scholarly journals p38 MAP kinase signalling is required for hypertrophic chondrocyte differentiation

2004 ◽  
Vol 378 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Lee-Anne STANTON ◽  
Shalev SABARI ◽  
Arthur V. SAMPAIO ◽  
T. Michael UNDERHILL ◽  
Frank BEIER
Keyword(s):  
Molecular Mechanisms ◽  
P38 Map Kinase ◽  
Limb Bud ◽  
Marker Genes ◽  
Chondrocyte Differentiation ◽  
P38 Kinase ◽  
Matrix Mineralization ◽  
Myocyte Enhancer Factor ◽  
Mitogen Activated Protein ◽  
Enhancer Factor

Longitudinal growth of endochondral bones is accomplished through the co-ordinated proliferation and hypertrophic differentiation of growth plate chondrocytes. The molecular mechanisms and signalling cascades controlling these processes are not well understood. To analyse the expression and roles of p38 mitogen-activated protein kinases in this process, we have established a micromass system for the reproducible hypertrophic differentiation of mouse mesenchymal limb bud cells. Our results show that all four mammalian p38 kinase genes are expressed during the chondrogenic programme, as well as their upstream regulators MKK3 (mitogen-activated protein kinase kinase 3) and MKK6. Treatment of micromass cultures with pharmacological inhibitors of p38 results in a marked delay in hypertrophic differentiation in micromass cultures, indicating a requirement for p38 signalling in chondrocyte differentiation. Inhibition of p38 kinase activity leads to reduced and delayed induction of alkaline phosphatase activity and matrix mineralization. In addition, p38 inhibition causes reduced expression of hypertrophic marker genes such as collagen X, matrix metalloproteinase 13 and bone sialoprotein. The function of p38 in hypertrophic differentiation appears to be mediated, at least in part, by the transcription factor myocyte enhancer factor 2C. In summary, we have demonstrated a novel requirement for p38 signalling in hypertrophic differentiation of chondrocytes and identified myocyte enhancer factor 2C as an important regulator of chondrocyte gene expression.

scholarly journals Nemo-Like Kinase-Myocyte Enhancer Factor 2A Signaling Regulates Anterior Formation in Xenopus Development

2007 ◽  
Vol 27 (21) ◽  
pp. 7623-7630 ◽  
Author(s):  
Kiyotoshi Satoh ◽  
Junji Ohnishi ◽  
Atsushi Sato ◽  
Michio Takeyama ◽  
Shun-ichiro Iemura ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Neural Development ◽  
Marker Genes ◽  
Neural Structure ◽  
Animal Pole ◽  
Endogenous Expression ◽  
Myocyte Enhancer Factor ◽  
Molecular Events ◽  
Bone Morphogenic Protein 4 ◽  
Enhancer Factor

ABSTRACT The development of anterior neural structure in Xenopus laevis requires the inhibition of bone morphogenic protein 4 and Wnt signaling. We previously reported that Nemo-like kinase (NLK) negatively regulates Wnt signaling via the phosphorylation of T-cell factor/lymphoid enhancer factor. However, the molecular events occurring downstream of NLK pathways in early neural development remain unclear. In the present study, we identified the transcription factor myocyte enhancer factor 2A (MEF2A) as a novel substrate for NLK. NLK regulates the function of Xenopus MEF2A (xMEF2A) via phosphorylation, and this modification can be inhibited by the depletion of endogenous NLK. In Xenopus embryos, the depletion of either NLK or MEF2A results in a severe defect in anterior development. The endogenous expression of anterior markers was blocked by the depletion of endogenous Xenopus NLK (xNLK) or xMEF2A but, notably, not by the depletion of other xMEF2 family proteins, xMEF2C and xMEF2D. Defects in head formation or the expression of the anterior marker genes caused by the depletion of endogenous xMEF2A could be eliminated by the expression of wild-type xMEF2A, but not xMEF2A containing mutated xNLK phosphorylation sites. Furthermore, the expression of xNLK-induced anterior markers was efficiently blocked by the depletion of endogenous xMEF2A in animal pole explants. These results show that NLK specifically regulates the MEF2A activity required for anterior formation in Xenopus development.

