History of protein–protein interactions: From egg‐white to complex networks

Today, it is widely appreciated that protein–protein interactions play a fundamental role in biological processes. This was not always the case. The study of protein interactions started slowly and evolved considerably, together with conceptual and technological progress in different areas of research through the late 19th and the 20th centuries. In this review, we present some of the key experiments that have introduced major conceptual advances in biochemistry and molecular biology, and review technological breakthroughs that have paved the way for today's systems‐wide approaches to protein–protein interaction analysis.