THE PRINCIPAL TARGET OF RAPAMYCIN-INDUCED P70(S6K) INACTIVATION IS A NOVEL PHOSPHORYLATION SITE WITHIN A CONSERVED HYDROPHOBIC DOMAIN
THE PRINCIPAL TARGET OF RAPAMYCIN-INDUCED P70(S6K) INACTIVATION IS A NOVEL PHOSPHORYLATION SITE WITHIN A CONSERVED HYDROPHOBIC DOMAIN
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DOI：
10.1002/j.1460-2075.1995.tb00212.x
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发表时间：
1995-11-01
期刊：
影响因子：
11.4
通讯作者：
THOMAS, G
中科院分区：
文献类型：
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作者：
PEARSON, RB;DENNIS, PB;THOMAS, G
免疫抑制剂雷帕霉素诱导p70（s6k）失活，而对其他有丝分裂原激活的激酶没有影响。在这里，我们采用了包括质谱在内的多种技术组合，来证明这种作用与三个先前未识别的p70（s6k）磷酸化位点的选择性去磷酸化有关：T229， T389和S404， T229位于催化结构域的保守位置，其磷酸化对于其他丝裂原诱导的激酶的激活是必不可少的。然而，雷帕霉素诱导的p70（s6k）失活的主要靶点是T389，它位于催化结构域外的一个不寻常的疏水序列中。T389突变为丙氨酸会减弱激酶活性，而突变为谷氨酸则会产生组成激酶活性和雷帕霉素抗性。这个位点及其周围基序对激酶功能的重要性被强调了，因为它存在于第二信使家族的大量蛋白激酶中，并且它在来自远亲生物（如酵母和植物）的p70（s6k）同源物中也有保存。
The immunosuppressive agent rapamycin induces inactivation of p70(s6k) with no effect on other mitogen-activated kinases, Here we have employed a combination of techniques, including mass spectrometry, to demonstrate that this effect is associated with selective dephosphorylation of three previously unidentified p70(s6k) phosphorylation sites: T229, T389 and S404, T229 resides at a conserved position in the catalytic domain, whose phosphorylation is essential for the activation of other mitogen-induced kinases. However, the principal target of rapamycin-induced p70(s6k) inactivation is T389, which is located in an unusual hydrophobic sequence outside the catalytic domain, Mutation of T389 to alanine ablates kinase activity, whereas mutation to glutamic acid confers constitutive kinase activity and rapamycin resistance. The importance of this site and its surrounding motif to kinase function is emphasized by its presence in a large number of protein kinases of the second messenger family and its conservation in putative p70(s6k) homologues from as distantly related organisms as yeast and plants.