Collections > Electronic Theses and Dissertations > Cellular Optogenetics for Spatiotemporal Control of Kinase Signaling and Biological Trojan Horses for Light-mediated Drug Release
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Light provides an instantaneous, orthogonal, and spatially targeted tool to control cellular biochemistry and perform photochemistry. In the first three chapters of my thesis, I will discuss light as a tool for controlling intracellular communication. Intracellular signaling via kinases is highly controlled in space and time. While many tools exist that allow us to modulate signaling events on a global scale or observe signaling events with high spatial and temporal resolution, there are relatively few tools that are amenable to studying subcellular compartmentalized signaling. To this end, I have developed two optogenetic proteins for investigating the localized functions of 1) protein kinase A and 2) its second messenger cAMP. The optogenetic protein kinase A takes advantage of the Cry2-Cib photodimerizing pair. In short, a protein kinase A catalytic subunit with low constitutive activity was fused to Cry2 such that, upon stimulation with light, it translocates to whatever subcellular region Cib is localized to and activity is restored. In order to investigate localized cAMP signaling, a photoactivated adenylate cyclase was engineered to be expressed at specific subcellular locations. Upon activation with light, large increases in cellular cAMP levels are observed resulting in down-stream signaling events. I am still tweaking the photoactivated adenylate cyclase to control local cAMP signaling. The second half of my thesis discusses efforts to develop cell mediated delivery of phototherapeutics. Chapter 5 discusses the use of erythrocyte membranes as protective pools and launching pads for peptide therapeutics. Chapter 6 focuses on efforts to develop a treatment strategy for glioblastoma multiforme by loading tumor-homing neural stem cells with cobalamin-drug conjugates.