The Rho1p Exchange Factor Rgf1p Signals Upstream from the Pmk1 Mitogen-activated Protein Kinase Pathway in Fission Yeast

The Schizosaccharomyces pombe exchange factor Rgf1p specifically regulates Rho1p during polarized growth. Rgf1p activates the β-glucan synthase (GS) complex containing the catalytic subunit Bgs4p and is involved in the activation of growth at the second end, a transition that requires actin reorganization. In this work, we investigated Rgf1p signaling and observed that Rgf1p acted upstream from the Pck2p-Pmk1p MAPK signaling pathway. We noted that Rgf1p and calcineurin play antagonistic roles in Cl− homeostasis; rgf1Δ cells showed the vic phenotype (viable in the presence of immunosuppressant and chlorine ion) and were unable to grow in the presence of high salt concentrations, both phenotypes being characteristic of knockouts of the MAPK components. In addition, mutations that perturb signaling through the MAPK pathway resulted in defective cell integrity (hypersensitivity to caspofungin and β-glucanase). Rgf1p acts by positively regulating a subset of stimuli toward the Pmk1p-cell integrity pathway. After osmotic shock and cell wall damage HA-tagged Pmk1p was phosphorylated in wild-type cells but not in rgf1Δ cells. Finally, we provide evidence to show that Rgf1p regulates Pmk1p activation in a process that involves the activation of Rho1p and Pck2p, and we demonstrate that Rgf1p is unique in this signaling process, because Pmk1p activation was largely independent of the other two Rho1p-specific GEFs, Rgf2p and Rgf3p.

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Atf1 Is a Target of the Mitogen-activated Protein Kinase Pmk1 and Regulates Cell Integrity in Fission Yeast

Molecular Biology of the Cell ◽

10.1091/mbc.e07-03-0282 ◽

2007 ◽

Vol 18 (12) ◽

pp. 4794-4802 ◽

Cited By ~ 40

Author(s):

Hirofumi Takada ◽

Masayuki Nishimura ◽

Yuta Asayama ◽

Yoshiaki Mannse ◽

Shunji Ishiwata ◽

...

Keyword(s):

Protein Kinase ◽

Fission Yeast ◽

Mapk Pathway ◽

Mapk Signaling ◽

Negative Regulator ◽

Mitogen Activated Protein Kinase ◽

Mrna Levels ◽

Cell Integrity ◽

Dual Specificity ◽

Mitogen Activated Protein

In fission yeast, knockout of the calcineurin gene resulted in hypersensitivity to Cl−, and the overexpression of pmp1+ encoding a dual-specificity phosphatase for Pmk1 mitogen-activated protein kinase (MAPK) or the knockout of the components of the Pmk1 pathway complemented the Cl− hypersensitivity of calcineurin deletion. Here, we showed that the overexpression of ptc1+ and ptc3+, both encoding type 2C protein phosphatase (PP2C), previously known to inactivate the Wis1–Spc1–Atf1 stress-activated MAPK signaling pathway, suppressed the Cl− hypersensitivity of calcineurin deletion. We also demonstrated that the mRNA levels of these two PP2Cs and pyp2+, another negative regulator of Spc1, are dependent on Pmk1. Notably, the deletion of Atf1, but not that of Spc1, displayed hypersensitivity to the cell wall-damaging agents and also suppressed the Cl− hypersensitivity of calcineurin deletion, both of which are characteristic phenotypes shared by the mutation of the components of the Pmk1 MAPK pathway. Moreover, micafungin treatment induced Pmk1 hyperactivation that resulted in Atf1 hyperphosphorylation. Together, our results suggest that PP2C is involved in a negative feedback loop of the Pmk1 signaling, and results also demonstrate that Atf1 is a key component of the cell integrity signaling downstream of Pmk1 MAPK.

