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

在细胞黏菌中，盘基网柄霉（Dictyosteelium discoideum）在用引起定向伪足延伸的化学引诱物cAMP挑战后迅速建立细胞极性。我们的目标是研究定义的第二信使的作用，并确定参与这一过程的蛋白质。细胞内游离Ca ~（2+）浓度（[Ca ~（2+）]i）的变化对D. discoideum讨论有争议。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网骨藻细胞中的[Ca 2 +] i动力学，这将阐明[Ca 2 +]i在产生前端至后端轴中的模式和精确作用。[H+]i的动力学也将被研究，因为[H+]i的快速变化可能构成仅在一个方向上限制伪足形成的未知抑制信号。将选择通过“限制酶介导整合”（REMI）获得的突变体，以改变方向和迁移。突变基因将被分离和测序，相应的蛋白质产物将被表征。这种方法将允许剖析控制定向迁移的事件级联。

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.