Roles of Vav Domains in Integrin Signaling

Vav 结构域在整合素信号转导中的作用

• 批准号: 6636671
• 负责人: JULIE L WILSBACHER
• 金额: $ 4.81万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-01 至 2004-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6636671
• 关键词: CHO cells; actins; biological signal transduction; cytoskeleton; gene targeting; guanine nucleotide exchange factors; integrins; laboratory mouse; mitogen activated protein kinase; phosphorylation; polymerase chain reaction; posttranslational modifications; protein binding; protein protein interaction; protein structure function

DESCRIPTION (provided by applicant) Many cellular functions are regulated by integrins, which transduce signals from the extracellular environment to the interior of the cell. The manner by which integrin activation is coupled to phenotypic effects is not fully understood. Our laboratory has identified an integrin-induced pathway in hematopoietic cells which leads to activation of Vav, a guanine nucleotide exchange factor (GEF). Vav activates the smGTPase Rac, which induces lamellipodia formation and cell spreading and strongly enhances activation of many downstream signaling proteins like ERK and the P1-3 kinase target Akt. Vav is composed of multiple structural domains that mediate its GEF function and its binding interactions with many cellular proteins. Thus, Vav is able to both activate Rac and recruit signaling proteins to receptor complexes. Vav serves as a prototype to understand how a single protein can coordinate signals to proteins that regulate changes in the actin cytoskeleton and activate important intracellular signaling pathways. The purpose of this proposal is to determine which domains are required for linking Vav to integrins and its upstream kinase, Syk and which are required for activation of different downstream effectors. I propose to initially characterize mutants of Vav for the ability to transduce signals from integrins in a Chinese hamster ovary (CHO) cell model system. This model system will be used to identify the requirements for interaction of Vav with Syk, activation of Rac, MAP kinases, and Akt, phosphorylation of Cbl, and stimulation of cytoskeletal rearrangement. Wild type and mutant Vav proteins will also be tested for the ability to rescue defects in cell morphology, adhesion, migration, and phagocytosis in macrophages from Vav knockout mice. Studying the role of different Vav domains in signaling from integrin receptors will allow us to investigate how Vav is able to integrate signals from receptors to the actin cytoskeleton as well as many key cellular signaling pathways.

描述（由申请人提供）许多细胞功能受整合素的调节，整联蛋白会将信号从细胞外环境转移到细胞内部。整联蛋白激活与表型效应耦合的方式尚不完全了解。我们的实验室已经确定了造血细胞中整联蛋白诱导的途径，从而导致VAV激活，鸟嘌呤核苷酸交换因子（GEF）。 VAV激活了SMGTPase RAC，该RAC诱导了层状脂蛋白膜片和细胞扩散，并强烈增强了许多下游信号蛋白（例如ERK和P1-3激酶靶AKT）的激活。 VAV由介导其GEF功能及其与许多细胞蛋白的结合相互作用的多个结构结构域组成。因此，VAV能够激活RAC和募集信号蛋白向受体复合物。 VAV是一个原型，以了解单个蛋白如何将信号与调节肌动蛋白细胞骨架变化并激活重要的细胞内信号通路的蛋白质进行协调。该提案的目的是确定将VAV与整合素及其上游激酶SYK链接所需的域以及激活不同下游效应子所必需的。我建议最初表征VAV的突变体，以便能够从中国仓鼠卵巢（CHO）细胞模型系统中从整联蛋白传递信号。该模型系统将用于确定VAV与SYK相互作用的要求，RAC激活，MAP激酶和AKT，CBL的磷酸化以及细胞骨架重排的刺激。还将测试野生型和突变体VAV蛋白，以挽救来自VAV敲除小鼠的巨噬细胞中细胞形态，粘附，迁移和吞噬作用的能力。研究不同VAV结构域在整联蛋白受体信号传导中的作用将使我们能够研究VAV如何能够将信号从受体整合到肌动蛋白细胞骨架以及许多关键的细胞信号传导途径。