scholarly journals Mitogen-Activated Protein Kinase in Pfiesteria piscicida and Its Growth Rate-Related Expression

2003 ◽  
Vol 69 (1) ◽  
pp. 343-349 ◽  
Author(s):  
Senjie Lin ◽  
Huan Zhang
Keyword(s):  
Growth Rate ◽  
Amino Acid ◽  
Protein Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Amino Acid Residues ◽  
Amino Acid Similarity ◽  
Reverse Transcription Pcr ◽  
Pfiesteria Piscicida ◽  
Mitogen Activated Protein ◽  
Salinity Shock

ABSTRACT A full-length cDNA (1,434 bp) of mitogen-activated protein kinase (MAPK), a key molecule of a signal transduction cascade, was isolated from the estuarine heterotrophic dinoflagellate Pfiesteria piscicida. This cDNA (Ppmapk1) encoded a protein (PpMAPK1) of 428 amino acid residues that shared about 30 to 40% amino acid similarity with MAPKs in other organisms. Phylogenetic analysis indicated that PpMAPK1 was tightly clustered with MAPK3 in protozoans. Using reverse transcription-PCR, expression of this gene was evaluated for P. piscicida cultures grown under different conditions. While salinity shock, heat shock, starvation, and a subsequent encounter with prey did not appear to affect expression of this gene, Ppmapk1 expression level was correlated with growth rate, suggesting involvement of this gene in the regulation of cell proliferation in the organism.

scholarly journals Inhibition of mitogen-activated protein kinase by a Drosophila dual-specific phosphatase

2000 ◽  
Vol 349 (3) ◽  
pp. 821-828 ◽  
Author(s):  
Won-Jae LEE ◽  
Sun-Hong KIM ◽  
Yong-Sik KIM ◽  
Sung-Jun HAN ◽  
Ki-Sook PARK ◽  
...  
Keyword(s):  
Amino Acid ◽  
Protein Kinase ◽  
Expressed Sequence Tag ◽  
Mapk Pathway ◽  
Sequence Similarity ◽  
Mitogen Activated Protein Kinase ◽  
Amino Acid Sequence Similarity ◽  
Calculated Molecular Mass ◽  
High Amino Acid ◽  
Mitogen Activated Protein

The Drosophila extracellular signal-regulated kinase (DERK) mitogen-activated protein kinase (MAPK) is involved in the regulation of multiple differentiation and developmental processes. Tight control of MAPK activity is critical for normal cell behaviour. We identified a novel Drosophila MAPK phosphatase (DMKP) cDNA from the expressed-sequence-tag database and characterized it. Analysis of the nucleotide sequence revealed an open reading frame encoding the 203-amino acid protein, with a calculated molecular mass of 23kDa, which has a high amino acid sequence similarity with ‘VH1-like’dual-specific phosphatases at the broad region near the catalytic sites. The expression of DMKP mRNA occurs from the late larval stages to adulthood in Drosophila development. The recombinant DMKP protein produced in yeast retained its phosphatase activity. When expressed in Schneider cells, DMKP dose-dependently inhibited DERK and Drosophila c-Jun N-terminal kinase activities with high selectivity towards DERK. However, DMKP did not have any affect on Drosophila p38 activity. When DMKP was expressed in yeast, it down-regulated the fus1-lacZ trans-reporter gene of the pheromone MAPK pathway without any significant effect on the high-osmolarity-glycerol-response pathway.

scholarly journals The fission yeast pmk1+ gene encodes a novel mitogen-activated protein kinase homolog which regulates cell integrity and functions coordinately with the protein kinase C pathway.

1996 ◽  
Vol 16 (12) ◽  
pp. 6752-6764 ◽  
Author(s):  
T Toda ◽  
S Dhut ◽  
G Superti-Furga ◽  
Y Gotoh ◽  
E Nishida ◽  
...  
Keyword(s):  
Cell Wall ◽  
Protein Kinase C ◽  
Amino Acid ◽  
Protein Kinase ◽  
Fission Yeast ◽  
Mitogen Activated Protein Kinase ◽  
Cell Integrity ◽  
Kinase C ◽  
Mitogen Activated Protein ◽  
Mapk Gene