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Specific Functional Features of the Cell Integrity MAP Kinase Pathway in the Dimorphic Fission Yeast Schizosaccharomyces japonicus

Journal of Fungi ◽

10.3390/jof7060482 ◽

2021 ◽

Vol 7 (6) ◽

pp. 482

Author(s):

Elisa Gómez-Gil ◽

Alejandro Franco ◽

Beatriz Vázquez-Marín ◽

Francisco Prieto-Ruiz ◽

Armando Pérez-Díaz ◽

...

Keyword(s):

Fission Yeast ◽

Environmental Changes ◽

Yeast Species ◽

Mapk Signaling ◽

Fine Tuning ◽

Mitogen Activated Protein Kinase ◽

Major Influence ◽

Cell Integrity ◽

Mitogen Activated Protein ◽

Functional Features

Mitogen activated protein kinase (MAPK) signaling pathways execute essential functions in eukaryotic organisms by transducing extracellular stimuli into adaptive cellular responses. In the fission yeast model Schizosaccharomyces pombe the cell integrity pathway (CIP) and its core effector, MAPK Pmk1, play a key role during regulation of cell integrity, cytokinesis, and ionic homeostasis. Schizosaccharomyces japonicus, another fission yeast species, shows remarkable differences with respect to S. pombe, including a robust yeast to hyphae dimorphism in response to environmental changes. We show that the CIP MAPK module architecture and its upstream regulators, PKC orthologs Pck1 and Pck2, are conserved in both fission yeast species. However, some of S. pombe’s CIP-related functions, such as cytokinetic control and response to glucose availability, are regulated differently in S. japonicus. Moreover, Pck1 and Pck2 antagonistically regulate S. japonicus hyphal differentiation through fine-tuning of Pmk1 activity. Chimeric MAPK-swapping experiments revealed that S. japonicus Pmk1 is fully functional in S. pombe, whereas S. pombe Pmk1 shows a limited ability to execute CIP functions and promote S. japonicus mycelial development. Our findings also suggest that a modified N-lobe domain secondary structure within S. japonicus Pmk1 has a major influence on the CIP signaling features of this evolutionarily diverged fission yeast.

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APPL1 mediates adiponectin-stimulated p38 MAPK activation by scaffolding the TAK1-MKK3-p38 MAPK pathway

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00427.2010 ◽

2011 ◽

Vol 300 (1) ◽

pp. E103-E110 ◽

Cited By ~ 59

Author(s):

Xiaoban Xin ◽

Lijun Zhou ◽

Caleb M. Reyes ◽

Feng Liu ◽

Lily Q. Dong

Keyword(s):

Protein Kinase ◽

P38 Mapk ◽

Mapk Pathway ◽

Adaptor Protein ◽

Mapk Signaling ◽

Mitogen Activated Protein Kinase ◽

Scaffolding Protein ◽

Mapk Activation ◽

P38 Mapk Pathway ◽

Mitogen Activated Protein

The adaptor protein APPL1 mediates the stimulatory effect of adiponectin on p38 mitogen-activated protein kinase (MAPK) signaling, yet the underlying mechanism remains unclear. Here we show that, in C2C12 cells, overexpression or suppression of APPL1 enhanced or suppressed, respectively, adiponectin-stimulated p38 MAPK upstream kinase cascade, consisting of transforming growth factor-β-activated kinase 1 (TAK1) and mitogen-activated protein kinase kinase 3 (MKK3). In vitro affinity binding and coimmunoprecipitation experiments revealed that TAK1 and MKK3 bind to different regions of APPL1, suggesting that APPL1 functions as a scaffolding protein to facilitate adiponectin-stimulated p38 MAPK activation. Interestingly, suppressing APPL1 had no effect on TNFα-stimulated p38 MAPK phosphorylation in C2C12 myotubes, indicating that the stimulatory effect of APPL1 on p38 MAPK activation is selective. Taken together, our study demonstrated that the TAK1-MKK3 cascade mediates adiponectin signaling and uncovers a scaffolding role of APPL1 in regulating the TAK1-MKK3-p38 MAPK pathway, specifically in response to adiponectin stimulation.

