Rictor and integrin-linked kinase interact and regulate Akt phosphorylation and cancer cell survival
Rictor and integrin-linked kinase interact and regulate Akt phosphorylation and cancer cell survival
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DOI：
10.1158/0008-5472.can-07-5869
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发表时间：
2008-03-15
期刊：
影响因子：
11.2
通讯作者：
Dedhar, Shoukat
中科院分区：
文献类型：
--
作者：
McDonald, Paul C.;Oloumi, Arusha;Dedhar, Shoukat
用于鉴定整合素连接的激酶(ILK)相互作用的无偏蛋白质组筛选显示，Rictor是一种ILK结合蛋白。这一发现很有趣，因为Rictor最初被确定为细胞骨架动力学的调节因子，也是哺乳动物雷帕霉素复合体2(MTORC2)的组成部分，mTORC2是一种与Akt磷酸化有关的复合体。这些函数与已知的ILK函数重叠。免疫共沉淀分析证实了这种相互作用，ILK和Rictor共同定位于癌细胞的膜皱纹和前沿。酵母双杂交实验表明，Rictor的NH2-和COOH-末端结构域与ILK激活区之间存在直接的相互作用。在乳腺癌和前列腺癌细胞系中，ILK和Rictor的缺失导致Akt Ser(473)磷酸化的抑制和细胞凋亡的诱导，而在一些细胞系中，mTor的缺失增加了Akt的磷酸化。在ILK免疫沉淀物和小干扰RNA介导的Rictor耗竭中检测到AKT和Ser(473)P-Akt：，但不能抑制ILK复合体中Ser(473)P-Akt的含量。NH2末端(1-398个氨基酸)Rictor结构域的表达也抑制了ILK相关的AK-t Ser(473)的磷酸化。这些数据表明，Rictor调控ILK促进Akt磷酸化和癌细胞存活的能力。
An unbiased proteomic screen to identify integrin-linked kinase (ILK) interactors revealed rictor as an ILK-binding protein. This finding was interesting because rictor, originally identified as a regulator of cytoskeletal dynamics, is also a component of mammalian target of rapamycin complex 2 (mTORC2), a complex implicated in Akt phosphorylation. These functions overlap with known ILK functions. Coimmunoprecipitation analyses confirmed this interaction, and ILK and rictor colocalized in membrane ruffles and leading edges of cancer cells. Yeast two-hybrid assays showed a direct interaction between the NH2- and COOH-terminal domains of rictor and the ILK kinase domain. Depletion of ILK and rictor in breast and prostate cancer cell lines resulted in inhibition of Akt Ser(473) phosphorylation and induction of apoptosis, whereas, in several cell lines, depletion of mTOR increased Akt phosphorylation. Akt and Ser(473)P-Akt: were detected in ILK immunoprecipitates and small interfering RNA-mediated depletion of rictor, but not mTOR, inhibited the amount of Ser(473)P-Akt in the ILK complex. Expression of the NH2-terminal (1-398 amino acids) rictor domain also resulted in the inhibition of ILK-associated Ak-t Ser(473) phosphorylation. These data show that rictor regulates the ability of ILK to promote Akt phosphorylation and cancer cell survival.