scholarly journals Insulin regulation of mitogen-activated protein kinase kinase (MEK), mitogen-activated protein kinase and casein kinase in the cell nucleus: a possible role in the regulation of gene expression

1997 ◽  
Vol 323 (3) ◽  
pp. 621-627 ◽  
Author(s):  
Sung-Jin KIM ◽  
Ronald C. KAHN
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Map Kinases ◽  
Nuclear Protein ◽  
Insulin Signalling ◽  
Receptor Activation ◽  
Casein Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Intact Cells ◽  
Mitogen Activated Protein

After insulin receptor activation, many cytoplasmic enzymes, including mitogen-activated protein (MAP) kinase, MAP kinase kinase (MEK) and casein kinase II (CKII) are activated, but exactly how insulin signalling progresses to the nucleus remains poorly understood. In Chinese hamster ovary cells overexpressing human insulin receptors [CHO(Hirc)], MEK, CKII and the MAP kinases ERK I and ERK II can be detected by immunoblotting in the nucleus, as well as in the cytoplasm, in the unstimulated state. Nuclear localization of MAP kinase is also observed in 3T3-F442A adipocytes, NIH-3T3 cells and Fao hepatoma cells, whereas MEK is found in the nucleus only in Fao and CHO cells. Insulin treatment for 5–30 min induces a translocation of MEK from the cytoplasm to the nucleus, whereas the MAP kinases and CKII are not translocated into the nucleus in response to insulin during this period. However, nuclear MAP kinase and CKII activities increase by 2–3-fold within 1–10 min after stimulation with insulin. By using gel-shift assays, it has been shown that insulin also stimulates nuclear protein binding to an AP-1 site with kinetics similar to MEK translocation and MAP kinase and CKII activation. Treatment of the extracts in vitro with protein phosphatase 2A or treatment of the intact cells with 5,6-dichloro-1-β-d-ribofuranosylbenzimidazole, a cell-permeable inhibitor of CKII, almost completely blocks the insulin-induced DNA-binding activity, whereas incubation of cells with a MEK inhibitor produces only a slight decrease. These results suggest that insulin signalling results in the activation of serine kinases in the nucleus via two pathways: (1) insulin stimulates the nuclear translocation of some kinases, such as MEK, which might directly phosphorylate nuclear protein substrates or activate other nuclear kinases, and (2) insulin activates nuclear kinases without translocation. The latter is true of CKII, which seems to regulate the binding of nuclear proteins to the AP-1 site, possibly by phosphorylation of AP-1 transcription factors.

scholarly journals Genetic Complementation Screen Identifies a Mitogen-activated Protein Kinase Phosphatase, MKP3, as a Regulator of Dopamine Transporter Trafficking

2008 ◽  
Vol 19 (7) ◽  
pp. 2818-2829 ◽  
Author(s):  
Ole Valente Mortensen ◽  
Mads Breum Larsen ◽  
Balakrishna M. Prasad ◽  
Susan G. Amara
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Dopamine Transporter ◽  
Map Kinases ◽  
Kinase Inhibitors ◽  
Mitogen Activated Protein Kinase ◽  
Genetic Complementation ◽  
Monoamine Transporters ◽  
Map Kinase Phosphatase ◽  
Mitogen Activated Protein

The antidepressant and cocaine sensitive plasma membrane monoamine transporters are the primary mechanism for clearance of their respective neurotransmitters and serve a pivotal role in limiting monoamine neurotransmission. To identify molecules in pathways that regulate dopamine transporter (DAT) internalization, we used a genetic complementation screen in Xenopus oocytes to identify a mitogen-activated protein (MAP) kinase phosphatase, MKP3/Pyst1/DUSP6, as a molecule that inhibits protein kinase C–induced (PKC) internalization of transporters, resulting in enhanced DAT activity. The involvement of MKP3 in DAT internalization was verified using both overexpression and shRNA knockdown strategies in mammalian cell models including a dopaminergic cell line. Although the isolation of MKP3 implies a role for MAP kinases in DAT internalization, MAP kinase inhibitors have no effect on internalization. Moreover, PKC-dependent down-regulation of DAT does not correlate with the phosphorylation state of several well-studied MAP kinases (ERK1/2, p38, and SAPK/JNK). We also show that MKP3 does not regulate PKC-induced ubiquitylation of DAT but acts at a more downstream step to stabilize DAT at the cell surface by blocking dynamin-dependent internalization and delaying the targeting of DAT for degradation. These results indicate that MKP3 can act to enhance DAT function and identifies MKP3 as a phosphatase involved in regulating dynamin-dependent endocytosis.