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15-deoxy-Δ12,14-prostaglandin J2Down-Regulates Activin-Induced Activin Receptor, Smad, and Cytokines Expression via Suppression of NF-κB and MAPK Signaling in HepG2 Cells

PPAR Research ◽

10.1155/2013/751261 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Seung-Won Park ◽

Chunghee Cho ◽

Byung-Nam Cho ◽

Youngchul Kim ◽

Tae Won Goo ◽

...

Keyword(s):

Cell Proliferation ◽

Hepg2 Cells ◽

Mapk Pathway ◽

Mapk Signaling ◽

Activin A ◽

Mitogen Activated Protein Kinase ◽

Erk Phosphorylation ◽

Mitogen Activated Protein ◽

Regulatory Effects ◽

Activin Receptors

15-Deoxy-Δ12,14-prostaglandin J2(15d-PGJ2) and activin are implicated in the control of apoptosis, cell proliferation, and inflammation in cells. We examined both the mechanism by which 15d-PGJ2regulates the transcription of activin-induced activin receptors (ActR) and Smads in HepG2 cells and the involvement of the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways in this regulation. Activin A (25 ng/mL) inhibited HepG2 cell proliferation, whereas 15d-PGJ2(2 μM and 5 μM) had no effect. Activin A and 15d-PGJ2showed different regulatory effects on ActR and Smad expression, NF-κB p65 activity and MEK/ERK phosphorylation, whereas they both decreased IL-6 production and increased IL-8 production. When co-stimulated with 15d-PGJ2and activin, 15d-PGJ2inhibited the activin-induced increases in ActR and Smad expression, and decreased activin-induced IL-6 production. However, it increased activin-induced IL-8 production. In addition, 15d-PGJ2inhibited activin-induced NF-κB p65 activity and activin-induced MEK/ERK phosphorylation. These results suggest that 15d-PGJ2suppresses activin-induced ActR and Smad expression, down-regulates IL-6 production, and up-regulates IL-8 production via suppression of NF-κB and MAPK signaling pathway in HepG2 cells. Regulation of ActR and Smad transcript expression and cytokine production involves NF-κB and the MAPK pathway via interaction with 15d-PGJ2/activin/Smad signaling.

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Extracellular Signal-Regulated Kinase 2 Interacts with and Is Negatively Regulated by the LIM-Only Protein FHL2 in Cardiomyocytes

Molecular and Cellular Biology ◽

10.1128/mcb.24.3.1081-1095.2004 ◽

2004 ◽

Vol 24 (3) ◽

pp. 1081-1095 ◽

Cited By ~ 101

Author(s):

Nicole H. Purcell ◽

Dina Darwis ◽

Orlando F. Bueno ◽

Judith M. Müller ◽

Roland Schüle ◽

...

Keyword(s):

Mammalian Cells ◽

Mapk Pathway ◽

Mapk Signaling ◽

Mitogen Activated Protein Kinase ◽

Erk Signaling ◽

Interacting Protein ◽

Hypertrophic Response ◽

Extracellular Signal ◽

Mitogen Activated Protein

ABSTRACT The mitogen-activated protein kinase (MAPK) signaling pathway regulates diverse biologic functions including cell growth, differentiation, proliferation, and apoptosis. The extracellular signal-regulated kinases (ERKs) constitute one branch of the MAPK pathway that has been implicated in the regulation of cardiac differentiated growth, although the downstream mechanisms whereby ERK signaling affects this process are not well characterized. Here we performed a yeast two-hybrid screen with ERK2 bait and a cardiac cDNA library to identify novel proteins involved in regulating ERK signaling in cardiomyocytes. This screen identified the LIM-only factor FHL2 as an ERK interacting protein in both yeast and mammalian cells. In vivo, FHL2 and ERK2 colocalized in the cytoplasm at the level of the Z-line, and interestingly, FHL2 interacted more efficiently with the activated form of ERK2 than with the dephosphorylated form. ERK2 also interacted with FHL1 and FHL3 but not with the muscle LIM protein. Moreover, at least two LIM domains in FHL2 were required to mediate efficient interaction with ERK2. The interaction between ERK2 and FHL2 did not influence ERK1/2 activation, nor was FHL2 directly phosphorylated by ERK2. However, FHL2 inhibited the ability of activated ERK2 to reside within the nucleus, thus blocking ERK-dependent transcriptional responsiveness of ELK-1, GATA4, and the atrial natriuretic factor promoter. Finally, FHL2 partially antagonized the cardiac hypertrophic response induced by activated MEK-1, GATA4, and phenylephrine agonist stimulation. Collectively, these results suggest that FHL2 serves a repressor function in cardiomyocytes through its ability to inhibit ERK1/2 transcriptional coupling.

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Identification of RAS-Mitogen-Activated Protein Kinase Signaling Pathway Modulators in an ERF1 Redistribution® Screen

CrossRef Listing of Deleted DOIs ◽

10.1177/1087057106287136 ◽

2006 ◽

Vol 11 (4) ◽

pp. 423-434 ◽

Cited By ~ 12

Author(s):

Charlotta Grånäs ◽

Betina Kerstin Lundholt ◽

Frosty Loechel ◽

Hans-Christian Pedersen ◽

Sara Petersen Bjørn ◽

...

Keyword(s):

Protein Kinase ◽

Signaling Pathway ◽

Kinase Inhibitors ◽

Mapk Pathway ◽

Mapk Signaling ◽

Mitogen Activated Protein Kinase ◽

Mitogen Activated Protein ◽

A Cell ◽

Protein Kinase Signaling

The RAS-mitogen-activated protein kinase (MAPK) signaling pathway has a central role in regulating the proliferation and survival of both normal and tumor cells. This pathway has been 1 focus area for the development of anticancer drugs, resulting in several compounds, primarily kinase inhibitors, in clinical testing. The authors have undertaken a cell-based, high-throughput screen using a novel ERF1 Redistribution® assay to identify compounds that modulate the signaling pathway. The hit compounds were subsequently tested for activity in a functional cell proliferation assay designed to selectively detect compounds inhibiting the proliferation of MAPK pathway-dependent cancer cells. The authors report the identification of 2 cell membrane-permeable compounds that exhibit activity in the ERF1 Redistribution® assay and selectively inhibit proliferation of MAPK pathway-dependent malignant melanoma cells at similar potencies (IC50 =< 5 μM). These compounds have drug-like structures and are negative in RAF, MEK, and ERK in vitro kinase assays. Drugs belonging to these compound classes may prove useful for treating cancers caused by excessive MAPK pathway signaling. The results also show that cell-based, high-content Redistribution® screens can detect compounds with different modes of action and reveal novel targets in a pathway known to be disease relevant.

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Evidence of a New Role for the High-Osmolarity Glycerol Mitogen-Activated Protein Kinase Pathway in Yeast: Regulating Adaptation to Citric Acid Stress

Molecular and Cellular Biology ◽

10.1128/mcb.24.8.3307-3323.2004 ◽

2004 ◽

Vol 24 (8) ◽

pp. 3307-3323 ◽

Cited By ~ 88

Author(s):

Clare L. Lawrence ◽

Catherine H. Botting ◽

Robin Antrobus ◽

Peter J. Coote

Keyword(s):

