scholarly journals EphA kinase activation regulates HGF-induced epithelial branching morphogenesis

2003 ◽  
Vol 162 (7) ◽  
pp. 1281-1292 ◽  
Author(s):  
Hui Miao ◽  
Christian H. Nickel ◽  
Lloyd G. Cantley ◽  
Leslie A. Bruggeman ◽  
Laura N. Bennardo ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Mdck Cells ◽  
Branching Morphogenesis ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Protein Kinase Activity ◽  
Kinase Activation ◽  
Cell Protrusion ◽  
Mitogen Activated Protein

Eph kinases and their ephrin ligands are widely expressed in epithelial cells in vitro and in vivo. Our results show that activation of endogenous EphA kinases in Madin-Darby canine kidney (MDCK) cells negatively regulates hepatocyte growth factor/scatter factor (HGF)–induced branching morphogenesis in collagen gel. Cotreatment with HGF and ephrin-A1 reduced sprouting of cell protrusions, an early step in branching morphogenesis. Moreover, addition of ephrin-A1 after HGF stimulation resulted in collapse and retraction of preexisting cell protrusions. In a newly developed assay that simulates the localized interactions between Ephs and ephrins in vivo, immobilized ephrin-A1 suppressed HGF-induced MDCK cell scattering. Ephrin-A1 inhibited basal ERK1/2 mitogen-activated protein kinase activity; however, the ephrin-A1 effect on cell protrusion was independent of the mitogen-activated protein kinase pathway. Ephrin-A1 suppressed HGF-induced activation of Rac1 and p21-activated kinase, whereas RhoA activation was retained, leading to the preservation of stress fibers. Moreover, dominant-negative RhoA or inhibitor of Rho-associated kinase (Y27632) substantially negated the inhibitory effects of ephrin-A1. These data suggest that interfering with c-Met signaling to Rho GTPases represents a major mechanism by which EphA kinase activation inhibits HGF-induced MDCK branching morphogenesis.

scholarly journals A Redox-Sensitive Thiol in Wis1 Modulates the Fission Yeast Mitogen-Activated Protein Kinase Response to H2O2 and Is the Target of a Small Molecule

2020 ◽  
Vol 40 (7) ◽  
Author(s):  
Johanna J. Sjölander ◽  
Agata Tarczykowska ◽  
Cecilia Picazo ◽  
Itziar Cossio ◽  
Itedale Namro Redwan ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Fission Yeast ◽  
Inhibitory Effect ◽  
Mitogen Activated Protein Kinase ◽  
Activation Loop ◽  
Content Type ◽  
Kinase Activation ◽  
Mitogen Activated Protein

ABSTRACT Oxidation of a highly conserved cysteine (Cys) residue located in the kinase activation loop of mitogen-activated protein kinase kinases (MAPKK) inactivates mammalian MKK6. This residue is conserved in the fission yeast Schizosaccharomyces pombe MAPKK Wis1, which belongs to the H2O2-responsive MAPK Sty1 pathway. Here, we show that H2O2 reversibly inactivates Wis1 through this residue (C458) in vitro. We found that C458 is oxidized in vivo and that serine replacement of this residue significantly enhances Wis1 activation upon addition of H2O2. The allosteric MAPKK inhibitor INR119, which binds in a pocket next to the activation loop and C458, prevented the inhibition of Wis1 by H2O2 in vitro and significantly increased Wis1 activation by low levels of H2O2 in vivo. We propose that oxidation of C458 inhibits Wis1 and that INR119 cancels out this inhibitory effect by binding close to this residue. Kinase inhibition through the oxidation of a conserved Cys residue in MKK6 (C196) is thus conserved in the S. pombe MAPKK Wis1.

Pervanadate-mediated tyrosine phosphorylation of keratins 8 and 19 via a p38 mitogen-activated protein kinase-dependent pathway

1999 ◽  
Vol 112 (13) ◽  
pp. 2081-2090 ◽  
Author(s):  
L. Feng ◽  
X. Zhou ◽  
J. Liao ◽  
M.B. Omary
Keyword(s):  
Protein Kinase ◽  
Tyrosine Phosphorylation ◽  
Serine Phosphorylation ◽  
Mitogen Activated Protein Kinase ◽  
P38 Kinase ◽  
Intact Mouse ◽  
Kinase Activation ◽  
Mitogen Activated Protein ◽  
Egf Signaling

