(Link-Sign-Mech-Furr) Linking Signalling to Mechanics and Shape Changes in Mitotic Furrowing

在有丝分裂期间，细胞经历复杂的形状变化，它们在那里聚集、拉长并组装成分裂沟。形状变化是由复杂的信号网络控制的皮质张力的时空梯度引起的。皮质张力的模式由RhoGTP酶的活性控制，RhoGTP酶是细胞骨架和收缩的关键调节因子。它们受到一组不同的RhoGEF/RhoGAP的调控，这些RhoGEF/RhoGAP的时空招募到膜上形成了张力梯度。我们不知道为什么多个RhoGEF和RhoGAP在空间和时间上重叠来控制沟槽的形成和入侵。虽然我们知道皱纹内陷需要肌球蛋白收缩能力的增加和皮质的重组，但我们不知道每个Rhogef/GAP是如何促成这些事件的。我的总体目标是确定RhoGEF/GAP的时空招募如何控制细胞力学，以驱动沟槽期间的形状变化。首先，将描述开沟过程中的分子、结构和力学变化。我们将研究每个Rhogef/GAP参与开沟所引起的分子和力学变化。然后，将研究RhoGEF/GaP的相互作用。我将使用光学活显微镜和超分辨率显微镜以及原子力显微镜相结合的方法来研究结构和力学变化。为了确定每个Rhogef/GAP的作用，我将设计能够实现信号时空控制的光遗传执行器。通过组合两个致动器，我将研究RhoGEF/GAP之间的相互作用。我将使用结果作为输入参数，用于基于信号的时空局部化的细胞形状变化的计算建模。

During mitosis, cells undergo complex shape changes, where they round up, elongate and assemble a division furrow. Shape changes arise in response to spatiotemporal gradients in cortical tension controlled by an intricate signalling network. Patterning of cortical tension is controlled by the activity of RhoGTPases, which are key regulators of the cytoskeleton and contractility. They are regulated by a diverse set of RhoGEFs/RhoGAPs, and spatiotemporal recruitment of these to the membrane patterns the tension gradients. We do not know why multiple RhoGEFs and RhoGAPs overlap spatially and temporally to control furrow formation and ingression. While we know that furrow ingression necessitates an increase in myosin contractility and a reorganisation of the cortex, we do not know how each RhoGEF/GAP contributes to these events. My overall goal is to determine how spatiotemporal recruitment of RhoGEFs/GAPs controls cell mechanics to drive shape change during furrowing. First, the molecular, structural and mechanical changes during furrowing will be characterised. Molecular and mechanical changes induced by each RhoGEF/GAP participating in furrowing will be investigated. Then, the interplay of RhoGEFs/ GAPs will be examined.I will use a combination of optical live and super-resolution microscopy and Atomic force microscopy to investigate structural and mechanical changes. To determine the role of each RhoGEF/GAP, I will design optogenetic actuators that enable spatiotemporal control of signalling. By combining two actuators, I will investigate the interplay between RhoGEFs/GAPs. I will use the results as input parameters for computational modelling of cell shape change based on the spatiotemporal localisation of signalling.