Vie de l'IBPC

Séminaires

Séminaire UMR8226

UMR8226

30/11/2015

Serge Pelet - Synthetic biosensors for quantitative analysis of signaling cascades in single cells

Synthetic biosensors for quantitative analysis of signaling cascades in single cells

Serge Pelet
Université de Lausanne
 Suisse


invité  par Zhou Xu


le lundi 30 novembre 2015 à 11h - Salle de conférence de l'IBPC - 3e étage


Saccaromyces Cerevisiae has been used for decades as a model system to study Mitogen Activated Protein Kinase (MAPK) signal transduction. Four pathways have been shown to be active in haploid yeast cells: the mating pathway, the filamentous growth pathway, the high osmolarity glycerol (HOG) pathway and the cell wall integrity (CWI) pathway. Extensive evidences have demonstrated that these pathways do not work in isolation from each other but rather form a complex interaction network where cross-activation or cross-inhibition between MAPK is often present. Due to the highly dynamic nature of the cross-interactions in the yeast MAPK network, quantitative real-time measurements at the single cell level are required.
In order to generate these measurements, we have developed new microscopy assays to quantify in real time the kinase and protein expression output delivered by these signaling cascades. To achieve this, we have engineered synthetic proteins, which undergo nuclear to cytoplasmic shuttling upon phosphorylation or transcriptional activation. Combination of these biosensors within the same strain enabled us to correlate multiple readouts in individual cells. This offers the unique ability to measure how the dynamics of the MAPK kinase activity are linked to the dynamics of gene expression within a pathway. Moreover, it allows to measure directly the cross-talk between different signaling cascades. Our objective is to use these biosensors to uncover the regulatory links between the MAPKs of the network and to obtain a quantitative understanding of how signaling specificity is achieved in this network.

 

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