| Autor: |
Whitehurst, C E, Owaki, H, Bruder, J T, Rapp, U R, Geppert, T D |
| Zdroj: |
Journal of Biological Chemistry; March 1995, Vol. 270 Issue: 10 p5594-9, 6p |
| Abstrakt: |
Deletion of the amino-terminal domain of Raf-1, which contains the Ras-binding region, results in the constitutive activation of the liberated Raf-1 catalytic domain in fibroblast cell lines. We demonstrate that the MEK kinase activity of the isolated Raf-1 catalytic domain, Raf-BXB, is not constitutively active, but is regulated in Jurkat T cells. Raf-BXB is activated by engaging the antigen receptor-CD3 complex, or treating cells with phorbol myristate acetate or okadaic acid. Increasing intracellular cAMP inhibits Raf-1 activation stimulated by phorbol myristate acetate, but not the activation of Raf-BXB. Serine 621, but not serine 499, is essential for Raf-BXB MEK kinase activity. Because Raf-BXB does not bind Ras, the data establishes a Ras-independent signal in directly regulating the activity of the Raf-1 catalytic domain. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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