinases pathway (MAPKs), as shown previously for the cells that express pGHRH-R. Our results show, for the first time, the activation of the MAPKs cascade by the SV1 receptor. Since SV1 receptor is found in various tumors and mediates the responses to GHRH and synthetic antagonists, our findings shed light on the mechanism of action of SV1 receptor in cancer cells.

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