Maciej Dobrzynski (CWI) gives a talk about the signaling networks in cells without cell nucleus (prokaryotes like bacteria).

Location: CWI, room M279

Most prokaryotes sense the environmental changes through two-component signaling networks. These systems consist of a sensor and a response regulator, typically a transcription factor controlling many genes. The question we address in this study is how two-component systems can convey extra-cellular signals quickly but robustly at a single cell level.

For a generic model of such a network we perform detailed spatial simulations and derive analytical approximations for the mean signaling response time and its noise. We find that already tens of molecules are sufficient in order to significantly reduce the time to activate a gene in response to an environmental cue. In this regime the response time is robust to fluctuations in the copy number of molecules comprising a two-component network. We estimate these fluctuations using realistic transcription and translation models. Finally, we show that the shortest response time requires more response regulators that sensors. This suggests an advantage for operon organization such that the response regulator is transcribed earlier than the sensor. We confirm those findings using a large bioinformatics screen of prokaryotic genomes.

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