Yeast surface 2-hybrid to detect protein-protein interactions via the secretory pathway as a platform for antibody discovery

Abstract

High throughput methods to measure protein-protein interactions will facilitate uncovering pairs of unknown interactions as well as designing new interactions. We have developed a platform to detect protein interactions on the surface of yeast, where one protein (bait) is covalently anchored to the cell wall and the other (prey) is expressed in secretory form. The prey is released either outside of the cells or remains on the cell surface by its binding to the bait. The strength of their interaction is measured by antibody binding to the epitope tag fused to the prey or direct readout of split fluorescence protein complementation. Our novel 'yeast surface 2-hybrid' system was found to differentiate 6-log difference in binding affinities between coiled coil associations and to measure specific interactions of antibodies and antigens. We demonstrate the use of YS2H in exploring activation allostery in integrins and isolating heavy chain only antibodies against botulinum neurotoxin.