183 MITOGEN-ACTIVATED PROTEIN KINASES ARE ACTIVATED BY ADENOSINE TRIPHOSPHATE IN RAT OVARIAN SURFACE EPITHELIAL CELLS

2011 ◽  
Vol 23 (1) ◽  
pp. 193
Author(s):  
K.-A. Hwang ◽  
K.-C. Choi
Keyword(s):  
Protein Kinases ◽  
Cellular Proliferation ◽  
Control Level ◽  
Growth Stimulation ◽  
Mapk Cascade ◽  
Mapk Activation ◽  
Mitogen Activated Protein Kinases ◽  
Ovarian Surface ◽  
Mitogen Activated Protein ◽  
Ovarian Surface Epithelial

Extracellular ATP has been suggested to play a role in cellular proliferation and intracellular calcium concentrations (Ca2+) in ovarian cells. To investigate the role of ATP in rat ovarian folliculogenesis or steroidogenesis, we examined the expression of the P2U purinoceptor (P2U-R) and the effect of ATP on growth stimulation in rat ovarian surface epithelial (OSE) cells. Rat OSE cells were isolated and cultured in DMEM media with 10% fetal bovine serum. Our results indicated that P2U-R mRNA was expressed and that ATP exerted a growth-stimulatory effect in rat OSE cells. To investigate the mechanism of the growth-stimulatory effect, we examined the activation of mitogen-activated protein kinases (MAPK) by ATP. Treatment with ATP resulted in MAPK activation in these cells, whereas the stimulatory effect of ATP in cellular proliferation and MAPK activation was completely abolished in the presence of PD98059 [a MAPK/ERK kinase (MEK) inhibitor] and staurosporin [a protein kinase C (PKC) inhibitor], suggesting that the growth-stimulatory effect of ATP may be mediated via PKC-dependent MAPK activation in rat OSE cells. In a time-dependent study, ATP significantly increased MAPK activity at 5 to 20 min, and the activated MAPK in these cells declined to the control level after 20 min. Similarly, treatment with ATP significantly induced MAPK activation after 5 min and sustained it for 60 min in these OSE cells. In addition, treatment with ATP resulted in substantial phosphorylation of Elk-1, confirming that ATP action is mediated by activation of MAPK. In conclusion, we demonstrated that P2U-R was expressed and that ATP induced growth stimulation in rat OSE cells. Furthermore, treatment with ATP resulted in activation of the MAPK cascade and phosphorylation of Elk-1 in these cells. Taken together, these results suggest that the MAPK cascade may be involved in growth stimulation in response to ATP in rat OSE cells. This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST; No. 2010-0003093).

scholarly journals Follicle-Stimulating Hormone Activates Mitogen-Activated Protein Kinase in Preneoplastic and Neoplastic Ovarian Surface Epithelial Cells

2002 ◽  
Vol 87 (5) ◽  
pp. 2245-2253 ◽  
Author(s):  
Kyung-Chul Choi ◽  
Sung Keun Kang ◽  
Chen-Jei Tai ◽  
Nelly Auersperg ◽  
Peter C. K. Leung
Keyword(s):  
Cellular Proliferation ◽  
Kinase Inhibitor ◽  
Control Level ◽  
Growth Stimulation ◽  
Ovarian Surface Epithelium ◽  
Mapk Cascade ◽  
Mitogen Activated Protein Kinase ◽  
Surface Epithelium ◽  
Mapk Activation ◽  
Ovarian Surface

To investigate the role of FSH in ovarian cancer development, the present study examined the expression of FSH receptor (FSH-R) and the effect of FSH on proliferation of normal, preneoplastic, and neoplastic ovarian surface epithelium (OSE) cells. Recently, immortalized OSE (IOSE) cell lines, including IOSE-29 (preneoplastic) and IOSE-29EC (neoplastic), were used. Our results indicated that FSH-R mRNA was expressed and that FSH exerted a growth stimulatory effect in normal, preneoplastic, and neoplastic OSE cells. To investigate the mechanism of the growth stimulatory effect, the activation of MAPKs by FSH was examined in preneoplastic and neoplastic OSE cells. Treatment with FSH resulted in MAPK activation of IOSE-29 and IOSE-29EC cells, whereas the stimulatory effect of FSH on cellular proliferation and MAPK activation was completely abolished in the presence of PD98059, a MAPK kinase inhibitor, suggesting that the growth stimulatory effect of FSH is mediated through MAPK activation in these OSE cells. In a time-dependent study, FSH significantly increased MAPK activity at 5–10 min in IOSE-29 cells. The activated MAPK declined to the control level after 20 min in these cells. Similarly, treatment with FSH significantly induced MAPK activation after 5 min and sustained it for 60 min in IOSE-29EC cells. In addition, treatment with FSH resulted in substantial phosphorylation of Elk-1, confirming that FSH action is mediated via activation of MAPK. In conclusion, we have demonstrated that FSH-R was expressed, and FSH induced growth stimulation in normal, preneoplastic, and neoplastic OSE cells. Furthermore, treatment with FSH stimulated activation of the MAPK cascade and phosphorylated Elk-1 in neoplastic OSE cells. These results suggest that the MAPK cascade may be involved in cellular functions such as growth stimulation in response to FSH in preneoplastic and neoplastic OSE cells.

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.

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.

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