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John Flannery, Kenneth Greenberg, Kate Kolstad; Light. Journal of Vision 2007;7(15):48. doi: 10.1167/7.15.48.
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© ARVO (1962-2015); The Authors (2016-present)
A major challenge for biomedicine is to develop new ways of determining how proteins operate in complexes in cells. This requires molecularly focused methods for dynamic interrogation and manipulation. An attractive approach is to use light as both the input and output to probe molecular machines in cells. While there has been significant progress in optical detection of protein function, little advance has been made in control. The UC Berkeley Nanomedicine Development Center (NDC) for the Optical Control of Biological Function is developing methods for rapidly turning select proteins in cells on and off with light. The strategies are broadly applicable across protein classes. We have both biological and disease- related targets for these methods. Initially, we are concentrating upon three central signaling systems: ion channels, G-protein coupled receptors and kinases and phosphatases. These represent some of the largest protein families, together comprising about 7% of the human genome. The proteins are implicated as causes and drug targets in major human diseases. By enabling rapid, reversible and local switching these tools should make it possible to overcome two major problems in standard drug delivery: a) side effects due to systemic delivery, or systemic leak of locally delivered drugs, and b) long delays between delivery and action, and difficulty to terminate action. Our plan is to generate toolkits of light-gated signaling proteins and of light-gated peptides that selectively modify protein function. We are using structure-based design to chemically synthesize two classes of nanoscale photoswitches: 1) ligand photoswitches - that attach to native and engineered target proteins, and remote control their function (with both activating and blocking ligands); 2) light-gated peptides - which bind to target proteins (at interaction domains or substrates binding sites) in a light-dependent manner, interfering with function only in the bound state. A critical challenge is to transfer our methods from basic research in cell biology to therapeutics. We will focus on animal models of human disease, including using light-gated channels to restore vision to retina that have lost photoreceptor cells, treatment of retinal disease due to angiogenesis, and prevention of cardiac damage due to ischemia. We have three technology platforms: toolkits of photoswitches and methods for their site-directed integration into proteins vectors for delivery of photoswitchable proteins into cells in vitro and in vivo light delivery systems that make it possible to address these nanodevices in vivo We are addressing 3 engineering and clinical challenges: Devise a general strategy for optical control over the functional state of individual proteins and the signaling interactions of pairs or groups of proteins, Gain optical control over signaling and enzymatic activity within cells in vitro Adapt these approaches to treat retinal and cardiac pathologies in vivo.
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