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。

基本信息

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
项目类别：
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

项目摘要

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.

项目概要： KRAS 小 GTP 酶激活丝裂原激活蛋白激酶 (MAPK) 并参与细胞增殖。 KRAS 是癌症中突变最多的蛋白质之一，其突变存在于 98% 的胰腺肿瘤、45% 的胰腺肿瘤中结直肠肿瘤和肺肿瘤的 31%。尽管经过数十年的密切关注，我们仍然没有任何有效的方法抑制 KRAS 肿瘤发生的方法。 KRAS 功能主要分布在细胞质中膜 (PM)，其中 KRAS 与一组选定的脂质相互作用，形成效应器的信号纳米簇募集和信号转导。我们最近表明 KRAS 纳米团簇特别富含混合链磷脂酰丝氨酸 (PS) 种类。因此，KRAS 纳米簇和效应子结合在混合链 PS 存在的情况下选择性地发生。因此，KRAS功能取决于PS酰基链结构。我们在这里建议使用溶血磷脂酰胆碱酰基转移酶调节 PS 酰基链（LPCAT）。特别是，我们现在表明增加 LPCAT1 水平会减少主要的混合链 PS 物种人胰腺肿瘤细胞，并破坏 PM 上 KRAS 的纳米簇。这进一步得到了支持癌症患者数据显示，KRAS 依赖性胰腺癌或肺癌患者的水平较低 LPCAT1 的。另一个 LPCAT 成员 LPCAT4 可以提高混合链脂质，并已被证明可以促进 KRAS 患者的肿瘤发生。我们假设，通过改变混合链 PS 的比例 LPCAT1 和 LPCAT4 调节 KRAS 纳米簇和功能。我们的测试成功假设可能为 KRAS 依赖性患者扰乱 KRAS 病理学提供替代策略肿瘤。我们的假设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，其丰度受 LPCAT1/4 调节。为了检验我们的假设，我们提出 3 个具体目标。在目标 1 中，我们将检查 LPCAT1/4 改变的脂质组学之间的相关性全细胞、PM 和内膜，LPCAT1/4 对 PM 特性的影响对 KRAS 功能至关重要。在目标2，我们将研究LPCAT1/4调节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 LPCAT1/4 如何发挥作用的分子机制在一组哺乳动物和人类肿瘤系以及体内秀丽隐杆线虫中调节 KRAS 功能线虫（已建立的用于研究 KRAS 肿瘤发生的模型系统）。在此，我们建议严格审查新机制，通过 LPCAT 重塑 PS 酰基链谱来调节 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。从生物学上来说，虽然脂质酰基链有助于各种重要的脂质双层特性，但细胞中的酰基链通常含有数以千计的脂质种类，但尚未得到充分了解。我们的所提出的机制将有助于我们了解脂质酰基链的潜在生物学作用。