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

• Applicant: Privatdozentin Dr. Christina Schlatterer
• Subject Area: Cell Biology
• Term: from 2001 to 2005
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5332565

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.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1111: Cell Polarity