The Role of CARMIL2 in Cell Migration and Invasion

描述（申请人提供）：癌症患者死亡的主要原因是肿瘤细胞转移侵入身体组织。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才能形成极化结构，如板足和内adopodia。波形蛋白的表达是癌细胞上皮-间质转化的一个标志，并且与侵袭电位密切相关。尽管最近的研究表明，vimentin调节板足的形成和侵入足的伸长，但vimentin影响肌动蛋白组装的机制尚不清楚；然而，CARMIL2是发挥关键作用的强有力候选者。CARMIL2定位于细胞中的静脉蛋白丝，并在肌动蛋白聚合分析中调节肌动蛋白网络的关键调节剂——封盖蛋白（CP）。CARMIL2敲低的细胞表现出迁移缺陷，减少板足褶皱和巨噬细胞增多，并具有显著的多板足表型。波形蛋白定位与CARMIL2功能的关系以及CARMIL2调控CP对细胞迁移和侵袭的重要性尚不明确。此外，CARMIL2还具有一个功能未知的CARMIL2同源结构域（CHD）。CHD在CARMIL家族成员中具有高度的序列相似性，提示其具有保守作用。该提案的中心假设是，CARMIL2通过调节CP和协调肌动蛋白丝与静脉蛋白网络的动态，调节细胞迁移和侵袭过程中肌动蛋白网络的极性和动态。以下具体目的将使用分子、细胞生物学和生化方法来验证这一假设：1)测试CARMIL2对CP调控对细胞迁移和侵袭的重要性；2)验证CARMIL2在静脉蛋白丝上的定位对细胞迁移和侵袭的重要性；3)鉴定与CARMIL2保守型冠心病相互作用的蛋白。该项目的长期目标是阐明在肿瘤转移过程中细胞如何组装极化细胞骨架网络来驱动细胞迁移和侵袭。这项建议的完成将提供对这些机制的更好理解，并将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.