Deciphering the mechanism of SHIP1 regulation in human neutrophils

研究摘要声明 免疫细胞解释环境中的化学信号，并做出决定控制它们的命运。为 例如，人类嗜中性粒细胞通常通过极化和向化学源迁移来响应信号。 这些细胞功能的关键是细胞表面受体、小GTP酶和 合成磷脂酰肌醇磷酸（PIP）脂质的酶。这项研究旨在破译 在血浆中控制这些不同类型的信号分子之间的通信机制 膜的使用人中性粒细胞，我们发现Cdc42 GT3和一种脂质磷酸酶SHIP 1， 触发分子信号以行波的形式在质膜上传播。这 行为，创造兴奋性，涉及蛋白质募集的重复循环和关闭膜。的 本研究的目的是确定SHIP 1如何通过整合信号调节可兴奋信号网络 来源于脂质和膜系蛋白。使用各种体外生物化学技术，包括 支持膜技术和单分子成像，我们将确定脂质成分如何控制 SHIP 1膜结合和磷酸酶活性（Aim 1）。利用调节兴奋性的因素 细胞中的信号网络，我们将重建控制SHIP 1膜募集，释放 自抑制和激活（目的2）。同时，我们将使用基于CRISPR的基因组编辑，光遗传学， 和荧光生物传感器的定量活细胞成像，以阐明PIP脂质之间的通信 而小GTdR受SHIP 1调节。使用这些工具，我们将确定SHIP 1作为信令的角色 网络支架与脂质磷酸酶（Aim 3）。总的来说，这项研究将统一膜生物物理学和细胞 生物学解释PIP脂质，小GTP酶和SHIP1如何协同控制可兴奋信号传导 中性粒细胞中的网络和细胞迁移。通过揭示白色血细胞如何感知、解释和响应 我们将填补关于这些信号分子如何协调细胞的知识空白， 运动与潜在的兴奋网络。这一发现可以为研究人员开发 新的治疗方法，可以用来调节免疫细胞功能的方式，打击感染， 炎症和癌症。

Research Summary Statement Immune cells interpret chemical cues in their environment and make decisions that control their fate. For example, human neutrophils often respond to signals by polarizing and migrating toward the chemical source. Critical for these cellular functions is the dynamic interplay between cell surface receptors, small GTPases, and the enzymes that synthesize phosphatidylinositol phosphate (PIP) lipids. This study aims to decipher the mechanisms the control communication between these different classes of signaling molecules at the plasma membrane. Using human neutrophils, we find that Cdc42 GTPase and a lipid phosphatase denoted SHIP1 trigger a molecular signal that propagates across the plasma membrane in the form of a traveling wave. This behavior, coined excitability, involves repetitive cycles of protein recruitment ON and OFF the membrane. The goal of this study is to determine how SHIP1 regulates the excitable signaling network by integrating signals derived from lipids and membrane tethered proteins. Using a variety of in vitro biochemistry techniques, including supported membrane technology and single molecule imaging, we will determine how lipid composition controls SHIP1 membrane association and phosphatase activity (Aim 1). Using factors that regulate the excitable signaling network in cells, we will reconstitute mechanisms that control SHIP1 membrane recruitment, release of autoinhibition, and activation (Aim 2). In parallel, we will use CRISPR based genome editing, optogenetics, and quantitative live cell imaging of fluorescent biosensors to elucidate how communication between PIP lipids and small GTPase is regulated by SHIP1. Using these tools we will determine the role SHIP1 serves as signaling network scaffold versus a lipid phosphatase (Aim 3). Overall, this study will unify membrane biophysics and cell biology to explain how PIP lipids, small GTPases, and SHIP1 synergistically control the excitable signaling network and cell migration in neutrophils. By unraveling how white blood cells sense, interpret, and respond to pathogenic signals we will fill a gap in knowledge concerning how these signaling molecules coordinate cellular movement with the underlying excitable network. This discovery could open doors for researchers to develop new therapeutics that can be used to modulate immune cell functions in ways that combat infection, inflammation, and cancer.