Examining the role of Cbk1/NDR kinase in regulating mRNA localization

检查 Cbk1/NDR 激酶在调节 mRNA 定位中的作用

• 批准号: 8436822
• 负责人: FRANCIS C LUCA
• 金额: $ 31.2万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-12-31 至 2016-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8436822
• 关键词: Active Biological Transport; B-Lymphocytes; Biochemical Genetics; Biological; Cancer Control; Cancer Etiology; Canis familiaris; Carrier Proteins; Cell Polarity; Cell division; Cell physiology; Cells; Cellular Morphology; Cellular Stress; Complex; Critical Pathways; Cytolysis; Cytoplasmic Granules; Data; Defect; Development; Diagnostic; Disease; Family; Future; Gene Expression; Genetic Translation; Goals; Growth; Growth and Development function; Heterogeneous-Nuclear Ribonucleoproteins; Human; Laboratories; Leber' s amaurosis; Malignant Neoplasms; Malignant neoplasm of ovary; Malignant neoplasm of pancreas; Malignant neoplasm of prostate; Mammalian Cell; Mediating; Messenger RNA; Methods; Mission; Molecular; Morphogenesis; Morphology; Mutation; NDRG1 gene; Neurons; Pathway interactions; Phosphoric Monoester Hydrolases; Phosphorylation Site; Phosphotransferases; Play; Prions; Process; Proteins; Public Health; Publishing; Recruitment Activity; Regulation; Research; Retinal Degeneration; Ribonucleoproteins; Role; Saccharomyces cerevisiae; Site; Stress; T-Cell Lymphoma; Testing; Therapeutic; Translation Process; Translational Repression; Translations; Tumor Suppressor Proteins; Ursidae Family; Work; Yeasts; anti-cancer therapeutic; base; biological adaptation to stress; cell growth; cell motility; hnRNP A1; hnRNP A2-B1; in vivo; insight; mutant; novel; novel therapeutics; polarized cell; protein expression; protein phosphatase 6; public health relevance; research study; response; sarcoma; soft tissue; therapeutic development

DESCRIPTION (provided by applicant): NDR kinases are tumor suppressors implicated in a variety of cancers, including soft tissue sarcomas, B and T cell lymphomas, pancreatic, prostate and ovarian cancers. NDR mutations cause cell growth and polarized morphogenesis defects in a variety of cells, including neurons. Despite the importance of NDR kinases, the mechanisms by which they influence cellular morphogenesis and cancer progresion are poorly understood, thus limiting the development of diagnostics and therapeutics for NDR-mediated cancers. Our recent data support a novel role for the S. cerevisiae NDR1/2 orthologue Cbk1 in regulating mRNA polarity and translation, processes that play defining roles in cell polarity, asymmetric cell division, development, and morphogenesis. Specifically, we have shown that Cbk1 phosphorylates the ribonucleoprotein (RNP) Ssd1 and promotes the polar localization of a subset of Ssd1-mRNA complexes, suggesting that NDR kinases promote cell polarity by directing mRNA-RNP complexes to sites of localized protein expression. In contrast, Cbk1 inhibition or cellular stress redirect Ssd1-mRNA complexes to P bodies and stress granules, thereby repressing mRNA translation and causing cell morphology and lysis defects. Moreover, Ssd1 recruitment to the P bodies is abolished by Sit4/PP6 phosphatase deletion, suggesting that Sit4/PP6 is an NDR-opposing phosphatase. Finally, preliminary data suggest that human hnRNP A1 and A2/B1 serve as functional Ssd1 orthologues. Based on these data, we hypothesize that NDR kinases play a universal role in promoting cell polarity by enhancing mRNA-RNP interactions with mRNA transport proteins and concurrently inhibiting mRNA-RNP recruitment to translational repressing P bodies/stress granules. Because mRNA polarity and localized translation are critical for cell polarity, development and cell motility these data may help explain how NDR mutations give rise to morphogenesis defects in neurons and other cells. Moreover, the regulatory mechanisms for modulating active transport of mRNA-RNP complexes during polarized growth and in response to stress are unknown. The main objective of this proposal is to reveal how NDR kinases and a counteracting phosphatase pathway control cell growth and development via RNP regulation. In Aim 1 we determine how Cbk1 promotes Ssd1- mediated asymmetric mRNA localization, in Aim 2 we will determine how Sit4 phosphatase regulates Ssd1 recruitment to P bodies and in Aim 3 we test the hypothesis that NDR kinases regulate cell polarity via hnRNP A1 and A2/B1. It is expected that these studies will provide mechanistic insight into how NDR and counteracting pathways regulate hnRNP-dependent mRNA localization. As such, these studies may reveal a key mechanism for NDR kinases in cell polarity, neuronal morphogenesis and tumor suppressor activity.

描述(申请人提供)：NDR激酶是一种肿瘤抑制因子，与多种癌症有关，包括软组织肉瘤、B细胞和T细胞淋巴瘤、胰腺癌、前列腺癌和卵巢癌。NDR突变导致细胞生长和包括神经元在内的各种细胞的极化形态发生缺陷。尽管NDR激酶很重要，但它们影响细胞形态发生和肿瘤生长的机制尚不清楚，从而限制了NDR介导的癌症诊断和治疗的发展。我们最近的数据支持酿酒酵母NDR1/2同源基因Cbk1在调节mRNA极性和翻译方面的新作用，这些过程在细胞极性、不对称细胞 分裂、发育和形态发生。具体地说，我们已经证明Cbk1磷酸化核糖核蛋白(RNP)Ssd1，并促进Ssd1-mRNA复合体的子集的极性定位，这表明NDR激酶通过引导mRNA-RNP复合体到局部蛋白质表达的位置来促进细胞极性。相反，Cbk1抑制或细胞应激将Ssd1-mRNA复合体重定向到P小体和应激颗粒，从而抑制mRNA翻译，导致细胞形态和裂解缺陷。此外，Sit4/PP6磷酸酶缺失后，Ssd1向P小体的募集被取消，表明Sit4/PP6是一种与NDR相反的磷酸酶。最后，初步数据表明，人类hnRNP A1和A2/B1是功能上的SSD1同源物。基于这些数据，我们推测，NDR激酶通过增强mRNA-RNP与mRNA转运蛋白的相互作用，同时抑制mRNA-RNP募集到翻译抑制P体/应激颗粒，在促进细胞极性方面起着普遍的作用。由于mRNA的极性和定位翻译对细胞的极性、发育和细胞运动至关重要，这些数据可能有助于解释NDR突变是如何导致神经元和其他细胞的形态发生缺陷的。此外，调节mRNA-RNP复合体在极化生长和对胁迫的反应中主动运输的调节机制尚不清楚。这个建议的主要目的是揭示NDR激酶和一个拮抗磷酸酶途径是如何通过RNP调节来控制细胞的生长和发育的。在目标1中，我们将确定Cbk1如何促进Ssd1介导的不对称mRNA定位；在目标2中，我们将确定Sit4磷酸酶如何调节Ssd1向P小体的募集；在目标3中，我们将检验NDR激酶通过hnRNP A1和A2/B1调节细胞极性的假设。预计这些研究将为NDR和抵消途径如何调控hnRNP依赖的mRNA本地化提供机械性的见解。因此，这些研究可能揭示NDR激酶在细胞极性、神经元形态发生和肿瘤抑制活性方面的关键机制。