FRAP, FLIP, FRET, BRET, FLIM, PRIM… De nouvelles techniques pour voir la vie en couleur !

[Towards optical in vivo electrophysiology]

Optical imaging of voltage indicators is a promising approach for detecting the activity of neuronal circuits with high spatial and temporal resolution. In this context, genetically encoded voltage indicators, combining genetic targeting and optical readout of transmembrane voltage, represent a technological breaktrough that will without doubt have a major impact in neuroscience. However, so far the existing genetically encoded voltage indicators lacked the capabilities to detect individual action potentials and fast spike trains in live animals. Here, we present a novel indicator allowing high-fidelity imaging of individual spikes and dentritic voltage dynamics in vivo. Used in combination with optogenetics, which allows to manipulate neuronal activity, this opens the possibility of an all-optical electrophysiology.

[Cellular and molecular motions: order and disorder]

Video-microscopy allows monitoring the dynamics of biological components, specifically labeled, usually by fluorescent tags such as GFP or quantum dots, either at the cellular or at the molecular scale. Reconstructing trajectories over time with dedicated algorithms allows to characterize on both scale different categories of movement, such as random, linear or confined, and to report events such as transient confinements among recorded species and with their environment. Single cell or molecule measurements hence provide detailed access not only to mean values of relevant descriptors, such as speed or interaction duration, but also to the exhaustive distribution of recorded values.

Protein-protein interaction map is a key gateway into liver regeneration

Recent studies indicate that the process of liver regeneration involves multiple signaling pathways and a variety of genes, cytokines and growth factors. Protein-protein interactions (PPIs) play a role in nearly all events that take place within the cell and PPI maps should be helpful in further understanding the process of liver regeneration. In this review, we discuss recent progress in understanding the PPIs that occur during liver regeneration especially those in the transforming growth factor β signaling pathways. We believe the use of large-scale PPI maps for integrating the information already known about the liver regeneration is a useful approach in understanding liver regeneration from the standpoint of systems biology.

Des agents thérapeutiques ciblant des interactions protéine-protéine

Protein-protein interactions have a key role in transduction pathways that regulate many cellular functions. Structural and functional properties of protein-protein interface are now better understood, therefore offering attractive opportunities for therapeutic intervention. Developping small molecules that modulate protein-protein interactions is challenging. Nethertheless, significant progress in this endeavour has been made on several fronts. Here, we use few illustrative examples to summarize recent work in this emerging field.

Tracking of human Y receptors in living cells--a fluorescence approach

Non-invasive methods for studying biological processes in living cells have become very important, also in the field of GPCR biochemistry. Great advancements in the application of fluorescence techniques as well as in the development and improvement of novel fluorophores allow the visualization of dynamic processes. Using these technologies, problems concerning receptor biosynthesis, internalization, recycling and degradation can be investigated. Here we compare the application of the different fluorescent tags EYFP, Lumiotrade mark and SNAPtrade mark to track hY(1) and hY(5) receptors in living cells.