We have isolated a gene, pmk1+, a third mitogen-activated protein kinase (MAPK) gene homolog from the fission yeast Schizosaccharomyces pombe. The predicted amino acid sequence shows the most homology (63 to 65% identity) to those of budding yeast Saccharomyces Mpk1 and Candida Mkc1. The Pmk1 protein contains phosphorylated tyrosines, and the level of tyrosine phosphorylation was increased in the dsp1 mutant which lacks an attenuating phosphatase for Pmk1. The level of tyrosine phosphorylation appears constant during hypotonic or heat shock treatment. The cells with pmk1 deleted (delta pmk1) are viable but show various defective phenotypes, including cell wall weakness, abnormal cell shape, a cytokinesis defect, and altered sensitivities to cations, such as hypersensitivity to potassium and resistance to sodium. Consistent with a high degree of conservation of amino acid sequence, multicopy plasmids containing the MPK1 gene rescued the defective phenotypes of the delta pmk1 mutant. The frog MAPK gene also suppressed the pmk1 disruptant. The results of genetic analysis indicated that Pmk1 lies on a novel MAPK pathway which does not overlap functionally with the other two MAPK pathways, the Spk1-dependent mating signal pathway and Sty1/Spc1/Phh1-dependent stress-sensing pathway. In Saccharomyces cerevisiae, Mpk1 is involved in cell wall integrity and functions downstream of the protein kinase C homolog. In contrast, in S. pombe, Pmk1 may not act in a linear manner with respect to fission yeast protein kinase C homologs. Interestingly, however, these two pathways are not independent; instead, they regulate cell integrity in a coordinate manner.

scholarly journals mkp-1 Encoding Mitogen-Activated Protein Kinase Phosphatase 1, a Verotoxin 1 Responsive Gene, Detected by Differential Display Reverse Transcription-PCR in Caco-2 Cells

2000 ◽  
Vol 68 (5) ◽  
pp. 2791-2796 ◽  
Author(s):  
Shihoko Kojima ◽  
Itaru Yanagihara ◽  
Gengo Kono ◽  
Tomomi Sugahara ◽  
Hatsumi Nasu ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Differential Display ◽  
Reverse Transcription ◽  
Mitogen Activated Protein Kinase ◽  
28S Rrna ◽  
Rt Pcr ◽  
Reverse Transcription Pcr ◽  
Mitogen Activated Protein ◽  
A Subunit ◽  
Differential Display Reverse Transcription

ABSTRACT The major cytotoxic effect of the verotoxins (VTs) produced by strains of VT-producing Escherichia coli is the inhibition of host-cell protein synthesis, but VTs are also suspected to play a role in apoptotic cell signaling and cytokine release. Four differentially expressed genes, including mkp-1 (encoding mitogen-activated protein kinase phospatase 1), were detected by differential display reverse transcription-PCR (DD RT-PCR) stimulated by VT1 in Caco-2 cells. Northern blot analysis showed the induction ofmkp-1 mRNA 6 h after VT1 stimulation. Neither mutant VT1 (mutVT1), harboring two mutations in the A subunit (E167Q-R170L), nor cycloheximide induced mkp-1 mRNA, but mkp-1mRNA was detected with both wild-type VT1 (wtVT1) and anisomycin, a 28S rRNA inhibitor. Therefore, we concluded that the A subunit of VT1 was essential for mkp-1 induction. Increased amounts of phosphorylated c-Jun protein were also found with wtVT1 and anisomycin. Although the precise mechanism of induction of MKP-1 is unknown, we hypothesized that 28S rRNA not only was a sensor for ribotoxic stress, but also was involved in the signal cascade of MKP-1. This is the first report of detection by DD RT-PCR of cellular genes induced by bacterial toxins.

scholarly journals Analysis of mitogen-activated protein kinase activation by naturally occurring splice variants of TrkC, the receptor for neurotrophin-3

1997 ◽  
Vol 322 (1) ◽  
pp. 193-198 ◽  
Author(s):  
Frank J. GUNN-MOORE ◽  
Alan G. WILLIAMS ◽  
Jeremy M. TAVARÉ
Keyword(s):  
Amino Acid ◽  
Protein Kinase ◽  
Tyrosine Kinase ◽  
Splice Variants ◽  
Mitogen Activated Protein Kinase ◽  
Kinase Activation ◽  
High Affinity ◽  
Naturally Occurring ◽  
Neurotrophin 3 ◽  
Mitogen Activated Protein

TrkC is a receptor tyrosine kinase that binds neurotrophin-3(NT-3) with high affinity. A number of naturally occurring splice variants of TrkC exist, including one (TrkC.ki14) with a 14 amino acid insertion between subdomains VII and VIII of the tyrosine kinase domain. This kinase insert blocks the ability of NT-3 to stimulate neurite outgrowth in PC12 cells and proliferation in fibroblasts. The inserts also block the ability of TrkC to form a high-affinity complex with Shc and phospholipase Cγ(PLCγ) and the activation of PtdIns 3-kinase, and attenuates the sustained activation of mitogen-activated protein kinase (MAPK). In the current study we set out to determine whether the attenuation of the activation of MAPK by the insert was the result of the inability of TrkC to activate the ShcŐRas pathway, PtdIns 3-kinase activation, PLCγ activation, or a combination thereof. Experiments with the use of cell-permeant inhibitors argue against a major role for PLCγ and PtdIns 3-kinase in the activation of MAPK by TrkC. The introduction of the 14 amino acid kinase insert appeared to slow the kinetics of NT-3-stimulated Shc phosphorylation and ShcŐGrb2 association and reduce their magnitude; an effect which was associated with a delayed, and only transient, activation of MAPK. Taken together, our data suggest that the apparent defect in MAPK activation caused by the kinase insert may result predominantly from an inhibition of high-affinity Shc binding, although a role for PLCγ and PtdIns 3-kinase cannot be completely excluded.

