Disentangling the recognition complexity of a protein hub using a nanopore
Lauren A. Mayse, Ali Imran, Motahareh Ghahari Larimi, Michael S. Cosgrove, Aaron J. Wolfe, Liviu Movileanu
Abstract
Abstract WD40 repeat proteins are frequently involved in processing cell signaling and scaffolding large multi-subunit machineries. Despite their significance in physiological and disease-like conditions, their reversible interactions with other proteins remain modestly examined. Here, we show the development and validation of a protein nanopore for the detection and quantification of WD40 repeat protein 5 (WDR5), a chromatin-associated hub involved in epigenetic regulation of histone methylation. Our nanopore sensor is equipped with a 14-residue Win motif of mixed lineage leukemia 4 methyltransferase (MLL4 Win ), a WDR5 ligand. Our approach reveals a broad dynamic range of MLL4 Win -WDR5 interactions and three distant subpopulations of binding events, representing three modes of protein recognition. The three binding events are confirmed as specific interactions using a weakly binding WDR5 derivative and various environmental contexts. These outcomes demonstrate the substantial sensitivity of our nanopore sensor, which can be utilized in protein analytics.