Establishment of cell polarity and the role of calcium during chemotaxis of Dictyostelium discoideum

在细胞黏菌盘状盘齿龙（Dictyostelium disideum）中，细胞极性在化学引诱剂cAMP激发后迅速建立，引起定向伪足伸展。我们的目标是研究确定的第二信使的作用，并确定参与这一过程的蛋白质。游离细胞质Ca2+浓度（[Ca2+]i）的变化对盘状豆科植物趋化性的作用有争议。我们将在趋化迁移过程中以高时间和空间分辨率测量单个盘状骨细胞中的[Ca2+]i动力学，这将阐明[Ca2+]i在前后端轴生成中的模式和精确作用。[H+]i的动态也将被研究，因为[H+]i的快速变化可能构成了目前未知的抑制信号，仅在一个方向上限制假足的形成。通过“限制性内切酶介导的整合”（REMI）获得的突变体将被选择用于改变取向和迁移。将对突变基因进行分离和测序，并对相应的蛋白产物进行表征。这种方法将允许剖析控制面向对象迁移的事件级联。

In the cellular slime mould, Dictyostelium discoideum, cell polarity is rapidly established after challenge with the chemoattractant cAMP which evokes oriented pseudopod extension. We aim to study the role of defined second messengers and to identify proteins participating in this process. The function of changes in the free cytosolic Ca2+ concentration ([Ca2+]i) for chemotaxis of D. discoideum is discussed controversially. We will measure the [Ca2+]i-dynamics in single Dictyostelium cells with high temporal and spatial resolution during chemotactic migration which will clarify the pattern and precise role of [Ca2+]i in the generation of a front-to-rear end axis. The dynamics of [H+]i will also be studied as rapid changes in [H+]i might constitute the as yet unknown inhibitory signal restricting pseudopod formation in one direction only. Mutants obtained by "restriction enzyme mediated integration" (REMI) will be selected for altered orientation and migration. The mutated genes will be isolated and sequenced and the corresponding protein products will be characterized. This approach will allow to dissect the cascade of events controlling oriented migration.