Adaptor protein Shc undergoes translocation and mediates up‐regulation of the tyrosine kinase c‐Src in EGF‐stimulated A431 cells

Sato, Ken; Kimoto, Miwa; Kakumoto, Miki; Horiuchi, Dai; Iwasaki, Tetsushi; Tokmakov, Alexander A.; Fukami, Yasuo

doi:10.1046/j.1365-2443.2000.00358.x

Cited by 45 publications

(37 citation statements)

References 60 publications

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“…Tyrosine residues 239 and 240 of Shc can be phosphorylated by Src (43), and Src only interacts with the two larger isoforms of Shc, but not with p46 (43,47). We only observed an effect on the small isoform.…”

Section: Discussionmentioning

confidence: 50%

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Sequence-specific Peptide Aptamers, Interacting with the Intracellular Domain of the Epidermal Growth Factor Receptor, Interfere with Stat3 Activation and Inhibit the Growth of Tumor Cells

Buerger

Nagel-Wolfrum

Künz

et al. 2003

Journal of Biological Chemistry

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Receptor tyrosine kinases of the epidermal growth factor (EGF) receptor family regulate essential cellular functions such as proliferation, survival, migration, and differentiation but also play central roles in the etiology and progression of tumors. We have identified short peptide sequences from a random peptide library integrated into the thioredoxin scaffold protein, which specifically bind to the intracellular domain of the EGF receptor (EGFR). These molecules have the potential to selectively inhibit specific aspects of EGF receptor signaling and might become valuable as anticancer agents. Intracellular expression of the aptamer encoding gene construct KDI1 or introduction of bacterially expressed KDI1 via a protein transduction domain into EGFR-expressing cells results in KDI1⅐EGF receptor complex formation, a slower proliferation, and reduced soft agar colony formation. Aptamer KDI1 did not summarily block the EGF receptor tyrosine kinase activity but selectively interfered with the EGF-induced phosphorylation of the tyrosine residues 845, 1068, and 1148 as well as the phosphorylation of tyrosine 317 of p46 Shc. EGFinduced phosphorylation of Stat3 at tyrosine 705 and Stat3-dependent transactivation were also impaired. Transduction of a short synthetic peptide aptamer sequence not embedded into the scaffold protein resulted in the same impairment of EGF-induced Stat3 activation.

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Section: Discussionmentioning

confidence: 50%

“…7). Shc preferentially interacts with the tyrosine residues 1148 and 1173 of the receptor and becomes phosphorylated (43). The binding of the aptamer impeded phos- FIG.…”

Section: Discussionmentioning

confidence: 99%

Sequence-specific Peptide Aptamers, Interacting with the Intracellular Domain of the Epidermal Growth Factor Receptor, Interfere with Stat3 Activation and Inhibit the Growth of Tumor Cells

Buerger

Nagel-Wolfrum

Künz

et al. 2003

Journal of Biological Chemistry

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“…A431 cells were washed twice with PBS and then lysed in ice-cold lysis buffer containing 20 mM Tris-HCl (pH 7.5), 1% Triton-X 100, 1 mM EDTA, 1 mM EGTA, 10 mM β-mercaptoethanol, 1 mM sodium orthovanadate, 10 µg / ml leupeptin, and 1 mM PMSF (22). After 60 min of incubation on ice, the cells were swelled and then centrifuged at 12,000 × g for 20 min.…”

Section: Preparation For Cytosolic Extractsmentioning

confidence: 99%

Oridonin-Induced A431 Cell Apoptosis Partially Through Blockage of the Ras/Raf/ERK Signal Pathway

