• Molecules and Cells
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• v.26 no.4
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• pp.329-337
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• 2008

Src-family kinases are critically involved in the control of cytoskeleton organization and in the generation of integrin-dependent signaling responses, inducing tyrosine phosphorylation of many signaling and cytoskeletal proteins. Activity of the Src family of tyrosine kinases is tightly controlled by inhibitory phosphorylation of a carboxy-terminal tyrosine residue, inducing an inactive conformation through binding with its SH2 domain. Dephosphorylation of C-ter tyrosine, as well as its deletion of substitution with phenylalanine in oncogenic Src kinases, leads to autophosphorylation at a tyrosine in the activation loop, thereby leading to enhanced Src activity. Beside this phophorylation/dephosphorylation circuitry, cysteine oxidation has been recently reported as a further mechanism of enzyme activation. Mounting evidence describes Src activation via its redox regulation as a key outcome in several circumstances, including growth factor and cytokines signaling, integrin-mediated cell adhesion and motility, membrane receptor cross-talk as well in cell transformation and tumor progression. Among the plethora of data involving Src kinase in physiological and pathophysiological processes, this review will give emphasis to the redox component of the regulation of this master kinase.

• Korean Journal of Pharmacognosy
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• v.30 no.4
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• pp.404-408
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• 1999

SH2 domains and their associated catalytic or noncatalytic proteins constitute critical signal transduction targets for drug discovery. Grb2 associates with phosphotyrosine sites of the activated receptors or Shc via their SH2 domain to link receptor tyrosine kinases to ras signalling. Blocking of the Grb2-Shc complex may be to intervene the oncogenic signal transduction pathways and to develop a new antitumor drug. In the search for blockers of Grb2 SH2-Shc interaction, Lutein, a family of carotenoids, was isolated from the extract of the leaf of Agastache rugosa O. Kuntze as SH2 domain antagonists. The $IC_{50}$ of Lutein against Grb2-Shc binding was $6.8\;{\mu}M$.

• Animal cells and systems
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• v.1 no.3
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• pp.521-526
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• 1997

We isolated a mouse nck cDNA from the thymus cDNA expression library. The cDNA encodes a 377 amino acid protein and displays 97% amino acid sequence identity to human oncogenic protein nck, which is composed almost exclusivelv of three src homology 3 (SH3) domains and one SH2 domain. The sequence analysis also showed that the isolated cDNA is the mouse counterpart of the human nck and different from the mouse grb4, which has been reported to be highly similar to the human nck and, therefore considered as a mouse nck, Northern blot analysis showed that the transcript of the gene was 1.8 kb and was highly expressed in the testis, thymus, and brain but moderately in the liver and lymph node. Western blot analysis showed that the size of the protein was about 47 kDa. Overexpression of the mouse Nck transformed a mouse fibroblast cell line, NIH3T3. The results clearly indicate that normal nck gene has transforming ability and provide an argument against a suggested possibility that the transforming ability of the human nck gene is due to a mutation(s) in the gene.