scholarly journals Kinase-deficient Pak1 mutants inhibit Ras transformation of Rat-1 fibroblasts.

1997 ◽  
Vol 17 (8) ◽  
pp. 4454-4464 ◽  
Author(s):  
Y Tang ◽  
Z Chen ◽  
D Ambrose ◽  
J Liu ◽  
J B Gibbs ◽  
...  
Keyword(s):  
Cellular Transformation ◽  
Mitogen Activated Protein Kinase ◽  
3T3 Cells ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Jun Kinase ◽  
Ras Activation ◽  
Mitogen Activated Protein ◽  
Nih 3T3 ◽  
Dependent Mechanism

Among the mechanisms by which the Ras oncogene induces cellular transformation, Ras activates the mitogen-activated protein kinase (MAPK or ERK) cascade and a related cascade leading to activation of Jun kinase (JNK or SAPK). JNK is additionally regulated by the Ras-related G proteins Rac and Cdc42. Ras also regulates the actin cytoskeleton through an incompletely elucidated Rac-dependent mechanism. A candidate for the physiological effector for both JNK and actin regulation by Rac and Cdc42 is the serine/threonine kinase Pak (p65pak). We show here that expression of a catalytically inactive mutant Pak, Pak1(R299), inhibits Ras transformation of Rat-1 fibroblasts but not of NIH 3T3 cells. Typically, 90 to 95% fewer transformed colonies were observed in cotransfection assays with Rat-1 cells. Pak1(R299) did not inhibit transformation by the Raf oncogene, indicating that inhibition was specific for Ras. Furthermore, Rat-1 cell lines expressing Pak1(R299) were highly resistant to Ras transformation, while cells expressing wild-type Pak1 were efficiently transformed by Ras. Pak1(L83,L86,R299), a mutant that fails to bind either Rac or Cdc42, also inhibited Ras transformation. Rac and Ras activation of JNK was inhibited by Pak1(R299) but not by Pak1(L83,L86,R299). Ras activation of ERK was inhibited by both Pak1(R299) and Pak1(L83,L86,R299), while neither mutant inhibited Raf activation of ERK. These results suggest that Pak1 interacts with components essential for Ras transformation and that inhibition can be uncoupled from JNK but not ERK signaling.

scholarly journals Multiple Mitogen-Activated Protein Kinase Signaling Pathways Connect the Cot Oncoprotein to the c-junPromoter and to Cellular Transformation

2000 ◽  
Vol 20 (5) ◽  
pp. 1747-1758 ◽  
Author(s):  
Mario Chiariello ◽  
Maria Julia Marinissen ◽  
J. Silvio Gutkind
Keyword(s):  
Protein Kinase ◽  
Molecular Mechanisms ◽  
Cellular Transformation ◽  
Mitogen Activated Protein Kinase ◽  
Serine Threonine Kinase ◽  
Activated T Cells ◽  
Mapk Kinase ◽  
Threonine Kinase ◽  
Mitogen Activated Protein

ABSTRACT The serine/threonine kinase Cot is a member of the mitogen-activated protein kinase (MAPK) kinase kinase family implicated in cellular transformation. Enhanced expression of this protein has been shown to activate both the MAPK and the c-Jun N-terminal kinase (JNK) pathways and to stimulate the nuclear factor of activated T cells and NF-κB-dependent transcription. However, the nature of the normal functions of the Cot protein and the molecular mechanisms responsible for its oncogenic potential are still largely unknown. Here, we show that overexpression of the cot proto-oncogene is sufficient to stimulate the expression of c-jun and that, in turn, the activity of c-Jun is required for Cot-induced transformation. These observations prompted us to explore the molecular events by which Cot regulates c-jun expression. We found that Cot potently stimulates the activity of the c-jun promoter utilizing JNK-dependent and -independent pathways, the latter involving two novel members of the MAPK family, p38γ (ERK6) and ERK5. Molecularly, this activity was found to be dependent on the ability of Cot to activate, in vivo, members of each class of the MAPK kinase superfamily, including MEK, SEK, MKK6, and MEK5. Furthermore, the use of dominant interfering molecules revealed that Cot requires JNK, p38s, and ERK5 to stimulate the c-jun promoter fully and to induce neoplastic transformation. These findings indicate that Cot represents the first example of a serine/threonine kinase acting simultaneously on all known MAPK cascades. Moreover, these observations strongly suggest that the transforming ability of Cot results from the coordinated activation of these pathways, which ultimately converge on the regulation of the expression and activity of the product of the c-junproto-oncogene.

scholarly journals Consequences of Lmna Exon 4 Mutations in Myoblast Function

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1286 ◽  
Author(s):  
Déborah Gómez-Domínguez ◽  
Carolina Epifano ◽  
Fernando de Miguel ◽  
Albert García Castaño ◽  
Borja Vilaplana-Martí ◽  
...  
Keyword(s):  
Dna Damage ◽  
Myogenic Differentiation ◽  
Congenital Muscular Dystrophy ◽  
Mitogen Activated Protein Kinase ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Wide Range ◽  
Mitogen Activated Protein ◽  
Exon 4 ◽  
2D And 3D

