Many cellular processes require cell polarization to be maintained as the cell changes shape, grows or moves. Without feedback mechanisms relaying information about cell shape to the polarity molecular machinery, the coordination between cell polarization and morphogenesis, movement or growth would not be possible. Here we theoretically and computationally study the role of a genetically-encoded mechanical feedback (in the Cell Wall Integrity Pathway) as a potential coordination mechanism between cell morphogenesis and polarity during budding yeast mating projection growth. We developed a coarse-grained continuum description of the coupled dynamics of cell polarization and morphogenesis as well as 3D stochastic simulations of the molecular polarization machinery in the evolving cell shape. Both theoretical approaches show that in the absence of mechanical feedback (or in the presence of weak feedback), cell polarity cannot be maintained at the projection tip during growth, with the polarization cap wandering off the projection tip, arresting morphogenesis. In contrast, for mechanical feedback strengths above a threshold, cells can robustly maintain cell polarization at the tip and simultaneously sustain mating projection growth. These results indicate that the mechanical feedback encoded in the Cell Wall Integrity pathway can provide important positional information to the molecular machinery in the cell, thereby enabling the coordination of cell polarization and morphogenesis.

中文翻译：

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通过机械反馈协调细胞极化和形态发生

许多细胞过程需要随着细胞改变形状，生长或移动而保持细胞极化。如果没有反馈机制将有关细胞形状的信息传递给极性分子机制，则细胞极化与形态发生，运动或生长之间的协调将无法实现。在这里，我们在理论上和计算上研究了遗传编码的机械反馈（在细胞壁完整性途径中）作为发芽酵母交配投影生长期间细胞形态发生和极性之间潜在的协调机制的作用。我们开发了细胞极化和形态发生的耦合动力学的粗粒度连续体描述，以及在演化的细胞形状中分子极化机制的3D随机模拟。两种理论方法都表明，在没有机械反馈的情况下（或在存在弱反馈的情况下），在生长过程中无法在突起尖端维持细胞极性，极化帽会从突起尖端徘徊，从而阻止形态发生。相反，对于高于阈值的机械反馈强度，细胞可以在尖端牢固地维持细胞极化，同时维持配对的突起生长。这些结果表明，在细胞壁完整性途径中编码的机械反馈可以为细胞中的分子机制提供重要的位置信息，从而实现细胞极化和形态发生的协调。偏振帽从投影尖端徘徊，阻止形态发生。相反，对于高于阈值的机械反馈强度，细胞可以在尖端牢固地维持细胞极化，同时维持配对的突起生长。这些结果表明，在细胞壁完整性途径中编码的机械反馈可以为细胞中的分子机制提供重要的位置信息，从而实现细胞极化和形态发生的协调。偏振帽从投影尖端徘徊，阻止形态发生。相反，对于高于阈值的机械反馈强度，细胞可以在尖端牢固地维持细胞极化，同时维持配对的突起生长。这些结果表明，在细胞壁完整性途径中编码的机械反馈可以为细胞中的分子机制提供重要的位置信息，从而实现细胞极化和形态发生的协调。