Citric Acid ◽

Protein Kinase ◽

Mapk Pathway ◽

Osmotic Shock ◽

Acid Stress ◽

Tca Cycle ◽

Mitogen Activated Protein Kinase ◽

High Osmolarity ◽

High Osmolarity Glycerol ◽

Mitogen Activated Protein

ABSTRACT Screening the Saccharomyces cerevisiae disruptome, profiling transcripts, and determining changes in protein expression have identified an important new role for the high-osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathway in the regulation of adaptation to citric acid stress. Deletion of HOG1, SSK1, PBS2, PTC2, PTP2, and PTP3 resulted in sensitivity to citric acid. Furthermore, citric acid resulted in the dual phosphorylation, and thus activation, of Hog1p. Despite minor activation of glycerol biosynthesis, the inhibitory effect of citric acid was not due to an osmotic shock. HOG1 negatively regulated the expression of a number of proteins in response to citric acid stress, including Bmh1p. Evidence suggests that BMH1 is induced by citric acid to counteract the effect of amino acid starvation. In addition, deletion of BMH2 rendered cells sensitive to citric acid. Deletion of the transcription factor MSN4, which is known to be regulated by Bmh1p and Hog1p, had a similar effect. HOG1 was also required for citric acid-induced up-regulation of Ssa1p and Eno2p. To counteract the cation chelating activity of citric acid, the plasma membrane Ca2+ channel, CCH1, and a functional vacuolar membrane H+-ATPase were found to be essential for optimal adaptation. Also, the transcriptional regulator CYC8, which mediates glucose derepression, was required for adaptation to citric acid to allow cells to metabolize excess citrate via the tricarboxylic acid (TCA) cycle. Supporting this, Mdh1p and Idh1p, both TCA cycle enzymes, were up-regulated in response to citric acid.

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Comparative Analysis of Transmembrane Regulators of the Filamentous Growth Mitogen-Activated Protein Kinase Pathway Uncovers Functional and Regulatory Differences

Eukaryotic Cell ◽

10.1128/ec.00085-15 ◽

2015 ◽

Vol 14 (9) ◽

pp. 868-883 ◽

Cited By ~ 5

Author(s):

Hema Adhikari ◽

Lauren M. Caccamise ◽

Tanaya Pande ◽

Paul J. Cullen

Keyword(s):

Protein Kinase ◽

Mapk Pathway ◽

Filamentous Growth ◽

Mapk Signaling ◽

Fine Tuning ◽

Mitogen Activated Protein Kinase ◽

Rate Limiting Step ◽

Mitogen Activated Protein ◽

Multiple Signaling ◽

Growth Pathway

ABSTRACTFilamentous growth is a microbial differentiation response that involves the concerted action of multiple signaling pathways. In budding yeast, one pathway that regulates filamentous growth is a Cdc42p-dependent mitogen-activated protein kinase (MAPK) pathway. Several transmembrane (TM) proteins regulate the filamentous growth pathway, including the signaling mucin Msb2p, the tetraspan osmosensor Sho1p, and an adaptor Opy2p. The TM proteins were compared to identify common and unique features. Msb2p, Sho1p, and Opy2p associated by coimmunoprecipitation analysis but showed predominantly different localization patterns. The different localization patterns of the proteins resulted in part from different rates of turnover from the plasma membrane (PM). In particular, Msb2p (and Opy2p) were turned over rapidly compared to Sho1p. Msb2p signaled from the PM, and its turnover was a rate-limiting step in MAPK signaling. Genetic analysis identified unique phenotypes of cells overexpressing the TM proteins. Therefore, each TM regulator of the filamentous growth pathway has its own regulatory pattern and specific function in regulating filamentous growth. This specialization may be important for fine-tuning and potentially diversifying the filamentation response.

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Transcriptional Coregulation by the Cell Integrity Mitogen-Activated Protein Kinase Slt2 and the Cell Cycle Regulator Swi4

Molecular and Cellular Biology ◽

10.1128/mcb.21.19.6515-6528.2001 ◽

2001 ◽

Vol 21 (19) ◽

pp. 6515-6528 ◽

Cited By ~ 84

Author(s):

Kristin Baetz ◽

Jason Moffat ◽

Jennifer Haynes ◽

Michael Chang ◽

Brenda Andrews

Keyword(s):