Activation of members of the mitogen-activated protein kinase family by glucose in endothelial cells

2000 ◽  
Vol 279 (4) ◽  
pp. E782-E790 ◽  
Author(s):  
Wenli Liu ◽  
Aaron Schoenkerman ◽  
William L. Lowe
Keyword(s):  
Endothelial Cells ◽  
Protein Kinase ◽  
Molecular Mechanisms ◽  
Normal Growth ◽  
Inhibitory Effect ◽  
Mitogen Activated Protein Kinase ◽  
P38 Kinase ◽  
Hexosamine Pathway ◽  
Mitogen Activated Protein ◽  
Effect Of Glucose

To better understand the molecular mechanisms for hyperglycemia-induced proatherogenic changes in endothelial cells, the effect of high glucose on activation of members of the mitogen-activated protein kinase (MAPK) family, including c-Jun NH2-terminal kinase (JNK), extracellular signal-regulated kinase (ERK)-1, -2, and -5, and p38 kinase, was examined in bovine pulmonary artery endothelial cells (PAEC). Glucose, fructose, and raffinose induced a concentration-dependent decrease in PAEC growth. Addition of 25 mM glucose, fructose, or raffinose to normal growth medium stimulated an approximately twofold increase in JNK1 activity that was maximal after 24 h, whereas only glucose markedly increased ERK5 activity. Neither ERK1/2 nor p38 kinase activity was increased by glucose, fructose, or raffinose. The antioxidant N-acetylcysteine partially abrogated the glucose-induced increase in ERK5 activity but had no effect on the increase in JNK1 activity. In contrast, azaserine, which prevents increased flux through the hexosamine pathway, decreased glucose-induced JNK1 activity but had no effect on fructose- or raffinose-induced JNK1 activity. Consistent with this finding, glucosamine stimulated a 2.4-fold increase in JNK1 activity and reproduced the inhibitory effect of glucose on PAEC growth. In summary, glucose activates different members of the MAPK family in PAEC via distinct mechanisms. Moreover, the correlation between the ability of different sugars to activate JNK1 and inhibit cell growth suggests that activation of this signaling pathway may contribute to the growth inhibitory effect of glucose in endothelial cells.

Endothelin signalling and regulation of protein kinases in glomerular mesangial cells

2002 ◽  
Vol 103 (s2002) ◽  
pp. 132S-136S ◽  
Author(s):  
Andrey SOROKIN ◽  
Marco FOSCHI ◽  
Michael J. DUNN
Keyword(s):  
Map Kinase ◽  
Map Kinases ◽  
Molecular Mechanisms ◽  
Mesangial Cells ◽  
Mapk Pathway ◽  
P38 Map Kinase ◽  
Dominant Negative ◽  
Glomerular Mesangial Cells ◽  
Calcium Dependent ◽  
Mitogen Activated Protein

The molecular mechanisms of endothelin (ET)-dependent activation of extracellular signal-regulated kinase (ERK)and p38 mitogen-activated protein (MAP) kinase were studied in rat and human renal glomerular mesangial cells. ET-1 induced a rapid and transient activation of Ras in renal mesangial cells, which was dependent upon the formation of the Shc/Grb2/Sos1 signalling complex and resulted in transient ERK activation. We have observed that Pyk2, a calcium-dependent cytoplasmic tyrosine kinase, was expressed in human renal mesangial cells and was tyrosine phosphorylated after ET-1 treatment. ET-1-induced activation of p38 MAPK pathway (but not ERK pathway) was inhibited in human and in rat glomerular mesangial cells expressing dominant-negative form of Pyk2, suggesting the engagement of Pyk2 in ET-1-mediated activation of p38 MAP kinase cascade. Contractive responsiveness of renal mesangial cells was shown to depend on activation of the p38 MAP kinases. Thus, p38 MAP kinase stimulation could perhaps partially account for ET-1 contractive properties, whereas ET-1-induced cell proliferation occurs primarily via Ras-dependent activation of the ERK.

scholarly journals ERK5 is targeted to myocyte enhancer factor 2A (MEF2A) through a MAPK docking motif

2004 ◽  
Vol 381 (3) ◽  
pp. 693-699 ◽  
Author(s):  
Dalia BARSYTE-LOVEJOY ◽  
Alex GALANIS ◽  
Anne CLANCY ◽  
Andrew D. SHARROCKS
Keyword(s):  
Catalytic Domain ◽  
Mutational Analysis ◽  
Mitogen Activated Protein Kinase ◽  
Kinase Substrate ◽  
Myocyte Enhancer Factor ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Enhancer Factor

