Alzheimer’s disease (AD) is a proteinopathy designated as a major public health concern that is primarily pathologically characterised pathologically by the aggregation of the proteins tau and amyloid beta (Aβ). However, interventions based purely upon either of these aggregated proteins have had mixed results. Evidence is growing that other proteins also have important contributions to the development of AD. Understanding how these other proteins contribute to AD, as well as their interactions, is thus extremely important to developing novel therapeutics and diagnostics for AD.
The protein p53, colloquially known as the ‘Guardian of the Genome’, controls a wide variety of functions, particularly involving DNA damage repair and is known to be involved in neurodegenerative diseases. In particular, it was previously found by Farmer et al. to be aggregated in AD and to co-localise with tau. By understanding the drivers of this aggregation, we aim to be able to inhibit and reverse p53 aggregation as a potential treatment method for AD.
Using molecular dynamics simulations, we have found specific mutations of p53 that are more inclined to aggregate due to alterations in their conformations, focusing in particular on mutations of p53 that are known to be disease relevant. We have then produced recombinant proteins of these simulated mutants, and used Thioflavin T time course assays, DNA-protein interaction ELISAs and atomic force microscopy to determine how these mutant proteins vary from the wild type in terms of aggregation and how interactions with tau occur, thereby finding how aggregation is affected by specific conformational changes.
We found that there is a distinct alteration in the fibrils of p53 formed depending upon the mutations (and hence, conformational shift) that occurs in the protein. Moreover, there is a near-total loss of p53 function upon aggregation into either oligomers or fibrils.