scholarly journals Binding of pEL98 protein, an S100-related calcium-binding protein, to nonmuscle tropomyosin

1994 ◽  
Vol 124 (5) ◽  
pp. 757-768 ◽  
Author(s):  
K Takenaga ◽  
Y Nakamura ◽  
S Sakiyama ◽  
Y Hasegawa ◽  
K Sato ◽  
...  

The cDNA coding for mouse fibroblast tropomyosin isoform 2 (TM2) was placed into a bacterial expression vector to produce a fusion protein containing glutathione-S-transferase (GST) and TM2 (GST/TM2). Glutathione-Sepharose beads bearing GST/TM2 were incubated with [35S]methionine-labeled NIH 3T3 cell extracts and the materials bound to the fusion proteins were analyzed to identify proteins that interact with TM2. A protein of 10 kD was found to bind to GST/TM2, but not to GST. The binding of the 10-kD protein to GST/TM2 was dependent on the presence of Ca2+ and inhibited by molar excess of free TM2 in a competition assay. The 10-kD protein-binding site was mapped to the region spanning residues 39-107 on TM2 by using several COOH-terminal and NH2-terminal truncation mutants of TM2. The 10-kD protein was isolated from an extract of NIH 3T3 cells transformed by v-Ha-ras by affinity chromatography on a GST/TM2 truncation mutant followed by SDS-PAGE and electroelution. Partial amino acid sequence analysis of the purified 10-kD protein, two-dimensional polyacrylamide gel analysis and a binding experiment revealed that the 10-kD protein was identical to a calcium-binding protein derived from mRNA named pEL98 or 18A2 that is homologous to S100 protein. Immunoblot analysis of the distribution of the 10-kD protein in Triton-soluble and -insoluble fractions of NIH 3T3 cells revealed that some of the 10-kD protein was associated with the Triton-insoluble cytoskeletal residue in a Ca(2+)-dependent manner. Furthermore, immunofluorescent staining of NIH 3T3 cells showed that some of the 10-kD protein colocalized with nonmuscle TMs in microfilament bundles. These results suggest that some of the pEL98 protein interacts with microfilament-associated nonmuscle TMs in NIH 3T3 cells.

2006 ◽  
Vol 26 (1) ◽  
pp. 50-62 ◽  
Author(s):  
Rashmi N. Kumar ◽  
Ji Hee Ha ◽  
Rangasudhagar Radhakrishnan ◽  
Danny N. Dhanasekaran

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.


2006 ◽  
Vol 398 (2) ◽  
pp. 215-224 ◽  
Author(s):  
Sara Sánchez-Molina ◽  
José Luis Oliva ◽  
Susana García-Vargas ◽  
Ester Valls ◽  
José M. Rojas ◽  
...  

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.


2000 ◽  
Vol 113 (21) ◽  
pp. 3805-3814 ◽  
Author(s):  
J. Xu ◽  
D. Ziemnicka ◽  
G.S. Merz ◽  
L. Kotula

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.


FEBS Letters ◽  
2001 ◽  
Vol 511 (1-3) ◽  
pp. 15-20 ◽  
Author(s):  
Kaoru Sakabe ◽  
Hidemi Teramoto ◽  
Muriel Zohar ◽  
Babak Behbahani ◽  
Hiroshi Miyazaki ◽  
...  

2020 ◽  
Author(s):  
Chunhe Lu ◽  
Jia Liu ◽  
Mingze Yao ◽  
Lun Li ◽  
Guangyu Li

Abstract Introduction: S100 Calcium Binding Protein A12 (S100A12) is a member of the S100 protein family and is widely expressed in neutrophil and low expressed in lymphocytes and monocyte. However, the role of S100A12 in glioma has not yet been identified. Methods: In the present study, we carried out immunohistochemical investigation of S100A12 in 81 glioma tissues to determine the expression of s100A12 in glioma cells, and evaluate the clinical significance of S100A12 in glioma patients. Futher we knockdown the S100A12 by ShRNA, and evaluated cell proliferation, cell migration and cell apoptosis by MTT,clony formation assay, transwell assay ,flow cytometry assa and westernblot. Results: We found that S100A12 was upregulated in tissues of glioma patients and the expression was correlated to WHO stage and tumor size. Further, we found that knockdown S100A12 inhibits the proliferation, migration and invasion of glioma cells through regulating cell apoptosis and EMT. Conclusions: These findings demonstrated a novel function for S100A12 in glioma progression and suggested that S100A12 may be served as a new marker in the tumorigenesis and progression of glioma.


