Abstract 2223: Identification of novel protein modulators of p53 family function using photochemical crosslinking of stapled peptides.

Abstract

Considered to be the “guardian of the genome,” the tumor suppressor p53 works to counteract genetic mutation through cell cycle arrest, DNA repair or apoptosis to prevent proliferation of damaged cells. Dysfunction of the p53 pathway is a large driver of tumorigenesis, with an estimated more than 50% of cancers bearing some p53 abnormality; hence, the normalization of p53 function is considered an important clinical goal for cancer therapy. Many of the interactions involving p53 have been extensively studied; however, absent structural information, the identification of the precise nature of the binding interactions proves challenging, more so if they are transient. Using the hydrocarbon stapled peptide methodology previously used by our group to study interactions mediated by alpha-helices, we have begun identifying novel binding targets of the p53 transactivation domain (TAD) as well as its related proteins p63 and p73 through biochemically specific, covalent photochemical crosslinking reactions. Methodologically, we have developed the use of photoreactive stapled alpha helices (pSAHs) representing a unique way to use highly selective, biochemically specific cross-linking reagents. These can be used more broadly to study protein-protein binding interactions in cell-free and cell based assays. The technique has allowed us to learn more about the biologically active state of proteins that interact with the p53-family member TADs as well as the identification of unexplored binding partners and their mechanism of action in disease. Citation Format: Kenneth M. Felsenstein, Kathryn M. Headley, Kevin A. Murray, Elisabeth A. Russell, Federico Bernal. Identification of novel protein modulators of p53 family function using photochemical crosslinking of stapled peptides. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2223. doi:10.1158/1538-7445.AM2013-2223