scholarly journals A Role for Mitogen-activated Protein Kinase in the Spindle Assembly Checkpoint in XTC Cells

1997 ◽  
Vol 137 (2) ◽  
pp. 433-443 ◽  
Author(s):  
Xiao Min Wang ◽  
Ye Zhai ◽  
James E. Ferrell
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Map Kinases ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Mitogen Activated Protein Kinase ◽  
Mitotic Progression ◽  
Map Kinase Phosphatase ◽  
Mitogen Activated Protein ◽  
Map Kinase Kinase

The spindle assembly checkpoint prevents cells whose spindles are defective or chromosomes are misaligned from initiating anaphase and leaving mitosis. Studies of Xenopus egg extracts have implicated the Erk2 mitogen-activated protein kinase (MAP kinase) in this checkpoint. Other studies have suggested that MAP kinases might be important for normal mitotic progression. Here we have investigated whether MAP kinase function is required for mitotic progression or the spindle assembly checkpoint in vivo in Xenopus tadpole cells (XTC). We determined that Erk1 and/or Erk2 are present in the mitotic spindle during prometaphase and metaphase, consistent with the idea that MAP kinase might regulate or monitor the status of the spindle. Next, we microinjected purified recombinant XCL100, a Xenopus MAP kinase phosphatase, into XTC cells in various stages of mitosis to interfere with MAP kinase activation. We found that mitotic progression was unaffected by the phosphatase. However, XCL100 rendered the cells unable to remain arrested in mitosis after treatment with nocodazole. Cells injected with phosphatase at prometaphase or metaphase exited mitosis in the presence of nocodazole—the chromosomes decondensed and the nuclear envelope re-formed—whereas cells injected with buffer or a catalytically inactive XCL100 mutant protein remained arrested in mitosis. Coinjection of constitutively active MAP kinase kinase-1, which opposes XCL100's effects on MAP kinase, antagonized the effects of XCL100. Since the only known targets of MAP kinase kinase-1 are Erk1 and Erk2, these findings argue that MAP kinase function is required for the spindle assembly checkpoint in XTC cells.

Distribution of MAP kinase, S6 kinase, and casein kinase II in rat tissues: activation by insulin in spleen

1994 ◽  
Vol 72 (1-2) ◽  
pp. 49-53 ◽  
Author(s):  
Yong-Jiang Hei ◽  
Xunsheng Chen ◽  
Jack Diamond ◽  
John H. McNeill
Keyword(s):  
Map Kinase ◽  
Map Kinases ◽  
Casein Kinase Ii ◽  
Casein Kinase ◽  
Exchange Chromatography ◽  
Mitogen Activated Protein Kinase ◽  
Single Peak ◽  
Rat Tissues ◽  
S6 Kinase ◽  
Mitogen Activated Protein

We examined the distribution of mitogen-activated protein (MAP) kinase, S6 kinase, and casein kinase II (CK-II) in the muscle, spleen, brain, and testes of Wistar rats. It was observed that spleen extracts contained the highest activity of all the kinases. Anion-exchange chromatography of spleen extracts by a MonoQ column resolved a single peak of myelin basic protein phosphotransferase activity that eluted after the usual position of the previously described p42 and p44 MAP kinases. Immunoblotting of the peak fractions with anti-MAP kinase antibody did not detect any immunoreactive bands that coincided with the activity peak, suggesting that the activity may represent a potentially novel MAP kinase. The MonoQ fractionation also resolved a single peak of phosvitin phosphotransferase activity which coincided with the intensity of two immunoreactive bands of 39 and 43 kilodaltons that were detected with antibodies against CK-II. The chromatographic behaviour and immunoblotting data indicate that the phosvitin kinase peak represented CK-II and suggested that the rat spleen CK-II had a molecular structure of αα′β2. Furthermore, using an intact rat model, we showed that the potentially novel spleen MAP kinase and CK-II were markedly activated following intravenous injection of insulin. The significance of these findings remains to be determined.Key words: mitogen-activated protein kinase, S6 kinase, casein kinase II, insulin, spleen.

