Agonist Activated Phosphoinositide Kinase Scaffolds Control Motility and Survival Signals

激动剂激活的磷酸肌醇激酶支架控制运动和生存信号

• 批准号: 9310697
• 负责人: Richard A. Anderson
• 金额: $ 41.35万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-05-01 至 2021-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9310697
• 关键词: 1-Phosphatidylinositol 3-Kinase; 1-Phosphatidylinositol 4-Kinase; 3-Phosphoinositide Dependent Protein Kinase-1; Agonist; Binding; Binding Sites; Biological; Biological Process; Biology; Cancer cell line; Cardiovascular system; Cell Proliferation; Cell Survival; Cell membrane; Cells; Cellular Metabolic Process; Complex; Disease; EGF gene; Endosomes; Enzymes; Epidermal Growth Factor Receptor; G-Protein-Coupled Receptors; Gap Junctions; Generations; Growth; Growth Factor Receptors; Immune system; In Vitro; Integrins; Knock-out; Link; Lipids; MMP14 gene; Malignant Neoplasms; Maps; Membrane; Molecular; Monomeric GTP-Binding Proteins; Neurons; Normal tissue morphology; Oncogenic; Oncoproteins; PI3 gene; Pathway interactions; Peptides; Permeability; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Phosphorylation; Phosphotransferases; Process; Production; Proliferating; Protein Isoforms; Protein Kinase; Receptor Protein-Tyrosine Kinases; Receptor Signaling; Regulation; Role; SERPINA4 gene; Second Messenger Systems; Signal Pathway; Signal Transduction; Site; Specificity; Tumor Suppression; Tumor Suppressor Proteins; Tyrosine Phosphorylation; anticancer treatment; cancer cell; cancer survival; cell motility; inhibitor/antagonist; killings; migration; mutant; new therapeutic target; novel; novel therapeutics; receptor; reconstitution; scaffold; targeted cancer therapy; therapeutic target; trafficking; tumor

PI3K/Akt signaling is fundamental in the immune system, cardiovascular and neuronal diseases, and cancers. It is the most commonly deregulated signaling pathway in cancers and is therapeutically targeted. We show that the multi-domain scaffolding oncoprotein, IQGAP1 provides a novel molecular platform for assembly of PI4P-, PI4,5P2- and PI3,4,5P3-generating enzymes (PI4KIIIα, PIPKIα and PI3K). This close proximity allows for concerted and efficient generation of the PI3,4,5P3 lipid messenger that activates the also associated PDK1/Akt kinases. Multiple agonists including integrins, receptor tyrosine kinases and G-protein coupled receptors stimulate this scaffold. Importantly, this scaffold appears crucial for cancer cell survival, uncovering a phosphoinositide signaling nexus utilized by cancer cells for their survival. IQGAP1 associates with PI3K and PIPKIα via its WW and IQ sub-domains. Disrupting this IQGAP1 scaffold abrogates PI3,4,5P3 generation and Akt activation and selectively blocks survival of cancer cells. This indicates that concerted PI3,4,5P3 synthesis with PDK1 and Akt activation in cancer cells via the IQGAP1 scaffold opens the door for novel therapeutic strategy targeting PI3K/Akt signaling in cancers. Further, IQGAP2 has tumor suppressor activity and also binds the PIPn kinases blocks Akt activation within the same pathways. Hypothesis: Upon agonist stimulation, IQGAP1 scaffolds phosphoinositide kinases for concerted production of the PI3,4,5P3 lipid messenger, leading to self-contained PI3K/Akt signaling platform. Selective integration of PIPKI isoforms (e.g. PIPKIα vs. PIPKIγ) into IQGAP1 scaffolds and their regulation of PI4,5P2 and/or PI3,4,5P3 generation and downstream activation controls distinct processes including cell proliferation, survival, invasion and motility. IQGAP2 binding to the PIPn kinases blocks the tumor promoting activity of the PIPn kinases. This hypothesis will be interrogated with the following aims: Aim 1. How does EGF-stimulation specifically assemble the IQGAP1-PI3K scaffold? (a) Role of tyrosine phosphorylation, (b) define interaction sites, substrate channeling, and identify mutants that lose binding and study integration of oncogenic PI3K mutants, and (c) examine if these require EGFR signaling. Aim 2. Study how EGFR and small G-proteins regulate IQGAP1-PIPn kinase scaffolds during migration and invasion. Roles of: (a) the IQGAP1-PI3K scaffold in cell motility, (b) the IQGAP1-PIPKIγ scaffold in trafficking of EGFR and integrins in EGF-stimulated migration and invasion, (c) IQGAP1 in Arf6 and Rac1 in control of invasion and (d) study the role of PIPn binding to IQGAP1 in spatial targeting, survival, and invasion. Aim 3. Investigate the IQGAP2-phosphoinositide kinase scaffold as a tumor suppressor. (a) Study interactions of phosphoinositide kinases with IQGAP2 and peptide inhibitors will be developed, (b) define the mechanism how IQGAP2 blocks Akt activation, (c) manipulate expression of IQGAP2 to examine roles in the PI3K signaling and biology.

