P68 and Ca-calmodulin interaction in cell migration

描述(由申请人提供)：细胞迁移是细胞在许多基本生物学过程中的基本特征，如胚胎发育、组织发育、伤口愈合和免疫反应系统中淋巴细胞的迁移。控制这一重要细胞过程的分子机制得到了广泛的研究。然而，尽管有大量的特征描述，一些重要的知识差距仍然存在，特别是关于关键角色钙调素(CaM)在细胞迁移过程中的功能作用。我们观察到p68-CaM相互作用是上皮细胞迁移所必需的。在细胞迁移刺激下，p68-CaM的相互作用显著增强。与CaM结合后，p68从胞核定位到胞浆。在迁移细胞中，p68和CaM共同定位于迁移前缘(片状脂膜或足膜)。取消p68 ATPase活性的突变阻止了CaM定位于迁移细胞的前沿。P68-钙调素融合蛋白的表达导致了片状脂膜的形成和细胞形态的变化，并显著增加了细胞的运动性。免疫纯化的p68-CaM融合蛋白在体外可与细胞骨架微管相互作用。此外，p68 IQ基序衍生的多肽强烈抑制细胞迁移。因此，用IQ肽治疗荷瘤小鼠几乎完全消除了癌症转移。我们的观察表明，p68-CaM相互作用是调节细胞迁移的一个新的参与者。本研究的目的是了解p68-CaM相互作用在细胞迁移过程中的作用。我们提出了三个具体的目标来研究功能 P68-CaM相互作用在细胞迁移中的意义。在特定的目标1中，我们将阐明p68-CaM相互作用的调节机制。我们将检验我们的假设，即细胞迁移信号触发p68的磷酸化，从而导致p68-CaM的相互作用。在具体目标2中，我们将解开p68在迁移前沿的功能。在具体目标3中，我们计划重点解决在不同细胞过程中控制p68底物选择的分子机制。我们相信，我们的结果最终将被应用于开发新的疾病诊断/预后和治疗策略。

DESCRIPTION (provided by applicant): Cell migration is an essential characteristic of cells in numerous fundamental biological processes, such as embryogenesis, tissue development, wound healing, and migration of lymphocytes in the immune response system. The molecular mechanism that governs this important cellular process is extensively studied. However, despite intensive characterizations, several important knowledge gaps remain, especially regarding the functional role of the key player, Ca-calmodulin (CaM), in the cell migration process. We have observed that the p68-CaM interaction is necessary for epithelial cell migration. Upon cell migration stimulation, the p68-CaM interaction was substantially enhanced. Binding to CaM caused localization of p68 from the cell nucleus to the cytoplasm. In the migrating cells, p68 and CaM co-localized to the migration leading edges (lamellipodia or fillopodia). Mutations that abolished p68 ATPase activity blocked the localization of CaM to the leading edge of migrating cells. Expression of a p68-calmodulin fusion protein led to the formation of lamellipodium and cell morphological changes and dramatically increased cell motility. The immunopurified p68-CaM fusion protein interacted with the cytoskeleton microtubule in vitro. In addition, a peptide derived from p68 IQ motifs strongly inhibited cell migration. As a consequence, treatment of tumor bearing mouse with the IQ peptide almost completely abolished cancer metastasis. Our observations suggest that the p68-CaM interaction is a new player in regulating the cell migration. The goal of this proposed research project is to understand the role of the p68-CaM interaction in cell migration process. We propose three specific aims to investigate the functional significance of p68-CaM interaction in cell migration. In specific aim 1, we will elucidate the mechanism that regulates the p68-CaM interaction. We will test our hypothesis that cell migration signals trigger phosphorylation of p68, which subsequently lead to the p68-CaM interaction. In specific aim 2, we will unravel the function of p68 at migration leading edge. In specific aim 3, we plan to focus on addressing the molecular mechanism that governors the substrate selection of p68 in different cellular processes. We believe that our results will ultimately be applied to develop new strategies for diseases diagnosis/prognosis and treatments.