Li-jun

Tashiro

et al. 2007

J Pharmacol Sci

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Abstract. We have reported that oridonin, a diterpenoid isolated from the plant Rabdosia rubescens, had apoptosis-inducing activities in many cell lines (e.g., human melanoma A375-S2, human cervical cancer HeLa, human breast adenocarcinoma MCF-7, and murine fibrosarcoma L929). In this study, we further investigated signaling events involved in oridonin-induced apoptosis in human epidermoid carcinoma A431 cells. It was found that the total tyrosine kinase activity was inhibited and the protein expressions of epidermal growth factor receptor (EGFR) and phosphorylated EGFR were decreased in oridonin-induced A431 cell apoptosis. Expression of EGFR downstream effector proteins, Grb2, Ras, Raf-1, and extracellular signal-regulated kinase (ERK), was also downregulated by oridonin. Moreover, the oridonin-induced apoptosis was augmented by the Ras inhibitor manumycin A, Raf-1 inhibitor GW5074, or ERK inhibitor PD98059, suggesting that inactivation of Ras, Raf, or ERK participates in oridonin-induced apoptosis. Taken together, oridonin-induced apoptosis in A431 cells might be through blocking EGFR and its downstream Ras / Raf/ ERK signal pathway.

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“…Cell lysates were prepared to examine the expression of Akt, phosphoAkt, Beclin-1, LC3, Ras, Bax and Bcl-2. In brief, A431 cells washed twice with PBS, and lysed in ice-cold lysis buffer containing 20 mmol / L Tris-HCl (pH 7.5), 1% Triton- (27). After 60 min of incubation on ice, the cells were swelled, and then centrifuged at 12,000 × g for 20 min.…”

Section: Western Blot Analysismentioning

confidence: 99%

Inactivation of Ras and Changes of Mitochondrial Membrane Potential Contribute to Oridonin-Induced Autophagy in A431 Cells

Cui

Chen

et al. 2007

J Pharmacol Sci

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Abstract. We have previously shown that oridonin isolated from Rabdosia rubescens augmented apoptosis while inhibiting autophagy within 24 h in HeLa cells. However, the mechanisms between apoptosis and autophagy induced by oridonin in A431 cells are largely unknown. Here, it was found that autophagic level is significantly upregulated when A431 cells are pretreated with manumycin A (Ras specific inhibitor) compared with oridonin alone treatment, whereas cells precultured with GW5074 (Raf inhibitor) or PD98059 (ERK inhibitor) did not exhibit such an effect. Ras, but not Raf or ERK, was engaged in the control of oridonininduced autophagy. At the same time, manumycin A contributes to oridonin-induced downregulation of Ras protein expression. Treatment with the combination of oridonin and manumycin A downregulated phosphorylation of Akt, downstream of phosphatidylinositol 3-OH kinase (PI3-K). Preincubation with the PI3-K inhibitor wortmannin and Akt inhibitor KP372-1 enhanced oridonin-induced apoptosis, whereas it inhibited oridonin-induced autophagy. However, under oridonin treatment, the expression of Beclin-1, which has autophagy-inducing activity, was reduced, suggesting that Beclin-1 did not participate in the oridonin-induced autophagy. Morphologic observations, DNA fragmentation analysis, and LDH activity-based assay showed that 3-methyladenine (3-MA), an inhibitor of autophagy, increased the apoptotic sensitivity of A431 cells to oridonin. In addition, manumycin A contributed to oridonin-induced decrease of mitochondrial membrane potential (∆ψm), consistent with the upregulation of Bax/ Bcl-2 ratio. In conclusion, Ras negatively regulated autophagy in oridonin-treated A431 cells, which might be associated with activation of class I PI3-K. Downregulation of ∆ψm and increasing of the ratio of Bax / Bcl-2 might also be partially responsible for the initiation of the autophagic process.

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Adaptor protein Shc undergoes translocation and mediates up‐regulation of the tyrosine kinase c‐Src in EGF‐stimulated A431 cells

Cited by 45 publications

References 60 publications

Sequence-specific Peptide Aptamers, Interacting with the Intracellular Domain of the Epidermal Growth Factor Receptor, Interfere with Stat3 Activation and Inhibit the Growth of Tumor Cells

Sequence-specific Peptide Aptamers, Interacting with the Intracellular Domain of the Epidermal Growth Factor Receptor, Interfere with Stat3 Activation and Inhibit the Growth of Tumor Cells

Oridonin-Induced A431 Cell Apoptosis Partially Through Blockage of the Ras/Raf/ERK Signal Pathway

Inactivation of Ras and Changes of Mitochondrial Membrane Potential Contribute to Oridonin-Induced Autophagy in A431 Cells

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