New Chemical Strategies for the Modification and Control of Endogenous Proteins in Living Cells

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Nature of the ResearchResearch in the Menard lab lies at the interface of chemistry and neurobiology. We seek to answer fundamental questions about how neurons communicate with their neighbouring cells, the astrocytes. This proposal describes the first steps we must take to achieve this goal. A long-term goal of our Chemical Biology research program is to create a chemical toolbox to study proteins that will complement the current genetic methods used by biologists. Specifically, we will: (1) design chemical tools to label proteins in live cells, and (2) apply these probes to understand the molecular mechanisms of synapse elimination in the aging brain. Our multidisciplinary research program integrates techniques of synthetic chemistry, molecular and cell biology, cell imaging, and electrophysiology. A central theme to this proposal is to modify natural products that have been evolved by Nature and use them as molecular probes to target specific proteins.SignificanceTo better understand the mechanisms of neurodegeneration, scientists need new sets of tools to investigate protein-protein interactions at the molecular level. Having access to chemical means to monitor proteins without genetic modification would greatly accelerate the study of important cellular processes in health and disease. Current genetic methods to study protein dynamics suffer from significant drawbacks, e.g., protein expression or activity is often perturbed, and new vectors must be re-engineered for each organism. Chemists are uniquely positioned to design small molecules that can be applied at the time of experiment. This ensures we observe normal protein activity; moreover, in neurobiology, the molecules can easily be transferred from one organism to another due to the conserved nature of brain receptors across species. The successful implementation of our proposed methods will help unravel fundamental scientific questions at the frontiers of chemistry and biology. Such molecules will also be attractive tools for live cell assays in the pharmaceutical industry.Expected OutcomesThis research proposal centers on the synthesis of small molecules that will offer novel means to visualize, label, and influence specific proteins in their native environment. Specifically, we expect this research will afford the chemical biology community with new reagents to achieve the traceless labeling of lysines residues in proteins. The broad applicability of the strategy of modifying natural products will demonstrate that new tools can be created from any ligand to study its associated protein in live cells. While we focus herein on cellular communication between neurons and astrocytes, the set of molecular tools we will use to study the calcium cascade will be applicable to any calcium-active tissue, such as heart cells and muscles. Finally, the systematic approach we will take to learn about chemical reactivity under physiological conditions should also lead to fundamental knowledge to help medicinal chemists design new drugs with covalent linkers (an emerging concept that can increase drug effiency several-fold).Benefits to CanadiansStudents and researchers in our lab will gain a unique training in interdisciplinary research including chemistry, molecular biology and neurobiology. While the field of chemical biology is growing rapidly, the expertise we bring is unique in Canada. In view of the pressing needs to treat neurodegenerative diseases, the students trained in our lab will be highly sought-after scientists at the national and international level. It is anticipated that the knowledge gained through these studies will provide valuable insight into how to develop pharmaceutical agents to treat or prevent neurodegenerative diseases.