Decoding dynamic interplay between signaling and membranes in chemotaxis by molecular actuators

趋化性发生在许多关键的生理事件中，包括血管生成、胚胎发育、细胞增殖和细胞凋亡。 发育和伤口愈合。它还有助于病理条件下的疾病进展， 癌症转移和关节炎。目前的建议的目标是揭示如何生化反应和 物理特性，如膜的曲率，变形和组装阶段，相互作用， 另一个是实现动态、准确但高效的细胞迁移。趋化性已经被理解为 主要是从信号转导的角度，而膜的物理性质是否以及如何发挥作用， 以及它们如何与信号转导相互作用仍然是未知的。通过新开发和实施 一系列分子执行器，可以直接探测膜特性，具有高时空精度 在活跃的迁移细胞内，我们将揭示信号转导和膜力学之间的相互作用。 是什么分子机制产生了局部膜弯曲发展成丝状伪足， 片状伪足？在感受化学引诱物时，细胞通过经历不对称的膜变形来吸引 由前部的丝状伪足和片状伪足组成，后部的膜收缩。我们最近发现， 曲率敏感蛋白是肌动蛋白细胞骨架和膜之间缺失的一环。结果让我们 假设肌动蛋白机械和曲率传感和重塑蛋白，当在一个适当的调节， 反馈回路，足以产生所需类型的膜变形，例如板状伪足和 丝状伪足因此，我们将鉴定Rho GTP酶、肌动蛋白调节剂和BAR蛋白的特定组合， 其分子逻辑，负责丝状伪足和片状伪足的形成。 迁移细胞中的信号成分如何响应膜变形？迁移细胞 在质膜和核膜上表现出动态的形态学变化，“作为" 由信号成分调控的细胞骨架重排。为了探索膜变形 回到细胞骨架和信号成分，我们将部署分子执行器，可以直接变形 膜。然后，我们将量化随后出现的信号成分，如受体 酪氨酸激酶、PI 3 K和小GTP酶，以及转录因子如雅普和Elk。 相分离的细胞骨架生物分子凝聚物在膜中是如何发挥作用的 变形？肌动蛋白网络可以在质膜上形成生物分子凝聚物， 到肌动蛋白调节器之间的弱多价相互作用。为了检验这个阶段的生理重要性， 分离事件，我们将采用分子技术来组装或拆卸冷凝物。这些 操作将独特地实现函数操作的获得或丢失，而无需改变函数的量。 分子组成;改变的是它们的物理组装状态。我们将描述细胞迁移 在部署相位操作之前和之后的表型。

Chemotaxis occurs during a number of key physiological events including angiogenesis, embryonic development and wound healing. It also contributes to disease progression in pathological conditions such as cancer metastasis and arthritis. The goal of the current proposal is to reveal how biochemical reactions and physical characteristics, such as membrane curvature, deformation, and assembly phase, interact with one another in achieving dynamic, accurate yet highly efficient cell migration. Chemotaxis has been understood mainly in the perspective of signal transduction, while if and how physical properties of membranes play a role, and how they interact with signal transduction remain largely unknown. By newly developing and implementing a series of molecular actuators that can directly probe membrane properties with high spatio-temporal precision inside lively migrating cells, we will reveal an interplay between signal transduction and membrane mechanics. What molecular mechanisms generate local membrane curvatures developing into filopodia and lamellipodia? In sensing chemoattractants, cells polarize by undergoing asymmetric membrane deformation consisting of filopodia and lamellipodia at the front, and membrane retraction at the rear. We recently found that curvature-sensitive proteins are a missing link between actin cytoskeleton and membranes. The result made us hypothesize that actin machinery and curvature sensing and remodeling proteins, when properly modulated in a feedback loop, are sufficient to produce desired types of membrane deformations such as lamellipodia and filopodia. We will thus identify a particular combination of Rho GTPases, actin regulators, and BAR proteins, and the molecular logic thereof, that are responsible for formation of filopodia and lamellipodia. How do signaling components in migrating cells respond to membrane deformation? Migrating cells exhibit dynamic morphological changes at plasma membranes and nuclear envelopes “as a consequence” of cytoskeletal rearrangement regulated by signal components. To explore a possibility that membrane deformation talks back to cytoskeletal and signal components, we will deploy molecular actuators that can directly deform membranes. We will then quantify subsequently emerging activity of signaling components such as receptor tyrosine kinases, PI3K, and small GTPases, as well as transcription factors such as YAP and Elk. How does the phase-separated cytoskeletal biomolecular condensate play a role in membrane deformation? Actin networks can undergo formation of biomolecular condensates at the plasma membrane due to weak multivalent interactions among actin regulators. To examine the physiological importance of such phase separation events, we will adapt molecular techniques to assemble or disassemble the condensates. These operations will uniquely achieve gain- or loss-of function manipulations without altering an amount of the molecular constituents; what is altered is their physical assembly status. We will characterize cell migration phenotypes before and after deploying phase manipulations.