About the Project
This project will identify key amino acids influencing the mechanism and regulation of two proteins that control axon survival and degeneration. Programmed axon death is a widespread mechanism of axon loss in injury and disease, mediated by both the NAD degrading and pro-degenerative enzyme SARM1, and its upstream regulator, the NAD synthesising and pro-survival enzyme NMNAT2. Modulation of each protein, whether by gene mutation or by neurotoxins, influences axon degeneration in animal models and in human diseases. These include peripheral neuropathies and motor neuron disease, and potentially many more. Knowledge of their enzymatic and regulatory mechanisms is emerging, and important for developing therapeutic strategies, but this is far from complete. Some structural data are available, along with a rapidly growing wealth of human genomic data for both SARM1 and NMNAT2. The successful candidate will combine information from each of these resources, identifying regions of mutational constraint, evolutionary conservation and structural interest to predict which amino acids in SARM1 and NMNAT2 are of particular importance to enzyme mechanism and regulation. They will test these hypotheses in the laboratory using molecular biology methods including site directed mutagenesis, primary neuronal cultures, microinjection of DNA constructs, fluorescence microscopy, enzyme kinetics and analysis of NAD-related metabolites. The work will contribute to ongoing drug discovery efforts to target these proteins in therapies for axonal disorders. Together with colleagues carrying out functional analysis of naturally occurring variants in the human proteins, this will also help identify variants of particular importance in human disease.
References
Coleman, M.P. and Höke, A. (2020) Programmed axon degeneration: from mouse to mechanism to medicine. Nat Rev Neurosci 21: 183-196
Gilley, J., Jackson, O., Pipis, M., Estiar, M., Gan-Or, Z., Goutman, S., Harms, M., Kaye, J., Lima, L., Ravits, J., Rouleau, G., Zuchner, S., Reilly, M. and Coleman, M.P. (2021) Enrichment of SARM1 alleles encoding variants with constitutively hyperactive NADase in patients with ALS and other motor nerve disorders. Preprint. medRxiv 2021.06.17.21258268; doi: https://doi.org/10.1101/2021.06.17.21258268.
Loreto, A., Angeletti, C., Gilley, J., Arthur-Farraj, P., Merlini, E., Amici, A., Desrochers. L.M., Wang, Q., Orsomando, G., Coleman, M.P. (2020). Potent activation of SARM1 by NMN analogue VMN underlies vacor neurotoxicity. BioRxiv 2020.09.18.30426 (and under review)
And links to further articles in the Coleman lab blog: https://colemanlab.brc.cam.ac.uk/blog