scholarly journals Selective deficiency in protein kinase C isoenzyme expression and inadequacy in mitogen-activated protein kinase activation in cord blood T cells

2003 ◽  
Vol 370 (2) ◽  
pp. 497-503 ◽  
Author(s):  
Charles S.T. HII ◽  
Maurizio COSTABILE ◽  
George C. MAYNE ◽  
Channing J. DER ◽  
Andrew W. MURRAY ◽  
...  
Keyword(s):  
T Cells ◽  
Protein Kinase ◽  
Cord Blood ◽  
Map Kinase ◽  
Map Kinases ◽  
Mitogen Activated Protein Kinase ◽  
Biochemical Basis ◽  
Kinase Activation ◽  
Extracellular Signal ◽  
Mitogen Activated Protein

The biochemical basis for the reduced lymphokine production by neonatal T cells compared with adult T cells remains poorly defined. Previous studies have raised the possibility that neonatal T cells could be deficient in their ability to transmit signals via protein kinase (PK) C. We now report that while PKC-dependent activation of the mitogen-activated protein (MAP) kinases, c-Jun N-terminal protein kinase and the extracellular signal-regulated protein kinase (ERK)1/ERK2, was deficient in cord blood T cells compared with adult blood T cells, marked activation of the MAP kinases in cord blood T cells was achieved via PKC-independent means. Consistent with a deficiency in the signalling capability of PKC, cord blood T cells were selectively deficient in the expression of PKCβI, ∊, θ and ζ. Stimulation of cord blood T cells resulted in a time-dependent increase in PKC expression, with increases detectable by 4h. This was accompanied by an enhancement in MAP kinase activation via PKC-dependent means. These novel data suggest that an inadequacy in PKC-MAP kinase signalling may be responsible, at least in part, for the phenotype of cord blood T cells.

scholarly journals The JIP Group of Mitogen-Activated Protein Kinase Scaffold Proteins

1999 ◽  
Vol 19 (10) ◽  
pp. 7245-7254 ◽  
Author(s):  
Jun Yasuda ◽  
Alan J. Whitmarsh ◽  
Julie Cavanagh ◽  
Manoj Sharma ◽  
Roger J. Davis
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Map Kinases ◽  
Scaffold Proteins ◽  
Mitogen Activated Protein Kinase ◽  
Signaling Mechanism ◽  
Jnk Pathway ◽  
Mitogen Activated Protein ◽  
Kinase Cascade ◽  
Protein Kinase Cascade

ABSTRACT Activation of the c-Jun NH2-terminal kinase (JNK) group of mitogen-activated protein (MAP) kinases is mediated by a protein kinase cascade. This signaling mechanism may be coordinated by the interaction of components of the protein kinase cascade with scaffold proteins. The JNK-interacting protein (JIP) group of scaffold proteins selectively mediates signaling by the mixed-lineage kinase (MLK)→MAP kinase kinase 7 (MKK7)→JNK pathway. The scaffold proteins JIP1 and JIP2 interact to form oligomeric complexes that accumulate in peripheral cytoplasmic projections extended at the cell surface. The JIP proteins function by aggregating components of a MAP kinase module (including MLK, MKK7, and JNK) and facilitate signal transmission by the protein kinase cascade.

scholarly journals Serum-induced translocation of mitogen-activated protein kinase to the cell surface ruffling membrane and the nucleus

