Spatial Segregation of Cell Functioning during Motility

我们的长期目标是确定细胞如何建立和维持渐进运动以重新填充组织 响应外部信号。在伤口修复中，可溶性生长因子指导成纤维细胞和内皮细胞 重新填充未成熟的基质以形成再生血管所需的支持基质和脉管系统。 组织结构最初的迁移是由伤口床内产生的刺激线索驱动的。 然而，一旦在伤口床内，细胞必须经常在没有刺激梯度的情况下分布。一 因此，核心问题是细胞如何建立渐进迁移所需的持续不对称性。 细胞迁移需要生物物理力相关过程的不对称性;在真核细胞中， 由细胞内信号控制在前部，细胞必须延伸板状伪足并形成新的粘附， 稳定主要突出，同时需要后部去粘连和回缩，以实现渐进式 运动在这两个细胞区域之间，发生收缩以使细胞体向前移动。到 为了有效地编排这些过程，细胞必须建立持久的方向性。在初始 在本研究期间，我们发现在由几乎无处不在的趋化动力学EGFR配体诱导的运动期间， PLC γ（磷脂酶-Cy）的初始活化建立了重要膜部分的不对称性， PIP 2（磷酸肌醇二磷酸）。我们的初步数据表明，导致 生物物理过程的调节至少部分地通过该膜部分和对接位点。因此，在本发明中， 我们假设，局部激活关键的生化信号级联所需的， 生产性细胞运动是由于血浆中磷酸肌醇不对称性的整合 膜的我们建议检验以下假设： /.在运动过程中后部释放所需的m-钙蛋白酶（CAPN 2）定位于可激活的血浆周围， 膜位点通过结合到PIP 2。 二. PKCS介导的收缩性，需要使细胞体和尾向前移动，定位于 PLC γ活性与磷酸肌醇周转有关。 三. PI 3激酶指定并稳定主导的，占主导地位的片足类动物，以提供方向性。 我们专注于人成纤维细胞和内皮细胞，并扩展到间充质干细胞。这些 研究将确定受体信号传导空间限制的分子基础， 反应，为组织工程设计“智能”支架以支持组织功能提供了希望。

Our long-term goal is to determine how cells establish and maintain progressive motility to repopulate tissues in response to external signals. In wound repair, soluble growth factors direct fibroblasts and endothelial cells repopulate the immature matrix to form both the supporting matrix and vasculature required to regenerate the tissue structures. The initial migration is driven by stimulatory cues arising from within the wound bed. However, once within the wound bed, the cells must distribute often in the absence of stimuli gradients. A central question is therefore how cells establish the sustained asymmetry required for progressive migration. Cell migration requires asymmetry of biophysical force-related processes; in eukaryotic cells this is likely governed by intracellular signals. At the front, the cells must extend lamellipodia and form new adhesions to stabilize the dominant protrusion, while rear de-adhesion and retraction is required to enable progressive movement. Between these two cell regions, contractility occurs to bring the cell body forward. To productively choreograph these processes, a cell must establish persistent directionality. During the initial grant period we have found that during motility induced by near ubiquitous chemokinetic EGFR ligands, that the initial actviation of PLCy (phospholipase-Cy) establishes an asymmetry of an important membrane moiety, PIP2 (phosphoinositide bisphosphate). Our preliminary data suggest that the biochemical cascades leading to the biophysical processes are regulated at least in part by this membrane moiety and docking site. Thus, we hypothesize that the localized activation of key biochemical signaling cascades required for productive cell motility results from the integration of phospho-inositide asymmetry in the plasma membrane. We propose to test the following postulates: /. That m-calpain (CAPN2), required for rear release during motility, is localized to an activatable peri-plasma membrane locale by binding to PIP2. II. That PKCS-mediated contractility, required topull the cell body and tail forward, is localized to regions of PLCy activity linked by phospho-inositide turnover. III. That PI3 kinase designates andstabilizes the leading, dominant lamellipod to provide directionality. We focus on human fibroblasts and endothelial cells, with extension to mesenchymal stem cells. These studies will define molecular bases for spatial restriction of receptor signaling and resultant biophysical responses, offering promise for design of 'smart' scaffolds for tissue engineering to support tissue function.