scholarly journals Growth Factor–induced p42/p44 MAPK Nuclear Translocation and Retention Requires Both MAPK Activation and Neosynthesis of Nuclear Anchoring Proteins

1998 ◽  
Vol 142 (3) ◽  
pp. 625-633 ◽  
Author(s):  
Philippe Lenormand ◽  
Jean-Marc Brondello ◽  
Anne Brunet ◽  
Jacques Pouysségur

Mitogen-activated protein kinases (p42/p44 MAPK, also called Erk2 and Erk1) are key mediators of signal transduction from the cell surface to the nucleus. We have previously shown that the activation of p42/p44 MAPK required for transduction of mitogenic signaling is associated with a rapid nuclear translocation of these kinases. However, the means by which p42 and p44 MAPK translocate into the nucleus after cytoplasmic activation is still not understood and cannot simply be deduced from their protein sequences. In this study, we have demonstrated that activation of the p42/ p44 MAPK pathway was necessary and sufficient for triggering nuclear translocation of p42 and p44 MAPK. First, addition of the MEK inhibitor PD 98059, which blocks activation of the p42/p44 MAPK pathway, impedes the nuclear accumulation, whereas direct activation of the p42/p44 MAPK pathway by the chimera ΔRaf-1:ER is sufficient to promote nuclear accumulation of p42/p44 MAPK. In addition, we have shown that this nuclear accumulation of p42/p44 MAPK required the neosynthesis of short-lived proteins. Indeed, inhibitors of protein synthesis abrogate nuclear accumulation in response to serum and accelerate p42/p44 MAPK nuclear efflux under conditions of persistent p42/p44 MAPK activation. In contrast, inhibition of targeted proteolysis by the proteasome synergistically potentiated p42/p44 MAPK nuclear localization by nonmitogenic agonists and markedly prolonged nuclear localization of p42/p44 MAPK after mitogenic stimulation. We therefore conclude that the MAPK nuclear translocation requires both activation of the p42/p44 MAPK module and neosynthesis of short-lived proteins that we postulate to be nuclear anchors.

1997 ◽  
Vol 17 (9) ◽  
pp. 4991-5000 ◽  
Author(s):  
M C Rouyez ◽  
C Boucheron ◽  
S Gisselbrecht ◽  
I Dusanter-Fourt ◽  
F Porteu

Thrombopoietin (TPO) is the major regulator of both growth and differentiation of megakaryocytes. We previously showed that both functions can be generated by TPO in the megakaryoblastic cell line UT7, in which murine Mpl was introduced, and are independently controlled by distinct regions of the cytoplasmic domain of Mpl. Particularly, residues 71 to 94 of this domain (deleted in the mutant mpl delta3) were found to be required for megakaryocytic maturation but dispensable for proliferation. We show here that TPO-induced differentiation in UT7 cells is tightly dependent on a strong, long-lasting activation of the mitogen-activated protein kinase (MAPK) pathway. Indeed, (i) in UT7-mpl cells, TPO induced a strong activation of extracellular signal-regulated kinases (ERK) which was persistent until at least 4 days in TPO-containing medium; (ii) a specific MAPK kinase (MEK) inhibitor inhibited TPO-induced megakaryocytic gene expression; (iii) the Mpl mutant mpl delta3, which displayed no maturation activity, transduced only a weak and transient ERK activation in UT7 cells; and (iv) TPO-induced megakaryocytic differentiation in UT7-mpl delta3 cells was partially restored by expression of a constitutively activated mutant of MEK. The capacity of TPO to trigger a strong and prolonged MAPK signal depended on the cell in which Mpl was introduced. In BAF3-mpl cells, TPO triggered a weak and transient ERK activation, similar to that induced in UT7-mpl delta3 cells. In these cells, no difference in MAPK activation was found between normal Mpl and mpl delta3. Thus, depending on the cellular context, several distinct regions of the cytoplasmic domain of Mpl and signaling pathways may contribute to generate quantitative variations in MAPK activation.


