Mapping Protein Interactions: Techniques and Applications

This lecture discusses the integrative approach to neuroscience, focusing on interaction proteomics and the mapping of protein-protein interactions (PPIs). The instructor outlines three primary techniques for studying PPIs: affinity purification, proximity labeling, and co-fractionation. Affinity purification is described as a classical method where a protein of interest is enriched using a specific tag or antibody, allowing for the identification of co-purifying proteins. Proximity labeling involves fusing the protein of interest to an enzyme, which biotinylates nearby proteins, thus providing insights into the protein's environment. The instructor emphasizes that this method can label proteins that are not directly interacting but are in proximity. Lastly, co-fractionation is introduced as a less specific technique that involves fractionating a cell lysate by size, allowing for the identification of proteins that elute together, suggesting potential interactions. This method is particularly useful for assessing known interactions rather than discovering new ones, highlighting the dynamic nature of protein interactions in biological systems.