2020 ◽  
Author(s):  
Chunhe Lu ◽  
Jia Liu ◽  
Mingze Yao ◽  
Lun Li ◽  
Guangyu Li

Abstract Background: S100 Calcium Binding Protein A12 (S100A12) is a member of the S100 protein family and is widely expressed in neutrophil and low expressed in lymphocytes and monocyte. However, the role of S100A12 in glioma has not yet been identified. Methods: In the present study, we carried out immunohistochemical investigation of S100A12 in 81 glioma tissues to determine the expression of s100A12 in glioma cells, and evaluate the clinical significance of S100A12 in glioma patients. Futher we knockdown the S100A12 by ShRNA, and evaluated cell proliferation, cell migration and cell apoptosis by MTT, clony formation assay, transwell assay ,flow cytometry assa and western blot. Results: We found that S100A12 was upregulated in tissues of glioma patients and the expression was correlated to WHO stage and tumor size. Further, we found that knockdown S100A12 inhibits the proliferation, migration and invasion of glioma cells through regulating cell apoptosis and EMT. Background: S100 Calcium Binding Protein A12 (S100A12) is a member of the S100 protein family and is widely expressed in neutrophil and low expressed in lymphocytes and monocyte. However, the role of S100A12 in glioma has not yet been identified. Methods: In the present study, we carried out immunohistochemical investigation of S100A12 in 81 glioma tissues to determine the expression of s100A12 in glioma cells, and evaluate the clinical significance of S100A12 in glioma patients. Futher we knockdown the S100A12 by ShRNA, and evaluated cell proliferation, cell migration and cell apoptosis by MTT, clony formation assay, transwell assay ,flow cytometry assa and western blot. Results: We found that S100A12 was upregulated in tissues of glioma patients and the expression was correlated to WHO stage and tumor size. Further, we found that knockdown S100A12 inhibits the proliferation, migration and invasion of glioma cells through regulating cell apoptosis and EMT.


2019 ◽  
Vol 35 (3) ◽  
pp. 239-247 ◽  
Author(s):  
Runan Qin ◽  
Yue Wang ◽  
Shengyuan Wang ◽  
Bing Xia ◽  
Rui Xin ◽  
...  

Nickel (Ni) is a metal known to be a human carcinogen that occupational workers can be exposed to during the process of Ni refining. We investigated the molecular mechanism of inflammation that is induced by Ni-refining dust in a factory, using concentrations of 0, 25, 50, and 100 µg/mL for 24 h and 48 h, in vitro. Quantitative real-time polymerase chain reactions (qRT-PCR), Western blot analysis, and enzyme-linked immunosorbent assays (ELISA) were used to detect the transcriptional expression levels of nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). Results showed that Ni-refining dust decreased the secretion of IL-6 under the experimental conditions. In contrast, Ni-refining dust activated NF-κB expression and stimulated the secretion of TNF-α, IL-1β, iNOS, and COX-2 in a dose- and time-dependent manner. To summarize, we demonstrated that exposure to Ni-refining dust can induce the expression of NF-κB in NIH/3T3 cells and the secretion of inflammation related factors. This provides a new basis for further study of the inflammatory effects of Ni-refining dust.


1996 ◽  
Vol 319 (1) ◽  
pp. 9-12 ◽  
Author(s):  
Patrick J. DONOHUE ◽  
Sheau-Line Y. FENG ◽  
Gregory F ALBERTS ◽  
Yan GUO ◽  
Kimberly A PEIFLEY ◽  
...  

Polypeptide growth factors promote cell-cycle progression in part by the transcriptional activation of a diverse group of specific genes. We have used an mRNA differential-display approach to identify several fibroblast growth factor (FGF)-1 (acidic FGF)-inducible genes in NIH 3T3 cells. Here we report that one of these genes, called FGF-regulated (FR)-3, is predicted to encode G/T mismatch-binding protein (GTBP), a component of the mammalian DNA mismatch correction system. The murine GTBP gene is transiently expressed after FGF-1 or calf serum treatment, with maximal mRNA levels detected at 12 and 18 h post-stimulation. FGF-1-stimulated NIH 3T3 cells also express an increased amount of GTBP as determined by immunoblot analysis. These results indicate that elevated levels of GTBP may be required during the DNA synthesis phase of the cell cycle for efficient G/T mismatch recognition and repair.


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