2001 ◽  
Vol 114 (8) ◽  
pp. 1579-1589 ◽  
Author(s):  
M. Reyes-Reyes ◽  
N. Mora ◽  
A. Zentella ◽  
C. Rosales

Integrin-mediated signals play an important but poorly understood role in regulating many leukocyte functions. In monocytes and monocytic leukemia cells, (β)1 integrin-mediated adhesion results in a strong induction of immediate-early genes that are important in inflammation. To investigate the signaling pathways from integrins in monocytic cells, THP-1 cells were stimulated via (β)1 integrins by binding to fibronectin and by crosslinking the integrins with specific monoclonal antibodies. The involvement of MAPK and PI 3-K on nuclear factor (κ)B (NF-(κ)B) activation was then analyzed. We found that integrins activated both NF-(κ)B and MAPK in a PI 3-K-dependent manner, as wortmannin and LY294002 blocked these responses. However, the specific MEK inhibitor PD98059 did not prevent integrin-mediated NF-(κ)B activation. In contrast, a dominant negative mutant of Rac completely prevented NF-(κ)B activation, but it did not affect MAPK activation. These results indicate that integrin signaling to NF-(κ)B is not mediated by the MAPK pathway, but rather by the small GTPase Rac. In addition, a dominant negative form of Ρ augmented NF-(κ)B activation and blocked MAPK activation, implying that these two pathways are in competition with each other. These data suggest that integrins activate different signaling pathways in monocytic cells. One uses PI 3-K and Rac to activate NF-(κ)B, while the other uses PI 3-K, MEK, and MAPK to activate other nuclear factors, such as Elk-1.


2011 ◽  
Vol 300 (1) ◽  
pp. E103-E110 ◽  
Author(s):  
Xiaoban Xin ◽  
Lijun Zhou ◽  
Caleb M. Reyes ◽  
Feng Liu ◽  
Lily Q. Dong

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.


2003 ◽  
Vol 23 (3) ◽  
pp. 975-987 ◽  
Author(s):  
Odile Filhol ◽  
Arsenio Nueda ◽  
Véronique Martel ◽  
Delphine Gerber-Scokaert ◽  
Maria José Benitez ◽  
...  

ABSTRACT Protein kinase CK2 is a multifunctional enzyme which has long been described as a stable heterotetrameric complex resulting from the association of two catalytic (α or α′) and two regulatory (β) subunits. To track the spatiotemporal dynamics of CK2 in living cells, we fused its catalytic α and regulatory β subunits with green fluorescent protein (GFP). Both CK2 subunits contain nuclear localization domains that target them independently to the nucleus. Imaging of stable cell lines expressing low levels of GFP-CK2α or GFP-CK2β revealed the existence of CK2 subunit subpopulations exhibiting differential dynamics. Once in the nucleus, they diffuse randomly at different rates. Unlike CK2β, CK2α can shuttle, showing the dynamic nature of the nucleocytoplasmic trafficking of the kinase. When microinjected in the cytoplasm, the isolated CK2 subunits are rapidly translocated into the nucleus, whereas the holoenzyme complex remains in this cell compartment, suggesting an intramolecular masking of the nuclear localization sequences that suppresses nuclear accumulation. However, binding of FGF-2 to the holoenzyme triggers its nuclear translocation. Since the substrate specificity of CK2α is dramatically changed by its association with CK2β, the control of the nucleocytoplasmic distribution of each subunit may represent a unique potential regulatory mechanism for CK2 activity.


2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Revathee Rajajendram ◽  
Chau Ling Tham ◽  
Mohamad Nadeem Akhtar ◽  
Mohd Roslan Sulaiman ◽  
Daud Ahmad Israf

