Prions are infectious proteins that can cause deadly diseases like bovine spongiform encephalopathy, or mad cow disease. They also infect yeast cells and this simple fungus has been found to produce a protein, Btn2, that targets prions and kettles them into a small area inside the cell, rather like the way riot police control an unruly crowd. When the cell divides, one of the two offspring is free from prions and can thrive. Intriguingly, Btn2 has similarities to human hook proteins, which play an important role in positioning components inside human cells so they can divide correctly. Pictured are three yeast colonies, the top right producing Btn2 and with mainly healthy cells (stained red) and some infected by prions (white). The lower colony is producing Cur1, a protein allied to Btn2 and has some healthy cells, while the top left colony is producing neither protein and is heavily infected.
Written by Mick Warwicker
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