1993 ◽  
Vol 122 (5) ◽  
pp. 1089-1101 ◽  
Author(s):  
FA Gonzalez ◽  
A Seth ◽  
DL Raden ◽  
DS Bowman ◽  
FS Fay ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Protein Kinase ◽  
Cell Surface ◽  
Map Kinase ◽  
Map Kinases ◽  
Kinase Activity ◽  
Mitogen Activated Protein Kinase ◽  
Protein Kinase Activity ◽  
Mitogen Activated Protein ◽  
Cellular Compartments

The mitogen-activated protein (MAP) kinase signal transduction pathway represents an important mechanism by which growth factors regulate cell function. Targets of the MAP kinase pathway are located within several cellular compartments. Signal transduction therefore requires the localization of MAP kinase in each sub-cellular compartment that contains physiologically relevant substrates. Here, we show that serum treatment causes the translocation of two human MAP kinase isoforms, p40mapk and p41mapk, from the cytosol into the nucleus. In addition, we report that p41mapk (but not p40mapk) is localized at the cell surface ruffling membrane in serum-treated cells. To investigate whether the protein kinase activity of MAP kinase is required for serum-induced redistribution within the cell, we constructed mutated kinase-negative forms of p40mapk and p41mapk. The kinase-negative MAP kinases were not observed to localize to the cell surface ruffling membrane. In contrast, the kinase-negative MAP kinases were observed to be translocated to the nucleus. Intrinsic MAP kinase activity is therefore required only for localization at the cell surface and is not required for transport into the nucleus. Together, these data demonstrate that the pattern of serum-induced redistribution of p40mapk is different from p41mapk. Thus, in addition to common targets of signal transduction, it is possible that these MAP kinase isoforms may differentially regulate targets located in distinct sub-cellular compartments.

scholarly journals Regulation of cyclin-dependent kinase (Cdk) 2 Thr-160 phosphorylation and activity by mitogen-activated protein kinase in late G1 phase

2000 ◽  
Vol 349 (3) ◽  
pp. 869-876 ◽  
Author(s):  
Mario CHIARIELLO ◽  
Eliana GOMEZ ◽  
J. Silvio GUTKIND
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Dna Synthesis ◽  
Map Kinase ◽  
Map Kinases ◽  
Mitogen Activated Protein Kinase ◽  
G1 Phase ◽  
Cyclin Dependent Kinase ◽  
Mitogen Activated Protein ◽  
Stimulation Of

Mitogen-activated protein (MAP) kinases, p42MAPK and p44MAPK, are central components of growth-promoting signalling pathways. However, how stimulation of MAP kinases culminates in cell-cycle progression is still poorly understood. Here we show that mitogenic stimulation of NIH 3T3 cells causes a sustained activation of MAP kinases, which lasts until cells begin progressing through the G1/S boundary. Furthermore, we observed that disruption of the MAP-kinase pathway with a selective MEK (MAP kinase/extracellular-signal-regulated protein kinase kinase) inhibitor, PD98059, prevents the activation of cyclin-dependent kinase (Cdk) 2 and DNA synthesis, even when added during late G1 phase, once the known mechanisms by which MAP kinase controls G1 progression, accumulation of G1 cyclins and degradation of Cdk inhibitors have already taken place. Moreover, we provide evidence indicating that MAP kinases control Cdk2 Thr-160 activating phosphorylation and function, possibly by regulating the activity of a Cdk-activating kinase, thus promoting the re-initiation of DNA synthesis. These findings suggest the existence of a novel mechanism whereby signal-transducing pathways converging on MAP kinases can affect the cell-cycle machinery and, ultimately, participate in cell-growth control.

