Small-molecule inhibitors of protein-protein interactions: progressing towards the dream

Protein–protein interactions have a key role in most biological processes, and offer attractive opportunities for therapeutic intervention. Developing small molecules that modulate protein–protein interactions is difficult, owing to issues such as the lack of well-defined binding pockets. Nevertheless, there has been important progress in this endeavour in recent years. Here, we use illustrative examples to discuss general strategies for addressing the challenges inherent in the discovery and characterization of small-molecule inhibitors of protein–protein interactions.