PI3 kinase PIK3CB (p110beta) in membrane trafficking and metabolism

膜运输和代谢中的 PI3 激酶 PIK3CB (p110beta)

• 批准号: 10001471
• 负责人: Wei-Xing Zong
• 金额: $ 35.46万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10001471
• 关键词: 1-Phosphatidylinositol 3-Kinase; Ablation; Abnormal Cell; Address; Alleles; Autophagocytosis; Binding; Biochemical; Bioenergetics; Biological; Cancer Model; Cell Line; Cell Lineage; Cell surface; Cells; Cellular Metabolic Process; Clinical Data; Cultured Cells; Data; Defect; Development; Embryo; Endocytosis; Event; FRAP1 gene; Failure; G-Protein-Coupled Receptors; GTP Binding; GTPase-Activating Proteins; Genetic; Glucose; Growth; Growth Factor; Guanosine Triphosphate; Hematologic Neoplasms; Hematopoietic; Homeostasis; Human; Hydrolysis; Intracellular Membranes; Lead; Lymphocyte; MCF10A cells; Malignant Neoplasms; Mammary gland; Mediating; Membrane; Metabolic; Metabolic Diseases; Metabolism; Molecular; Monomeric GTP-Binding Proteins; Mus; Mutation; Nutrient; Oncogenes; Oncogenic; PIK3CA gene; PIK3CB gene; Pathologic; Pathway interactions; Phosphotransferases; Physiological; Process; Protein Isoforms; Protein Tyrosine Kinase; Proteome; Receptor Signaling; Reporting; Role; SLC2A1 gene; Signal Pathway; Signal Transduction; Signaling Molecule; Surface; Testing; Tumor Suppressor Proteins; animal data; cell growth; deprivation; design; glucose uptake; human disease; in vivo; in vivo Model; mutant; novel; phosphatidylinositol 3,4,5-triphosphate; phosphatidylinositol phosphate, PtdIns(4,5)P2; phosphoinositide-3,4,5-triphosphate; prevent; public health relevance; receptor; response; scaffold; small hairpin RNA; trafficking; tumorigenesis

PROJECT SUMMARY: The Class IA phosphatidylinositol 3-kinases (PI3Ks) p110a and p110b isoforms are ubiquitously expressed and respond to membrane receptor signals. They PI(3,4,5)P3, which acts as a signaling molecule to activate downstream signaling pathways including the Akt/mTOR pathway. Despite their similarities, two isoforms have distinct biochemical and biological features, one of which is that p110b has a kinase-independent function. We have reported that p110b positively regulates the small GTPase Rab5 in a manner that is independent of its catalytic activity. p110b, through a direct binding and as a molecular scaffold, keeps Rab5 in its “active” GTP- bound form by preventing Rab5 from interacting with its GTPase-activating protein (GAP), which inactivates Rab5 by hydrolyzing its GTP to GDP. Rab5 is well known for regulating endocytosis. Our preliminary data strongly indicate that p110b can regulate endocytic turnover of cell surface nutrient transporters such as glucose transporter 1 (GLUT1) in response to growth factor deprivation. We found that genetic ablation or shRNA silencing of p110b decreased the level of Rab5-GTP. This resulted in increased cell surface GLUT1 that led to increased glucose utilization of cell lines and promoted their oncogenic transformation. These findings lead us to propose the hypothesis that p110b, as a molecular scaffold, activates Rab5 and endocytic turnover of nutrient transporters. We further propose that this novel function of p110b regulates membrane trafficking and cell metabolism and homeostasis. We have designed two Specific Aims to test this hypothesis and establish its biological relevance. Aim 1: Test the hypothesis that p110b facilitates Rab5-mediated endocytic turnover of nutrient transporters. We will use FL5.12, MEFs, HK-2, and MCF10A cells to determine that p110b deficiency can lead to the stabilization of nutrient transporters, and to determine if the failure of endocytic turnover is the result of Rab5 inactivation. Aim 2. Determine the molecular and cell biological consequence of the stabilized nutrient transporters in p110b-deficient cells (with a focus on GLUT1). We will characterize the metabolic features associated with the nutrient transporter stabilization, and characterize the growth/proliferation signaling in p110b-deficient cells. We will also determine the physiological effects of the p110b-Rab5 interaction in vivo. !

项目概要： IA 类磷脂酰肌醇 3-激酶 (PI3K) p110a 和 p110b 亚型普遍表达 并对膜受体信号做出反应。它们是 PI(3,4,5)P3，作为信号分子激活 下游信号通路包括 Akt/mTOR 通路。尽管有相似之处，但两种异构体 独特的生化和生物学特征，其中之一是 p110b 具有激酶独立功能。我们 据报道，p110b 以独立于其自身的方式正向调节小 GTPase Rab5 催化活性。 p110b 通过直接结合并作为分子支架，使 Rab5 保持其“活性”GTP- 通过阻止 Rab5 与其 GTP 酶激活蛋白 (GAP) 相互作用而形成结合形式，从而使 Rab5 失活 Rab5 通过将其 GTP 水解为 GDP。 Rab5 因调节内吞作用而闻名。我们的初步数据 强烈表明 p110b 可以调节细胞表面营养转运蛋白的内吞周转，例如 葡萄糖转运蛋白 1 (GLUT1) 对生长因子剥夺的反应。我们发现基因消融或 p110b 的 shRNA 沉默降低了 Rab5-GTP 的水平。这导致细胞表面 GLUT1 增加 这导致细胞系的葡萄糖利用率增加并促进其致癌转化。这些 研究结果使我们提出这样的假设：p110b 作为分子支架，激活 Rab5 和内吞 营养转运体的周转。我们进一步提出 p110b 的这种新功能调节膜 运输以及细胞代谢和体内平衡。我们设计了两个具体目标来检验这个假设 并建立其生物学相关性。目标 1：检验 p110b 促进 Rab5 介导的假设 营养转运蛋白的内吞周转。我们将使用 FL5.12、MEF、HK-2 和 MCF10A 细胞来确定 p110b 缺乏可以导致营养转运蛋白的稳定，并确定是否 内吞周转是 Rab5 失活的结果。目标 2. 确定分子和细胞生物学 p110b 缺陷细胞中营养转运蛋白稳定的结果（重点关注 GLUT1）。我们将 表征与营养转运蛋白稳定性相关的代谢特征，并表征 p110b 缺陷细胞中的生长/增殖信号。我们还将确定其生理效应 p110b-Rab5 体内相互作用。 ！