Date of Award

Summer 7-1-2022

Degree Type


Degree Name

Doctor of Philosophy (PhD)




Movileanu, Liviu


Cancer, Histone Methylation, Protein-protein Interactions, RbBP5, SET1, WDR5

Subject Categories

Biochemistry, Biophysics, and Structural Biology | Biophysics | Life Sciences


Understanding the properties of protein-protein interactions (PPIs) is necessary to deconvolute the processes inside living organisms. As such, research in this regard has significant implications for gaining insight into cancers and other diseases. Once understood, drugs can be designed to target these diseases. In these chapters we focus on the network of interactions of WD40 repeat protein 5 (WDR5), a known hub protein. Several of its interactions are significant for regulation of histone methylation and consequently epigenetic regulation. These interacting partners include the SET1 family of proteins and retinoblastoma binding protein-5 (RbBP5). In this work we used multiple ensemble measurement based bulk-phase techniques to characterize WDR5's interactions. We utilized biolayer interferometry (BLI) and surface plasmon resonance (SPR) to calculate the association and dissociation rate constants. Furthermore, we used fluorescence polarization (FP) to calculate the equilibrium dissociation constants. After characterizing these PPIs under wild-type conditions we quantified the impact of key WDR5 cancer mutants on these interactions. These mutants can impact downstream gene expression, which ultimately controls various cellular processes. Therefore, evaluating their modification of WDR5's kinetics is key to understanding their potential impact on tumor development. Additionally, by using different tether conditions, we have explored the role of surface-tethering in modulating the kinetics of these PPIs. The work shows the impact of tethering on tethered ligand-receptor complexes that are common in biological signaling and cellular adhesion. Moreover, it shows how surface-tethering can be used to modulate a typical PPI. We also characterized the role of the N-terminal intrinsically disordered region (IDR) of WDR5. Our work explores the self-association behavior catalyzed by this IDR and the potential ramifications of this self-association on WDR5's role inside the nucleus.


Open Access

Included in

Biophysics Commons