Development of Genetically Encoded Biosensors
Yasmina Bousmah (Assistant Engineer), Marie Erard (Professor), Hélène Pasquier (Associate Professor, HDR)
Alumni: Fabienne Merola (Senior Researcher, retired in 2020)
Different types of architectures can be adopted to build biosensors from fluorescent proteins. Generally, a protein module specifically sensitive to the biochemical activity or entity of interest is fused to one or more GFPs.
Various biosensor modalities that either utilize the intrinsic sensitivity of the fluorescent protein (a and b) or a sensor module fused to one or more fluorescent proteins, which then act as optical reporters (c and d).
Ions or small molecules can directly alter the fluorescence signal of certain GFPs by disrupting their absorption or emission properties. In particular, we have exploited the pH sensitivity of the fluorescence lifetime of certain cyan fluorescent proteins to develop pH sensors in FLIM [PoeaGuyo 2013], or the modulation of their fluorescence properties following reactions with ROS to detect H₂O₂ [Nault 2016].
FRET-based biosensors require the use of two spectrally compatible GFPs, one acting as the energy donor (usually a cyan fluorescent protein) and the other as the acceptor (usually a yellow fluorescent protein), with a protein module sensitive to a cellular parameter sandwiched between them. Conformational changes in the sensor module alter the relative configuration of the donor -acceptor pair, thereby affecting the FRET level. FRET variations can be monitored using various fluorescence microscopy techniques, such as ratiometric imaging or FLIM. We have proposed improved versions of kinase activity biosensors [Bertolin 2019] and recently contributed to strategies for enhancing FRET-based force sensors [Dubois 2023] and heavy ion sensors [Sauge-Merle 2023].
We also leverage our detailed knowledge of fluorescent proteins to propose multimodal detection approaches, such as fluorescence/NMR@Xe [Mari 2019].