Determining the Effects of N‐Terminal Acetylation on the Microtubule‐associated Protein Tau

The microtubule‐associated protein tau is notably associated with neurodegenerative diseases such as Alzheimer's Disease and more recently the disease found in deceased NFL players, Chronic Traumatic Encephalopathy (CTE). Aggregation of the protein tau causes these diseases, which endogenously stabilizes microtubules in neurons. Tau is a target for the most common mammalian post‐translational modification (PTM), N‐terminal acetylation. This modification alters the structure of a protein by changing the positive N‐terminus to a neutral one by adding an acetyl functional group. Any alteration to the structure of a protein also affects the function, and the N‐terminus of tau has been implicated with aggregation rates. Since tau and N‐terminal acetylation have never been studied together before, the effects are unknown. Historically, tau has been efficiently expressed and purified out of Escherichia coli and studied in vitro , however, N‐terminal acetylation is a eukaryotic specific PTM, but occurs in a prokaryotic system when the catalytic acetyltransferase complex is co‐expressed with tau. This project determines the effects of N‐terminal acetylation on the microtubule‐associated protein tau by assessing the differences between acetylated and unacetylated tau. Expression, purification, and precipitation of tau with around 98% purity occurs by lysing and boiling samples. Various tests determine that tau is N‐terminally acetylated, estimated by SDS‐PAGE and Western blot, and confirmed by mass spectrometry and isoelectric gel electrophoresis. Furthermore, various environments can have an effect on aggregation, and exposing fibers made from the purified protein to different stressors can give insight into optimized aggregation conditions. Increased amounts of thioflavin T evaluates aggregation, an assay measured by florescent spectroscopy. Also, tubulin stability in the presence of acetylated and unacetylated tau can give insight into microtubule stability in the cell. The microtubule‐associated protein tau has been widely associated with neurodegenerative diseases because of its tendency to aggregate. Proteins aggregate because of their structure, so exploring structural and functional changes to tau is important to understanding why it aggregates. This system looks specifically at one post‐translational modification and how it affects the protein tau, and studying tau with the correct PTMs will give a more correct understanding of the protein, and by extension the neurodegenerative diseases it causes. Support or Funding Information RI‐INBRE This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .