Early events in the signalling pathway for the activation of MAPKs in rice roots exposed to nickel

2007 ◽  
Vol 34 (11) ◽  
pp. 995 ◽  
Author(s):  
Po-Yu Chen ◽  
Tsai-Lien Huang ◽  
Hao-Jen Huang
Keyword(s):  
Plant Growth ◽  
Phospholipase D ◽  
Molecular Mechanisms ◽  
Basic Protein ◽  
Oryza Sativa L ◽  
Signalling Pathways ◽  
Mapk Activation ◽  
Mitogen Activated Protein Kinases ◽  
Rice Roots ◽  
Mitogen Activated Protein

It is well known that small quantities of nickel (Ni) are essential for plant species, and higher concentrations of Ni retard plant growth. However, the molecular mechanisms responsible for the regulation of plant growth by Ni are not well understood. The aim of this study is to investigate the early signalling pathways activated by Ni on rice (Oryza sativa L.) root. We showed that Ni elicited a remarkable increase in myelin basic protein (MBP) kinase activities. By immunoblot and immunoprecipitation analyses, it is suggested that Ni-activated 40- and 42-kDa MBP kinases are mitogen-activated protein kinases (MAPKs). Pretreatment of rice roots with the antioxidant, glutathione (GSH), the phospholipase D (PLD) inhibitor, n-butanol, and the calmodulin and CDPK antagonist and W7 inhibited Ni-induced MAPK activation. These results suggest that various signalling components are involved in transduction of the Ni signal in rice roots.

scholarly journals Expression and modulation of p42/p44 MAPKs and cell cycle regulatory proteins in rat pancreas regeneration

1999 ◽  
Vol 277 (5) ◽  
pp. G953-G959 ◽  
Author(s):  
Jean Morisset ◽  
JoséCristobal Aliaga ◽  
Ezéquiel L. Calvo ◽  
Judith Bourassa ◽  
Nathalie Rivard
Keyword(s):  
Cell Cycle ◽  
Molecular Mechanisms ◽  
Kinase Inhibitors ◽  
Regulatory Proteins ◽  
Mitogen Activated Protein Kinase ◽  
Cyclin Dependent Kinase ◽  
Mapk Activation ◽  
Pancreas Regeneration ◽  
Mitogen Activated Protein ◽  
Cell Cycle Regulatory Proteins

Pancreatic growth occurs after CCK, CCK-induced pancreatitis, and pancreatectomy; the mechanisms involved remain unknown. This study evaluates mitogen-activated protein kinase (MAPK) activation and expression of cell cycle regulatory proteins after pancreatectomy to understand the cellular and molecular mechanisms involved in pancreas regeneration. Rats were killed 1–12 days after pancreatectomy, and p42/p44 MAPK activation, expression of the cyclins D and E, cyclin-dependent kinase (Cdk)-2 activity, retinoblastoma protein (pRb) hyperphosphorylation, and expression of the cyclin kinase inhibitors p15, p21, and p27 were examined. Pancreatic remnants exhibited sustained p42/p44 MAPK activation within 8 h. Cyclins D1 and E showed maximal expression after 2 and 6 days, coinciding with maximal hyperphosphorylation of pRb and Cdk2 activity. The expression of p15 vanished after 12 h, p27 disappeared gradually, and p21 increased early. The p27 complexed with Cdk2 dissociated after 2 days, whereas p21 associated in a reverse fashion. In conclusion, sustained activation of p42/p44 MAPKs and Cdk2 along with overexpression of cyclins D1 and E and reduction of p15 and p27 cyclin inhibitors occurred early after pancreatectomy and are active factors involved in signaling that leads to pancreas regeneration.

scholarly journals The multi-site docking protein Grb2-associated binder 1 (Gab1) enhances interleukin-6-induced MAPK-pathway activation in an SHP2-, Grb2-, and time-dependent manner

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Hannes Bongartz ◽  
Karen Gille ◽  
Wiebke Hessenkemper ◽  
Katharina Mandel ◽  
Marc Lewitzky ◽  
...  
Keyword(s):  
Interleukin 6 ◽  
Molecular Mechanisms ◽  
Mapk Pathway ◽  
Sh2 Domain ◽  
Time Dependent ◽  
Signalling Pathways ◽  
Dependent Manner ◽  
Mapk Activation ◽  
Pathway Activation ◽  
Mapk Signalling

Abstract Background Cytokine-dependent activation of signalling pathways is tightly orchestrated. The spatiotemporal activation of signalling pathways dictates the specific physiological responses to cytokines. Dysregulated signalling accounts for neoplastic, developmental, and inflammatory diseases. Grb2-associated binder (Gab) family proteins are multi-site docking proteins, which expand cytokine-induced signal transduction in a spatial- and time-dependent manner by coordinating the recruitment of proteins involved in mitogen activated protein kinase (MAPK)/extracellular-signal regulated kinase (ERK) and phosphatidyl-inositol-3-kinase (PI3K) signalling. Interaction of Gab family proteins with these signalling proteins determines strength, duration and localization of active signalling cascades. However, the underlying molecular mechanisms of signal orchestration by Gab family proteins in IL-6-induced signalling are only scarcely understood. Methods We performed kinetic analyses of interleukin-6 (IL-6)-induced MAPK activation and analysed downstream responses. We compared signalling in wild-type cells, Gab1 knock-out cells, those reconstituted to express Gab1 mutants, and cells expressing gp130 receptors or receptor mutants. Results Interleukin-6-induced MAPK pathway activation can be sub-divided into an early Gab1-independent and a subsequent Gab1-dependent phase. Early Gab1-independent MAPK activation is critical for the subsequent initiation of Gab1-dependent amplification of MAPK pathway activation and requires binding of SH2 domain-containing phosphatase 2 (SHP2) to the interleukin-6 receptor complex. Subsequent and coordinated recruitment of Grb2 and SHP2 to Gab1 is essential for Gab1-dependent amplification of IL-6-induced late MAPK pathway activation and subsequent gene expression. Conclusions Overall, we elaborated the molecular requirements for Gab1-dependent, spatiotemporal orchestration of interleukin-6-dependent MAPK signalling. We discriminated IL-6-induced Gab1-independent, early activation of MAPK signalling and Gab1-dependent, sustained activation of MAPK signalling.

scholarly journals Microbial Diversity of Upland Rice Roots and Their Influence on Rice Growth and Drought Tolerance

2020 ◽  
Vol 8 (9) ◽  
pp. 1329
Author(s):  
Zhiqiang Pang ◽  
Ying Zhao ◽  
Peng Xu ◽  
Diqiu Yu
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Plant Growth ◽  
Upland Rice ◽  
Oryza Sativa L ◽  
Soluble Sugar ◽  
Stress Conditions ◽  
Rice Roots ◽  
Microbial Resources

Among abiotic stresses, drought is one of the most important factors limiting plant growth. To increase their drought tolerance and survival, most plants interact directly with a variety of microbes. Upland rice (Oryza sativa L.) is a rice ecotype that differs from irrigated ecotype rice; it is adapted to both drought-stress and aerobic conditions. However, its root microbial resources have not been explored. We isolated bacteria and fungi from roots of upland rice in Xishuangbanna, China. Four hundred sixty-two endophytic and rhizospheric isolates (337 bacteria and 125 fungi) were distributed. They were distributed among 43 genera on the basis of 16S rRNA and internal transcribed spacer (ITS) gene sequence analysis. Notably, these root microbes differed from irrigated rice root microbes in irrigated environments; for example, members of the Firmicutes phylum were enriched (by 28.54%) in the roots of the upland plants. The plant growth-promoting (PGP) potential of 217 isolates was investigated in vitro. The PGP ability of 17 endophytic and 10 rhizospheric isolates from upland rice roots was evaluated under well-irrigated and drought-stress conditions, and 9 fungal strains increased rice seedling shoot length, shoot and root fresh weight (FW), antioxidant capability, and proline (Pro) and soluble sugar contents. Our work suggests that fungi from upland rice roots can increase plant growth under irrigated and drought-stress conditions and can serve as effective microbial resources for sustainable agricultural production in arid regions.

Signalling pathways and the regulation of SUMO modification

2007 ◽  
Vol 35 (6) ◽  
pp. 1414-1418 ◽  
Author(s):  
B. Guo ◽  
S.-H. Yang ◽  
J. Witty ◽  
A.D. Sharrocks
Keyword(s):  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Mitogen Activated Protein Kinase ◽  
Signalling Pathways ◽  
Protein Protein Interactions ◽  
E3 Ligases ◽  
Sumo Modification ◽  
Mitogen Activated Protein ◽  
The Impact ◽  
Protein Sumoylation

The modification of proteins by SUMO (small ubiquitin-related modifier) conjugation is becoming increasingly recognized as an important regulatory event. Protein SUMOylation can control a whole range of activities, including subcellular localization, protein–protein interactions and enzymatic activity. However, the SUMOylation process can itself be controlled. In the present review, the mechanisms through which protein SUMOylation is regulated are discussed, with particular emphasis on the impact of signalling pathways. A major point of regulation of the SUMO pathway is through targeting the E3 ligases, and a number of different ways to achieve this have been identified. More generally, the MAPK (mitogen-activated protein kinase) pathways represent one way through which SUMOylation of specific proteins is controlled, by using molecular mechanisms that at least in part also function by modifying the activity of SUMO E3 ligases. Further intricacies in signalling pathway interactions are hinted at through the growing number of examples of cross-talk between different post-translational modifications and SUMO modification.

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.

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).

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