Inside the Cell (Part 3/3)

A brief history of understanding our tiny building blocks.

Some of the breakthroughs described in this series so far revealed a complex network of proteins working together in each cell to perform many activities. But, how does each protein know where should it be placed in the cell, and where it needs to go? In 1999, American scientist Günter Blobel was a single laureate of the Nobel prize in physiology or medicine “for the discovery that proteins have intrinsic signals that govern their transport and localization in the cell”. He showed — as early as 1975 — that amino acids within a cellular protein can serve as an “address label” that defines exactly where that protein needs to be delivered. The precise sequence of amino acids will signal whether a protein needs to be sent through the cell membrane into the intercellular space, should it be transported into an organelle within the cell, or perhaps built into the cellular membrane.

Remarkably, more than twenty years of Blobel’s work showed that the principles of “tagging” proteins to determine their location in the cell are universal across species — from yeast and plant to animal cells. Any disruption in genetic code related to these signals and transport mechanisms will lead to very difficult hereditary diseases in humans. There was a further practical application of Blobel’s discovery: cells could be used more effectively as “protein-producing factories”, which is useful in the pharmaceutical production of certain drugs.