scholarly journals A Novel Mitogen-Activated Protein Kinase Phosphatase Is an Important Negative Regulator of Lipopolysaccharide-Mediated c-Jun N-Terminal Kinase Activation in Mouse Macrophage Cell Lines

2001 ◽  
Vol 21 (20) ◽  
pp. 6999-7009 ◽  
Author(s):  
Tetsuya Matsuguchi ◽  
Tipayaratn Musikacharoen ◽  
Thomas R. Johnson ◽  
Andrew S. Kraft ◽  
Yasunobu Yoshikai
Keyword(s):  
Amino Acid ◽  
Protein Kinase ◽  
Cell Lines ◽  
Mitogen Activated Protein Kinase ◽  
Sequence Motif ◽  
Mouse Macrophage ◽  
Macrophage Cell ◽  
Tnf Α ◽  
Mitogen Activated Protein ◽  
Jnk Activation

ABSTRACT We have isolated a cDNA homologous to known dual-specificity phosphatases from a mouse macrophage cDNA library and termed it MKP-M (for mitogen-activated protein kinase phosphatase isolated from macrophages). Three other presumed splice variant isoforms have also been identified for MKP-M. The longest and most abundant mRNA contains an open reading frame corresponding to 677 amino acids and produces an 80-kDa protein. The deduced amino acid sequence of MKP-M is most similar to those of hVH-5 (or mouse M3/6) and VHP1, aCaenorhabditis elegans tyrosine phosphatase. It includes an N-terminal rhodanase homology domain, the extended active-site sequence motif (V/L)X(V/I)HCXAG(I/V)SRSXT(I/V)XXAY(L/I)M (where X is any amino acid), and a C-terminal PEST sequence. Northern blot analysis revealed a dominant MKP-M mRNA species of approximately 5.5 kb detected ubiquitously among all tissues examined. MKP-M was constitutively expressed in mouse macrophage cell lines, and its expression levels were rapidly increased by lipopolysaccharide (LPS) stimulation but not by tumor necrosis factor alpha (TNF-α), gamma interferon, interleukin-2 (IL-2), or IL-15 stimulation. Immunocytochemical analysis showed MKP-M to be present within cytosol. When expressed in COS7 cells, MKP-M blocks activation of mitogen-activated protein kinases with the selectivity c-Jun N-terminal kinase (JNK) ≫ p38 = extracellular signal-regulated kinase. Furthermore, expression of a catalytically inactive form of MKP-M in a mouse macrophage cell line increased the intensity and duration of JNK activation and TNF-α secretion after LPS stimulation, suggesting that MKP-M is at least partially responsible for the desensitization of LPS-mediated JNK activation and cytokine secretion in macrophages.

Signalling by amino acid nutrients

2011 ◽  
Vol 39 (2) ◽  
pp. 443-445 ◽  
Author(s):  
Lijun Yan ◽  
Richard F. Lamb
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Kinase ◽  
Tumour Progression ◽  
Mammalian Target Of Rapamycin ◽  
Negative Regulator ◽  
Mitogen Activated Protein Kinase ◽  
Regulatory Subunit ◽  
Upstream Regulator ◽  
Mitogen Activated Protein

It is clear that mTORC1 (mammalian target of rapamycin complex 1) is regulated by the presence of ambient amino acid nutrients. However, the mechanism by which amino acids regulate mTORC1 is still open to question, despite extensive efforts. Our recent work has revealed that PR61ϵ, a B56 family regulatory subunit of PP2A (protein phosphatase 2A), associates with and regulates the activity of MAP4K3 (mitogen-activated protein kinase kinase kinase kinase 3), a protein kinase regulated by amino acid sufficiency that acts upstream of mTORC1. In searching for a physiological process regulated by amino acids, we have demonstrated recently that arginine plays a role in the activation of LPS (lipopolysaccharide)-induced MEK [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase]/ERK signalling in macrophages. PP2A similarly associates with the upstream regulator of MEK in this signalling pathway, TPL-2 (tumour progression locus-2), in response to arginine availability. Thus PP2A is a negative regulator of both MAP4K3 and TPL-2 in both mTORC1 and MEK/ERK signalling pathways.

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