The Role of CARMIL2 in Cell Migration and Invasion

描述(申请人提供)：癌症患者的主要死因是转移的肿瘤细胞侵袭身体组织。肿瘤细胞在转移过程中的迁移和侵袭需要细胞骨架网络的协调，以形成极化结构，如片状脂膜和内陷。波形蛋白的表达是癌细胞上皮向间充质转化的标志，与肿瘤的侵袭潜能密切相关。虽然最近的研究表明，波形蛋白调节片状脂膜的形成和跨足的延长，但波形蛋白影响肌动蛋白组装的机制尚不清楚；然而，CARMIL2是一个很有可能发挥关键作用的候选基因。CARMIL2定位于细胞中的波形蛋白细丝，并在肌动蛋白聚合分析中调节肌动蛋白网络的关键调节蛋白--盖蛋白(CP)。CARMIL2基因敲除细胞表现出缺陷的迁移、减少的片状脂胞褶皱和巨噬细胞吞噬，并具有显著的多片状脂体表型。Vimentin定位如何与CARMIL2功能相关，以及CARMIL2调控CP对细胞迁移和侵袭的重要性尚未确定。此外，CARMIL2还含有一个未知功能的CARMIL同源结构域(CHD)。CARMIL家族成员之间CHD的序列相似性很高，表明它起着保守的作用。该方案的中心假设是，CARMIL2通过调节CP和协调肌动蛋白细丝与波形蛋白网络的动力学来调节细胞迁移和侵袭过程中肌动蛋白网络的极性和动力学。以下特定目标将使用分子、细胞生物学和生化方法验证这一假说：1)测试CARMIL2对CP调控对细胞迁移和侵袭的重要性；2)测试CARMIL2定位于波形蛋白细丝对细胞迁移和侵袭的重要性；3)寻找与CARMIL2保守的CHD相互作用的蛋白质。该项目的长期目标是阐明细胞如何组装极化的细胞骨架网络，以在肿瘤转移过程中驱动细胞迁移和侵袭。这项提议的完成将提供对这些机制的更好的理解，并将有助于寻找新的癌症疗法。 公共卫生相关性：癌症患者死亡的主要原因是转移的肿瘤细胞侵袭身体组织。这项建议探索了在肿瘤转移过程中细胞极化和组装细胞骨架网络以驱动迁移和侵袭的分子基础。这项提议的完成将提供对转移的更好的理解，并有助于寻找新的癌症治疗方法。

DESCRIPTION (provided by applicant): The main cause of death in patients with cancer is the invasion of body tissues by metastasizing tumor cells. Migration and invasion by tumor cells during metastasis require the coordination of cytoskeletal networks to form polarized structures, such as lamellipodia and invadopodia. Vimentin expression is a hallmark of the epithelial-mesenchymal transition in carcinoma cells and correlates strongly with invasive potential. Although recent studies demonstrate that vimentin regulates lamellipodia formation and invadopodia elongation, the mechanisms through which vimentin exerts influence over actin assembly are not well understood; however, CARMIL2 is a strong candidate to play a key role. CARMIL2 localizes to vimentin filaments in cells and regulates capping protein (CP), a key regulator of actin networks, in actin polymerization assays. CARMIL2 knockdown cells exhibit defective migration, diminished lamellipodial ruffling and macropinocytosis, and possess a striking multi-lamellipodia phenotype. How vimentin localization relates to CARMIL2 function and the importance of CP regulation by CARMIL2 for cell migration and invasion are not established. Additionally, CARMIL2 possesses a CARMIL homology domain (CHD) of unknown function. The high level of sequence similarity of the CHD among CARMIL family members suggests that it serves a conserved role. The central hypothesis of this proposal is that CARMIL2 regulates the polarity and dynamics of the actin network during cell migration and invasion by regulating CP and coordinating actin filament dynamics with the vimentin network. The following specific aims will test this hypothesis using molecular, cell biological, and biochemical approaches: 1) To test the importance of CP regulation by CARMIL2 for cell migration and invasion; 2) To test the importance of CARMIL2 localization to vimentin filaments for cell migration and invasion; 3) To identify proteins that interact with the conserved CHD of CARMIL2. The long-term objective of this project is to elucidate how cells assemble polarized cytoskeletal networks to drive cell migration and invasion during tumor metastasis. Completion of this proposal will provide an improved understanding of these mechanisms and will aid in the search for new cancer therapies. PUBLIC HEALTH RELEVANCE: The main cause of death in patients with cancer is the invasion of body tissues by metastasizing tumor cells. This proposal explores the molecular basis by which cells polarize and assemble cytoskeletal networks to drive migration and invasion during tumor metastasis. Completion of this proposal will provide an improved understanding of metastasis and aid in the search for new cancer therapies.