Scientists at the Natural and Medical Sciences Institute (NMI) in Reutlingen and the Eberhard Karls University of Tuebingen have developed new molecular probes to monitor and quantify changes in the concentration of endogenous proteins by live-cell fluorescence microscopy.
In a study now published in Molecular & Cellular Proteomics, the authors describe how fluorescently labeled intrabodies (so-called chromobodies) are stabilized in the presence of their target proteins. Based on this newly uncovered property of chromobodies, Keller and co-workers present a broadly applicable strategy to optimize chromobodies in order to visualize and measure changes of endogenous target proteins within living cells.
Currently available procedures to measure cellular protein concentration such as quantitative immunoblotting or mass spectrometry analysis are very laborious and time consuming. Moreover, these approaches require destructive sample preparation and thus only deliver results at a single point in time.
“Our new approach using antigen-mediated chromobody stabilization (AMCBS) allows us to continuously visualize and quantify dynamic changes of specific endogenous proteins directly within living cells – something that could not be done before”, stated Bettina-Maria Keller, the study´s first author. “We expect this approach to enable unprecedented insights into the dynamic regulation of proteins, e.g. during cellular signaling, cell differentiation, or upon drug action”.