BPS2026 – Discovering chemical determinants of p53 amyloid formation

Protein aggregation into toxic amyloid fibrils underlies diseases including neurodegeneration and numerous cancers. p53 is a critical transcription factor and tumor suppressor protein that regulates a broad range of cellular processes but has been observed to accumulate in filamentous amyloid aggregates in cancer cells. Such amyloid formation is likely to contribute to loss-of-function phenotypes observed in cancer. However, the cellular environmental factors driving the transformation of p53 to its amyloid state remain poorly understood. Moreover, mutations in TP53, present in approximately 50% of human cancers, result in either loss of function or gain of function, upregulating oncogenic pathways. Here, we bridge this gap by systematically testing a library of thousands of endogenous human metabolites for their ability to destabilize or induce p53 amyloid formation in vitro. We use differential scanning fluorimetry (DSF) to measure p53 stability; we also use thioflavin T fluorescence assays and limited proteolysis experiments to measure amyloid formation rates, propensities, and resulting conformation. Through these studies, we will define the molecular grammar of p53 conformational modulation in cells, generating predictions about which cellular pathways may become misregulated in cancer states. We expect that our results will enable mechanistic models of p53 aggregation and inform drug development efforts to prevent p53 loss of function in oncogenesis.