Actin regulation of CD36 receptor organization and signaling

这个项目的目标是加深我们对细胞如何调节感知和响应环境的过程的理解。这将通过研究细胞表面蛋白质（称为受体）和肌动蛋白皮质（细胞骨架的一个组成部分，附属于细胞表面，是细胞表面受体的主要调节因子）之间的相互作用来实现。该研究将以一种称为CD36的特定受体作为模型系统，因为它可能代表许多受肌动蛋白皮质影响而不直接与其结合的细胞表面受体。使用新型的综合显微镜和计算分析工具，研究人员的研究团队将（i）定量表征肌动蛋白皮质对附近细胞表面受体行为的影响，（ii）阐明这种影响的分子机制，（iii）研究这种影响如何使受体功能对细胞环境的刚度敏感，因为肌动蛋白皮质对环境刚度的敏感性。通过参与上述研究，以及通过同伴入门级暑期课程计算图像分析的本科生，该项目将培训研究生，本科生和高中学生在尖端的定量显微镜，现代生物研究越来越重要的技术。CD36是一种完整的膜蛋白，在许多细胞类型的表面上表达，并结合不同的配体。与许多受体一样，CD36信号传导需要聚集，肌动蛋白细胞骨架在其中起着重要作用。然而，仍然是一个缺乏机制和定量的理解肌动蛋白细胞骨架，特别是肌动蛋白皮质，调节组织和细胞表面受体的信号。为了填补这一空白，该项目将追求三个具体目标：（i）通过定量了解其对细胞表面CD 36组织的影响，确定肌动蛋白皮质对CD 36信号传导的影响。(ii)检验整合素和四跨膜蛋白形成细胞表面CD36和肌动蛋白皮质之间的分子连接的假设。(iii)检验肌动蛋白皮质介导微环境硬度和CD36信号传导之间串扰的假设。为此，研究人员的研究团队将采用一种新的方法，将活细胞中细胞表面受体和皮质肌动蛋白的高时空分辨率成像与它们之间关系的统计分析相结合，以及CD36的诱变和细胞暴露于不同硬度的微环境。总之，这些研究将有助于揭示肌动蛋白介导的细胞表面受体组织的机制和信号传导后果的一般原则。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

The goal of this project is to deepen our understanding of how cells regulate the process of sensing and responding to their environment. This will be achieved by investigating the interplay between cell surface proteins, called receptors, which allow cells to sense and respond to their environment, and the actin cortex, a component of the cell skeleton that is subjacent to the cell surface and that is a major regulator of cell surface receptors. The research will take one particular receptor, called CD36, as a model system, as it is likely representative of many cell surface receptors that are influenced by the actin cortex without directly binding to it. Using novel integrative microscopy and computational analysis tools, the investigator’s research team will (i) quantitatively characterize the influence of the actin cortex on nearby cell surface receptor behavior, (ii) shed light on the molecular mechanisms underlying this influence, and (iii) investigate how this influence may render receptor function sensitive to the stiffness of the cell’s environment, because of the sensitivity of the actin cortex to environmental stiffness. Through participation in the described research, as well as through a companion entry-level summer course on computational image analysis for undergraduate students, this project will train graduate, undergraduate and high school students in cutting-edge quantitative microscopy, an increasingly critical technique for modern biological research. CD36 is an integral membrane protein that is expressed on the surface of many cell types and that binds diverse ligands. As for many receptors, CD36 signaling requires clustering, for which the actin cytoskeleton plays an important role. However, there still is a lack of mechanistic and quantitative understanding of how the actin cytoskeleton, and in particular the actin cortex, regulates the organization and signaling of cell surface receptors. To fill this gap, this project will pursue three specific aims: (i) Determine the influence of the actin cortex on CD36 signaling through a quantitative understanding of its influence on cell surface CD36 organization. (ii) Test the hypothesis that integrins and tetraspanins form the molecular link between cell surface CD36 and the actin cortex. (iii) Test the hypothesis that the actin cortex mediates crosstalk between microenvironmental stiffness and CD36 signaling. For this, the investigator’s research team will employ a novel approach combining simultaneous high spatiotemporal resolution imaging of cell surface receptors and cortical actin in live cells with statistical analysis of the relationships between them, as well as mutagenesis of CD36 and exposure of cells to microenvironments of different stiffness. Altogether, these studies will help reveal general principles of the mechanisms and signaling consequences of actin-mediated cell surface receptor organization.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.