Potent transforming activity of the small GTP-binding protein Rit in NIH 3T3 cells: evidence for a role of a p38γ-dependent signaling pathway

FEBS Letters ◽  
2001 ◽  
Vol 511 (1-3) ◽  
pp. 15-20 ◽  
Author(s):  
Kaoru Sakabe ◽  
Hidemi Teramoto ◽  
Muriel Zohar ◽  
Babak Behbahani ◽  
Hiroshi Miyazaki ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Binding Protein ◽  
3T3 Cells ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Transforming Activity ◽  
Nih 3T3 ◽  
Dependent Signaling Pathway ◽  
Nih 3T3 Cells

scholarly journals Transactivation of Platelet-Derived Growth Factor Receptor α by the GTPase-Deficient Activated Mutant of Gα12

2006 ◽  
Vol 26 (1) ◽  
pp. 50-62 ◽  
Author(s):  
Rashmi N. Kumar ◽  
Ji Hee Ha ◽  
Rangasudhagar Radhakrishnan ◽  
Danny N. Dhanasekaran
Keyword(s):  
Growth Factor ◽  
Cell Growth ◽  
Signaling Pathway ◽  
Growth Factor Receptor ◽  
Platelet Derived Growth Factor ◽  
Dominant Negative Mutant ◽  
Dependent Manner ◽  
3T3 Cells ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

ABSTRACT The GTPase-deficient, activated mutant of Gα12 (Gα12Q229L, or Gα12QL) induces neoplastic growth and oncogenic transformation of NIH 3T3 cells. Using microarray analysis, we have previously identified a role for platelet-derived growth factor receptor α (PDGFRα) in Gα12-mediated cell growth (R. N. Kumar et al., Cell Biochem. Biophys. 41:63-73, 2004). In the present study, we report that Gα12QL stimulates the functional expression of PDGFRα and demonstrate that the expression of PDGFRα by Gα12QL is dependent on the small GTPase Rho. Our results indicate that it is cell type independent as the transient expression of Gα12QL or the activation of Gα12-coupled receptors stimulates the expression of PDGFRα in NIH 3T3 as well as in human astrocytoma 1321N1 cells. Furthermore, we demonstrate the presence of an autocrine loop involving PDGF-A and PDGFRα in Gα12QL-transformed cells. Analysis of the functional consequences of the Gα12-PDGFRα signaling axis indicates that Gα12 stimulates the phosphatidylinositol 3-kinase (PI3K)-AKT signaling pathway through PDGFR. In addition, we show that Gα12QL stimulates the phosphorylation of forkhead transcription factor FKHRL1 via AKT in a PDGFRα- and PI3K-dependent manner. Since AKT promotes cell growth by blocking the transcription of antiproliferative genes through the inhibitory phosphorylation of forkhead transcription factors, our results describe for the first time a PDGFRα-dependent signaling pathway involving PI3K-AKT-FKHRL1, regulated by Gα12QL in promoting cell growth. Consistent with this view, we demonstrate that the expression of a dominant negative mutant of PDGFRα attenuated Gα12-mediated neoplastic transformation of NIH 3T3 cells.

134 Analysis of the role of small GTP binding protein Rab in intracellular melanosome transport

1996 ◽  
Vol 12 (2) ◽  
pp. 204
Author(s):  
K. Araki ◽  
T. Horikawa ◽  
K. Nakagawa ◽  
Y. Funasaka ◽  
M. Ichihashi
Keyword(s):  
Binding Protein ◽  
Gtp Binding Protein ◽  
Gtp Binding

scholarly journals Induction of β3-Integrin Gene Expression by Sustained Activation of the Ras-Regulated Raf–MEK–Extracellular Signal-Regulated Kinase Signaling Pathway

2001 ◽  
Vol 21 (9) ◽  
pp. 3192-3205 ◽  
Author(s):  
Douglas Woods ◽  
Holly Cherwinski ◽  
Eleni Venetsanakos ◽  
Arun Bhat ◽  
Stephan Gysin ◽  
...  
Keyword(s):  
Cell Surface ◽  
Signaling Pathway ◽  
Erk Signaling ◽  
Integrin Expression ◽  
3T3 Cells ◽  
Extracellular Signal ◽  
Integrin Gene ◽  
Β3 Integrin ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