Glandular epithelia express the keratin intermediate filament (IF) polypeptides 8, 18 and 19 (K8/18/19). These proteins undergo significant serine phosphorylation upon stimulation with growth factors and during mitosis, with subsequent modulation of their organization and interaction with associated proteins. Here we demonstrate reversible and dynamic tyrosine phosphorylation of K8 and K19, but not K18, upon exposure of intact mouse colon or cultured human cells to pervanadate. K8/19 tyrosine phosphorylation was confirmed by metabolic 32PO4-labeling followed by phosphoamino acid analysis, and by immunoblotting with anti-phosphotyrosine antibodies. Pervanadate treatment increases keratin solubility and also indirectly increases K8/18 serine phosphorylation at several known sites, some of which were previously shown to be associated with EGF stimulation, extracellular signal-regulated kinase (ERK), or p38 kinase activation. However, K8/19 tyrosine phosphorylation is independent of EGF signaling or ERK activation while inhibition of p38 kinase activity blocks pervanadate-induced K8/19 tyrosine phosphorylation. Our results demonstrate tyrosine phosphatase inhibitor-mediated in vivo tyrosine phosphorylation of K8/19, but not K18, and suggest that tyrosine phosphorylation may be a general modification of other IF proteins. K8/19 tyrosine phosphorylation involves a pathway that utilizes the p38 mitogen-activated protein kinase, but appears independent of EGF signaling or ERK kinase activation.

scholarly journals Yeast Mpk1 Mitogen-Activated Protein Kinase Activates Transcription through Swi4/Swi6 by a Noncatalytic Mechanism That Requires Upstream Signal

2008 ◽  
Vol 28 (8) ◽  
pp. 2579-2589 ◽  
Author(s):  
Ki-Young Kim ◽  
Andrew W. Truman ◽  
David E. Levin
Keyword(s):  
Cell Wall ◽  
Protein Kinase ◽  
Dna Binding ◽  
Transcriptional Activation ◽  
Kinase Activity ◽  
Wall Stress ◽  
Mitogen Activated Protein Kinase ◽  
Protein Kinase Activity ◽  
Mitogen Activated Protein

ABSTRACT The cell wall integrity mitogen-activated protein kinase (MAPK) cascade of Saccharomyces cerevisiae drives changes in gene expression in response to cell wall stress. We show that the MAPK of this pathway (Mpk1) and its pseudokinase paralog (Mlp1) use a noncatalytic mechanism to activate transcription of the FKS2 gene. Transcriptional activation of FKS2 was dependent on the Swi4/Swi6 (SBF) transcription factor and on an activating signal to Mpk1 but not on protein kinase activity. Activated (phosphorylated) Mpk1 and Mlp1 were detected in a complex with Swi4 and Swi6 at the FKS2 promoter. Mpk1 association with Swi4 in vivo required phosphorylation of Mpk1. Promoter association of Mpk1 and the Swi4 DNA-binding subunit of SBF were codependent but did not require Swi6, indicating that the MAPK confers DNA-binding ability to Swi4. Based on these data, we propose a model in which phosphorylated Mpk1 or Mlp1 forms a dimeric complex with Swi4 that is competent to associate with the FKS2 promoter. This complex then recruits Swi6 to activate transcription. Finally, we show that human ERK5, a functional ortholog of Mpk1, is similarly capable of driving FKS2 expression in the absence of protein kinase activity, suggesting that this mammalian MAPK may also have a noncatalytic function in vivo.

scholarly journals Characterization of tpp1+ as Encoding a Main Trehalose-6P Phosphatase in the Fission YeastSchizosaccharomyces pombe

2000 ◽  
Vol 182 (20) ◽  
pp. 5880-5884 ◽  
Author(s):  
Alejandro Franco ◽  
Teresa Soto ◽  
Jero Vicente-Soler ◽  
Pedro Valero Guillen ◽  
Jose Cansado ◽  
...  
Keyword(s):  
Heat Shock ◽  
Protein Kinase ◽  
Positive Control ◽  
Mitogen Activated Protein Kinase ◽  
Protein Kinase Activity ◽  
Gene Encoding ◽  
Reading Frame ◽  
Protein Levels ◽  
Mitogen Activated Protein

ABSTRACT We have characterized an open reading frame of 2,454 bp on chromosome I of Schizosaccharomyces pombe as the gene encoding trehalose-6P phosphatase (tpp1 +). Disruption of tpp1 + caused in vivo accumulation of trehalose-6P upon heat shock and prevented cell growth at 37 to 40°C. Accumulation of trehalose-6P in cells bearing a chromosomal disruption of the tpp1 + gene and containing a plasmid with tpp1 + under the control of the thiamine-repressible promotor correlated withtpp1 + repression. The level oftpp1 + mRNA rose upon heat shock, osmostress, or oxidative stress and was negatively controlled by cyclic AMP-dependent protein kinase activity. Expression oftpp1 + during oxidative or osmotic stress, but not during heat shock, was under positive control by thewis1-sty1 (equivalent to phh1 andspc1) mitogen-activated protein kinase pathway. Analysis of Tpp1 protein levels suggests that the synthesis of trehalose-6P phosphatase may also be subjected to translational or posttranslational control.

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