One critical component in determining the specificity, and efficiency of MAPK (mitogen-activated protein kinase) substrate phophorylation is the presence of distinct docking domains in the substrate proteins. Docking domains have been shown to be important for the activities of members of the ERK (extracellular-signal-regulated kinase), JNK (c-Jun N-terminal kinase) and p38 subfamilies of MAPKs towards their substrates. Here, we demonstrate that docking domains also play an important role in ERK5-mediated substrate phosphorylation. The presence of a docking domain promotes both phosphorylation of myocyte enhancer factor, MEF2A, in vitro and its activation in vivo by ERK5. Mutational analysis of the MEF2A docking domain demonstrates that the specificity determinants for ERK5 are similar to those observed with members of the p38 subfamily. A docking domain recognized by ERK5 can direct ERK5 to activate heterologous substrates. Deletion analysis demonstrates that as with other MAPKs, it is the catalytic domain of ERK5 that recognizes the docking domain. Our data therefore extend previous observations on other MAPKs and demonstrate that the requirement for specific docking domains in promoting MAPK action towards substrates is a general property of MAPKs.

scholarly journals Nemo-Like Kinase, an Essential Effector of Anterior Formation, Functions Downstream of p38 Mitogen-Activated Protein Kinase

2009 ◽  
Vol 30 (3) ◽  
pp. 675-683 ◽  
Author(s):  
Eriko Ohnishi ◽  
Toshiyasu Goto ◽  
Atsushi Sato ◽  
Mi-sun Kim ◽  
Shun-ichiro Iemura ◽  
...  
Keyword(s):  
Protein Kinase ◽  
P38 Mapk ◽  
Molecular Mechanisms ◽  
Phosphorylation Site ◽  
Mitogen Activated Protein Kinase ◽  
Marker Genes ◽  
Head Formation ◽  
Mitogen Activated Protein ◽  
Upstream Kinase ◽  
Morpholino Oligonucleotides

ABSTRACT Nemo-like kinase (NLK) is known to function as a mitogen-activated protein kinase (MAPK)-like kinase. However, the upstream molecules and molecular mechanisms that regulate NLK activity remain unclear. In the present study, we identified p38 MAPK as an upstream kinase and activator of NLK. p38 regulates the function of NLK via phosphorylation, and this modification can be abrogated by depletion of endogenous p38. In Xenopus laevis embryos, depletion of either p38β or NLK by antisense morpholino oligonucleotides results in a severe defect in anterior development and impaired expression of endogenous anterior markers. It is notable that morphants of Xenopus p38α, another isoform of the p38 MAPK family, exhibited no obvious defects in anterior development. Defects in head formation or in the expression of anterior marker genes caused by suppression of endogenous p38β expression could be rescued by expression of wild-type NLK but not by expression of mutant NLK lacking the p38β phosphorylation site. In contrast, defects in head formation or in the expression of anterior marker genes caused by suppression of endogenous NLK expression could not be rescued by expression of p38. These results provide the first evidence that p38 specifically regulates NLK function, which is required for anterior formation in Xenopus development.

scholarly journals Essential Role of p38 Mitogen-activated Protein Kinase in Cathepsin K Gene Expression during Osteoclastogenesis through Association of NFATc1 and PU.1

2004 ◽  
Vol 279 (44) ◽  
pp. 45969-45979 ◽  
Author(s):  
Masahito Matsumoto ◽  
Masakazu Kogawa ◽  
Seiki Wada ◽  
Hiroshi Takayanagi ◽  
Masafumi Tsujimoto ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Map Kinase ◽  
Cathepsin K ◽  
P38 Map Kinase ◽  
Nuclear Accumulation ◽  
Marker Genes ◽  
Specific Marker ◽  
Dependent Manner ◽  
Mitogen Activated Protein

The receptor activator of NF-κB ligand (RANKL) induces various osteoclast-specific marker genes during osteoclast differentiation mediated by mitogen-activated protein (MAP) kinase cascades. However, the results of transcriptional programming of an osteoclast-specific cathepsin K gene are inconclusive. Here we report the regulatory mechanisms of RANKL-induced cathepsin K gene expression during osteoclastogenesis in a p38 MAP kinase-dependent manner. The reporter gene analysis with sequential 5′-deletion constructs of the cathepsin K gene promoter indicates that limited sets of the transcription factors such as NFATc1, PU.1, and microphthalmia transcription factor indeed enhance synergistically the gene expression when overexpressed in RAW264 cells. In addition, the activation of p38 MAP kinase is required for the maximum enhancement of the gene expression. RANKL-induced NFATc1 forms a complex with PU.1 in nuclei of osteoclasts following the nuclear accumulation of NFATc1 phosphorylated by the activated p38 MAP kinase. These results suggest that the RANKL-induced cathepsin K gene expression is cooperatively regulated by the combination of the transcription factors and p38 MAP kinase in a gradual manner.