ABSTRACT Alterations in the expression of integrin receptors for extracellular matrix (ECM) proteins are strongly associated with the acquisition of invasive and/or metastatic properties by human cancer cells. Despite this, comparatively little is known of the biochemical mechanisms that regulate the expression of integrin genes in cells. Here we demonstrate that the Ras-activated Raf–MEK–extracellular signal-regulated kinase (ERK) signaling pathway can specifically control the expression of individual integrin subunits in a variety of human and mouse cell lines. Pharmacological inhibition of MEK1 in a number of human melanoma and pancreatic carcinoma cell lines led to reduced cell surface expression of α6- and β3-integrin. Consistent with this, conditional activation of the Raf-MEK-ERK pathway in NIH 3T3 cells led to a 5 to 20-fold induction of cell surface α6- and β3-integrin expression. Induced β3-integrin was expressed on the cell surface as a heterodimer with αv-integrin; however, the overall level of αv-integrin expression was not altered by Ras or Raf. Raf-induced β3-integrin was observed in primary and established mouse fibroblast lines and in mouse and human endothelial cells. Consistent with previous reports of the ability of the Raf-MEK-ERK signaling pathway to induce β3-integrin gene transcription in human K-562 erythroleukemia cells, Raf activation in NIH 3T3 cells led to elevated β3-integrin mRNA. However, unlike immediate-early Raf targets such as heparin binding epidermal growth factor and Mdm2, β3-integrin mRNA was induced by Raf in a manner that was cycloheximide sensitive. Surprisingly, activation of the Raf-MEK-ERK signaling pathway by growth factors and mitogens had little or no effect on β3-integrin expression, suggesting that the expression of this gene requires sustained activation of this signaling pathway. In addition, despite the robust induction of cell surface αvβ3-integrin expression by Raf in NIH 3T3 cells, such cells display decreased spreading and adhesion, with a loss of focal adhesions and actin stress fibers. These data suggest that oncogene-induced alterations in integrin gene expression may participate in the changes in cell adhesion and migration that accompany the process of oncogenic transformation.

scholarly journals The histone acetyltransferases CBP/p300 are degraded in NIH 3T3 cells by activation of Ras signalling pathway

2006 ◽  
Vol 398 (2) ◽  
pp. 215-224 ◽  
Author(s):  
Sara Sánchez-Molina ◽  
José Luis Oliva ◽  
Susana García-Vargas ◽  
Ester Valls ◽  
José M. Rojas ◽  
...  
Keyword(s):  
Binding Protein ◽  
Camp Response Element Binding ◽  
Signalling Pathway ◽  
3T3 Cells ◽  
Protein Levels ◽  
3T3 Fibroblasts ◽  
Differentiation And Proliferation ◽  
Nih 3T3 ◽  
Ras Signalling ◽  
Nih 3T3 Cells

The CBP [CREB (cAMP-response-element-binding protein)-binding protein]/p300 acetyltransferases function as transcriptional co-activators and play critical roles in cell differentiation and proliferation. Accumulating evidence shows that alterations of the CBP/p300 protein levels are linked to human tumours. In the present study, we show that the levels of the CBP/p300 co-activators are decreased dramatically by continuous PDGF (platelet-derived growth factor) and Ras signalling pathway activation in NIH 3T3 fibroblasts. This effect occurs by reducing the expression levels of the CBP/p300 genes. In addition, CBP and p300 are degraded by the 26 S proteasome pathway leading to an overall decrease in the levels of the CBP/p300 proteins. Furthermore, we provide evidence that Mdm2 (murine double minute 2), in the presence of active H-Ras or N-Ras, induces CBP/p300 degradation in NIH 3T3 cells. These findings support a novel mechanism for modulating other signalling transduction pathways that require these common co-activators.

Specific activation of the cellular Harvey-ras oncogene in dimethylbenzanthracene-induced mouse mammary tumors

1986 ◽  
Vol 6 (11) ◽  
pp. 4104-4108
Author(s):  
S Dandekar ◽  
S Sukumar ◽  
H Zarbl ◽  
L J Young ◽  
R D Cardiff
Keyword(s):  
Mammary Tumors ◽  
3T3 Cells ◽  
Mouse Mammary Tumor ◽  
Mouse Mammary Tumors ◽  
Transforming Activity ◽  
Radiation Induced ◽  
Genomic Dnas ◽  
Nih 3T3 ◽  
Adenosine Nucleotide ◽  
Nih 3T3 Cells

Genomic DNAs from dimethylbenzanthracene-induced BALB/c mouse mammary tumors arising from the transplantable hyperplastic outgrowth (HPO) line designated DI/UCD transformed NIH 3T3 cells upon transfection. Transforming activity was attributed to the presence of activated Harvey ras-1 oncogenes containing an A----T transversion at the middle adenosine nucleotide in codon 61. DNAs from untreated DI/UCD HPO cells and radiation-induced and spontaneous mammary tumors from the DI/UCD HPO line failed to transform NIH 3T3 cells. The results indicated that the mutation activation of Harvey ras-1 oncogenes was specific to dimethylbenzanthracene treatment in the mouse mammary tumor system.

