Role of Shc and LRP1 in Transformation by v-Src

描述（由申请人提供）：v-Src作为一种模型癌基因已经被研究了25年以上，目前尚不清楚哪些底物对其转化细胞的能力起关键作用。我们最近在v-Src转化细胞中发现LRPI是一种Shc相关蛋白。酪氨酸磷酸化后，LRP1与Shc和其他可能的信号蛋白结合。这些观察结果导致了一种模型，其中Shc通过与LRPI结合而被招募到血浆中。正是在细胞膜上，Shc被认为参与了Ras的激活。该资助旨在了解Shc和LRP1在v-Src细胞转化中的作用。此外，我们建议鉴定新的v-Src底物。鉴定在细胞转化过程中起重要作用的底物是很重要的，因为它将导致对这一过程的新见解。此外，这些底物为干预提供了靶点。为了找出在v-Src转化过程中Shc或LRP1是否重要，我们将分析v-Src转化Shc缺陷和lrpl缺陷细胞的能力。为了研究Src如何选择LRP1作为底物，我们将突变Src中的不同结构域，并了解哪些结构域对LRP1的酪氨酸磷酸化至关重要。初步证据表明，Shc与一种或多种LRP1亚型结合。我们建议进行实验来鉴定这些同工异构体。最后，我们提出了纯化和鉴定新的v-Src底物。

DESCRIPTION (provided by applicant): v-Src has been studied as a model oncogene for over 25 years and it is still unclear which substrates contribute critically to its ability to tranform cells. We recently identified LRPI as a Shc associated protein in v-Src transformed cells. Upon tyrosine phosphorylation LRP1 associates with Shc and possibly other signaling proteins. These observations led to a model in which Shc is recruited to the plasma by binding to LRPI. It is at the membrane that Shc is thought to be involved in Ras activation. This grant is aimed at understanding the role of Shc and LRP1 in cellular transformation by v-Src. In addition, we propose to identify novel v-Src substrates. Identification of substrates that play an important role during cellular transformation is important because it will lead to new insights into this process. In addition these substrates provide targets for intervention. To find out whether either Shc or LRP1 are important during transformation by v-Src we will analyze the ability of v-Src to transform Shc-deficient and LRPl-deficient cells. To investigate how Src selects LRP1 as a substrate, we will mutate the different domains in Src and ask which of them are essential for the tyrosine phosphorylation of LRP1. Preliminary evidence suggests that Shc binds to one or more LRP1 isoforms. We propose experiments to identify those isoforms. Finally we propose purify and identify novel v-Src substrates.