Professor Soichiro Yamada, Biomedical Engineering, University of California, USA

Biochemical Isolation of Force-Sensitive Proteins at Adhesive Contacts

Physical force emerged as a key regulator of tissue homeostasis, and plays an important role in embryogenesis, tissue regeneration, and disease progression. Currently, the details of protein interactions under elevated physical stress are largely missing, therefore, preventing the fundamental, molecular understanding of mechano-transduction. This is in part due to the isolation of protein complexes under force-bearing condition is impossible using traditional solution biochemistry.

I will outline an innovative biochemical strategy to identify force-induced protein interactions surrounding the adhesive contacts using proximal biotinylation technique. Our innovative biochemical analysis is based on in situ proximal biotin labeling using promiscuous biotin ligase, BirA*, with a cell stretch device that promotes the formation of force-sensitive complexes.

Our founding observation is that the biotinylation is stretch-dependent. For example, the biotinylation of myosin IIA by BirA* tagged α-catenin increases with mechanical stimulation, suggesting that close spatial proximity of myosin IIA and α-catenin under force-bearing conditions{Ueda, 2015 #374}{Ueda, 2015 #374}. Based on our innovative strategy, we are in an ideal position to uncover the composition of force-sensitive complexes, a critical first step for understanding the molecular basis of mechano-transduction.