scholarly journals Phosphorylation and Alternative Pre-mRNA Splicing Converge To Regulate Myocyte Enhancer Factor 2C Activity

2004 ◽  
Vol 24 (18) ◽  
pp. 8264-8275 ◽  
Author(s):  
Bangmin Zhu ◽  
Tod Gulick
Keyword(s):  
Dna Binding ◽  
Cell Types ◽  
Heart Tissue ◽  
Serine Phosphorylation ◽  
Mitogen Activated Protein Kinase ◽  
Dimerization Domain ◽  
Amino Terminal ◽  
Myocyte Enhancer Factor ◽  
Mitogen Activated Protein ◽  
Enhancer Factor

ABSTRACT Myocyte enhancer factor 2 (MEF2) transcription factors play pivotal roles in cardiac, muscle, and neuron gene expression. All products of MEF2 genes have a common amino-terminal DNA binding and dimerization domain, but the four vertebrate MEF2 gene transcripts are alternatively spliced among coding exons to produce splicing isoforms. In MEF2C alone, alternative splice acceptors in the last exon give forms that include or exclude a short domain that we designate γ. We show that MEF2C is expressed exclusively as γ− isoforms in heart tissue and predominantly as γ− in other adult tissues and in differentiating myocytes. MEF2C γ− isoforms are much more robust than γ+ forms in activating MEF2-responsive reporters in transfected fibroblasts despite indistinguishable expression levels, and they better synergize with MyoD in promoting myogenic conversion. One-hybrid transcription assays using Gal4-MEF2C fusions give similar distinctions between γ− and γ+ isoforms in all cell types tested, including myocytes. Cis effects of γ on MEF2C DNA binding, dimerization, protein stability, or response to CaM or p38 mitogen-activated protein kinase signaling are not apparent, and the isolated γ domain represses transcription when fused to Gal4. One phosphoserine residue is present within the γ domain according to tandem mass spectrometry, and mutation of this residue abolishes γ-mediated transrepression. A similar activity is present in the constitutive γ domain and serine phosphoacceptor of MEF2A. Our findings indicate that γ functions autonomously as a phosphoserine-dependent transrepressor to downregulate transactivation function of MEF2 factors and that alternative splicing and serine phosphorylation converge to provide complex combinatorial control of MEF2C activity.

scholarly journals Activation of p38 Mitogen-Activated Protein Kinase In Vivo Selectively Induces Apoptosis of CD8+ but Not CD4+ T Cells

2000 ◽  
Vol 20 (3) ◽  
pp. 936-946 ◽  
Author(s):  
Chris Merritt ◽  
Hervé Enslen ◽  
Nicole Diehl ◽  
Dietrich Conze ◽  
Roger J. Davis ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Map Kinase ◽  
Molecular Mechanisms ◽  
P38 Map Kinase ◽  
Mitogen Activated Protein ◽  
Map Kinase Pathway ◽  
Kinase Pathway

ABSTRACT CD4+ and CD8+ T cells play specific roles during an immune response. Different molecular mechanisms could regulate the proliferation, death, and effector functions of these two subsets of T cells. The p38 mitogen-activated protein (MAP) kinase pathway is induced by cytokines and environmental stress and has been associated with cell death and cytokine expression. Here we report that activation of the p38 MAP kinase pathway in vivo causes a selective loss of CD8+ T cells due to the induction of apoptosis. In contrast, activation of p38 MAP kinase does not induce CD4+T-cell death. The apoptosis of CD8+ T cells is associated with decreased expression of the antiapoptotic protein Bcl-2. Regulation of the p38 MAP kinase pathway in T cells is therefore essential for the maintenance of CD4/CD8 homeostasis in the peripheral immune system. Unlike cell death, gamma interferon production is regulated by the p38 MAP kinase pathway in both CD4+ and CD8+ T cells. Thus, specific aspects of CD4+and CD8+ T-cell function are differentially controlled by the p38 MAP kinase signaling pathway.

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