Photoreceptor rod outer segment 48-kDa protein has ATPase activity

1990 ◽  
Vol 5 (6) ◽  
pp. 585-589 ◽  
Author(s):  
Ari Sitaramayya ◽  
Shereen Hakki
Keyword(s):  
Atpase Activity ◽  
Cyclic Gmp ◽  
Slow Rate ◽  
Binding Protein ◽  
Rod Outer Segments ◽  
Light Activation ◽  
Visual Transduction ◽  
Gtp Binding Protein ◽  
Gtp Binding

AbstractThe role of 48-kDa protein in Visual transduction remains unresolved. Two hypotheses for its role in quenching the light activation of cyclic GMP cascade suggest that the protein binds to either phosphodiesterase or phosphorylated rhodopsin. Since the protein is also reported to bind ATP, we anticipated that the protein may have ATP hydrolyzing activity, and in analogy with the GTP-binding protein of the rod outer segments, such activity may be greatly enhanced by the elements of transduction cyclic GMP cascade, permitting the protein to function cyclically as GTP-binding protein does. We found that purified 48-kDa protein hydrolyzes ATP but at a slow rate of 0.04–0.05 per min. The Km for ATP is about 45–65 μM. The activity is inhibited noncompetitively by ADP with a Ki of about 50 μM. The ATPase activity of 48-kDa protein is not affected by rhodopsin, bleached rhodopsin, phosphorylated rhodopsin, unactivated cyclic GMP phosphodiesterase, or phosphodiesterase (PDE) activated by GMP PNP-bound G-protein. These data show that although 48-kDa protein has ATPase activity, lack of regulation of this activity by the elements of visual transduction makes it unlikely for this activity to have a role in quenching the light activation of cyclic GMP cascade.

Human spectrin Src homology 3 domain binding protein 1 regulates macropinocytosis in NIH 3T3 cells

2000 ◽  
Vol 113 (21) ◽  
pp. 3805-3814 ◽  
Author(s):  
J. Xu ◽  
D. Ziemnicka ◽  
G.S. Merz ◽  
L. Kotula
Keyword(s):  
Fluorescent Dyes ◽  
Fluorescent Protein ◽  
Cultured Cells ◽  
Binding Protein ◽  
Sh3 Domain ◽  
Water Soluble ◽  
Protein Markers ◽  
3T3 Cells ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

Macropinocytosis is an endocytic process that occurs through non-clathrin coated vesicles larger than 0.2 microm in diameter. Although macropinocytic vesicles are readily visualized in cultured cells by the introduction of fluorescent, water-soluble dyes into the culture medium, protein markers associated with this type of vesicles have not yet been well defined. Here, we report that human spectrin SH3 domain binding protein 1, or Hssh3bp1, associates with macropinosomes in NIH 3T3 fibroblasts. Hssh3bp1 macropinosomes are heterogeneous in morphology and size, do not endocytose transferrin and are resistant to brefeldin A treatment. Cytochalasin D, and wortmannin block endocytosis of fluorescent dyes into the Hssh3bp1 macropinosomes and dramatically affect their morphology. Overexpression of Hssh3bp1-green fluorescent protein abolished fusion of vesicles resulting in a decreased endocytosis of fluorescence dyes, thus suggesting a potential regulatory role of Hssh3bp1 in macropinocytosis. In the macropinosomes of NIH 3T3 cells, Hssh3bp1 associates with a 200-kDa protein that crossreacts with a monoclonal antibody to the erythroid alpha-spectrin SH3 domain. Thus macropinosomes in cells may contain a spectrin-like protein.

scholarly journals A transforming activity not detected by DNA transfer to NIH 3T3 cells is detected by JB6 mouse epidermal cells.

1985 ◽  
Vol 5 (4) ◽  
pp. 890-893 ◽  
Author(s):  
N H Colburn ◽  
M I Lerman ◽  
G A Hegamyer ◽  
T D Gindhart
Keyword(s):  
Tumor Cell ◽  
Cell Lines ◽  
Tumor Cell Lines ◽  
3T3 Cells ◽  
Anchorage Independence ◽  
Transforming Activity ◽  
Mouse Epidermal Cell ◽  
Nih 3T3 ◽  
Transforming Genes ◽  
Nih 3T3 Cells

Transfection of four different mouse epidermal tumor cell DNAs into NIH 3T3 cells yielded neither morphologically altered foci nor anchorage independence. However, promotion-sensitive, but not promotion-insensitive, JB6 mouse epidermal cell lines were permissive for the expression of anchorage independence after transfection of DNA from three of these tumor cell lines. This transforming activity and the promotion-sensitive activity that confers sensitivity to promotion of transformation show differences in restriction enzyme sensitivity. In view of this difference and the differences in both recipient cells and 12-O-tetradecanoyl-phorbol-13-acetate dependence of expression, it appears that the transforming activity and the promotion-sensitive activity are specified by different genes. The JB6 promotion-sensitive cell lines may be useful for detecting and cloning transforming genes that escape detection in the NIH 3T3 cell focus assay.

A chimeric toxin to study the role of the 21 kDa GTP binding protein rho in the control of actin microfilament assembly.

1993 ◽  
Vol 12 (3) ◽  
pp. 921-931 ◽  
Author(s):  
P. Aullo ◽  
M. Giry ◽  
S. Olsnes ◽  
M.R. Popoff ◽  
C. Kocks ◽  
...  
Keyword(s):  
Binding Protein ◽  
Gtp Binding Protein ◽  
Actin Microfilament ◽  
Gtp Binding
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