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: 6520519
• 负责人: JULIE L WILSBACHER
• 金额: $ 4.42万
• 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
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6520519
• 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） 许多细胞功能由整联蛋白调节，整联蛋白将信号从细胞外环境转导至细胞内部。整合素激活与表型效应耦合的方式尚不完全清楚。我们的实验室已经确定了造血细胞中整合素诱导的途径，该途径会导致 Vav（一种鸟嘌呤核苷酸交换因子 (GEF)）的激活。 Vav 激活 smGTPase Rac，诱导片状伪足形成和细胞扩散，并强烈增强许多下游信号蛋白（如 ERK 和 P1-3 激酶靶标 Akt）的激活。 Vav 由多个结构域组成，介导其 GEF 功能及其与许多细胞蛋白的结合相互作用。因此，Vav 能够激活 Rac 并招募信号蛋白至受体复合物。 Vav 作为原型来了解单个蛋白质如何协调信号到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。该提案的目的是确定哪些结构域是将 Vav 与整合素及其上游激酶 Syk 连接所需的，以及哪些结构域是激活不同下游效应器所需的。我建议初步表征 Vav 突变体在中国仓鼠卵巢 (CHO) 细胞模型系统中转导整合素信号的能力。该模型系统将用于确定 Vav 与 Syk 相互作用、Rac、MAP 激酶和 Akt 激活、Cbl 磷酸化以及刺激细胞骨架重排的要求。还将测试野生型和突变型 Vav 蛋白修复 Vav 敲除小鼠巨噬细胞形态、粘附、迁移和吞噬作用缺陷的能力。研究不同 Vav 结构域在整合素受体信号传导中的作用将使我们能够研究 Vav 如何能够将受体信号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。