Abstract

Biological molecules rarely act alone. For example, in many pediatric cancers, a chromosomal rearrangement results in a fusion protein with altered DNA and protein interactions that yield proliferative and aggressively metastatic cell subpopulations. In this talk, I will describe quantification of molecular interaction properties relevant to fusion oncoprotein biology using microscale tools with distinct forces tailored to each biological question. First, I will discuss measurement of cellular heterogeneity in cytoskeletal protein complex abundance as is needed to uncover ‘rogue’ metastatic and drug resistant cells. I introduced a microfluidic biochemical assay using electrophoretic forces and sieving hydrogels to fractionate dynamic protein complexes from single cells faster than dissociation kinetics. Second, I will describe biophysically probing protein-DNA molecular mechanics to understand how tension plays a role in DNA pairing during DNA damage repair. To reveal forces the Rad51 repair protein exerts on DNA, microscale tweezers apply a magnetic piconewton-scale force to single molecules of DNA. Finally, I will share future directions discerning the biochemical and biophysical roles of multi-component protein complexes in fusion oncoprotein-driven pediatric cancers, such as Ewing’s sarcoma. My group will uncover new targets for ‘molecularly surgical’ Ewing’s sarcoma therapies through interrogation of molecular interactions towards replacing combination chemotherapy and crude tumor removal surgeries.