PI 3 K/Akt信号传导是免疫系统、心血管和神经元疾病以及癌症的基础。 它是癌症中最常见的失调信号通路，并且是治疗靶向的。我们表明 多结构域支架癌蛋白IQGAP 1提供了一个新的分子平台， 产生PI 4P、PI 4，5 P2和PI 3，4，5 P3的酶（PI 4KIII α、PIPKIα和PI 3 K）。这种接近使得 用于协调和有效地产生PI 3，4，5 P3脂质信使，其激活还相关的 PDK 1/Akt激酶。多种激动剂，包括整联蛋白、受体酪氨酸激酶和G蛋白偶联 受体刺激这个支架。重要的是，这种支架似乎对癌细胞的存活至关重要，揭示了癌细胞的生长机制。 磷酸肌醇信号传导被癌细胞用于其存活。IQGAP 1与PI 3 K相关， PIPKIα通过其WW和IQ子域。破坏这种IQGAP 1支架消除了PI 3，4，5 P3的产生， 激活Akt并选择性地阻断癌细胞的存活。这表明协同的PI 3，4，5 P3合成 通过IQGAP 1支架在癌细胞中激活PDK 1和Akt，为新的治疗方法打开了大门。 靶向PI 3 K/Akt信号转导的癌症策略。此外，IQGAP 2具有肿瘤抑制活性，并且还结合 PIPn激酶阻断相同途径内的Akt活化。 假设：在激动剂刺激后，IQGAP 1支架磷酸肌醇激酶协同产生 PI 3，4，5 P3脂质信使，导致独立的PI 3 K/Akt信号平台。选择性整合 PIPKI同种型（例如PIPKIα与PIPKIγ）进入IQGAP 1支架及其对PI 4，5 P2和/或PI 3，4，5 P3的调节 生成和下游激活控制不同的过程，包括细胞增殖、存活、侵袭 和运动性。IQGAP 2与PIPn激酶的结合阻断了PIPn激酶的肿瘤促进活性。这 将对假设进行调查，目的如下： 目标1. EGF刺激如何特异性组装IQGAP 1-PI 3 K支架？(a)酪氨酸的作用 磷酸化，（B）定义相互作用位点，底物通道，并鉴定失去结合的突变体， 研究致癌PI 3 K突变体的整合，和（c）检查这些突变体是否需要EGFR信号传导。 目标二。研究EGFR和小G蛋白在迁移过程中如何调节IQGAP 1-PIPn激酶支架 和入侵。以下的作用：（a）IQGAP 1-PI 3 K支架在细胞运动性中的作用，（B）IQGAP 1-PIPKIγ支架在细胞运动性中的作用。 EGFR和整合素在EGF刺激的迁移和侵袭中的运输，（c）Arf 6中的IQGAP 1和Rac 1在EGFR刺激的迁移和侵袭中的表达。 控制侵袭和（d）研究PIPn与IQGAP 1结合在空间靶向、存活和侵袭中的作用。 目标3。研究IQGAP 2-磷酸肌醇激酶支架作为肿瘤抑制剂。(a)研究 将开发磷酸肌醇激酶与IQGAP 2和肽抑制剂的相互作用，（B）定义 IQGAP 2如何阻断Akt激活的机制，（c）操纵IQGAP 2的表达以检查IQGAP 2在Akt激活中的作用。 PI 3 K信号传导和生物学。