Role of Raf-1 conserved region 2 in regulation of Ras-dependent Raf-1 activation.
Role of Raf-1 conserved region 2 in regulation of Ras-dependent Raf-1 activation.
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Raf-1 保守区 2 在 Ras 依赖性 Raf-1 激活调节中的作用。
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
T. Kataoka
中科院分区：
文献类型：
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作者：
H. Sendoh;C. D. Hu;D. Wu;C. Song;Y. Yamawaki‐Kataoka;J. Kotani;T. Okada;F. Shima;K. Kariya;T. Kataoka
Raf-1的完全激活需要其CRD与Ras的相互作用。Raf-1的富含丝氨酸/苏氨酸的区域CR2参与了Raf-1的调控，但其潜在机制尚不清楚。本研究表明，当CRD与CR2结合表达时，CRD失去了ras结合活性，这表明CR2掩盖了CRD。这种掩蔽效应通过用Asp或Ala取代Ser-259（生长因子和tpa诱导的CR2磷酸化位点）而消除。用TPA处理表达Ha-Ras（Val-12）和Raf-1的COS-7细胞可增强Ha-Ras（Val-12）依赖性Raf-1激酶活性。相反，Raf-1（S259D）和Raf-1（S259A）突变体的Ha-Ras（Val-12）依赖性活性与野生型Raf-1在Ha-Ras（Val-12）和TPA刺激下的活性相当，TPA处理不能进一步刺激Raf-1。这些结果表明，Ser-259的体内磷酸化可能是Ras依赖性Raf-1激活的关键步骤，通过揭示CRD并促进其与Ras的关联。
Full activation of Raf-1 requires the interaction of its CRD with Ras. The serine/threonine-rich region, CR2, of Raf-1 was implicated in Raf-1 regulation, but the underlying mechanism was unclear. Here we show that CRD loses its Ras-binding activity when expressed in connection with CR2, suggesting that CR2 masks CRD. This masking effect is abolished by substitution of Asp or Ala for Ser-259, a growth factor- and TPA-induced phosphorylation site in CR2. Treatment of COS-7 cells expressing Ha-Ras(Val-12) and Raf-1 with TPA enhances the Ha-Ras(Val-12)-dependent Raf-1 kinase activity. In contrast, the Ha-Ras(Val-12)-dependent activities of the Raf-1(S259D) and Raf-1(S259A) mutants are comparable to that of wild-type Raf-1 stimulated by both Ha-Ras(Val-12) and TPA and cannot be further stimulated by TPA treatment. These results suggest that the in vivo phosphorylation of Ser-259 may comprise a crucial step for Ras-dependent Raf-1 activation by unmasking CRD and promoting its association with Ras.
DOI：
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发表时间：
1993-08
期刊：
The Journal of biological chemistry
影响因子：
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作者：
D. Morrison;G. Heidecker;U. Rapp;T. Copeland
通讯作者：
D. Morrison;G. Heidecker;U. Rapp;T. Copeland