RACK1: a novel substrate for the Src protein-tyrosine kinase
RACK1: a novel substrate for the Src protein-tyrosine kinase
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DOI：
10.1038/sj.onc.1206002
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发表时间：
2002-10-31
期刊：
影响因子：
8
通讯作者：
Cartwright, CA
中科院分区：
文献类型：
--
作者：
Chang, BY;Harte, RA;Cartwright, CA
RACK1是一组与PKC相互作用的蛋白质之一，统称为RAKS(活化C-激酶受体)。以前，我们发现RACK1也与Src酪氨酸激酶相互作用，是Src活性和细胞生长的抑制因子。PKC激活可诱导RACK1和Src在细胞内的运动和共定位，以及RACK1的酪氨酸磷酸化。为了确定RACK1是否是一种Src底物，我们在体外评估了各种酪氨酸激酶对RACK1的磷酸化作用，以及在体内对Src的激酶活性和非活性突变体的影响。我们发现RACK1是一种Src底物。此外，在PKC激活后，RACK1的酪氨酸磷酸化和RACK1与Src的SH2结构域的结合都需要Src的活性。为了鉴定RACK1上被Src磷酸化的酪氨酸(S)，我们产生并检测了一系列RACK1突变体。我们发现，Src磷酸化Tyr 228和/或Tyr 246上的RACK1，这是一种高度保守的酪氨酸，位于第六个WD重复序列中，与Src的SH2结构域相互作用。我们认为RACK1是一种重要的Src底物，它在生长因子受体酪氨酸激酶下游传递信号，参与了对Src功能和细胞生长的调节。
RACK1 is one of a group of PKC-interacting proteins collectively called RACKs (Receptors for Activated C-Kinases). Previously, we showed that RACK1 also interacts with the Src tyrosine kinase, and is an inhibitor of Src activity and cell growth. PKC activation induces the intracellular movement and co-localization of RACK1 and Src, and the tyrosine phosphorylation of RACK1. To determine whether RACK1 is a Src substrate, we assessed phosphorylation of RACK1 by various tyrosine kinases in vitro, and by kinase-active and inactive mutants of Src in vivo. We found that RACK1 is a Src substrate. Moreover, Src activity is necessary for both the tyrosine phosphorylation of RACK1 and the binding of RACK1 to Src's SH2 domain that occur following PKC activation. To identify the tyrosine(s) on RACK1 that is phosphorylated by Src, we generated and tested a series of RACK1 mutants. We found that Src phosphorylates RACK1 on Tyr 228 and/or Tyr 246, highly-conserved tyrosines located in the sixth WD repeat that interact with Src's SH2 domain. We think that RACK1 is an important Src substrate that signals downstream of growth factor receptor tyrosine kinases and is involved in the regulation of Src function and cell growth.