Laminopathies are causally associated with mutations on the Lamin A/C gene (LMNA). To date, more than 400 mutations in LMNA have been reported in patients. These mutations are widely distributed throughout the entire gene and are associated with a wide range of phenotypes. Unfortunately, little is known about the mechanisms underlying the effect of the majority of these mutations. This is the case of more than 40 mutations that are located at exon 4. Using CRISPR/Cas9 technology, we generated a collection of Lmna exon 4 mutants in mouse C2C12 myoblasts. These cell models included different types of exon 4 deletions and the presence of R249W mutation, one of the human variants associated with a severe type of laminopathy, LMNA-associated congenital muscular dystrophy (L-CMD). We characterized these clones by measuring their nuclear circularity, myogenic differentiation capacity in 2D and 3D conditions, DNA damage, and levels of p-ERK and p-AKT (phosphorylated Mitogen-Activated Protein Kinase 1/3 and AKT serine/threonine kinase 1). Our results indicated that Lmna exon 4 mutants showed abnormal nuclear morphology. In addition, levels and/or subcellular localization of different members of the lamin and LINC (LInker of Nucleoskeleton and Cytoskeleton) complex were altered in all these mutants. Whereas no significant differences were observed for ERK and AKT activities, the accumulation of DNA damage was associated to the Lmna p.R249W mutant myoblasts. Finally, significant myogenic differentiation defects were detected in the Lmna exon 4 mutants. These results have key implications in the development of future therapeutic strategies for the treatment of laminopathies.

scholarly journals Altered transcriptional activity of c-fos promoter plasmids in v-raf-transformed NIH 3T3 cells.

1990 ◽  
Vol 10 (11) ◽  
pp. 6073-6078 ◽  
Author(s):  
Z Siegfried ◽  
E B Ziff
Keyword(s):  
Cell Growth ◽  
Transcriptional Activity ◽  
Early Response ◽  
Regulatory Elements ◽  
3T3 Cells ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Untransformed Control ◽  
Early Response Genes ◽  
Nih 3T3

In cells transformed by v-raf, an oncogenic counterpart of the serine/threonine kinase Raf-1, regulatory elements of the c-fos promoter were active under conditions of cell growth or stimulation for which they were inactive in untransformed control cells. This suggests that v-raf transforms by deregulating transcription of early response genes.

Activation of mitogen-activated protein kinase kinase by v-Raf in NIH 3T3 cells and in vitro

Science ◽  
1992 ◽  
Vol 257 (5075) ◽  
pp. 1404-1407 ◽  
Author(s):  
P Dent ◽  
W Haser ◽  
T. Haystead ◽  
L. Vincent ◽  
T. Roberts ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Mitogen Activated Protein Kinase ◽  
3T3 Cells ◽  
Mitogen Activated Protein ◽  
Nih 3T3 ◽  
Protein Kinase Kinase ◽  
Nih 3T3 Cells

scholarly journals Synthetic dysmobility screen unveils an integrated STK40-YAP-MAPK system driving cell migration

2021 ◽  
Author(s):  
Ling-Yea Yu ◽  
Ting-Jen Tseng ◽  
Hsuan-Chao Lin ◽  
Ting-Xuan Lu ◽  
Chia-Jung Tsai ◽  
...  
Keyword(s):  
Cell Migration ◽  
Focal Adhesion ◽  
Synthetic Lethality ◽  
Control Cell ◽  
Mitogen Activated Protein Kinase ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Mitogen Activated Protein ◽  
Novel Strategy ◽  
Migration Of Cells

AbstractIntegrating signals is essential for cell survival, leading to the concept of synthetic lethality. However, how signaling is integrated to control cell migration remains unclear. By conducting a “two-hit” screen, we revealed the synergistic reduction of cell migration when serine-threonine kinase 40 (STK40) and mitogen-activated protein kinase (MAPK) were simultaneously suppressed. Single-cell analyses showed that STK40 knockdown reduced cell motility and coordination by strengthening focal adhesion (FA) complexes. Furthermore, STK40 knockdown reduced translocation of yes-associated protein (YAP) into the nucleus, while MAPK inhibition further weakened YAP activities in the nucleus to disturb FA remodeling. Altogether, we unveiled an integrated STK40-YAP-MAPK system regulating cell migration, and introduced “synthetic dysmobility” as a novel strategy to collaboratively control cell migration.One Sentence SummaryBlocking collaborative pathways within the integrated signaling network synergistically disrupts the migration of cells.

scholarly journals Characterization of R-Ras3/M-Ras Null Mice Reveals a Potential Role in Trophic Factor Signaling

2006 ◽  
Vol 26 (19) ◽  
pp. 7145-7154 ◽  
Author(s):  
Nelson Nuñez Rodriguez ◽  
Ivy N. L. Lee ◽  
Asoka Banno ◽  
Hui F. Qiao ◽  
Rui F. Qiao ◽  
...  
Keyword(s):  
Growth Factor ◽  
Active Form ◽  
Cellular Transformation ◽  
Mitogen Activated Protein Kinase ◽  
Trophic Factors ◽  
Small Molecular Weight ◽  
Ras Activation ◽  
Mitogen Activated Protein ◽  
The Central Nervous System ◽  
High Level

ABSTRACT R-Ras3/M-Ras is a member of the RAS superfamily of small-molecular-weight GTP-binding proteins. Previous studies have demonstrated high levels of expression in several regions of the central nervous system, and a constitutively active form of M-Ras promotes cytoskeletal reorganization, cellular transformation, survival, and differentiation. However, the physiological functions of M-Ras during embryogenesis and postnatal development have not been elucidated. By using a specific M-Ras antibody, we demonstrated a high level of M-Ras expression in astrocytes, in addition to neurons. Endogenous M-Ras was activated by several trophic factors in astrocytes, including epidermal growth factor (EGF), basic fibroblast growth factor, and hepatocyte growth factor. Interestingly, M-Ras activation by EGF was more sustained compared to prototypic Ras. A mouse strain deficient in M-Ras was generated to investigate its role in development. M-Ras null mice appeared phenotypically normal, and there was a lack of detectable morphological and neurological defects. In addition, primary astrocytes derived from Mras −/− mice did not appear to display substantial alterations in the activation of both the mitogen-activated protein kinase and phosphatidylinositol 3-kinase pathways in response to trophic factors.

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