Phosphatidylserine acyl chain remodeling regulates KRAS spatial distribution and function on the plasma membrane.

磷脂酰丝氨酸酰基链重塑调节 KRAS 在质膜上的空间分布和功能。

• 批准号: 10596102
• 负责人: Yong Zhou
• 金额: $ 32.76万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10596102
• 关键词: Acute; Acyl Coenzyme A; Acyltransferase; Back; Binding; Biological; Biological Models; Caenorhabditis elegans; Cancer Biology; Cancer Patient; Cell Proliferation; Cell Proliferation Regulation; Cell membrane; Cell physiology; Cells; Colorectal Neoplasms; Data; Diameter; Drug Targeting; Human; Impairment; KRAS oncogenesis; KRAS2 gene; Lecithin; Lipid Bilayers; Lipids; Lung Neoplasms; Lysophosphatidylcholines; Malignant Neoplasms; Malignant neoplasm of lung; Malignant neoplasm of pancreas; Membrane; Membrane Microdomains; Mitogen-Activated Protein Kinases; Modeling; Molecular; Molecular Conformation; Monomeric GTP-Binding Proteins; Mutate; Mutation; Normal Cell; Pancreas; Pathology; Patients; Phase; Phosphatidylserines; Plasma Cells; Probability; Proliferating; Property; Protein Isoforms; Proteins; RAS genes; Role; Sampling; Signal Transduction; Site; Solid; Sorting; Spatial Distribution; Specificity; Structure; Testing; Transmembrane Transport; Xenograft Model; cohort; improved; in vivo; lipidome; lipidomics; member; nanocluster; neoplastic cell; novel; overexpression; pancreatic cancer cells; pancreatic neoplasm; recruit; segregation; spatiotemporal; tumor

Project Summary: KRAS small GTPase activates mitogen-activated protein kinases (MAPKs) and participates in cell proliferation. KRAS is one of the most mutated proteins in cancer, with its mutations found in 98% of pancreatic tumors, 45% of colorectal tumors and 31% of lung tumors. Despite decades of intense focus, we still do not have any effective means of inhibiting KRAS oncogenesis. KRAS function is mostly compartmentalized to the cell plasma membrane (PM), where KRAS interacts with a select set of lipids to form signaling nanoclusters for effector recruitment and signal transduction. We recently showed that KRAS nanoclusters are specifically enriched with the mixed-chain phosphatidylserine (PS) species. In consequence, KRAS nanoclustering and effector binding occur selectively in the presence of the mixed-chain PS. Thus, KRAS function depends on PS acyl chain structures. We, here, propose to modulate PS acyl chains using lysophosphatidylcholine acyltransferases (LPCATs). In particular, we now show that increasing LPCAT1 levels reduces major mixed-chain PS species in human pancreatic tumor cells, and disrupts the nanoclustering of KRAS on the PM. This is further supported by cancer patient data showing that patients with KRAS-dependent pancreatic or lung cancer contain lower levels of LPCAT1. Another LPCAT member, LPCAT4, elevates the mixed-chain lipids and has been shown to promote KRAS oncogenesis in patients. We hypothesize that, by shifting the proportions of the mixed-chain PS species, LPCAT1 and LPCAT4 modulate KRAS nanoclustering and function. A successful testing of our hypothesis may provide an alternative strategy for perturbing KRAS pathology for patients with KRAS-dependent tumors. Our hypothesis is based on a well-established premise: KRAS nanoclustering and function selectiveluy depend on the mixed-chain PS species, whose abundance is modulated by LPCAT1/4. To test our hypothesis, we propose 3 Specific Aims. In Aim 1, we will examine a correlation between LPCAT1/4-altered lipidomics in whole-cell, the PM and endomembrane with effects of LPCAT1/4 on PM properties critical to KRAS function. In Aim 2, we will examine a molecular mechanism, by which LPCAT1/4 regulate spatial distribution of KRAS, potentially via remodeling PS acyl chains. In Aim 3, we will examine a molecular mechanism for how LPCAT1/4 modulate KRAS function in a cohort of mammalian and human tumor lines, as well as in vivo Caenorhabditis elegans (established model system for studying KRAS oncogenesis). Here, we propose to rigorously examine a novel mechanism, whereby remodeling PS acyl chain profiles by LPCATs modulates KRAS spatiotemporal organization, signaling and function. We aim to test LPCATs as novel regulators of KRAS oncogenesis. Biologically, although lipid acyl chains contribute to various important lipid bilayer properties, the importance of acyl chains in cells, which typically contain thousands of lipid species, has not been well-understood. Our proposed mechanism will contribute to our understanding of the potential biological roles of lipid acyl chain.

项目摘要： KRAS小GT激酶激活丝裂原活化蛋白激酶（MAPK）并参与细胞增殖。 KRAS是癌症中突变最多的蛋白质之一，其突变在98%的胰腺肿瘤中发现，45%的胰腺肿瘤中发现。 结直肠肿瘤和31%的肺肿瘤。尽管经过几十年的密切关注，我们仍然没有任何有效的 抑制KRAS肿瘤发生的手段。KRAS功能主要分布在细胞浆中 膜（PM），其中KRAS与选择的一组脂质相互作用以形成用于效应子的信号传导纳米簇。 募集和信号转导。我们最近发现KRAS纳米团簇特别富含 混合链磷脂酰丝氨酸（PS）种类。因此，KRAS纳米簇和效应物结合 在混合链PS的存在下选择性地发生。因此，KRAS功能取决于PS酰基链 结构.在此，我们建议使用溶血磷脂酰胆碱酰基转移酶来调节PS酰基链 （LPCAT）。特别是，我们现在表明，增加LPCAT 1水平减少了主要的混合链PS物种， 人胰腺肿瘤细胞，并破坏PM上KRAS的纳米簇。进一步支持了这一点 癌症患者数据显示，KRAS依赖性胰腺癌或肺癌患者的KRAS水平较低， LPCAT 1。LPCAT的另一个成员LPCAT 4升高混合链脂质，并已被证明促进 患者中的KRAS肿瘤发生。我们假设，通过改变混合链PS的比例， LPCAT 1和LPCAT 4调节KRAS纳米簇和功能。成功测试我们的 这一假设可能为KRAS依赖性KRAS患者提供了干扰KRAS病理学的替代策略， 肿瘤的我们的假设是基于一个既定的前提：KRAS纳米簇和功能选择性 取决于混合链PS物种，其丰度由LPCAT 1/4调节。为了检验我们的假设， 我们提出三个具体目标。在目标1中，我们将研究LPCAT 1/4改变的脂质组学与 全细胞、PM和内膜，LPCAT 1/4对KRAS功能关键的PM性质的影响。在 目的2：探讨LPCAT 1/4调控KRAS空间分布的分子机制， 可能通过重塑PS酰基链。在目标3中，我们将研究LPCAT 1/4 调节哺乳动物和人肿瘤系以及体内小杆线虫中的KRAS功能 elegans（用于研究KRAS肿瘤发生的已建立模型系统）。在这里，我们建议严格审查一个 一种新的机制，通过LPCAT重塑PS酰基链分布，调节KRAS时空 组织、信号和功能。我们的目标是测试LPCAT作为KRAS肿瘤发生的新型调节剂。 在生物学上，虽然脂酰基链有助于各种重要的脂双层性质，但脂酰基链的重要性是： 通常含有数千种脂质物质的细胞中的酰基链尚未得到很好的理解。我们 提出的机制将有助于我们理解脂酰基链的潜在生物学作用。