Asthma is associated with increased pulmonary inflammation and airway hyperresponsiveness. The interaction between airway epithelium and inflammatory mediators plays a key role in the pathogenesis of asthma.In vitrostudies evaluated the inhibitory effects of 3-(2,5-dimethoxyphenyl)-1-(5-methylfuran-2-yl)prop-2-en-1-one (DMPF-1), a synthetic chalcone analogue, upon inflammation in the A549 lung epithelial cell line. DMPF-1 selectively inhibited TNF-α-stimulated CC chemokine secretion (RANTES, eotaxin-1, and MCP-1) without any effect upon CXC chemokine (GRO-αand IL-8) secretion. Western blot analysis further demonstrated that the inhibitory activity resulted from disruption of p65NF-κB nuclear translocation without any effects on the mitogen-activated protein kinase (MAPK) pathway. Treatment of ovalbumin-sensitized and ovalbumin-challenged BALB/c mice with DMPF-1 (0.2–100 mg/kg) demonstrated significant reduction in the secretion and gene expression of CC chemokines (RANTES, eotaxin-1, and MCP-1) and Th2 cytokines (IL-4, IL-5, and IL-13). Furthermore, DMPF-1 treatment inhibited eosinophilia, goblet cell hyperplasia, peripheral blood total IgE, and airway hyperresponsiveness in ovalbumin-sensitized and ovalbumin-challenged mice. In conclusion, these findings demonstrate the potential of DMPF-1, a nonsteroidal compound, as an antiasthmatic agent for further pharmacological evaluation.


2017 ◽  
Vol 2017 ◽  
pp. 1-12
Author(s):  
Chang-ying Xing ◽  
De-xiang Zhang ◽  
Sui-qi Gui ◽  
Min-fang Tao

Kidney-replenishing herb is a traditional medicine formula in China which has been widely used for clinical treatment of recurrent miscarriage. Our previous study showed that Kidney-replenishing herb could promote proliferation and inhibit apoptosis of the human first-trimester trophoblasts. In the present study, we further explored the potential mechanism and signal pathway of Kidney-replenishing herb on human trophoblast cells. Our research showed that Kidney-replenishing herb stimulated proliferation and reduced apoptosis of human trophoblast cells in vitro, and this appeared to be positive correlation with SOCS-3 transcription, suggesting that Kidney-replenishing herb regulated biological functions of human trophoblast cells by inducing SCOS-3 expression. Furthermore, the Kidney-replenishing herb treatment stimulated the phosphorylation of ERK1/2, and blocking the signaling pathway by mitogen-activated protein MAPK (MEK) inhibitor, U0126, inhibited Kidney-replenishing herb-induced SOCS-3 transcription, depressed proliferation, and promoted apoptosis of human trophoblasts. Kidney-replenishing herbs still induced ERK1/2 phosphorylation after SOCS-3 siRNA silence. Overexpression of SOCS-3 stimulated the proliferation of trophoblast. These findings suggest that SOCS-3 expression is induced by Kidney-replenishing herbs via activation of MAPK pathways, and this may possibly be involved in promoting human trophoblast cells growth which is contributed to embryo development.


1988 ◽  
Vol 8 (10) ◽  
pp. 4048-4054 ◽  
Author(s):  
C V Dang ◽  
W M Lee

We identified and characterized two regions of the human c-myc protein that target proteins into the nucleus. Using mutant c-myc proteins and proteins that fuse portions of c-myc to chicken muscle pyruvate kinase, we found that residues 320 to 328 (PAAKRVKLD; peptide M1) induced complete nuclear localization, and their removal from c-myc resulted in mutant proteins that distributed in both the nucleus and cytoplasm but retained rat embryo cell cotransforming activity. Residues 364 to 374 (RQRRNELKRSP; peptide M2) induced only partial nuclear targeting, and their removal from c-myc resulted in mutant proteins that remained nuclear but were cotransformationally inactive. We conjugated synthetic peptides containing M1 or M2 to human serum albumin and microinjected the conjugate into the cytoplasm of Vero cells. The peptide containing M1 caused rapid and complete nuclear accumulation, whereas that containing M2 caused slower and only partial nuclear localization. Thus, M1 functions as the nuclear localization signal of c-myc, and M2 serves some other and essential function.


2002 ◽  
Vol 70 (8) ◽  
pp. 4743-4746 ◽  
Author(s):  
Clara Ameixa ◽  
Jon S. Friedland

ABSTRACT Mycobacterium tuberculosis upregulates NF-κB binding and interleukin-8 (IL-8) gene expression and secretion in primary human monocytes. Inhibition of tyrosine protein kinases but not of ERK1/2 or p38 mitogen-activated protein kinases downregulates tuberculosis-induced IL-8 secretion. The inhibitor genistein decreased NF-κB nuclear translocation and IL-8 gene transcription in addition to acting on posttranscriptional processing.


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