Optogenetic regulation of protein activity in live cell

Abstract

Signaling pathways extensively crosstalk among each other and result in different cellular phenotypes depending on the dynamic profile of protein activity. Conventional genetic and pharmacological approaches such as gene overexpression, use of growth factors or inhibitors have helped us delineate interaction maps of signaling components, however these techniques provide limited means to determine contribution of a target protein for specific cellular phenotype. Therefore, to find out the molecular mechanism for a cellular outcome, there is an urgent need for a tool that can specifically activate or inactivate a protein of interest and study it’s role towards a specific cell fate. Optogenetic techniques utilize light to control protein functions with high spatial and temporal resolution. Here, I First present a generalizable light modulated protein stabilization system (GLIMPSe) that enables target-independent optogenetic control of protein activities and minimizes the systematic variation embedded within different photoactivatable proteins. GLIMPSe was applied to control light-mediated post-translational stabilization of two distinct classes of proteins, phosphatase and kinase with rapid kinetics response. Second, I discuss role of speckle-type POZ protein (SPOP) in cell differentiation inhibition in PC12 and primary rat hippocampus neuron cell. Next, I combined the GLIMPSe system with the Sufu protein, a SPOP phenocopy and sonic hedgehog (Shh) signaling pathway inhibitor and generated the GLIMPSe-Sufu system for optogenetic inhibition of Shh signaling pathway. Finally, I review the molecular machinery of cargo trafficking with emphasis on new optogenetic and optochemical experimental strategies that enable direct modulation of cargo trafficking in live cells.