Functional Prions

Nature is always full of surprises, and prions are no exceptions. Although they cause a terrible disease in humans and other mammals, they are also used for specific tasks in other organisms. For instance, some fungi make the prion protein HET-s, shown here in its misfolded form from PDB entry 2rnm. It plays a specialized role in the growth of the fungi. Some individuals have a form of HET-s that only adopts one form, and others have a slightly different version of the protein that can adopt both forms. When neighboring colonies meet each other, they often mate by fusing cells together, forming large cells with many nuclei. However, these fused cells die if they have incompatible forms of the HET-s protein. This may be an advantage because it enforces diversity in the population, keeping some colonies separate and perhaps limiting the spread of viral infections.

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PDB Molecule of the Month May 2008, by David S. Goodsell

Last changed by: A.Honegger, 5/20/08