Excitable Networks in Directed Cell Migration

我们正在研究定向细胞迁移的分子机制，这是健康和 疾病，使用Dictyosteopathy作为发现工具，为我们的中性粒细胞，巨噬细胞和 上皮细胞我们工作模型的核心是耦合的信号转导和细胞骨架 兴奋性网络，称为STEN和CEN，驱动运动。STEN集成了来自 定向传感和极性网络，以实现定向迁移。在过去的一段时间里，我们 发现突起是由耦合STEN-CEN活动的波控制的， 膜内表面上的带负电荷的脂质可以改变网络的兴奋性并控制细胞 行为STEN-CEN概念在哺乳动物细胞中是保守的，并且网络被过度激活 在转化细胞中，增强运动性和巨胞饮作用。由于这些过程需要香叶基 香叶基化，他汀类药物引起癌细胞饥饿。最后，我们发现小泡从 缩回的突起将有助于极性的组分“带回”到电池的后部。 不同的细胞突起如何取决于STEN-CEN的设定点/阈值？我们 结合成像，合成生物学和计算研究，证明伪足， 板状体、形成吞噬体等在光谱上密切相关且相互转化。我们 将显示活动的时空模式和对急性分子扰动的反应， 在这些突起上是一致的，并且平行于在传播的STEN-CEN波中建立的突起。 如何解释STEN和CEN活动的非凡协调？推测一下 膜的内部小叶是组织者，我们1）设计直接监测电荷的方法 在局部区域; 2）确定阴离子脂质如何瞬时减少; 3）局部操纵电荷 与光遗传学系统; 4）研究关键蛋白质的位置是如何由表面电荷调节的。 降低的STEN阈值是转化细胞的一般特性吗？它可以被利用吗？解决 这个问题，我们是1）比较阈值指标，如传播波，与 在一系列转移性增加的细胞系和类器官中的巨胞饮和他汀敏感性; 2） 鉴定STEN中必需的香叶基香叶基化蛋白; 3）基因工程细胞以增加 降低阈值以使癌细胞正常化或进一步降低阈值以诱导细胞死亡。 细胞两极的STEN和CEN是如何控制方向感和极性的？第一、 使用一种新的抑制试验，我们正在筛选激酶和底物缺陷的细胞，以确定全球 抑制剂的第二，我们研究了各种条件下的膜流动，以追求我们的“逆 喷泉”模型，它与其他模型，认为膜流从前面到后面。 1

We are investigating molecular mechanisms of directed cell migration, a critical process in health and disease, using Dictyostelium as a discovery tool to inform our studies of neutrophils, macrophages, and epithelial cells. At the core of our working model are coupled Signal Transduction and Cytoskeletal Excitable Networks, referred to as STEN and CEN which drive motility. The STEN integrates inputs from directional sensing and polarity networks to bring about directed migration. In the last grant period, we found that protrusions are governed by waves of coupled STEN-CEN activities and that manipulation of negatively charged lipids on the inner face of the membrane can alter network excitability and control cell behavior. The STEN-CEN concept is conserved in mammalian cells and the networks are hyperactivated in transformed cells, augmenting motility and macropinocytosis. Since these processes require geranyl geranylation, statins cause starvation of cancer cells. Finally, we found that vesicles internalized from retracting protrusions carry “back” components to the rear of the cell contributing to polarity. How do diverse cellular protrusions depend on the setpoint/threshold of STEN-CEN? We are combining imaging, synthetic biological, and computational studies to prove that pseudopods, lamellipods, forming phagosomes, and so on are closely related on a spectrum and interconvertible. We will show that spatiotemporal patterns of activities and responses to acute molecular perturbations are consistent across these protrusions and parallel those established in propagating STEN-CEN waves. What explains the extraordinary coordination of activities in STEN and CEN? Surmising that charge on the inner leaflet of the membrane is an organizer, we are 1) designing methods to directly monitor charge in local regions; 2) determining how anionic lipids transiently decrease; 3) manipulating charge locally with optogenetic systems; 4) examining how the location of key proteins is regulated by surface charge. Is lowered STEN threshold a general property of transformed cells and can it be exploited? To address this question, we are 1) comparing threshold indicators, such as propagating waves, with macropinocytosis and statin sensitivity in a series of increasingly metastatic cell lines and organoids; 2) identifying the essential geranylgeranylated proteins in STEN; 3) genetically engineering cells to increase threshold to normalize cancer cells or further decrease threshold to induce cell death. How does control of STEN and CEN at the cell poles mediate directional sensing and polarity? First, using a novel suppression assay, we are screening kinase and substrate deficient cells to identify global inhibitors. Second, we are studying membrane flow in a variety conditions to pursue our “reverse fountain” model and it reconcile with alternate models that argue membrane flows from front to back. 1