Regulation of cell migration and signaling by phosphotyrosine and ubiquitin

描述（由申请人提供）：细胞迁移受来自细胞-细胞相互作用、细胞-基质相互作用以及化学引诱剂和化学排斥剂的信号调节。这些信号通过翻译后修饰和蛋白质-蛋白质相互作用的级联进行转导和协调。具体而言，Src家族酪氨酸激酶被有丝分裂原和粘附受体激活，并使组织迁移细胞中的前缘和焦点粘附的磷酸化蛋白质活化。Cullin 5 RING（CRL 5）E3泛素连接酶和SOCS蛋白（CRL 5的磷酸酪氨酸依赖性底物衔接子）被认为是潜在的肿瘤抑制剂。我们已经发现，SOCS-CRL 5复合物在几种细胞类型中调节Src活性、细胞迁移、增殖和/或转化。抑制上皮细胞中SOCS蛋白或Cul5的表达刺激迁移、增殖和Src激酶活性。Src的增加是必要的，但不足以增加CRL5缺陷细胞的迁移和增殖，这表明SOCS-CRL5复合物有额外的底物。我们提出了三个广泛的目标，深入了解CRL5如何调节Src和细胞迁移。首先，我们将确定CRL5如何调节Src活性。其次，我们将确定CRL5底物，重点是那些含有磷酸酪氨酸，并测试哪些底物调节细胞迁移和增殖。第三，我们将剖析SOCS蛋白和底物在细胞迁移过程中协调粘着斑和前沿动力学的机制。总的来说，我们的研究将展示蛋白质酪氨酸磷酸化和泛素化如何合作来调节细胞生物学。

DESCRIPTION (provided by applicant): Cell migration is regulated by signals from cell-cell interactions, cell-matrix interactions and chemo-attractants and -repellants. Such signals are transduced and coordinated by cascades of post-translational modifications and protein-protein interactions. Specifically, Src family tyrosine kinases are activated by mitogens and adhesion receptors and phosphorylate proteins that organize the leading edge and focal adhesions in migrating cells. The Cullin 5 RING (CRL5) E3 ubiquitin ligase and SOCS proteins (phosphotyrosine-dependent substrate adaptors for CRL5) have been implicated as potential tumor suppressors. We have found that SOCS-CRL5 complexes regulate Src activity, cell migration, proliferation and/or transformation in several cell types. Inhibiting the expression of SOCS proteins or Cul5 in epithelial cells stimulates migration, proliferation, and Src kinase activity. Increased Src is necessary but not sufficient for the increased migration and proliferation of CRL5-deficient cells, suggesting that SOCS-CRL5 complexes have additional substrates. We propose three broad aims to understand in depth how CRL5 regulates Src and cell migration. First, we will determine how CRL5 regulates Src activity. Second, we will identify CRL5 substrates, focusing on those that contain phosphotyrosine, and test which substrates regulate cell migration and proliferation. Third, we will dissect the mechanisms by which SOCS proteins and substrates coordinate focal adhesion and leading edge dynamics during cell migration. Collectively, our research will show how protein-tyrosine phosphorylation and ubiquitylation cooperate to regulate cell biology.