The challenge of reconciling chemical mechanisms with whole living systems has long troubled biologists since the advent of cell theory in the nineteenth century. Karl Matlin highlights how this complex issue was significantly advanced by cytologist and Nobel laureate Günter Blobel. In 1975, Blobel synthesized proteins without using any cells, proposing the signal hypothesis, which theorized how proteins communicate spatially within cells. Over the next two decades, Blobel and fellow scientists meticulously detailed this process. He expanded his signal concept into membrane topogenesis, suggesting that each protein is synthesized with an "address" guiding it to its correct cellular destination. For this groundbreaking work, Blobel received the Nobel Prize in Physiology or Medicine in 1999. Matlin argues that Blobel's investigative approach effectively addressed a fundamental dilemma in biology, enabling the field to overcome barriers to mechanistic explanations of life. The narrative illustrates how Blobel's research and life story underscore the significance of cell biology in twentieth-century science, demonstrating its role in advancing related disciplines such as biochemistry and molecular biology.
