UMR 8640 : Chimie Biophysique

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Fluorogenic Probing of Membrane Protein Trafficking

Bioconjugate Chem. 2018

 

Methods to differentially label cell-surface and intracellular membrane proteins are indispensable for understanding their function and the regulation of their trafficking. We present an effi cient strategy for the rapid and selective fluorescent labeling of membrane proteins based on the chemical-genetic fl uorescent marker FAST (fluorescence activating and absorption-shifting tag). Cell-surface FASTtagged proteins could be selectively and rapidly labeled using fluorogenic membrane-impermeant 4-hydroxybenzylidene rhodanine (HBR) analogs. This approach allows the study of protein trafficking at the plasma membrane with various fluorometric techniques, and opens exciting prospects for the high-throughput screening of small molecules able to restore disease-related trafficking defects.

Resonant out-of-phase fluorescence microscopy and remote imaging overcome spectral limitations

Nature Communications 8, 969 (2017)

 

We present speed out-of-phase imaging after optical modulation (OPIOM), which exploits reversible photoswitchable fluorophores as fluorescent labels and combines optimized periodic illumination with phase-sensitive detection to specifically retrieve the label signal. Speed OPIOM can extract the fluorescence emission from a targeted label in the presence of spectrally interfering fluorophores and autofluorescence. Up to four fluorescent proteins exhibiting a similar green fluorescence have been distinguished in cells either sequentially or in parallel. Speed OPIOM is compatible with imaging biological processes in real time in live cells. Finally speed OPIOM is not limited to microscopy but is relevant for remote imaging as well, in particular, under ambient light. Thus, speed OPIOM has proved to enable fast and quantitative live microscopic and remote-multiplexed fluorescence imaging of biological samples while filtering out noise, interfering fluorophores, as well as ambient light.

 

Programmed Self-Assembly of a Biochemical and Magnetic Scaffold to Trigger and Manipulate Microtubule Structures

Scientific REPOrtS | 7: 11344 | 2017

 

Artificial bio-based scaffolds offer broad applications in bioinspired chemistry, nanomedicine, and material science. One current challenge is to understand how the programmed self-assembly of biomolecules at the nanometre level can dictate the emergence of new functional properties at the mesoscopic scale. Here we report a general approach to design genetically encoded protein-based scaffolds with modular biochemical and magnetic functions. By combining chemically induced dimerization strategies and biomineralisation, we engineered ferritin nanocages to nucleate and manipulate microtubule structures upon magnetic actuation. Triggering the self-assembly of engineered ferritins into micrometric scaffolds mimics the function of centrosomes, the microtubule organizing centres of cells, and provides unique magnetic and self-organizing properties. We anticipate that our approach could be transposed to control various biological processes and extend to broader applications in biotechnology or material chemistry.

Dynamic multicolor protein labeling in living cells

Chem. Sci.2017, Advance Article 

 

Yellow Fluorescence-Activating and absorption-Shifting Tag (Y-FAST, hereafter called FAST) is a 14-kDa protein tag giving a bright green-yellow fluorescent complex upon interaction with the fluorogenic dye 4-hydroxy-3-methylbenzylidene rhodanine (HMBR). Here, we report a collection of fluorogens enabling to tune the fluorescence color of FAST from greenyellow to orange and red. Beyond allowing multicolor imaging of FAST-tagged proteins in live cells, these fluorogens enable dynamic color switching because of FAST’s reversible labeling. This unprecedented behavior allows selective detection of FAST-tagged proteins in cells expressing both green and red fluorescent species through two-color crosscorrelation, opening exciting prospects to overcome spectral crowding and push the frontiers of multiplexed imaging.

Interview Arnaud GAUTIER, a chemical biologist !

Arnaud GAUTIER, Maître de Conférence au sein du Département de Chimie de l'École normale supérieure est lauréat du financement ERC Consolidator Grant 2016 et Médaille de Bronze du CNRS.

 

Visionnez son interview où il nous explique ce qu'est la chémobiologie et nous détaille ses projets à venir !