Genetically encoded optical reporters of neuronal electrical activity
We are developing optical sensors of transmembrane voltage to enable visualization of neuronal circuit activity in the brain. We have recently created a sensor named ASAP1 where brightness of a fluorescent protein responds to voltage changes with high sensitivity and fast kinetics. ASAP1 is the first sensor that responds to the entire gamut of neuronal electrical activity, allowing neuroscientists to record electrical activity in multiple neurons in the brain. Current work is focused on further improving ASAP1.
Genetically encoded reporters of intracellular signals
A major interest in the lab is the development of new fluorescent proteins and FRET reporters for the purpose of investigating spatiotemporal regulation of protein synthesis pathways. We undertake an integrated development program from protein structure to protein engineering methods to analysis of signal transduction mechanisms in cells. This movie shows how a new fluorescent protein pair, Crimson-Clover, can be used to improve a sensor of protein kinase A and used in HeLa cells to image PKA activity in continuous streaming time-lapse mode.
Drug-controllable fluorescent tags of protein age
We have developed fluorecent proteins with drug-controllable onset for visualizing new protein synthesis and are using them to study stimulus-induced local protein translation. In this movie, fluorescence reveals the distribution of copies of a protein of interest synthesized after the additon of the drug. We are currently applying this technology to understand how proteins are locally synthesized in complex cell types such as neurons, and how this process may be disrupted in human diseases caused by mutations in protein synthesis pathways.
Chemical and optical control of protein function
Current gene-and cell-based therapies lack the ability to be regulated temporally or spatially. External control over activity will be essential for safety and in order to apply gene-and cell-based treatments to tissue reconstruction or complex diseases.
As described in our 2012 Science paper (see Publications), we have developed a breakthrough technology for optogenetic control of protein function using fluorescent proteins. This technology is superior to previous methods in being 100% genetically encoded, not requiring cofactors, and featuring a built-in reporter of protein location and activity level0the fluorescent protein domain itself.
We are also developing generalizable methods for controlling proetin function with drugs.
Synthetic signal transduction pathways for control of cellular therapeutics
We are applying chemical and structural knowledge of natural signaling proteins and to create synthtic signaling networks with defined input triggers and outpt programs. Our kinetics, and localization of specific protein domains to create new linkages. We are designing and testing these artificial networks to functionally connect detection of desease states with therapeutically useful cellular modifications.