FIGURE 3: Yeast systems involved in large scale protein-protein interaction studies in the context of human coding variation and disease. (A) Yeast is used to investigate the influence of human coding variation systematically at large scale. As protein-protein interaction is a uniform functional feature of all proteins, it is especially useful to uncover the influence of variants on protein-protein interaction and consequently its potential impact in disease. (B) As a quickly adaptive tool, yeast is currently also used in COVID-19 research. Deep mutagenesis on the SARS-CoV-2 spike protein receptor binding domain (RBD) was performed to characterize mutant variants in human ACE2 receptor and antibody binding. (A-B) Icons with dark blue background: observable; Icons with light blue background: readout; MS: mass spectrometry; PPI: protein-protein-interaction.