Gene Expression ◽

Cell Cycle ◽

Cell Wall ◽

Transcription Factor ◽

Protein Kinase ◽

Mapk Pathway ◽

Mitogen Activated Protein Kinase ◽

Regulatory Subunit ◽

Cell Integrity ◽

Mitogen Activated Protein

ABSTRACT In Saccharomyces cerevisiae, the heterodimeric transcription factor SBF (for SCB binding factor) is composed of Swi4 and Swi6 and activates gene expression at the G1/S-phase transition of the mitotic cell cycle. Cell cycle commitment is associated not only with major alterations in gene expression but also with highly polarized cell growth; the mitogen-activated protein kinase (MAPK) Slt2 is required to maintain cell wall integrity during periods of polarized growth and cell wall stress. We describe experiments aimed at defining the regulatory pathway involving the cell cycle transcription factor SBF and Slt2-MAPK. Gene expression assays and chromatin immunoprecipitation experiments revealed Slt2-dependent recruitment of SBF to the promoters of the G1 cyclinsPCL1 and PCL2 after activation of the Slt2-MAPK pathway. We performed DNA microarray analysis and identified other genes whose expression was reduced in both SLT2and SWI4 deletion strains. Genes that are sensitive to both Slt2 and Swi4 appear to be uniquely regulated and reveal a role for Swi4, the DNA-binding component of SBF, which is independent of the regulatory subunit Swi6. Some of the Swi4- and Slt2-dependent genes do not require Swi6 for either their expression or for Swi4 localization to their promoters. Consistent with these results, we found a direct interaction between Swi4 and Slt2. Our results establish a new Slt2-dependent mode of Swi4 regulation and suggest roles for Swi4 beyond its prominent role in controlling cell cycle transcription.

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Systems biology analysis of mitogen activated protein kinase inhibitor resistance in malignant melanoma

10.1101/231142 ◽

2017 ◽

Cited By ~ 2

Author(s):

Helma Zecena ◽

Daniel Tveit ◽

Zi Wang ◽

Ahmed Farhat ◽

Parvita Panchal ◽

...

Keyword(s):

Malignant Melanoma ◽

Mapk Pathway ◽

Treatment Resistance ◽

Mapk Signaling ◽

Mitogen Activated Protein Kinase ◽

Cellular Model ◽

Braf Mutations ◽

Mitogen Activated Protein ◽

Inhibitor Resistance ◽

Mapk Inhibitor

AbstractKinase inhibition in the mitogen activated protein kinase (MAPK) pathway is a standard therapy for cancer patients with activating BRAF mutations. However, the anti-tumorigenic effect and clinical benefit are only transient, and tumors are prone to treatment resistance and relapse. To elucidate mechanistic insights into drug resistance, we have established an in vitro cellular model of MAPK inhibitor resistance in malignant melanoma. The cellular model evolved in response to clinical dosage of BRAF inhibitor, vemurafenib, PLX4032. We conducted transcriptomic expression profiling using RNA-Seq and RT-qPCR arrays. Pathways of melanogenesis, MAPK signaling, cell cycle, and metabolism were significantly enriched among the set of differentially expressed genes of vemurafenib-resistant cells vs control. The underlying mechanism of treatment resistance and pathway rewiring based on non-genomic adaptation was validated in two distinct melanoma models, SK-MEL-28 and A375. Both cell lines have activating BRAF mutations and display metastatic potential. Downregulation of tumor suppressors and negative MAPK regulators, dual specific phosphatases, reengages mitogenic signaling. Upregulation of growth factors or cytokine receptors triggers signaling pathways circumventing BRAF blockage. Changes in amino acid and one-carbon metabolism support cellular proliferation despite MAPK inhibitor treatment. In addition, an upregulation of pigmentation in inhibitor resistant melanoma cells was observed. Cellular pathways utilized during inhibitor resistance promoted melanogenesis, a pathway which partially overlaps with MAPK signaling. Upstream regulator analysis suggested gene expression changes of forkhead box and hypoxia inducible factor family transcription factors. The established cellular models offer mechanistic insight into cellular changes and therapeutic targets under inhibitor resistance in malignant melanoma. At a systems biology level, the MAPK pathway undergoes major rewiring while acquiring inhibitor resistance. The outcome of this transcriptional plasticity is selection for a set of transcriptional master regulators, which circumvent upstream targeted kinases and provide alternative routes of mitogenic activation. A fine-woven network of redundant signals maintains similar effector genes allowing for tumor cell survival and malignant progression in therapy resistant cancer.

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