A yeast mitogen-activated protein kinase homolog (Mpk1p) mediates signalling by protein kinase C

1993 ◽  
Vol 13 (5) ◽  
pp. 3067-3075 ◽  
Author(s):  
K S Lee ◽  
K Irie ◽  
Y Gotoh ◽  
Y Watanabe ◽  
H Araki ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Protein Kinases ◽  
Map Kinases ◽  
Pheromone Response ◽  
Pheromone Response Pathway ◽  
Kinase C ◽  
Mitogen Activated Protein ◽  
Kinase Cascade ◽  
Protein Kinase Cascade

Mitogen-activated protein (MAP) kinases are activated in response to a variety of stimuli through a protein kinase cascade that results in their phosphorylation on tyrosine and threonine residues. The molecular nature of this cascade is just beginning to emerge. Here we report the isolation of a Saccharomyces cerevisiae gene encoding a functional analog of mammalian MAP kinases, designated MPK1 (for MAP kinase). The MPK1 gene was isolated as a dosage-dependent suppressor of the cell lysis defect associated with deletion of the BCK1 gene. The BCK1 gene is also predicted to encode a protein kinase which has been proposed to function downstream of the protein kinase C isozyme encoded by PKC1. The MPK1 gene possesses a 1.5-kb uninterrupted open reading frame predicted to encode a 53-kDa protein. The predicted Mpk1 protein (Mpk1p) shares 48 to 50% sequence identity with Xenopus MAP kinase and with the yeast mating pheromone response pathway components, Fus3p and Kss1p. Deletion of MPK1 resulted in a temperature-dependent cell lysis defect that was virtually indistinguishable from that resulting from deletion of BCK1, suggesting that the protein kinases encoded by these genes function in a common pathway. Expression of Xenopus MAP kinase suppressed the defect associated with loss of MPK1 but not the mating-related defects associated with loss of FUS3 or KSS1, indicating functional conservation between the former two protein kinases. Mutation of the presumptive phosphorylated tyrosine and threonine residues of Mpk1p individually to phenylalanine and alanine, respectively, severely impaired Mpk1p function. Additional epistasis experiments, and the overall architectural similarity between the PKC1-mediated pathway and the pheromone response pathway, suggest that Pkc1p regulates a protein kinase cascade in which Bck1p activates a pair of protein kinases, designated Mkk1p and Mkk2p (for MAP kinase-kinase), which in turn activate Mpk1p.

Identification and characterization of a new mammalian mitogen-activated protein kinase kinase, MKK2

1993 ◽  
Vol 13 (8) ◽  
pp. 4539-4548
Author(s):  
J Wu ◽  
J K Harrison ◽  
P Dent ◽  
K R Lynch ◽  
M J Weber ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Protein Kinases ◽  
Map Kinases ◽  
Sodium Dodecyl ◽  
Rat Tissues ◽  
Tyrosine Residues ◽  
Mitogen Activated Protein ◽  
Map Kinase Kinase

Mitogen-activated protein (MAP) kinases are serine/threonine protein kinases activated by dual phosphorylation on threonine and tyrosine residues. A MAP kinase kinase (MKK1 or MEK1) has been identified as a dual-specificity protein kinase that is sufficient to phosphorylate MAP kinases p42mapk and p44mapk on the regulatory threonine and tyrosine residues. Because of the multiplicity of MAP kinase isoforms and the diverse circumstances and agonists leading to their activation, we thought it unlikely that a single MKK could accommodate this complexity. Indeed, two protein bands with MKK activity have previously been identified after renaturation following sodium dodecyl sulfate-polyacrylamide gel electrophoresis. We now report the molecular cloning and characterization of a second rat MAP kinase kinase cDNA, MKK2. MKK2 cDNA contains an open reading frame encoding a protein of 400 amino acids, 7 residues longer than MKK1 (MEK1). The amino acid sequence of MKK2 is 81% identical to that of MKK1, but nucleotide sequence differences occur throughout the aligned MKK2 and MKK1 cDNAs, indicating that MKK2 is the product of a distinct gene. MKK1 and MKK2 mRNAs are expressed differently in rat tissues. Both cDNAs when expressed in COS cells displayed the ability to phosphorylate and activate p42mapk and p44mapk, both MKK1 and MKK2 were activated in vivo in response to serum, and both could be phosphorylated and activated by the v-Raf protein in vitro. However, differences between MKK1 and MKK2 in sites of phosphorylation by proline-directed protein kinases predict differences in feedback regulation.

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